Dust collection technical handbook

Dust Collection Technical Handbook
Index
Page
2 Glossary
35 Filter Media/Fibers
42 Gas/Air Tables
Electrical References (Missing Section)
54 Industrial Ventilation References
59 Material Properties
82 Miscellaneous References
87 Conversion Tables
The following pages were prepared as a reference for designing industrial dust collection and ventilation
systems. This is not a complete application and sizing manual.
DISCLAIMER: The information on the following pages is for reference only. There are no warranties,
express or implied, concerning the application or use of this information.

2
Glossary
A
Abrasion-Flex – Where cloth has abraded in a creased area by excessive bending.
Abrasion Surface – Localized area where the cloth’s surface has been abraded uniformly.
Absolute Temperature – In degrees Rankine, where absolute 0°R = -459.7°F.
°R = °F + 460°.
ρ = Density of air
ρ(actual) = ρ(std at 70°F) x
Absorber – A kind of scrubber utilizing the absorption principle.
Absorption – The penetration of a substance into or through another; distinct from adsorption.
Acceleration Loss – The velocity pressure required to accelerate the air from rest to the duct velocity or slot velocity,
whichever is higher.
ACFM – Actual Cubic Feet per Minute of gas volume at the actual condition temperature, pressure, moisture, elevation
and gas composition. See gas flow rate.
ACGIH – The American Conference Governmental Industrial Hygienists is a Professional Society devoted to the
development of administrative and technical aspects of worker health protection. Membership is limited to
professional personnel in governmental agencies or educational institutions engaged in occupational safety and health
programs. The ACGIH issues guidelines and recommendations in the form of Threshold Limit Values (TLV’s) which
are published annually.
Acid Deposition – (Acid Rain) A complex chemical and atmospheric phenomenon that occurs when emissions of
sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often
far from the original sources, and then deposited on earth in either a wet or dry form. The wet forms, popularly called
“acid rain”, can fall as rain, snow or fog. The dry forms are acidic gases or particulates.
Acrylic – A synthetic polymerized fiber which contains at least 85% acrylonitrile.
Acrylonitrile – A colorless, volatile, flammable liquid nitrile C3H3N used chiefly in organic synthesis and for
polymerization.
Actuator – Mechanical device attached to a damper to move its blades. May be manual, electric, pneumatic, or
hydraulic.
Adsorbent – In addition to the adjectival meaning, the term describes any of several substances that collect gaseous
pollutants. Used both for measurement and control.
Adsorption – The adhesion of a substance to the surface of a solid or liquid.
Aerosol – Particle of solid or liquid matter that can remain suspended in the air because of its small size. Particulates
under 1 micron in diameter are generally called aerosols.
AF – Fan wheel design with airfoil-shaped blades.
___70°F + 460°__
Actual °F + 460°

3
Air Changes Per Hour (ACH) – The movement of a volume of air in a given period of time; if a building has one air
change per hour, it means that all of the air in the building will be replaced in a one-hour period.
Air Conditioning – Treating air to meet the requirements of a conditioned space by controlling its temperature,
humidity, cleanliness, and distribution.
Air Contaminant – An impurity emitted to the outside air. It can be solid (dust, particulate matter), liquid
(vapor/mist), or gas (carbon monoxide, sulfur dioxide).
Air Curtain – Mechanical air-moving device designed to limit the influx of unwanted air at a building opening.
Air Handling Unit – Factory-made encased assembly consisting of a fan or fans and other equipment to circulate,
clean, heat, cool, humidify, dehumidify, or mix air.
Air Horsepower – The theoretical horsepower required to drive a fan if there are no losses in the fan, that is, if its
efficiency is 100%.
Air Leakage – Unwanted air intruding into an exhaust system (holes in ducts, missing and ineffective seals, etc.).
Airlock – Term generally applied to a rotary vane valve that keeps air from entering a dust collector, yet allows a
collected particulate to continuously discharge from the device.
Air Monitoring – The continuous sampling for and measuring of pollutants present in the atmosphere.
Air Quality Criteria – As the Federal government uses the term, the varying amounts of pollution and lengths of
exposure at which specific adverse effects to health and welfare take place.
Air Quality Standards – The approximate concentration level of a selected pollutant that is permitted in the
atmosphere to minimize detrimental effects.
Air Pollution – The presence in the atmosphere of gases, fumes, or particulate matter alone or in combination with
each other, in sufficient concentration to disturb the ecological balance; cause objectionable effects, especially sensory
offenses; cause transient or chronic illnesses; or impair or destroy property.
Air, Standard – Dry air at 70°F and 29.92 inches (Hg) barometer. This is substantially equivalent to 0.075 lb/ ft³.
Air-to-Cloth Ratio – See air to media ratio.
Air-to-Media Ratio – The ratio of air volume (ACFM) to square feet of effective filter media area. Also referred to as
the apparent or face velocity through the media (FPM). Typically 3 to 12 fpm for bag medias and 0.5 to 6 for pleated
type medias.
Air Toxics – Any air pollutant for which a national ambient air quality standard (NAAQS) does not exist (i.e.,
excluding ozone, carbon monoxide, PM-10, sulfur dioxide, nitrogen oxides) that may reasonably be anticipated to
cause cancer, developmental effects, reproductive dysfunctions, neurological disorders, heritable gene mutations or
other serious or irreversible chronic or acute health effects in humans.
Air Velocity – Rate of speed of an airstream, expressed in FPM.

4
Altitude – The height above sea level of a given location. Density corrections for altitude are made using the
following formula where Z is the feet above seal level.
Density (Alt) = Density (Std) x [1-(6.73x10-6
)Z]5.258
Ambient – Immediate surroundings or vicinity.
AMCA – Air Movement and Control Association.
Anemometer – A device which reads air velocity such as a wind vane. In fan applications, it is usually a spinning-
vane-type instrument used at read low velocities at registers and grills.
Anneal – The process of relieving stress and brittleness in metals by heating.
Anodize – An electrolytic action of affixing a protective coating or film, usually applied to aluminum.
ANSI – American National Standards Institute.
APC – Air Pollution Control.
API – American Petroleum Institute.
Appurtenances – Accessories added to a fan for the purposes of control, isolation, safety, static pressure regain, wear,
etc.
ARI – Air Conditioning and Refrigeration Institute.
Area Source – Any small source of non-natural air pollution which is not large enough to be classified as a major
source or point source.
Aromatics – A type of hydrocarbon, such as benzene or toluene, added to gasoline in order to increase octane. Some
aromatics are toxic.
ASHRAE – American Society of Heating, Refrigeration, and Air Conditioning Engineers.
ASME – American Society of Mechanical Engineers.
Aspect Ratio – The ratio of the width to the length.
AR=W/L
ASTM – American Society of Testing Materials.
Atmospheric Pressure – One atmosphere is approximately 14.7 PSI; 408” water gauge. Airflow is the result of a
difference in pressure (above or below atmospheric) between two points.
Attainment Area – An area considered to have air quality as good as or better than the National Ambient Air Quality
Standards as defined by the Clean Air Act. An area may be an attainment area for one pollutant and a non-attainment
area for others.
Attenuation – Absorption of sound pressure. Attenuation reduces the amplitude only of a sound wave while leaving
the frequency unchanged.

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Attrition – Wearing or grinding down by friction. One of the 3 basic contributing processes of air pollution, the others
being vaporization and combustion.
AVR (c) – Air Vent Round. MAC Equipment acronym for its round bottom bag removal pulse jet dust collectors. (c)
designates cartridges instead of bags.
AVS (c) – Air Vent Square. MAC Equipment acronym for its square bottom bag removal pulse jet dust collectors, up
to 64 bags. (c) designates cartridges instead of bags.
Axial Fan – Fan where the airflow through the impeller is predominantly parallel to the axis of rotation. The impeller
is contained in a cylindrical housing.
Axial Flow – In-line air movement parallel to the fan or motor shaft.
B
Backdraft Damper – Damper used in a system to relieve air pressure in one direction and to prevent airflow in the
opposite direction.
BACM (Best Available Control Measure) – A term used in the CAAA referring to the “best” measures (according to
EPA guidance) for controlling emissions.
BACT (Best Available Control Technology) – An emission limitation based on the maximum degree of emission
reduction achievable. Under Title 1 of the CAAA, EPA will establish BACT standards for serious, severe, and extreme
non-attainment areas.
Bag – The customary form of filter element. Also known as tube, stocking, etc. Can be unsupported (dust on inside)
or used on the outside of a grid (cage) support (dust on outside).
Baghouse – An air pollution abatement device that traps gas born particulates by forcing the gas through filter bags.
Balancing – (1) On a fan, the process of adding (or removing) weight on a rotor in order to move the center of gravity
toward the axis of rotation. (2) In a ventilation system, it’s the process of measuring or calculating the airflow at a
branch and altering duct size or a valve to attain desired airflow at that branch.
Barometric Pressure – A measurement of the pressure of the atmospheric; standard is 29.92” Hg.
Bernoulli’s Theorem – The principle that the total energy per unit of mass in the streamline flow of a moving fluid is
constant, being the sum of the potential energy, the kinetic energy, and the energy due to pressure. In terms of air
movement, the theorem states that the static pressure plus velocity pressure as measured at a point upstream in the
direction of airflow is equal to the static pressure plus velocity pressure as measured at a point downstream in the
direction of airflow plus the friction and dynamic losses between the points.
BI Fan – Centrifugal fan with backward inclined blades that move air more efficiently than straight blade fans. BI fans
are usually on the clean side of a piece of control equipment as the blades are not very abrasion resistant.
Blade Liners – Pieces of material added over the wheel blades to reduce abrasion of the blades.
Blade-Pass Frequency – The tone generated by the blades passing a fixed object.
Blast Area – The fan outlet area less the projected area of the cut-off.

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Bleed – Particles of dust or fumes that are able to leak through filter media.
Blind (Blinding) – The blockage of filtration media by dust, fume or liquid covering the filter media and not being
discharged by the cleaning mechanism. Once enough material has built up, air flow is severely restricted and the
elements have to be cleaned or replaced.
Blow-pipe – See manifold.
Blue Smoke – A descriptive term for the gaseous hydrocarbons that escape from hot asphalt and other sources of VOC.
Boiler Horsepower – The capability to evaporate 34.5 pounds of water per hour into dry steam at 212°F. at sea level;
33,500 BTU/hr.
Brake Horsepower – The horsepower actually required to drive a fan. This includes the energy losses in the fan and
can be determined only by actual tests of the fan (this does not include the drive losses between motor and fan).
Breakdown Torque – Maximum torque a motor will produce without a sudden decrease in speed. Often referred to as
pull-out torque or maximum torque.
Bridge – Material building across an opening (such as a screw conveyor) and blocking off that opening.
BTU – British Thermal Unit; heat required to raise the temperature of 1 pound of water by 1°F. The BTU/hr. required
to raise the temperature of a volume of standard air a specific number of degrees is calculated by the formula:
Btu/hr = Temp. Rise x CFM x 1.085
Bulked Yarn – Filament yarn which has been processed by high pressure air passing through the yarn and relaxing it
into gentle loops, bends, etc.
C
CAAA – Clean Air Act Amendments of 1990.
Title I: Nonattainment: Ambient Air Quality
Title II: Motor Vehicles
Title III: Hazardous Air Pollutants
Title IV: Acid Rain
Title V: Permits
Title VI: Stratospheric Ozone
Title VII: Enforcement
Title VIII: Miscellaneous
Caking – Material crusted on a bag that cannot be removed by the cleaning mechanism. Frequently caused by the dust
on the bags getting wet.
Calendered Finish – An available smooth finish for felt bags. Felt is drawn between two hot oil-filled rolls, where
heat and pressure press down “hairs” on the felt, imparting a smooth finish that improves dust release.
Calendering – The application of either hot or cold pressure to smooth or polish a fabric, thereby reducing the
thickness of the cloth by spreading the warp and filling yarns into a ribbon shape.

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Can Velocity – As related to baghouses, the gas velocity within the collector. Dividing the gas volume by the cross
sectional area of the collector determines “can velocity”. Also, see interstitial velocity.
Can Vel = __CFM__
ABH
CFM = Gas volume through baghouse
ABH = Cross sectional area of baghouse
Capacitor Start Motor – Type of single-phase induction motor with a capacitor connected in series with the starting
winding. High-starting and breakdown torque, medium starting current. Used in hard-starting applications;
compressors, pumps, etc.
Capture Velocity – The air velocity at any point in front of a hood or at a hood opening necessary to overcome
opposing air currents and to capture the contaminated air at the point by causing it to flow into the hood.
Carbon Monoxide – A colorless, odorless gas which is toxic because of its tendency to reduce the oxygen-carrying
capacity of the blood.
Carrying Velocity – The gas velocity that is necessary to keep the dust airborne. Usually 3500 to 4599 ft/min in
ductwork depending upon the nature of the dust.
Cartridge – See pleated filter elements.
Cartridge Filter – An air pollution control device that traps gas-borne particulates by forcing the gas through filter
element cartridges. The cartridges are typically made with pleated cellulose paper media. Recently, 100% spun
bonded media equipped filters have been placed in commerce.
CAS (Chemical Abstracts Service) – Registry Number is a numeric designation assigned by the American Chemical
Society’s Chemical Abstracts Service which uniquely identifies a specific chemical compound.
Cellplate – See tubesheet.
Cellulose – The chief part of fibrous products which are used to make the filter media for many cartridge filters. Also
referred to as “paper” media.
Centrifugal Collector – Any of several mechanical systems using centrifugal force to remove particulate from a gas
stream.
Celsius – A thermometric scale in which water boils at 100° and freezes at 0°, same as centigrade:
°C = .5556 x [°F. – 32°]
CFCs (Chlorofluorocarbons) – A family of inert, non-toxic, and easily liquefied chemicals used in refrigeration, air
conditioning, packaging insulation, or as solvents or aerosol propellants. because CFCs are not destroyed in the lower
atmosphere they drift into the upper atmosphere where chlorine is released and destroys ozone.
CFC-12 – A chlorofluorocarbon with a trademark name of Freon, commonly used in refrigeration and automobile air
conditioning.
CFM – Cubic Feet (of any gaseous matter) per Minute. See gas flow rate.

8
Clean Coal Technology – Any technology not in widespread use as of the date of enactment of the Clean Air Act
Amendments which will achieve significant reductions.
Clean Fuel – Blends and/or substitutes for gasoline fuels. These include compressed natural gas, methanol, ethanol,
and others.
Cloth – In general, a plant fabric; woven , knitted, felted or otherwise formed of any textile fiber, wire, or other suitable
material. Usually understood to mean a woven felted or textile fabric.
Cloth Weight – Is usually expressed in ounces per square yard or ounces per square foot. However, cotton sateen is
often specified as a certain number of linear yards per pound of a designated linear yards per pound in a 54” width.
Coefficient of Conductivity – The rate of heat transfer through a material, expressed in Btu transmitted per hour
through one square foot of surface per degree difference in temperature across the material. Figures are usually
expressed for basic materials, such as wood or insulation; per inch of thickness, and called by the symbol “K”.
COH – Abbreviation for coefficient of haze, unit of measurement of visibility interference.
Coke Oven – An industrial process which converts coal into coke, which is one of the basic materials used in blast
furnaces for the conversion of iron ore into iron.
Cold Spot – On an insulated baghouse, a point where metal goes through insulation, creating an uninsulated area where
heat dissipates rapidly.
Cold Temperature – A standard for automobile emissions of carbon monoxide (CO) to be met at a low temperature
(i.e., 20°F). Conventional catalytic converters are less efficient upon start-up at low temperatures.
Collecting Efficiency – The ability of a dust collector to remove particulate from the exhaust gas. The ratio of
particles entering the collection device vs. particles leaving is expressed in percent.
inlet loading – outlet loading x 100
inlet loading
Collector – Used interchangeably with “baghouse,” “cartridge filter,” or mechanical collector, as in “cyclone.”
Combustion – The production of heat and light energy through a chemical process, usually oxidation. One of the 3
basic contributing processes of air pollution, the others being attrition and vaporization.
Combustion Air – Amount of air necessary to burn the available fuel.
Combustion Products – 1) Primarily gaseous matter such as carbon oxides, nitrogen, oxygen, and water vapor –
resulting from the combustion of fossil fuels. 2) In the context of emission control – the gaseous products resulting
from the burning of any kind of material containing carbon in a free or combined state. Also referred to as
“combustion contaminants.”
Compressibility – A factor used by fan manufacturers to correct performance ratings in higher pressure ranges to
account for the fact that air is a compressible gas that does not follow the perfect gas laws.
Compression – A phenomenon related to positive pressure. When air is forced into a system it is compressed and
becomes more dense. Depending on the volume or weight of air required down stream in the positive pressure portion
of the system, the volume of air at the inlet of a fan may have to be adjusted by the ratio of absolute pressure at the
entrance of the fan versus the design requirements in the system.

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Concentration – The amount of dust in gas. Usually expressed in terms of grains per ft³, lbs per 1000 lbs of gas, parts
per million, or milligrams per cubic meter.
Conduction – The transfer of heat by physical contact between substances.
Conversion Factors – See pages 87 through 106.
Convection – The transfer of heat through a liquid or gas by the actual movement of the molecules.
Conveying Velocity – The air velocity required in a duct system to maintain entrainment of a specific material.
Corrosion – The deterioration of a material by chemical or electrochemical reaction resulting from exposure to
weathering, moisture, chemical, or other agents in the environment in which it is placed.
Cotton Number – Staple yarns are generally sized on the cotton system. Example: an 18 singles yarn is of such a size
that 18 hanks weighs one pound (each hank contains 840 yards).
Cotton System – A system of yarn manufacturing for spinning cotton fiber yarn whereby the individual fibers are
aligned parallel.
CRP – Certified Ratings Program.
CRST (Cellulose Fibers, Resin Impregnated, Silicone Treated) – A type of filter media used in high quality cartridges.
The treatments enhance filter life and moisture resistance.
CSA – Canadian Standards Association. Sets safety standards for motors and other electrical equipment used in
Canada.
CTG (Control Techniques Guideline) – Guidance documents issued by EPA which define Reasonably Available
Control Technology (RACT) to be applied to existing facilities that emit certain threshold quantities of air pollutants;
they contain information both on the economic and technological feasibility of available techniques.
Curve, Fan Performance – A graphic representation of static or total presence and fan BHP requirements over an
airflow volume range at a stated inlet density and fan speed.
Curve, System – A graphic representation of the pressure versus flow characteristics of a given system and density.
Cyclone Collector – A kind of centrifugal collector equipment.
D
Damper – Change in pressure, or pressure drop that occurs across a piece of control equipment.
dbA – Sound-pressure level corrected to the “A” weighing network.
Decibel – The logarithmic ratio between some known reference and some quantity of electrical or acoustic signal
power.
Delta P (∆P
) – Change in pressure, or pressure drop that occurs across a piece of control equipment.
Denier – The weight in grams that 9000 meters of a fiber weighs.

10
Density – The measure of unit mass equal to its weight divided by its volume (lbs/ft³); standard air is .075 lbs./ft³.
Density Factor – Ratio of actual air density of standard air. The product of the density factor and the density of
standard air (0.075 lbs/ft³) will give the actual air density in pounds per cubic foot.
Dew Point – The temperature at which the equilibrium vapor pressure of a liquid is equal to the existing partial
pressure of the respective vapor. (For air containing water vapor, it is the temperature at which liquid water begins to
condense for a given state of humidity and pressure as the temperature is reduced. For flue gas containing water vapor
and SO3, it is the set of conditions at which liquid sulphuric acid begins to condense as the temperature is reduced.)
DFT – Dry-film thickness usually expressed in thousandths of an inch (mils).
Diaphragm Valve – A compressed air operated valve that opens to allow a pulse to go the filter bags or cartridges.
Diffusion – Takes place on particles so small that their direction and velocity are influenced by molecular collisions.
These particles do not follow the air stream, but behave more like gases than particulate. They move across the
direction of air flow in a random fashion. When a particle does strike a fiber, it is retained by the van der Waals forces
existing between the particle and the fiber.
Dilution Ventilating – The mixing of contaminated air with uncontaminated supply air for the purpose of attaining
acceptable working or living conditions.
Dimensional Stability – Ability of the fabric to retain its size in hot or moist atmosphere.
DNAPLS – Dense non-aqueous phased liquids.
DOP – Acronym for dioctylphthalate, a chemical, used in aerosol form, to non-destructively test high efficiency
particulate air (HEPA) filters.
Double Bag – Features a conventional bag on a cage and an inner bag that filters from inside, out, with the bottom
open for dirty air entrance. Puts more, but not necessarily effective, cloth area in a given size baghouse.
Dry Bulb Temperature – The actual temperature of a gas, taken with a conventional thermometer.
Dry Collector – Dust collectors which use mechanical means (centrifugal force, impingement, filtration) to remove
particulate matter from exhaust gas. Such as: expansion chambers, knockout boxes, centrifugal collectors, cartridge
filters and baghouses. Devices not using H2O.
DSCFM – Dry Standard Cubic Feet per Minute. See gas flow rate.
Dust – A dispersion aerosol formed by the grinding or atomizing of a solid, or the transfer of a powder into a state of
suspension through the action of air currents or by vibration.
Dust Collector – An air-cleaning device used to remove heavy-particulate loadings from exhaust systems prior to
discharge.
Dust Collector, Cyclone – A mechanical device that utilizes the centrifugal force of the inlet gas to remove large
particulate matter suspended in the gas.
Dust Collector Efficiency – See collecting efficiency.

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Dust Permeability – Defined as the mass of dust (grains) per square foot of media divided by the resistance (pressure
drop) in inches of water gauge (WG) per unit of filtering velocity, feet per minute (fpm). Not to be compared with
cloth permeability.
DWDI – Double-width, double-inlet fans, Arrangement 3.
Dynamic Balance – The mechanical balancing of a rotating part of assembly in motion.
Dynamic Insertion Loss – A reduction of airborne noise levels affected by the installation of an acoustical silencer.
DYNE – A unit of force equal to that which would accelerate one gram by one centimeter per second.
E
Early Reduction/Early Compliance – A provision in the CAAA which provides incentives to a company for
complying with new standards before they are required to by Law.
Effective Stack Height – The height at which a plume becomes essentially level. It is the actual stack height plus the
plume rise.
Efficiency, Mechanical Total – The ratio of fan output to the power applied to the fan. Can be helpful in selecting fan
size, type, or manufacturer for the same application:
ME = ______TP x CFM______
6356 x BHP
Efficiency, Static – The ratio of fan output less the kinetic energy [outlet-velocity pressure] leaving the fan to the
power applied to the fan:
SE = ______SP x CFM______
6356 x BHP
Effluent – A discharge or emission of a fluid (liquid or gaseous).
Electrostatic Attraction – Mutual attraction, caused by static electricity, by which particles tend to draw together or
adhere.
Electrostatic Precipitator – A kind of precipitator that first charges particulate (ESD), allowing electrostatic forces to
attract particles to a collection point.
Elevation – The distance of the subject site above or below sea level.
EMD Airlock – Environmental Multi Duty airlock. MAC Equipment’s airlock to place under a dust collector when a
pneumatic convey system will be utilized beneath the airlock.
Emission – Release of pollutants into the air from a source.
Emission Control Diagnostics – Computerized devices placed on vehicles to detect malfunction of emissions controls
and notify the owner of the need for repair.
Emission Control Equipment – Machinery used to remove air contaminants from the discharge of industrial exhaust
streams.

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Emission Factor – The statistical average of the amount of a specific pollutant emitted from each type of polluting
source in relation to a unit quantity of material handled, processed or burned. E.g. the emission factor of oxides in
nitrogen in fuel oil combustion is 119 lbs. per 1,000 gallons of fuel oil used. By using the emission factor of a pollutant
and specific data regarding quantities of material used by a given source, it is possible to compute emissions for that
source – information necessary for an emission inventory.
Emission Inventory – A list of primary air pollutants emitted into a given community’s atmosphere, in amounts
(commonly tons) per day, by type of source. The emission inventory is basic to the establishment of emission
standards. Also see emission factor.
Emission Standard – The maximum amount of a pollutant that is permitted to be discharged from a single polluting
source; e.g., the number of pounds of fly ash per cubic foot of gas that may be emitted from a coal-fired boiler. Rule or
measurement established to regulate or control the amount of a given pollutant that may be discharged to the outdoor
atmosphere from its source.
End – See warp thread.
End Count – See warp count.
End Reflection – A known value of sound radiated back into duct or opening.
Enhanced I&M (Enhanced Inspection & Maintenance) – An improved automobile inspection and maintenance
program that includes, as a minimum, increases in coverage of vehicle types and model years, tighter stringency of
inspections and improved management practices to ensure more effectiveness. This may also include annual,
computerized, or centralized inspections, under-the-hood inspections to detect tampering with pollution control
equipment; and increased repair waiver cost. The purpose of Enhanced I&M is to reduce automobile emissions by
assuring that cars are running properly.
Enthalpy – The heat content per unit mass of a substance.
Entry Loss – The loss in pressure caused by air flowing into a system; normally expressed in fractions of velocity
pressure.
EPA – Environmental Protection Agency.
Equivalent Duct Diameter – For rectangular duct with sides a and b is:
D = (4ab/π)0.5
Evaporation – The physical transformation of a liquid to a gas at any temperature below its boiling point.
Evase – A diffuser at the fan outlet which gradually increases in area to decrease velocity and to convert kinetic energy
to static pressure [regain].
Excess Air – Air in excess of the amount necessary to combust all the available fuel.
Exhaust Gas – The gases emitting from an industrial process, generally a combustion process.
Exhaust Stack Temperature – The temperature of the exhaust gas, measured in the discharge stack.
Exhaust Volume – The amount of exhaust gas (air, products of combustion and water vapor) leaving the exhaust stack
usually measured in ACFM.

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F
Fabric – A collective term applied to cloth no matter how constructed, regardless of the kind of fiber used.
Fahrenheit – A thermometric scale in which water boils at 212° and freezes at 32°.
°F = (1.8 x °C) +32°
Fan – A power-driven machine which moves a continuous volume of air by converting rotational mechanical energy to
an increase in the total pressure of the moving air.
Fan Capacity – Performance requirement for which a fan is selected to meet specific system calculations given in
terms of ACFM at the fan inlet.
Fan Class – Operating limits at which a fan must be physically capable of operating safely.
Fan Laws – Theoretical constant relationships between CFM, RPM, SP, and BHP for a given fan used in a given fixed
system:
CFM varies as RPM
SP varies as (RPM)²
BHP varies as (RPM)³
FC – Fan wheel design using forward-curved blades.
Federal Implementation Plan (FIP) – Under current law, a Federally implemented plan to achieve attainment of an
air quality standard, used when a State is unable to develop an adequate plan. Under the Senate bill, a plan containing
control measures developed and promulgated by EPA in order to fill gaps in a State Implementation Plan (SIP).
Felted Fabric – Type bag used on most all pulse jet dust collectors. Features a heavy, thick cloth of short fibers on a
woven backing.
Fiber – The fundamental unit comprising a textile raw material such as cotton, wool, etc.
Filament – Mono – One continuous strand of fiber to indefinite length.
Filament – Multi – More than one mono-filament strand grouped together of definite length.
Fill – Crosswise threads woven by loom.
Fill Count – Number of threads per inch of cloth.
Filter Cake – The accumulation of dust on a bag before cleaning. This cake assists in the filtering of dust.
Filter Collector – A mechanical filtration system for removing particulate matter from a gas stream, for measurement,
analysis, or control. Also called bag collector. Filters are designed in a variety of sizes and materials for specific
purposes. Also called bag collector or cartridge.
Fines – Fine particulate, aerosol.
Flashing – Sheet metal strip placed at the junction of intersecting exterior building surfaces to make the joint water-
tight.

14
Flexing – Bending, or contracting and expanding.
Fly Ash – The particulate impurities resulting from the burning of coal and other material.
Fog – The condensation of water vapor in air. Also see Smog.
Foot-Pound (Ft.-Lb.) – Torque rating or requirement; equivalent to the force required to move a one-pound weight
one foot in distance, equal to 12 in-lb.
Forced Draft – How air is provided in a process such as a combustion process; when air is blown or forced into a
process, it is known as a “forced draft” system. Also see induced draft.
Forced Draft Burner – A burner which has its secondary air supplied under pressure. This is normally done by
surrounding the dryer opening by a plenum or windbox and supplying the air with a low pressure fan.
Fossil Fuels – Coal, oil, and natural gas; so-called because they are the remains of ancient plant and animal life.
FPM – Feet per minute, commonly defines air velocity (to determine velocity pressure or suitability for material
conveying), shaft/bearing speeds (used to determine lubrication requirements) and wheel tip speeds.
Frame Size – A set of physical dimensions of motors as established by National Electrical Manufacturers Association
(NEMA) for interchangeability between manufacturers. Dimensions include: shaft diameter, shaft height, and motor
mounting footprint.
Free Field – The surroundings of a specific equipment location in which no obstructions or reverberant surfaces exist
to distort or amplify sound waves.
Frequency – Any cyclic event whether vibration, alternating current, or rotational speed. Usually expressed in cycles
per second (cps) or just “cycles”.
Friction Loss – Resistance to air flow through any duct or fitting, given in terms of static pressure.
FRP – Abbreviation for fiberglass-reinforced-plastic.
Fugitive Emissions – Emissions not caught by a capture system.
Full-Load Speed – The speed at which the rated horsepower is developed. This speed is less than synchronous speed
and varies with the motor type and manufacturer.
Full-Load Torque – The torque required to produce the rated horsepower at full-load speed.
Fume – Solid particulates generated by condensation from the gaseous state, generally after volatilization from molten
metal, and often accompanied by a chemical reaction, such as oxidation. Fumes flocculate and sometimes coalesce.
G
Garbadine Weave – A regular or “steep” twill with higher warp than fill count.
GACT – (Generally Available Control Technology) Methods, practices, and techniques which are commercially
available and appropriate considering economic impacts and the technical capabilities of the firms to operate and
maintain the emissions control systems. Under Title III of the CAAA, EPA will establish either GACT or MACT
standards for each source of HAPs.

15
Gases – Normally, formless fluids which occupy the space of its enclosure and which can be changed to a Liquid or
solid state only by the combined effect of increased pressure and decreased temperature. Gases diffuse.
Gas Flow Rate, Cubic Feet per Minute (CFM) – The volume of process gas at any point of the plant exhaust system
measured in terms of minutes. There are several units of measurement:
ACFM – The actual gas flow measured (Actual Cubic Feet per Minute).
SCFM – The gas flow volume reduced to 70°F (standard temperature) and standard pressure (latm) by
calculation (Standard Cubic Feet per Minute).
DSCFM – The gas flow reduced to 70°F (standard temperature) and standard pressure (latm) and without
volume of steam or water vapor contained in the exhaust gas (Dry Standard Cubic Feet per Minute).
Gasoline Volatility – The property of gasoline whereby it evaporates into a vapor. Gasoline volatility is measured in
pounds per square inch (psi), with a higher number reflecting more gasoline evaporation. Gasoline vapor is a VOC
(Volatile Organic Compound).
Gauge (gage) – Metal manufacturers’ standard measure of thickness for sheer stock; some examples for steel are:
Thickness Weight of Steel
Gauge (Inches) (Lbs/Ft.²)
7 .1793 7.50
10 .1345 5.625
12 .1046 4.375
14 .0747 3.125
16 .0598 2.50
Gauge Pressure – The pressure differential between atmospheric and that measured in the system.
Grain – A dust weight unit commonly used in air pollution control. Equal to one seven thousandth of a pound.
One grain = 1 LB
7000
Grain Loading – The rate at which particles are emitted from a pollution source. Measurement is made by the number
of grains per cubic foot of gas emitted.
Griege (Griege goods) – Same as grey or unfinished goods. Does not imply a grey (gray) color.
Ground Motor – A short circuit between any point in the motor’s electrical circuit and its connection to the ground.
H
Halons – A family of compounds containing bromine, fluorine, iodine, and chlorine used in fighting fires, that break
down in the atmosphere depleting stratospheric ozone.
HAPs (Hazardous Air Pollutants) – Any of the 189 chemicals listed under Title III of the CAAA. All HAP sources
will have to comply with GACT or MACT standards. (See page 33 for a complete listing).
H Cyclone – MAC Equipment’s medium efficiency cyclone dust collector.

16
HCFC’s – Chlorofluorocarbons that have been chemically altered by the addition of hydrogen, and which are
significantly less damaging to stratospheric ozone than other CFC’s.
HD Airlock – Heavy Duty airlock. MAC Equipment’s all purpose, lowest priced cast iron airlock.
Header – As applied to pulse-jet baghouses, the pressurized pipe that contains the compressed air supply for pulsing.
If it is undersized, insufficient cleaning air will flow through the valve.
Heat Exchanger – A device such as a coil or radiator which is used to transfer heat between two physically separate
fluids.
HE Cyclone – MAC Equipment’s High Efficiency cyclone dust collector.
HEPA Filter (High Efficiency Particulate Air Filter) – Capable of removing at least 99.97% by count of a standard 0.3
micron challenge particulate (DOP test).
Hertz – Frequency measured in cycles per second.
Hg – Symbol for mercury. Pressure is often measured in inches of mercury. (1” Hg = 13.64” WG)
High Pressure Cleaning Air – Air at 80-100 PSIG used for cleaning air in baghouses and cartridge filters.
Hi-Volume Sampler – Also called a Hi-Vol. A device used in the measurement and analysis of suspended particulate
pollution.
HON – Hazardous Organic NESHAPS.
Horsepower – (As applied to motors) is an index of the amount of work the machine can perform in a period of time.
1HP equals 33,000 ft. lbs. of work per minute, also equal to 0.746 kilowatts. Horsepower can be calculated by:
HP = _Torque (ft.lbs.) x RPM_
5250
Humidity, Absolute – The weight of water vapor per unit volume, pounds per cubic foot or grams per cubic
centimeter.
Humidity, Relative – The ratio of the actual partial pressure of water vapor in a space to the saturated pressure of pure
water vapor in a space to the saturated pressure of pure water at the same temperature.
HVAC – Heating, ventilating, and air conditioning.
Hydrocarbon – Any of the vast family of compounds containing carbon and hydrogen in various combinations; found
especially in fossil fuels. Some of the hydrocarbon compounds are major air pollutants; they may be carcinogenic or
active participants in the photochemical smog process.
Hydrophobic Fibers – Those fibers or materials not readily water absorbent.
Hygroscopic – Materials having an affinity for water.

17
I
Impeller – Another term for fan “wheel”. The rotating portion of the fan designed to increase the energy level of the
gas stream.
Impeller Diameter – The maximum diameter measured over the impeller blades.
Impingement – When air flows through a filter, it changes direction as it passes around each fiber. Larger dust
particles, however cannot follow the abrupt changes in direction because of their inertia. As a result, they do not follow
the air stream and collide with a fiber.
Inch of Water – A unit of pressure equal to the pressure exerted by a column of water one inch high at a standard
temperature. (407” WC = 14.7 PSI)
Inches WG (Inches of Water Gauge) – See inch of water.
Incinerator – A device which burns household, industrial, pathological, or hazardous solid, liquid or gaseous wastes
under controlled conditions.
Inclined Manometer – A testing instrument using a liquid column, set at an incline to increase reading accuracy, to
measure pressure. Normally used to read velocity pressure.
Induced Draft – How air is provided in a process, such as a combustion process, where air is drawn or pulled through
a process. Also see forced draft.
Induction – The production of an electric current in a conductor in a changing magnetic field.
Inertia – Tendency of an object to remain in the state it is in; see WR².
Inertial Separators – Air pollution control equipment that uses the principle of inertia to remove particulate matter
from a stream of air or gas. See mechanical and cyclone collectors.
Inlet-Vane Damper – Round multiblade damper mounted to the inlet of a fan to vary the airflow.
Inspection & Maintenance (I&M) – A program providing for periodic inspections of motor vehicles to ensure that
emissions of specified pollutants are not exceeding established limitations.
Instability – The point of operation at which a fan or system will “hunt” or pulse; common in FC fans and some other
fan types where the point of operation is left of the peak of the static-pressure curve.
Insulation – Any method which will retard the flow of heat through a wall. In baghouses, it is commonly a lightweight
fiberglass mat.
Interception – A special case of impingement where a particle is small enough to move with the air stream, but,
because its size is very small in relation to the fiber, makes contact with a fiber while following the tortuous air flow
path of the filter. The contact is not dependent on inertia and the particle is retained on the fiber because of the inherent
adhesive forces that exist between the particle and fiber. These forces, called van der Waals forces, enable a fiber to
trap a particle without the use of inertia.
Interstices – The openings between the interlacings of the warp and filling yarns; i.e., the voids.

18
Inversion – An atmospheric condition caused by a layer of warm air preventing the rise of cooling air trapped beneath
it. This prevents the rise of pollutants that might otherwise be dispersed and results in a concentration of the air
pollution.
Interstitial Velocity – The apparent velocity of a gas as it passes by a filter bag matrix. It is found by dividing the
collector gas volume by its cross sectional area, after the cross sectional of the bags have been subtracted from the
collector cross sectional area.
K
Kelvin – Absolute Temperature in the SI system scale.
Kilopascal – Kpa; metric pressure unit; one inch water gauge is 0.24836 Kpa.
Kilowatt – Kw; measure of power equal to 1.34 horsepower.
Knockout Box – See primary collector.
L
L-10 Bearing Life – The theoretical number of hours after which 90% of the bearings subjected to a given set of
conditions will still be in operation; also known as B-10.
LAER (Lowest Achievable Emission Rate) – The rate of emissions which reflects either the most stringent emission
limit contained in the implementation plan of any state (unless it is proved that such limitations are not achievable), or
the most stringent emission limit achieved in practice, whichever is most stringent.
Laminar Flow – Gas or fluid in parallel layers with some sliding motion between the layers.
Leno – A weave in which the adjacent warp yarns are twisted on either side of the interlacing filling yarn.
Liquide Flowrate – The amount of water or “scrubbing liquid” introduced into a wet collector.
Louver – A device comprised of multiple blades which, when mounted in an opening, permits the flow of air but
inhibits the entrance of undesirable elements.
Low Nox Burners – One of several combustion technologies used to reduce emission of Nox.
Low Pressure Cleaning Air – Air at less than 30” WC used for cleaning baghouses.
Lower Explosive Limit – The lower limit of flammability or explosibility of a gas or vapor at ordinary ambient
temperature expressed in percent of a gas or a vapor in air by volume.
LST (c) – Large Square Top removal. MAC Equipment acronym for its square top bag removal pulse jet dust
collectors from 64 to 144 bags. (c) designates cartridges instead of bags.
LVS (c) – Large Air Vent Square. MAC Equipment acronym for its square bottom bag removal pulse jet dust
collectors from 64 to 144 bags. (c) designates cartridges instead of bags.

19
M
Mach Number – A fraction of the speed of sound; used in fan engineering where air moving at a mach of 0.9, or 9/10
the speed of sound, begins to deviate from the fan laws.
MACT (Maximum Achievable Control Technology) – The standard to which sources of HAPs will have to comply;
the CAAA defines MACT as “the maximum degree of reduction in emissions...achievable for new or existing
sources...taking into account the cost of achieving such reductions.” MACT standards for existing sources must be at
least as stringent as the average level of control achieved at the best controlled 12 percent of facilities, and MACT for
new sources will have to be even stricter.
Mactiflo – MAC Equipment’s trademark name for its down flow cartridge filter.
Major Source – A stationary source which emits a large amount of pollution. In non-attainment areas, under Title I of
the CAAA, a major source is one which emits more than 100, 50, 25, or 10 tons per year depending on whether the area
is classified as Marginal or Moderate, Serious, Severe, or Extreme, respectively. For hazardous air pollutants, under
Title III of the CAAA, a major source is one which can emit more than 10 TPY of any one HAP or 25 TPY of total
HAPs.
Make-up Air – A ventilating term which refers to the replacement of air lost because of exhaust air requirements.
Manifold – As used in conjunction with pulse jet baghouses, the pipe that extends over the bags with a hole over each
bag. It distributes the compressed pulse to the bags. Sometimes called a blow-pipe.
Manometer – A u-shaped device for measuring the static pressure at a point relative to some other point, the pressure
difference causes water to rise or fall. The difference in the level of the water columns is equivalent to the pressure
differential.
Maximum Continuous Rating – The point at which the fan is expected to operate.
MCF (c) – Medium Pressure Controlled Fire. MAC Equipment acronym for its dust collector that utilizes 7 psi air to
clean the bags through a rotating mechanism that is timed to release the air precisely over the bags. This patented dust
collector is available from 22 to 1652 bags. (c) designates cartridges instead of bags.
Mechanical Collector – Devices that are functionally dependent on the laws of mechanics governing the motion of
bodies in space. Can be operated dry or wet. When operated wet, devices are generally called scrubbers. Examples of
mechanical collectors are cyclones, settling chambers, and various types of impingement collectors.
Medium Pressure Cleaning Air – Air at 5-10 PSIG used for cleaning baghouses.
Mega – A prefix meaning 1 million.
MIASMACT – MAC Equipments trademark name for its Automatic Cleaning HEPA filter. MIASMACT is an
overlay of the words Miasma and MIACT. Miasma is a word meaning toxic materials in the air, and MACT is
Maximum Achievable Control Technology.
Micro – A prefix meaning 1/1,000,000 abbreviated by the Greek letter µ.
Microbar – A unit of pressure equal to one-millionth of an atmospheric pressure, 0.0000146 PSI.
Micrometer – See micron.

20
Micron – Symbol µ, a unit of length equal to one millionth of a meter. An average human hair is 70 microns in
diameter. In general, particles down to 10 microns can be seen without the aid of magnification.
MIL – A unit of measure equal to 25 microns or one thousandth of an inch.
Mildew Resistant Finish – An organic or inorganic finish to repel the growth of fungi on natural fibers.
Milli – A prefix meaning 1/1,000.
Mist – Suspended liquid droplets generated by condensation from the gaseous to the liquid state or by breaking up a
liquid into a dispersed state, such as by splashing, foaming and atomizing.
Modacrylic – A synthetic fiber which contains less than 85% acrylonitrile.
Modeling – An investigate technique using computer mathematical, or physical representation of a system that
accounts for all or some of its known properties.
Molecular Weight – The weight of a molecule expressed on a scale in which the carbon isotope weighs exactly 12.0;
represents the sum of the weights of all the atoms in a molecule. As air is a gas mixture, it does not have a true
molecular weight, but an apparent molecular weight determined by the percentages of the molecular weights of each
gas in a composition.
Montreal Protocol – An international environmental agreement to control chemicals that deplete the ozone layer. The
protocol, which was renegotiated in June 1990, calls for phase-out of CFCs, halons, and carbon tetrachloride by the
year 2000, a phase-out of chloroform by 2005, and provides financial assistance to help developing countries make the
transition from ozone-depleting substances.
MSDS (Material Safety Data Sheet) – Compilation of data and information on individual hazardous chemicals
produced by the manufacturers and importers of that chemical, as required by OSHA’s Hazard Communication
Standard, 29 CFR 1910.1200.
Mullen Burst – The pressure necessary to rupture a secured cloth specimen, usually expressed in pounds per square
inch.
Multi-Filament (Multi-fill) – A yarn composed of a number of filaments.
N
NACE – National Association of Corrosion Engineers.
Napped – The rupturing of the filling yarns to produce a fleecy surface on woven fabrics.
Natural Frequency – The frequency at which a component or system resonates.
NEC – National Electrical Code.
Needled Felt – A felt made by the placement of loose fiber in systematic alignment with barbed needles. The needles
move up and down, pushing and pulling fibers to form an interlocking of adjacent fibers. It is the most commonly used
construction method since it is stronger than pressed felt.
NEDS – National Emission Data System.

21
NEMA – The National Electrical Manufacturers Association; the trade association establishing standards of
dimensions, ratings enclosures, insulation, and other design criteria for electric motors.
NESHAP – National Emissions Standards for Hazardous Air Pollutants.
New Source – A stationary source, the construction or reconstruction of which is commenced after the proposal date of
the standard. Also NSPS (New Source Performance Standard).
NIOSH (National Institute for Occupational Safety and Health) – Created by the Occupational Safety and Health Act
of 1970. NIOSH is part of the Centers for Disease Control under the Department of Health and Human Services. Its
mandate includes conducting research in developing criteria and/or recommendations to be used in setting occupational
exposure standards, identifying and evaluating workplace hazards, measurement techniques, and control technologies,
and providing professional education as well as health and safety information.
Noise Criteria – A way for an architect to specify the maximum permissible sound-power level in each of the eight
octave bands. NC curves give, in a graphical form, maximum permissible intensity per octave band.
Non-Attainment – An area which has not achieved air quality as good as the National Ambient Air Quality Standards
as defined by the CAAA.
Non-Woven Felt – A felt made by either needling, matting of fibers or compressed with a bonding agent for
permanency.
Nox (Nitrogen Oxides) – Chemical compounds containing nitrogen and oxygen; reacts with volatile organic
compounds, in the presence of heat and sunlight to term ozone. It is also a major precursor to acid rain. Nationwide,
approximately 45% of Nox emissions come from mobile sources, 35% from electric utilities, and 15% from industrial
fuel combustion.
O
OCIS (OSHA Computerized Information System) – A comprehensive database that contains information and data on
standards interpretation, chemical information, hazardous waste activity 5(a)(1) citations, a health hazard evaluation
index, training materials, and other information compiled by OSHA on subjects related to occupational safety and
health.
Octave Bands – Ranges of frequencies. These octave bands are identified by their center frequencies (63, 125, 250,
etc.).
Ohm – A measure of electrical resistance. A wire in which one volt produces a current of one ampere has a resistance
of one Ohm.
Onboard Controls – Devices placed on vehicles to capture gasoline vapor during refueling.
Capacity – Refers to the amount of light that can pass through; normally refers to the degree of visibility of an exhaust
plume, Normal measurement technique used by EPA method 9.
Opposed-Blade Damper – A type of damper where the blades rotate in the opposite direction.
OSHA – Occupational Safety and Health Administration.
OSI – Ounces per square inch; a unit of pressure equal to one-sixteenth PSI or 1.733 inches of water.

22
Oxygenated Fuels – Gasoline which has been blended with alcohols or ethers that contain oxygen in order to reduce
carbon monoxide and other emissions.
Ozone – A compound consisting of three oxygen atoms, that is the primary constituent of smog. It is formed through
chemical reactions in the atmosphere involving volatile organic compounds, nitrogen oxides, and sunlight. Ozones can
initiate damage to the lungs as well as damage to trees, crops, and materials. There is a natural layer of ozone in the
upper atmosphere which shields the earth from harmful ultraviolet radiation.
P
Parallel-Blade Damper – A type of damper where the blades rotate in the same direction.
Parallel Fans – Two or more fans which draw air from a common source and exhaust into a common duct or plenum.
A parallel fan arrangement is generally used to meet volume requirements beyond that of single fans. Two identical
fans in parallel will effectively deliver twice the rated flow of any one of the fans at the same static pressure.
Particulate – A particle of solid or liquid matter.
Particulate Matter – Any solid or liquid material in the atmosphere.
PEL (Permissible Exposure Limits) – Limits developed by OSHA to indicate the maximum airborne concentration of a
contaminant to which an employee may be exposed.
Permanent Split Capacitor Motor – Very low starting torque. Performance and applications similar to shaded pole
but more efficient, with lower line current and higher horsepower capabilities.
Permeability, Fabric – Measured on Frazier porosity meter or Gurley permeometer, etc. Not to be confused with dust
permeability. The ability of air to pass through the fabric, expressed in cubic feet of air per minute per square foot of
fabric with 0.5 H2O pressure differential.
Permit – An authorization, license, or equivalent control document issued by EPA or an approved state agency to
implement the requirements of an environmental regulation; e.g., a permit to operate a facility that may generate
harmful emissions.
pH – A symbol as part of a logarithmic designation to indicate acidity or alkalinity on a scale from 0 to 14; pH7 is
taken as neutral, 6 to 0 increasingly acid, 8 to 14 increasingly alkaline.
Photochemical Process – The chemical changes brought about by the radiant energy of the sun acting upon various
polluting substances. The products are known as photochemical smog.
Pick – See fill.
Piezometer Ring – A device consisting of a number of pressure taps connected to a common manifold to measure
pressure.
Pilot Valve – The small solenoid valve that is electrically operated to relieve pressure on one side of the diaphragm and
cause the operation of a larger diaphragm valve.
Pitch Diameter – The mean diameter or point at which V-belts ride within a sheave. This dimension is necessary for
accurate drive calculations.

23
Pilot Tube – A metering device consisting of a double-walled tube with a short right-angle bend; the periphery of the
tube has several holes through which static pressure is measured; the bend end of the tube has a hole through which
total pressure is measured when pointed upstream in a moving gas stream.
Pleated Filter Element – Filter elements made from any pleated filter media; but primarily applying those equipped
with 100% synthetic fabric.
Plenum – Pressure equalizing chamber.
Plenum Pulse – Type of pulsing collector where entire sections of the clean air plenum are isolated and pulsed with
either compressed air or air from a high pressure blower.
Ply – Two or more yams joined together by twisting.
PM 10 – A new standard for measuring the amount of solid or liquid matter suspended in the atmosphere (“particulate
matter”). Refers to the amount of particulate matter under 10 micrometers in diameter. The smaller PM10 particles
penetrate to the deeper portions of the lung, affecting sensitive population groups such as children and people with
respiratory diseases.
Point of Operation – The intersection of a fan’s static pressure curve and the system curve to which the fan is being
applied; may be designated as velocity pressure divided by static pressure or by a given CFM and SP.
Point Source – A stationary location or facility from which pollutants are emitted. Also, any single identifiable source
of pollution.
POLIPLEET – MAC Equipment’s trademark for its line of pleated spun bond 100% polyester cartridges. The
POLIPLEET can be used in MAC Equipment’s entire product line of dust collectors.
Polymerized – A chemical reaction in which two or more small molecules combine to form larger molecules that
contain repeating structural units of the original molecules.
Porosity – Sometimes erroneously used as a synonym for permeability. Originally a designation for the amount of air
in a fabric, i.e. blankets.
Pounds Per 100 Pounds of Gas – A common quantitative definition of air pollution concentration.
PPM (Parts Per Million) – The number of parts of a given pollutant in a million parts of air. Units are expressed by
weight or volume.
Precipitators – Any number of devices using mechanical, electrical, or chemical means to collect particulates. Used
for measurement, analysis or control. See electrostatic precipitator.
Pre-Coating – The application of a relatively coarse, dry dust to a bag or cartilage before start-up to provide an initial
filter cake to enhance immediate high efficiency.
Pressed Felt – A type of felt manufactured by pressing fibers into the skrim.
Pressure, Atmospheric – The pressure due to the weight of the atmosphere. It is the pressure indicated by a
barometer; standard atmospheric pressure is 29.92 inches of mercury.
Pressure Drop – The differential pressure between two points in a system. The resistance to flow between the two
points.

24
Pressure, Static – The potential pressure exerted in all directions by fluid at rest. For a fluid in motion it is measured
in a direction normal (90°) to the direction of now. Usually expressed in inches water gauge when dealing with air.
Pressure, Velocity – The kinetic pressure in the directional flow necessary to cause a fluid at rest to flow at a given
velocity. Usually expressed in inches water gauge.
Prevention of Significant Deterioration (PSD) – EPA program in which state and/or federal permits are required that
are intended to restrict emissions for new or modified sources in places where air quality is already better than required
to meet primary and secondary ambient air quality standards.
Primary Collector – A dry or wet collector which is followed by a secondary collector with greater filtering
efficiency.
Process Weight – The weight per hour that is run through the process. Commonly used in APC codes to determine the
maximum allowance pollution exhausted.
Promulgate – To make a new law known and put it into effect. The EPA promulgates a rule when it issues the final
version in the Federal Register.
PSI (Pounds per square inch) – A measure of pressure. 1 psi equals 27.7” water gauge.
PSIA (Pounds per Square Inch Absolute) – The absolute pressure without reference to another point. Atmospheric
pressure is 14.7 PSIA.
PSIG (Pounds per Square Inch Gauge) – The pressure relative to atmosphere. For instance, 10 PSIG equals 24.7 PSIA.
This is the more common pressure term.
Psychromatic Chart – A graphic depiction of the relationship between pressure, density, humidity, temperature, and
enthalpy for any gas-vapor mixture, used extensively in comfort ventilation.
Pulse Cycle – As used in conjunction with pulse jet baghouses; the interval of time between pulsing a row of bags and
that row being pulsed again.
Pulse Duration – The length of time a pulse lasts. Generally described as the length of time the electrical signal the
pilot valve open (20-40 milliseconds), however would more correctly be the description of the length of time the
manifold is pressurized (120-180) milliseconds.
Pulse Interval – The time between pulsing one row of bags and pulsing the next row.
Pulse Jet – Generic name given to all pulsing collectors.
Pulse Jet Cleaning – A cleaning method where a momentary burst of compressed air is introduced through tube or
nozzle to the top cap of a bag. A bubble of air flows down the bag, causing bag walls to collapse behind it. Generic
name given to all pulsing collectors.
R
RACM (Reasonably Available Control Measures) – A broadly defined term referring to technologies and other
measures that can be used to control pollution; includes Reasonably Available Control Technology and other measures.
In the case of PM10, it refers to approaches for controlling small or dispersed source categories such as road dust,
woodstoves, and open burning.

25
RACT (Reasonably Available Control Technology) – An emission limitation on existing sources in non-attainment
areas, defined by EPA in a Control Techniques Guideline (CTG) and adopted and implemented by states. Under Title I
of the CAAA, EPA will establish RACT standards for marginal, moderate, and serious non-attainment areas.
Radial Blade – Fan wheel design, with blades positioned in straight radial direction from the hub.
Radionuclide – Radioactive element which can be man made or naturally occurring. They can have a long life as
pollutants, and are believed to have potentially mutagenic effects on the human body.
Radon – A colorless, naturally occurring, radioactive, inert gaseous element formed by radioactive decay of radium
atoms in soil or rocks.
Random Noise – A sound that has an average amplitude and constantly changing frequency.
Rankine – See Absolute Temperature.
Rarefication – A phenomenon related to negative pressure. When air is drawn put through resistance into a fain inlet,
the air is stretched out, or rarefied, and becomes less dense than at the entry to the system. While negligible at low
pressure and volumes, high pressure fan selection must be based on rarefied inlet density.
Ravel Strip Tensile – The tension strength, in pounds per inch of a 6” long textile sample cut, cut just over one inch
wide, (with yarns peeled off each side down to exactly one inch wide) pulled in two lengthwise between jaws set 3”
apart and pulled at a constant specified speed. The type of test always used unless specified. ASTM specs are
available at technical libraries.
Re-entrainment – The phenomenon whereby dust is collected from the air stream and then is returned to the air
stream. Occurs when dust is pulsed from a bag and then caught up by an upward moving air stream.
REL (Recommended Exposure Limits) – Issued by NIOSH to aid in controlling hazards in the workplace. These
limits are generally expressed as 8 or 10 hour TWAs for a 40-hour work week and/or calling levels with time limits
ranging from instantaneous to 120 minutes.
Relative Humidity – The ratio of existing water vapor to that of saturated air at the same dry-bulb temperature.
Repeat – The number of threads in a weave before the weave repeats or starts over again. The number of ends and
picks in the repeat may be equal or unequal but in every case the repeat must be in a rectangular form.
Repressuring Baghouse – Baghouse using bags that are cleaned by flowing air backwards through the cloth. Same as
reverse air baghouse.
Repowering – The replacement of an existing coal-fired boiler with one or more clean coal technologies, in order to
achieve significantly greater emission reduction relative to the performance of technology in widespread use as of the
enactment of the Clean Air Act Amendments.
Residual Risk – The quantity of health risk remaining after application of the MACT (Maximum Achievable Control
Technology).
Resistance – In air flow, it is caused by friction of the air against any surface, or by changing the momentum of the
gas.
Reverse Air Baghouse – Baghouse using bags that are cleaned by flowing air backwards through the cloth, to cause
dust cake release.

26
Reverse Jet – See pulse jet.
Reynolds Number – A mathematical factor used to express the relation between velocity, viscosity, density, and
dimensions in a system of flow, used to define fan proportionality.
Ringelman – A measure of the opacity caused by pollution from a stack. Grades opacity from 0 to 5, where 0 is an
invisible discharge and 5 is totally opaque.
Ringelman Chart – Actually, a series of charts, numbered from 0 to 5, that simulate various smoke densities, by
presenting different percentages of black. A Ringelman No. 1 is equivalent to 20 percent black; a Ringelman No. 5, to
100 percent. They are used for measuring the opacity of smoke rising from stacks and other sources, by matching with
the actual effluent, the various numbers, or densities, indicated by the charts. Ringelman numbers were sometimes
used in setting emission standards.
Rotor – The rotating part of most AC motors.
RPM – Revolutions per minute.
RPT (c) – Rectangular Pulse Top removal. MAC equipment acronym for its large rectangular, top bag removal pulse
jets that start at 196 bags and go up as high as needed. (c) designates cartridges instead of bags.
RT (c) – Round top removal. MAC Equipment acronym for its round top bag removal pulse jet dust collectors. (C)
RTECS (Registry of Toxic Effects of Chemical Substances) – A database that lists an identification number,
synonyms, Department of Transportation (DOT) hazard label information, EPA Toxic Substances Control Ad (TSCA)
Information, OSHA and Mine Safety and Health Administration (MSHA) air exposure limits, and animal and human
toxicologic data.
S
Sanctions – Actions taken against a State or local government for failure to plan or to implement a SIP, e.g., a ban on
construction of new sources.
Sateen – Cotton cloth made with a satin weave, expressed as warp sateen or filling sateen.
Satin Weave – A form of twill except that the points of intersection are separated from one another in a consistent or
inconsistent manner.
Saturated Air – Air containing the maximum amount of water vapor for a given temperature and pressure.
SB Fan – MAC Equipment’s Strait Blade fan. This all purpose fan can be placed on the clean air or dirty air side of
the dust collector in most cases.
SCFM (Standard Cubic Feet per Minute) – The volume that a gas would occupy at standard temperature and pressure
conditions (70°F and 14.7 PSIA). See gas flow rate.
Scour – A soap and water wash to “off loom” fabric.
Scroll – The general shape of a centrifugal fan housing; the formed piece to which housing sides are welded.

27
Scrubber – A device that uses a liquid spray to remove aerosol and gaseous pollutants from an air stream. The gases
are removed either by absorption or chemical reaction. Solid and liquid particulates are removed through contact with
the spray. Scrubbers are used for both the measurement and control of pollution.
Scrubber, Gas – Any device in which a contaminant, solid or gaseous, is removed from a gas stream by liquid
droplets. (Types include spray towers, packed towers, cyclone scrubbers, jet scrubbers, orifice scrubbers, venturi
scrubbers, impingement scrubbers, and mechanical scrubbers).
Secondary Collector – A dust collector which is preceded by primary collector(s). The secondary filter normally has a
higher filtering efficiency.
Seeding – The application of a relatively coarse, dry dust to a bag or cartridge before start-up to provide an initial filter
cake for immediate high efficiency and to protect bags from blinding. Also, in crystallizing, seeding is used to start the
crystallization process.
Sensible Heat – Any portion of heat which affects a change in a substance’s temperature but does not alter that
substance’s state.
Series Fans – A combination of fans connected such that the outlet of one fan exhausts into the inlet of another. Fans
connected in this manner are capable of higher pressures than a single fan and are used to meet pressure requirements
greater that single fans.
Service Factor – The number by which the horsepower rating is multiplied to determine the maximum safe load that a
motor may be expected to carry continuously.
Settling Chamber – A dry collection device which removes particulate matter from the gas stream by slowing down
the exhaust gas velocity.
Shaded-Pole Motor – A special type of single-phase induction motor. Low starting torque, low cost. Usually used on
direct-drive fans.
Shaft Seal – A device to limit gas leakage between the shaft and fan housing.
Shaker Baghouse – A baghouse using woven cloth bags; cleaning occurs by shaking bags from the top.
SI Units – Systeme International d’Unites, International System of Units, any one of the units of measure in the
international meter-kilogram-second system.
Silicone Finish – A treatment of felted bags with silicone to provide a slick finish for improved dust release. Most
commonly used on Dacron polyester and fiberglass bags.
Singed Finish – A felted bag finish that is designed to provide a finish similar to calendering. The “hairs” are burned
off to provide a smoother finish.
Singeing – The burning off of the protruding fibers from the warp and filling yarns of the fabric.
Singles – The term used to imply only one yarn.
SIP (State Implementation Plan) – Documents prepared by states, and submitted to EPA for approval, which identifies
actions and programs to be undertaken by the State and its subdivisions to implement their responsibilities under the
Clean Air Act.

28
Sizing – A protective coating applied to yarn to ensure safe handling, e.g., abrasion-free during weaving.
Skrim – A woven fabric that felt is needled onto.
Slip – The percentage difference between synchronous and operating speeds.
Slippage – The movement of yarns in a fabric due to insufficient interlacings.
Smog – The irritating haze resulting from the sun’s effect on certain pollutants in the air, notably those from
automobile exhaust; see photochemical process. Also a mixture of fog and smoke.
Smoke – Carbon or soot particles, less than 0.1 micrometers in size which result from the incomplete combustion of
carbonaceous materials such as coal, oil, tar and tobacco.
SO2 – Sulfur dioxide is an invisible, non-flammable acidic gas, formed during combustion of fuel containing sulfur.
SO3 – Sulfur trioxide oxidized from SO2 combines with atmospheric moisture to form sulfuric acid mist (H2SO4).
Soot – Very finely divided carbon particles clustered together in long chains.
Second-Power Level – Acoustic power radiating from a sound source. Expressed in watts or decibels.
Sound-Pressure Level – The acoustic pressure at a point in space where the microphone or listener’s ear is situated.
Expressed in units or pressure or in decibels.
Source – Any place or object from which pollutants are released.
SP – Static pressure; pressure as measured in all directions within an air-handling system, not including the force or
pressure of air movement.
Specific Gravity – The ratio of the weight or mass of a given volume of any substance to that of an equal volume of
some other substance taken as a standard. The ratio of the density of andy gas to the density of dry air at the same
temperature and pressure is the specific gravity of the gas.
Specific Heat – The ratio of the quantity of heat required to raise a certain volume one degree to that required to raise
an equal volume of water one degree.
SPI – Society of the Plastics Industry.
Split-Phase Motor – The most common type of single-phase induction motor. moderate starting torque, high starting
current, high breakdown torque, used on easy-starting equipment, such as belt-drive fans.
Spun Fabric – Fabric woven from staple spun fabric.
Squirrel-Cage Winding – A permanently short-circuited winding , usually uninsulated and chiefly used in induction
motors, having its conductors uniformly distributed around the periphery of the machine and joined by continuous end
rings.
SRC – Spark-Resistant Construction; AMCA standard of guidelines for general methods of fan construction when
handling potentially explosive or flammable particles, fumes, or vapors.
SSPC – Steel Structure Painting Council

29
ST (c) – Square Top removal. MAC acronym for its square top bag removal pulse jet dust collectors up to 64 bags. (c)
Stack – A smokestack, a vertical pipe or flue designed to exhaust gases.
Stage II Controls – Systems placed on service station gasoline pumps to control and capture gasoline vapors during an
automobile refueling.
Standard Air Density – 0.0750 lbs./ft³, corresponds approximately to dry air at 70°F. and 29.92 in. Hg.
Starting Torque – The torque produced by a motor as it begins to turn from a standstill and accelerate. Sometimes
called locked rotor torque.
Static Balance – The mechanical balance of a rotating part or assembly by adding weights to counter-balance
gravitational rotating of the part without power driving it.
Static Pressure (Cold) – The pressure caused by the resistance to air flow through the system if the gas were at
standard conditions or colder, if this is a possibility.
Static Pressure (Fan) – The static pressure for which a fan is to be selected based on system calculations;
fan SP = SP outlet-Sp inlet-VP inlet.
Static Pressure (Hot) – The pressure caused by the resistance to air flow through the system at actual conditions.
Measured in inches of water (WG).
Stator – The stationary parts of a magnetic circuit with associated windings.
Streamline Flow – Fluid flow in which the velocity pressure and fluid density of a given particle remains constant with
time.
STEL (Short Term Exposure Limit) – The employee’s 15 minute time weighted average exposure which cannot be
exceeded at any time. STEL is set by OSHA for each pollutant and expressed in terms of ppm or mg/m³.
Stoichlometric Air – The exact quantity of air required to combine with the given fuel so that the ensuing combustion
reaction is perfect and no free oxygen or unburned constituents remain. In reality, air in excess of the stoichlometric
ratio is usually provided to encourage complete combustion of the fuel.
Sulfur Dioxide (SO2) – A heavy, pungent, colorless air pollutant formed primarily by the combustion of fossil fuels. It
is a respiratory irritant, especially for asthmatics and is the major precursor to the formation of acid rain.
Sulfur Oxides – Pungent, colorless gases formed primarily by the combustion of fossil fuels; considered major air
pollutants; sulfur oxides may damage the respiratory tract as well as vegetation.
Surge Limit – That point near the peak of the pressure curve which corresponds to the minimum flow at which the fan
can be operated without instability.
SWSI – Single-Width Single-Inlet Centrifugal Fans.
Synchronous Speed – Rated motor speed expressed in RPM. Synchronous speed = 120 x frequency divided by
number of poles.

30
System – A series of ducts, conduits, elbows, filters, diffusers, etc., designed to guide the flow of air, gas, or vapor to
and from one or more locations. A fan provides the energy necessary to overcome the system’s resistance to flow and
causes air or gas to flow through the system.
System Curve – Graphic presentation of the pressure versus volume flow rate characteristics of a particular system.
System Effect – The effect on the performance of a fan resulting from the difference between the fan inlet and outlet
connections to the actual system, and the standardized connections used in laboratory tests to obtain fan-performance
ratings.
System gas Volume – All gases flowing through the exhaust gas system (including excess air, scavenger air, leakage
air).
T
Tachometer – an instrument which measures the speed of rotation, usually in RPM.
Tape Sampler – A device used in the measurement of both gases particulates. It allows air sampling to be made
automatically at predetermined times.
Tensile Strength – The maximum stress a material can withstand before it breaks; expressed in pounds per square
inch.
Test Block – An operating point above and beyond the maximum specified continuous rating demonstrating the fan
margin to the customer.
Textile – That which is or may be woven. Comes from the Latin “Texere” to weave. Hence any kind of fabric.
Thread Count – The number of warp and filling yarns in a fabric commonly expressed in square inch.
Threshold Limit Values (TLV) – Represents the air concentrations of chemical substances to which it is believed that
workers may be exposed daily without adverse effect.
Tip Speed – Fan wheel velocity at a point corresponding to the outside diameter of the wheel blades; normally
expressed in feet per minute (circumference times RPM).
TLV®
(Threshold Limit Value) – A registered trademark for an exposure limit developed by the American Conference
of Governmental Industrial Hygienists (ACGIH). A listing of TLVs may be found in the ACGIH’s “Documentation of
the Threshold Limit Values and Biological Exposure Indices for 1988-1989.”
Torque – A force which produces, or lends to produce, rotation; commonly measured in ft.-lbs. or in.-lbs. A force of
one pound applied to the handle of a crank, the center of which is displaced one foot from the center of the shaft,
produces a torque of one ft.-lb. on the shaft if the force is provided perpendicular to, not along the crank. Torque can
be calculated by:
Torque (Ft.-lbs.) = HP x 5250
RPM
Toxic Release Inventory (TRI) – A listing of pollutants and emissions Levels from each major source.
TP – Total pressure; the sum of velocity pressure plus static pressure.

31
TPI – Twist Per Inch.
TPY – Tons per year.
Transportation Control Measures (TCM’s) – Steps taken by a locality to adjust traffic patterns (e.g. lanes, right turn
on red) or reduce vehicle use (ridesharing, high-occupancy vehicle Lanes) to reduce vehicular emissions of air
pollutants.
Traverse – A method of sampling points in a duct where pressure readings will be taken to determine velocity. A
traverse divides the duct into equal, evenly distributed areas that are each tested, compensating for errors caused by
uneven gas flow in the duct.
TSCA (Toxic Substances Control Act) – Administered by the Environmental Protection Agency (EPA), was passed by
Congress to protect human health and the environment by requiring testing and necessary use restrictions to regulate
the commerce of certain chemical substances.
TSD (Facility) – Treatment, Storage, and Disposal.
Tubeaxial Fan – Axial fan without guide vanes.
Tubesheet – The steel plate that bags and cages are suspended from. Separates the clean air and dirty air sections of
the baghouse. Sometimes called cellplate, a term usually used for inside collector baghouses.
Tubular Centrifugal Fan – Fan with a centrifugal impeller within a cylindrical housing discharging the gas in an axial
direction.
Turbulent Flow – Airflow in which true velocities at a given point vary erratically in speed and direction.
Turning Vanes – Baffles put in a duct to straighten out the air flow.
TWA (Time Weighted Average) – Employee’s average airborne exposure which can not be exceeded in any 8 hour
work shift. TWA is set by OSHA and expressed in mg/m³.
Twist – The number of complete spiral turns in a yarn, in a right or left direction, e.g., “Z” or “S” respectively.
U
Unbalance – The condition of a rotor in which its rotation results in centrifugal force being applied to the rotor’s
supporting bearings.
Uniform Flow – Airflow in which velocities between any two given points remain fairly constant.
V
Valve – In baghouses, frequently the pilot valve and the diaphragm valve pulse are considered as one, simply called
“valve.”
van der Waals – Adhesive forces that exist between the particle and fiber.
Vaneaxial Fan – Axial fan with either inlet or discharge guide vanes or both. Includes fixed-pitch, adjustable-pitch,
and variable-pitch impellers.

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Vaporization – The change of a substance from the liquid to a gaseous state. One of the 3 basic contributing processes
of air pollution, the others being attrition and combustion.
Vapors – The gaseous form of substances which are normally in the solid or liquid state and which can be changed to
these states, either by increasing the pressure or decreasing the temperature alone. Vapors diffuse.
Variance – Permission granted for a limited time, under stated conditions, for a person or company to operate outside
the limits prescribed in a regulation. Usually granted to allow time for engineering and fabrication of abatement
equipment to bring the operation into compliance.
Velometer – A simple instrument for determining the velocity of gas in a duct, its operation is similar to an inclined
manometer, except that it automatically converts the reading to velocity.
Vena Contracta – The smallest flow area for flow through a sharp-edged orifice.
Ventilation – Supplying and removing air by natural or mechanical means to and from any space.
Venturi – Device used to theoretically increase the efficiency of a compressed air pulse. Designed with converging
circular sides to a throat and then diverging sides. Designed such that when a pulse is introduced at the top, a negative
pressure zone is created outside the top, and secondary air is induced into the venturi, increasing cleaning energy.
Venturi Scrubber – A wet type dust collector that can obtain very high efficiency, but requires large horsepower to do
so. The gas and dust particles are accelerated in a venturi throat, where finely atomized water is introduced and
water/dust take place.
Vibration – Alternating mechanical motion of an elastic system, components of which are amplitude, frequency, and
phase.
Viscosity – The characteristic of all fluids to resist flow.
VOC’s (Volatile Organic Compounds) – A group of chemicals that react in the atmosphere with nitrogen oxides in the
presence of heat and sunlight to form ozone; does not include methane and other compounds determined by EPA to
have negligible photochemical re-activity. Examples of VOC’s include gasoline fumes and oil-based paints.
Volt – A unit of electrical potential or pressure. 110 or 220 volts are normally found in the U.S.
VP – Velocity pressure; the kinetic energy pressure of air in motion. VP is used to get the velocity of a gas stream.
______
Velocity (SFPM) = 4005√ VP
______
Velocity (AFPM) = 1096√ VP
/ρ
ρ = Actual density of the air (lb/ft³)
VP = inches of water column
VP/SP – Velocity pressure divided by static pressure; a single number reference used to define a fan’s point of
operation. Each system curve has a unique VP/SP value.

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W
Warp Count – Number of warp threads per inch width.
Warp Sateen – The face of the cloth having the warp yarns floating over the filling yarns and being greater in number
than the filling yarns.
Warp Thread – Yarn or threads in a fabric running lengthwise.
Warp Yarns – Yarn in a fabric running lengthwise.
Water Gauge – Inches water is a pressure term defined as a pressure equal to that exerted by a column of water of the
same height. 27.7” WG equals 1 PSI.
Watt – A unit of power in electrical terms, the product of voltage and amperage. 746 watts are equal to one
horsepower.
Weave – The pattern of weaving, e.g., plain twill, satin, etc.
Weft – See fill.
Wet-Bulb Depression – The difference between the dry-bulb and wet-bulb temperature at the same location.
Wet-Bulb Temperature – The temperature of a gas stream taken with a wetted thermometer. It is approximately
equal to the adiabatic saturation temperature of the gas.
Wet Collector – Dust collector which uses water to remove particulate matter from the exhaust gas (wet washers,
venturis, wet fans).
WG – Water gauge, see inch of Water.
Wizard – MAC Equipment trademark for its intelligent dust collector controller. The MAC Baghouse Wizard controls
the pulse cleaning of a dust collector and monitors emissions, airflow, pressure drop, temperature, and hopper level and
displays it in a user friendly graphical interface.
Woof – See fill.
Woolen System – A system of yarn manufacturing suited for the shorter wools, various wastes, reclaimed wools, etc.
Worsted System – A system of yarn manufacturing suited for medium and longer wools. Includes additional
processing steps resulting in the most uniform yarn. The resulting yarn is compact and level.
Woven Cloth Bag – A bag made of woven material, similar to normal cloth. Used in re-pressuring and shaker
baghouses.
WR² -- The unit designation of fan wheel rotational inertia in lb.-ft², also known as WK².
Wrapper – Used in electrostatic precipitators, the light gauge steel or aluminum covering put over insulation.

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Y
Yarn – A term for an assemblage of fibers or filaments forming a strand (thread) which can be otherwise formed into a
textile material.
Yarn Size – A relative measure of fineness or coarseness of yarn. The smaller the number in spun yarns, the coarser
the yarn.
Yield Strength – Maximum stress to which a ductile material can be subjected before it physically distorts.
Z
Z-Twist – The yarn spirals conform in slop to the center portion of the letter “Z.”

35
Filter Media / Fibers
Definitions
Every industry has unique buzz words, terms and acronyms. Fabric filtration is especially blessed with a full
vocabulary. Jargon associated with fabrics, can be nearly as arcane as any found in the Military’s or Silicon Valley’s
lexicon. This section has been prepared to give you a basic understanding of the different filtration medias in the dust
collection marketplace.
Nonwoven – Nonwovens are defined by what they are not. Nonwoven is a generic term used to describe fabric that is
produced differently from a fabric made by weaving or, more broadly, a fabric that is different from traditional woven
or knitted fabrics. Like all fabrics, nonwovens are planar structures that are relatively flat, flexible, and porous. Unlike
traditional fabrics that re made by mechanically interlacing (weaving) or interlooping (knitting) yarns composed of
fibers of filaments, nonwovens are fabrics that are made by:
(a) mechanically, chemically, or thermally interlocking layers of networks or fibers or filaments or yarns,
(b) interlocking fibers or filaments concurrent with their extrusion,
(c) perforating films, or
(d) forming porous films concurrent with their extrusion.
The American Society for Testing and Materials (ASTM D 1117-80) defines a nonwoven fabric as: “A textile structure
produced by bonding or interlocking of fibers, or both, accomplished by mechanical chemical, or solvent means and
combinations thereof.”
How nonwoven fabrics are made – A basic concept used in making a nonwoven is to transform fiber-based materials
into flat, flexible, porous, sheet structures with fabric characteristics. In practice, this is accomplished several ways,
depending on the fiber material used and/or the fabric characteristics desired. Technologies used in three primary
manufacturing industries: textile, paper, and extrusion and various combinations of established processes from one or
more of these industries, form the basis of the processes for manufacturing nonwovens. Accordingly, process for
manufacturing nonwoven fabric can be grouped into four general technology bases: textile, paper, extrusion, or hybrid
(combination).
The textile technology base includes garneting, carding and aerodynamic forming of textile fibers into preferentially-
oriented webs. Fabrics produced by these systems are referred to as dry laid nonwovens and carry terms such as
“garneted”, “carded”, and “air laid.” These fabrics, or fiber-network structures, are manufactured with machinery
associated with staple fibers bonded by stitching filaments or yarns. Needle-felt fabric is produced by textile-based
technology.
Paper technology base includes dry laid pulp and modified wet laid paper systems designed to accommodate fibers
longer than wood pulps. Fabric produced by these systems are referred to as “dry laid pulp” and “wet laid” nonwovens.
These fabrics are manufactured with machinery associated with pulp fiberizing (i.e. hammer mills) and paper forming
(i.e. slurry pumping onto continuous screens) designed to manipulate short fibers suspended in a fluid.
Most cartridge filter media is produced by the wet laid systems. All wet laid cartridge paper contains high percentages
of cellulose, reducing its resistance to moisture. HEPA media is also produced on specialized, wet laid equipment.
The extrusion technology base includes spunbound, meltblown, and porous film systems. Fabrics produced by these
systems are referred to individually as “spun bounded”, “meltblown”, and “textured” or “apertured film” nonwovens;
or, generically, as “polymer laid” nonwovens. The fabrics are produced with machinery associated with polymer
extrusion (i.e. manufactured fiber spinning, film casting, extrusion coating). In polymer laid systems, fiber structures
are simultaneously formed and manipulated.

36
The hybrid base combine elements of the first three technologies. An example of a hybrid product, is the
MIASMACTTM
HEPA media, wet laid media is laminated with spun bounded support sheets, to form a combination
media.
Characteristics of Selected Fibers
Acrylic Fibers – Acrylic fibers are man made fibers, in which the fiber forming substance is any long chain polymer
composed of at least 85% acrylonitrile units, and the remainder a copolymer. Acrylic is non-thermoplastic.
Orlon®
(Dupont), Acilian®
(Monsanto), Creslan®
(American Cyanimid), Crylor®
(Crylor SA), Zefran®
(BASF), and
Draylon-T®
(Bayer) are trade names used by various producers of acrylic fibers.
Draylon-T®
(or equivalents), a homopolymer (100% acrylonitrile), is a widely used acrylic, for high-pressure cleaned
needled felts. For MAC Equipment applications, only acrylic homopolymer fabric should be used. Fiber cross sections
are dumbbell-shaped, and surfaces are striated. Diameters are typically 15 to 35 microns. Where polyesters are not
suitable, because of potential hydrolysis, acrylics offer a combination of abrasion resistance and resistance to wet heat
degradation, particularly under acid conditions. Homopolymer felt is a candidate for hot gas applications of less than
284 degrees F. Temperature resistance of copolymers is less, 250°F degrees.
Acrylic felts are used in drying raw flour, coal, gold and copper ores, galvanizing, and low temperature flue gas
applications. Polyester is superior for most dry heat applications.
Aromatic polymide (Nomex®
) – Nomex®
nylon was a proprietary (patent has expired) aromatic-polymide (aramide)
linked structure, developed by E.I. duPont de Nemours, for applications requiring dimensional stability and high heat
resistance. Nomex®
is a non-thermoplastic so it does not melt, but at temperatures above 700 degrees F, degradation
sets in rapidly. In dry heat up to and including 375 degrees F, this fabric may be used satisfactorily as long as there is
no acid dew point problem.
Nomex®
is unaffected by small amounts of water vapor and high temperatures. When exposed to saturated steam at
high temperatures, Nomex®
will progressively lose strength. However, it withstands these conditions better than many
other fibers.
Nomex®
withstands the attack by mild minerals and inorganic acids, mild alkali, and most hydrocarbons. It is
unaffected by florines and gases from metallurgical and rock processing operations. However, high active oxidizing
agents, such as sulphur oxides, will rapidly degrade Nomex®
.
The single biggest use for Nomex®
, needled felt, is asphalt batch plant dryers and drum-mix plants. Other uses include
raw and finish mill grinding on cement plants, carbon bake, clinker coolers, and many other hot gas processes.
Polyester – a manufactured fiber in which the fiber forming substance is any long chain synthetic polymer composed
of at least 85% by weight of an ester of a dihydric alcohol and terephtalic acid. This material is a thermoplastic.
Fiber is available under various trade names: Dacron®
(duPont), Enka Polyester®
(American Enka), Fortrel®
(Fiber
Industries/Celanese), and Kodel®
(Eastman Chemical). Polyester is the most widely used needled felt for pulse jet
applications.
Polyester (PE) is superior to most synthetics in dry heat installations but it is not comparable to Teflon®
nor Nomex®
.
Recommended operating temperature is 275 degrees F maximum.
Under moist, near-saturation, heat conditions, polyester is inferior to other synthetics. In the presence of a saturated
vapor, the fibers will hydrolyze, weakening the fabric.

37
PE provides good resistance to most oxidizing agents, mineral acids, and most organic solvents except high
concentrations of sulfuric, carbolic and nitric acids. It resists weak alkalis. However, strong alkalis, at high
temperatures, will dissolve the fabric.
Polyester fiber makes an excellent filter fabric, with efficient filtration and good energy absorption characteristics.
The fabric is widely used in many of the industries served by MAC Equipment. It is used in agricultural,
woodworking, chemical and other applications where chemical and mechanical characteristics are compatible. As
needled felt, it is available in 12, 16, and 18 oz./yd² versions. The use of 12 oz./yd² should be reserved for non-critical
applications, handling large particulate. Spunbonded POLIPLEETTM
media is available in plain, water/oil resistant
(TR), metalized-antistatic (ME), and with a laminated PTFE membrane.
Polypropylene – (polyolefin) is a manufactured fiber in which the fiber forming substance is any long chain synthetic
polymer, composed of at least 85% by weight of olefin units.
Herculon®
(Hercules) and Reevon®
(Phillips) are trade names used by various producers of polypropylene (PP) fibers.
The fibers combine excellent resistance to most acids and alkalis, plus high strength. It has one of the lowest specific
gravities of any synthetic fiber, and is one of the most economical synthetics, (about the same price as polyester). PP is
a good choice for replacement of cotton in low temperature applications.
PP absorbs no moisture and provides excellent cake discharge and resistance to blinding. Filtration efficiency is not
quite as good as polyester.
Polypropylene has very low heat resistance, even less than cotton, and should not be exposed to prolonged
temperatures of over 165 degrees F. Since it does not absorb moisture, its degradation characteristics in dry heat and
moist heat are virtually the same.
Within its limited temperature range, polypropylene provides good resistance to mineral and organic acids. It resists
alkalis, reducing agents and organic solvents. It is, however, soluble at 160 degrees F in chlorinated hydrocarbons.
P84 (Polyimide) – P84 is a proprietary fiber produced by Lenzing in Austria. P84 is a non-thermoplastic, and in 100%
form may be used for temperatures of 500 degrees F. Its fiber is highly convoluted, having a high surface area-to-
diameter ratio.
Extensive testing has shown that P84 fabric approaches Gortex®
in efficiency, but has all of the advantages of a needled
felt. It may be layered on top of lower cost fibers, to provide the benefits of the base fiber, but at lower costs than a
100% version of the P84 felt. Composites generally have a 4 oz.yd² P84 fiber layer, needled to a 12 oz.yd² carrier base.
100% P84 is readily available in 14 oz. weight, but other weights are available.
P84 needled felt, and composites, are used in many industrial applications where high efficiency is required. Examples
are: gold and copper ore processing, incinerators, boilers, and various chemical processes.
Teflon®
- is a proprietary fluorocarbon fiber, manufactured by E.I. duPont. It is composed of long chain carbon
molecules in which all of the available bonds are completely saturated with fluorine. These strong carbon-to-fluorine
bonds create fibers that are exceptionally stable to both heat and chemicals. Teflon®
is the most chemically resistant
fiber used in conventional dust filtration.
Teflon®
is not affected by any known solvents except some prefluorinated organic liquids at temperatures above 570
degrees F. Exposure to temperatures above 550 degrees F. will cause some decomposition, although it is slow to
develop. Teflon®
bags shrink when exposed to high temperatures, especially in length.

38
The low friction properties of Teflon®
fibers provide excellent cake discharge. In addition, Teflon®
fibers’ chemical
inertness and resistance to dry and moist heat degradation makes it ideal for use under severe conditions.
Teflon®
needled felt is extremely expensive. Recently a lower cost version, Tefaire®
, has been introduced. This felt is
a blend of 85% Teflon®
and 15% fiberglass fibers. Commercial uses are limited to extreme chemical environments
where the advantages of Teflon fibers’ great chemical resistance outweighs cost disadvantages.
Some boilers, carbon black plants, soil remediation systems, and incinerators have been equipped with Teflon®
products.
Glass – Glass fiber is a product of fusion, a non-crystalline silicate analogous to other fiber polymeric materials.
Selected silica sands, limestone, soda ash, and borax or other ingredients are melted at about 2500 degrees F. and the
mixture is extruded through spinnarets. The resulting filaments may be drawn while still molten and later twisted and
plied into filament yarn.
Or, as the extruded glass may be drawn and broken by jets of compressed air into staple of lengths 8 to 15 inches. The
fibers are then treated with a lubricant which is of great importance in the durability of the eventual fabric. Following
drying, the fibers are process much like the more conventional fibers.
Woven fiberglass and felted fiberglass medias are available for high energy cleaned fabric filters. These are specialty
products and are used for very specific applications; involving high (up to 500 degrees F.) temperatures, usually in the
presence of oxidizing agents.
Some common trade names for woven fiberglass are GL65 Tri-LoftTM
(BHA), and FL57 Hi-LoftTM
(BHA); other
companies have similar products. Available weights are 16 to 22 oz./yard². Huyglas®
(Air Purator Corporation) felted
fiberglass medias are available in a variety of weights, form 14 to 27 oz./yd². Bag/cage fit & support is very critical –
check with the vendors involved for specific recommendations.
Woven fiberglass, in particular, is very easy to damage, and is not as efficient as other medias. Felted fiberglass tends
to be heavy and difficult to handle. Suitable applications for this material are limited. Consult MAC Equipment
engineering before using these products for any application.
HEPA – High Efficiency Particulate Air filter is the maximum efficiency available in particulate filtration. Rated for
temperatures up to 275°F. Usually offered as a static after filter following a dust collector; however, a pulse cleaned
version is available. MAC Equipment’s style FG134/2 cleanable HEPA media, is a borosilicate microfiber glass,
supported by polyester webbing on each side. Refer to MAC Equipment for more application information.
Ryton®
(Polyphenylene Sulfide) – Ryton®
(Phillips) is a long chain synthetic polysulfide, with at least 85% of the
sulfide linkages attached directly to two aromatic rings. Standard fiber is 3-denier. The resin was developed by
Phillips Petroleum, in 1973.
Ryton®
is resistant to sulphur oxides, and is used for high temperature gas streams, up to 360 degrees F. Gas stream
oxygen content should not exceed 15%. Ryton®
does not hydrolyze and has flame retarding characteristics.
Typical applications are industrial/municipal solid waste incinerators and coal-fired boilers.
Other fibers and medias are available for very special temperature, chemical, pressure drop, or efficiency requirements.
Consult MAC Equipment for more details.

39
Properties of Filtration Fabrics
Temp. °F Polypropylene
170
Polyester
275
Acrylic
275
Fiberglass®
500
Nomex®
375
Ryton®
375
P-84TM
500
Teflon®
500
Abrasion
Energy
Absorption
Filtration
Properties
Moist Heat
Hydrolysis
Alkalines
Mineral Acids
Oxygen (15%+)
Relative Cost
Excellent
Good
Good
Excellent
Excellent
Excellent
Excellent
X
Excellent
Excellent
Excellent
Poor
Good
Fair
Excellent
X
Good
Good
Good
Excellent
Fair
Good
Excellent
XX
Fair
Fair
Fair
Excellent
Fair
Poor**
Excellent
XXX
Good
Good
Excellent
Good
Good
Poor
Excellent
XXXX
Good
Good
Very Good
Excellent
Excellent
Excellent
Poor
XXXXX
Good
Good
Excellent
Good
Fair
Good
Excellent
XXXXXX
Excellent
Good
Fair
Excellent
Excellent
Excellent
Excellent
XXXXXXX
* Sensitive bag-to-cage fit
** Fair with acid resistant finishes
Note: Combinations of variables alter the resistance of the fiber to the specified performance ratings, i.e., time, temperature and gas stream chemistry.
Chemical Compatibility of Fabrics with Common Chemicals
Salts A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Calcium Chloride (Ca Cl2) A A B A A A B B
Ferrous Chloride (Fe Cl2 4H2O) A A B A A A C B
Sodium Acetate (C2 H4 Na O2) A A B A A A B B
Sodium pyrosulfite (Na2 O5 S2)
(metan sulfite)
C A B A A A A B
Sodium Bromide (Na Br) A A A A A A C C
Sodium Perchbrate (Cl Na O4) A A A A A A - B
Sodium Cyanide (Na Cn) A A B A A A B B
Sodium Nitrate (Na NO3)
(Chile Saltpeter)
A A B A A A B B
Sodium Sulfate (Na2 SO4)
(Glaubers Salt)
A A A A A A B B
Sodium Sulfide (Na2 S) A A A A A A B B
Oxidizing Agents A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Bromine Calcium (Br) B B - B A A A B
Calcium Hypochlorite (Ca(OCL)2) A A - A A A A B
Carbon (C)
(Graphite/Diamond)
B B - B A A A B
Fluorine (F) B B - B A A C B
Hydrogen Peroxide (H2O2) A A - B A A A B
Iod A A - A A A A B
Ozone (O3) A A - - B A A B
Potassium Chloride (K Cl)
(Sylvine)
A A B A A A A B
Sodium Chlorate (Na Cl O3) - A - - A A A B
Sodium Hypochlorite (Na Ocl)
(Eau-de-Labarraque)
B A - B B A A B

40
Mineral Acids A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Chromium Trioxide (Cr O3)
(Chromic Acid Anhydride)
A A C A B A A B
Hydrogen Chloride (H Cl)
(Hydrochloric Acid)
(Muriatic Acid)
A A C A A A A B
Hydrofluoric Acid (HF) A A C B A A C B
Nitric Acid (HN O3) A A B A B A A B
Tripotic Acid (HO)3 P(O) A B A A A A A B
Sulphuric Acid (H2 SO4)
(Sulphuric Acid)
(Vitrol)
B B B B A A A B
Organic Acids A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Acetic Acid (C2 H4 O2) A A A A A A A B
Benzoic Acid (C7 H6 O2) A A B A A A A B
Phenol (C6 H6 O)
(Carbolic Acid)
A A C B A A C B
Formic Acid (CH2 O2) A A B A A A A C
Lactic Acid (C3 H6 O3) A A B A A A B B
Oxalic Acid (C2 H2 O4)
(Acid of Sugar)
A A C A A A A B
Salicylic Acid (C7 H8 O3) A A B A A A C B
Bases A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Ammonia (H3 N) B B B C A A B B
Calcium Hydroxide (Ca (OH)2)
(Hydrated Lime)
A A A A A A A B
Potassium Hydroxide (KOH)
(Caustic Potash)
B C B B B A C B
Potassium Carbonate (K2 CO3)
(Potash)
(Salt of Tarter)
B B A B A A C B
Sodium Hydroxide (Na OH)
(Caustic Soda)
B B B B B A C C
Sodium Carbonate (Na2 Co3)
(Washing Soda)
A A A A A A C B

41
Organic Solvents A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Acetone (H3 C-CO-CH3) A A A A B A A C
((CH2)4H3) A A A A B A A C
Benzene (C6 H6)
(Benzol)
A A A A A A A B
Carbon Disulfide (C S2) A A A B C A A B
Carbon Tetrachloride (C Cl3) A A A A B A A B
Chloroform (CH Cl3) A A A A B A A B
Cyclohexane (C6 H12) A A A A B A A B
Acetoin (C2 H6 O2) A A A A B A A B
Ethylalcohol or Methane Ether
(C2 H6 O)
(Vanillin)
A A A A A A A B
Butyl Alcohol or Ethyl Ether
(C4 H10 O)
A A A A A A A C
Methanol (CH4 O) A A A A A A A C
MEK A A A A B A A B
Nitrogen (N) A A A A B A A B
Ethylenes trichloro (C2 H CL3) A A A A A A A B
Methyl Benzene (C6 H5 CH.3)
(Toluene)
A A A A B A A C
O-Xylene (C6 H4 (CH3)2) A A A A B A A C
Miscellaneous A=Excellent Suitability B=Limited Suitability C=Not Recommended
Max. Operating
Temperature °F
Dralon T®
(Poly Acrylic)
275
Acrylic
(Poly Acrylic)
275
Nomex®
375
Polyester
275
Polypropylene
170
Teflon®
500
Glass
500
P84
500
Acetaldehyde (H3 C-CHO)
(Aldehyde)
A A A A - A A B
Vinyl Alcohol (H2 C-CH2 O)
(Ethenolivinol)
A A A A B A A B
Glycerol (C3 H8 O3)
Glycerin
A A A A A A A B
Clycol (C2 H6 O2) A A A C A A A B
Mineral Oil A A A A A A A B
Benzene, Nitro (C6 H5 NO2)
(Essence of Mirbane)
A A A A A A A B

42
Gas / Air Tables
Temperature and Altitude Corrections
Temperature – Density* Altitude – Density**
Temp.
°F
Density
factor
Wt.
per
cu. ft.
Eleva-
tion
ft.
Air
density
lb./cu. ft.
Density
factor
0 1.1.52 0.0864 0 0.075 1.0
70 1.000 0.0749 500 0.0736 0.982
100 0.946 0.0709 1,000 0.0723 0.964
150 0.869 0.0651 1,500 0.0710 0.947
200 0.803 0.0602 2,000 0.0697 0.930
250 0.747 0.0560 2,500 0.0684 0.913
300 0.697 0.0522 3,000 0.0672 0.896
350 0.654 0.0490 3,500 0.0659 0.880
400 0.616 0.0462 4,000 0.0647 0.864
450 0.582 0.0436 4,500 0.0635 0.848
500 0.552 0.0414 5,000 0.0623 0.832
550 0.525 0.0393 5,500 0.0612 0.817
600 0.500 0.0375 6,000 0.0600 0.801
650 0.477 0.0358 6,500 0.0589 0.786
700 0.457 0.0342 7,000 0.0578 0.772
750 0.438 0.0328 7,500 0.0567 0.757
800 0.421 0.0315 8,000 0.0557 0.743
850 0.404 0.0303 8,500 0.0546 0.729
900 0.390 0.0292 9,000 0.0536 0.715
950 0.376 0.0282 9,500 0.0525 0.701
1,000 0.363 0.0272 10,000 0.0515 0.688
*Table based on 29.92 in. Hq.
**Dry air at 70°F.
Composition of Air
Component of Air Symbol Content - % Volume
Nitrogen
Oxygen
Argon
Carbon dioxide
N2
O2
Ar
CO2
78.084 percent
20.947 percent >99.998%
0.934 percent
0.033 percent
Neon Ne 18.2 parts/million
Helium He 5.2 parts/million
Krypton Kr 1.1 parts/million
Sulfur dioxide SO2 1.0 parts/million
Methane CH4 2.0 parts/million
Hydrogen H2 0.5 parts/millions
Nitrous oxide N2O 0.5 parts/million
Hydrogen H2 0.5 parts/million
Xenon Xe 0.09 parts/million
Ozone O3 0.0 to 0.07 parts/million
Ozone – Winter O3 0.0 to 0.02 parts/million
Nitrogen dioxide NO2 0.02 parts/million
Iodine I2 0.01 parts/million
Carbon monoxide CO 0.0 to trace
Ammonia NH3 0.0 to trace
The above table is an average for clean, dry air at sea level.
1 part/million = 0.0001 percent.

51
Type 9 – Class II, Indoor hazardous locations.
May be classified Groups E, F, or G, depending on specific design as defined in the National Electrical Code.
Type 10 – Mining Enforcement Safety Administration.
Explosion proof. For use in mines with atmospheric containing methane or natural gas, with or without coal
dust.
Type 11 – Corrosion Resistant & Drip-proof – oil immersed indoor.
Provide, by oil immersion, protection against the corrosive effects of liquids and gases.
Type 12 – Dust-tight and Drip-tight – Indoor.
Protects against dust, falling dirt and dripping non-corrosive liquids.
Type 12K – Same as Type 12 except enclosures have knockouts.
Type 13 – Oil tight and Dust-tight – Indoor.
Protects against dust, spraying of water, oil and non-corrosive coolant.
Horsepower Formulas
Air Horsepower = CFM X TP
6356
Brake Horsepower = CFM X TP
6356 X MEfan
Where MEfan = Mechanical Efficiency of Fan

52
NEMA Electric Motor Frames
NEMA Frame Dimension – InchesMotor
Frame D E F U V M + N Keyway
42 2-5/8 1-3/4 27/32 3/8 ... 4-1/32 ...
48 3 2-1/8 1-3/8 1/2 ... 5-3/8 ...
56 3-1/2 2-7/16 1-1/2 5/8 ... 6-1/8 3/16x3/32
66 4-1/8 2-15/16 2-1/2 3/4 ... 7-7/8 3/16x3/32
143T 3-1/2 2-3/4 2 7/8 2 6-1/2 3/16x3/32
145T 3-1/2 2-3/4 2-1/2 7/8 2 7 3/16x3/32
182 4-1/2 3-3/4 2-1/4 7/8 2 7-1/4 3/16x3/32
182 4-1/2 3-3/4 2-1/4 1-1/8 2-1/2 7-3/4 1/4x1/8
184 4-1/2 3-3/4 2-3/4 7/8 2 7-3/4 3/16x3/32
184T 4-1/2 3-3/4 2-3/4 1-1/8 2-1/2 6-1/4 1/4x1/8
213 5-1/4 4-1/4 2-3/4 1-1/8 2-3/4 9-1/4 1/4x1/8
213T 5-1/4 4-1/4 2-3/4 1-3/8 3-1/8 9-5/8 5/16x5/32
215 5-1/4 4-1/4 3-1/2 1-1/8 2-3/4 10 1/4x1/8
215T 5-1/4 4-1/4 3-1/2 1-3/8 3-1/8 10-3/8 5/16x5/32
254T 6-1/4 5 4-1/8 1-5/8 3-314 12-3/8 3/8x3/16
254U 6-1/4 5 4-1/8 1-3/8 3-1/2 12-1/8 5/16x5/32
256T 6-1/4 5 5 1-5/8 3-3/4 13-1/4 3/8x3/16
256U 6-1/4 5 5 1-3/8 3-1/2 13 5/16x5/32
284T 7 5-1/2 4-3/4 1-7/8 4-3/8 14-1/8 1/2x1/4
284TS 7 5-1/2 4-1/4 1-5/8 3 13-1/2 3/8x3/16
284U 7 5-1/2 4-3/4 1-5/8 4-518 14-2/8 3/8x3/16
286T 7 5-1/2 5-1/2 1-7/8 4-318 14-7/8 1/2x1/4
286U 7 5-1/2 5-1/2 1-5/8 4-5/8 15-1/8 3/8x3/16
324T 8 6-1/4 5-1/4 2-1/8 5 15-3/4 1/2x1/4
324U 8 6-1/4 5-1/4 1-7/8 5-3/8 16-1/8 1/2x1/4
326T 8 6-1/4 6 2-1/8 5 16-1/2 1/2x1/4
326TS 8 6-1/4 6 1-7/8 3-1/2 15 1/2x1/4
326U 8 8-1/4 6 1-7/8 5-3/8 16-7/8 1/2x1/4
364T 9 7 5-5/8 2-3/8 5-5/8 17-3/8 5/8x5/16
364U 9 7 5-5/8 2-1/8 6-1/8 17-7/8 1/2x1/4
365T 9 7 6-1/8 2-318 5-518 17-7/8 5/8x5/16
365U 9 7 6-1/8 2-1/8 6-1/8 1-3/8 1/2x1/4
404T 10 8 6-1/8 2-7/8 7 20 3/4x3/8
404U 10 8 6-1/8 2-3/8 6-7/8 19-7/8 5/8x5/16
405T 10 8 6-7/8 2-7/8 7 20-3/4 3/4x3/8
405U 10 8 6-7/8 2-3/8 6-7/8 20-5/8 5/8x5/16
444T 11 9 7-1/4 3-3/8 8-1/4 23-1/4 7/8x7/16
444U 11 9 7-1/4 2-7/8 8-3/8 23-3/8 3/4x3/8
445T 11 9 8-1/4 3-3/8 8-1/4 24-1/4 7/8x7/16
445U 11 9 8-1/4 2-7/8 8-3/8 24-318 3/4x3/8
The above standards were established by the National Electrical Manufacturers Association (NEMA)

53
NEMA Electric Motor Frames
Frame dimensions for previous page
F F
M + N
V
U
E E
D

54
Industrial Ventilation References

55
Circular equivalents of rectangular ducts for equal friction
Sides 2 2 1/2 3 3 1/2 4 4 1/2 5 5 1/2 6 7 8 9 10 11 12 13 14 15 16 17
4 3.04 3.42 3.77 4.09 4.37 4.63 4.88 5.10
5 3.37 3.81 4.18 4.55 4.88 5.18 5.45 5.73
6 3.65 4.17 4.55 4.96 5.32 5.65 5.97 6.27 6.55
7 3.90 4.43 4.91 5.34 5.72 6.08 6.42 6.75 7.07 7.63
8 4.12 4.71 5.20 5.67 6.08 6.47 6.85 7.21 7.54 8.17 8.72
9 4.34 4.97 5.48 5.96 6.42 6.84 7.25 7.62 8.00 8.66 9.25 9.81
10 4.54 5.21 5.74 6.24 6.74 7.17 7.60 7.99 8.37 9.09 9.76 10.3 10.9
11 4.72 5.40 5.98 6.51 7.02 7.49 7.93 8.34 8.74 9.50 10.2 10.8 11.4 12.0
12 4.90 5.58 6.22 6.75 7.29 7.79 8.25 8.69 9.10 9.90 10.6 11.3 11.9 12.5 13.1
13 5.06 5.76 6.42 6.98 7.56 8.08 8.56 9.02 9.46 10.3 11.0 11.8 12.4 13.0 13.6 14.2
14 5.21 5.94 6.61 7.21 7.80 8.34 8.85 9.33 9.81 10.7 11.4 12.2 12.8 13.5 14.1 14.7 15.3
15 5.36 6.11 6.80 7.43 8.02 8.58 9.11 9.62 10.1 11.0 11.8 12.6 13.3 14.0 14.6 15.2 15.8 16.4
16 5.51 6.28 6.98 7.64 8.24 8.82 9.37 9.90 10.4 11.3 12.2 13.0 13.7 14.4 15.1 15.7 16.3 16.9 17.5
17 5.64 6.44 7.16 7.83 8.46 9.06 9.62 10.1 10.7 11.6 12.5 13.3 14.1 14.8 15.5 16.2 16.8 17.4 18.0 18.6
18 5.76 6.58 7.33 8.03 8.68 9.30 9.85 10.4 10.9 11.9 12.8 13.7 14.5 15.2 15.9 16.6 17.3 17.9 18.5 19.1
20 6.01 6.86 7.65 8.38 9.06 9.70 10.3 10.9 11.5 12.5 13.5 14.4 15.2 16.0 16.7 17.5 18.2 18.9 19.5 20.2
22 6.25 7.12 7.95 8.71 9.44 10.1 10.9 11.4 12.0 13.0 14.0 15.0 15.9 16.7 17.5 18.3 19.0 19.7 20.4 21.1
24 6.44 7.38 8.25 9.04 9.77 10.5 11.1 11.8 12.4 13.5 14.6 15.6 16.5 17.4 18.3 19.1 19.8 20.5 21.3 22.0
26 6.66 7.63 8.53 9.33 10.1 10.9 11.5 12.2 12.8 14.0 15.1 16.1 17.1 18.1 18.9 19.8 20.6 21.3 22.1 22.8
28 6.86 7.87 8.79 9.63 10.4 11.2 11.9 12.6 13.2 14.4 15.6 16.7 17.7 18.7 19.6 20.5 21.3 22.1 22.9 23.6
30 7.04 8.07 9.03 9.87 10.7 11.5 12.2 13.0 13.6 14.9 16.0 17.2 18.3 19.3 20.2 21.1 22.0 22.8 23.6 24.4
32 7.22 8.27 9.25 10.2 11.0 11.8 12.5 13.3 14.0 15.3 16.4 17.7 18.7 19.8 20.8 21.7 22.6 23.5 24.3 25.2
34 7.40 8.47 9.46 10.4 11.2 12.1 12.8 13.6 14.4 15.7 16.9 18.2 19.2 20.3 21.4 22.3 23.2 24.1 25.0 25.9
36 7.58 8.66 9.67 10.6 11.5 12.3 13.1 13.9 14.7 16.1 17.4 18.6 19.7 20.8 21.9 22.9 23.8 24.7 25.7 26.7
38 7.75 8.85 9.88 10.9 11.7 12.6 13.4 14.2 15.0 16.5 17.8 19.0 20.2 21.3 22.5 23.5 24.4 25.3 26.3 27.3
40 7.89 9.04 10.1 11.1 12.0 12.9 13.7 14.5 15.3 16.8 18.1 19.4 20.6 21.8 23.0 24.0 25.0 25.8 26.9 27.9
42 8.03 9.22 10.3 11.3 12.3 13.2 14.0 14.8 15.6 17.1 18.5 19.8 21.0 22.3 23.5 24.5 25.5 26.5 27.5 28.5
44 8.17 9.39 10.5 11.5 12.5 13.4 14.3 15.1 15.9 17.4 18.6 20.2 21.4 22.7 24.0 25.0 26.0 27.0 28.0 29.0
46 8.31 9.55 10.7 11.7 12.7 13.7 14.5 15.4 16.2 17.8 19.2 20.6 21.8 23.1 24.4 25.5 26.4 27.7 28.6 29.6
48 8.45 9.72 10.8 11.9 12.9 13.9 14.8 15.7 16.5 18.1 19.5 21.0 22.2 23.5 24.8 26.0 26.8 28.3 29.2 30.2
50 8.59 9.86 11.0 12.1 13.1 14.1 15.0 16.0 16.8 18.4 19.9 21.3 22.6 23.9 25.2 26.4 27.2 28.9 29.8 30.8
52 8.73 10.0 11.2 12.3 13.3 14.3 15.3 16.2 17.1 18.7 20.2 21.6 23.0 24.3 25.6 26.8 27.7 29.5 30.4 31.2
54 8.87 10.2 11.4 12.5 13.5 14.5 15.5 16.5 17.3 19.0 20.5 22.0 23.4 27.7 26.0 27.3 28.2 29.9 30.9 31.8
56 8.99 10.3 11.6 12.7 13.7 14.7 15.7 16.7 17.6 19.3 20.8 22.3 23.8 25.1 26.4 27.7 28.7 30.2 31.3 32.3
58 9.10 10.5 11.8 12.9 13.9 14.9 15.9 16.9 17.8 19.5 21.1 22.6 24.1 25.5 26.8 28.1 29.3 30.5 31.7 32.8

56
Velocity pressures for different velocities: standard air
Design procedure
Dry air at 70°F, 29.92” barometer, and less than 20” WC static pressure.
____
From: V = 4,005√ VP = Velocity FPM.
VP = Velocity pressure, inches of water
V VP V VP V VP
4,200 1.10 4,856 1.47 5,433 1.84
4,219 1.11 4,873 1.48 5,447 1.85
4,238 1.12 4,889 1.49 5,462 1.86
4,257 1.13 4,905 1.50 5,477 1.87
4,276 1.14 4,921 1.51 5,491 1.88
4,295 1.15 4,938 1.52 5,506 1.89
4,314 1.16 4,954 1.53 5,521 1.90
4,332 1.17 4,970 1.54 5,535 1.91
4,350 1.18 4,986 1.55 5,550 1.92
4,368 1.19 5,002 1.56 5,564 1.93
4,386 1.20 5,018 1.57 5,579 1.94
4,405 1.21 5,034 1.58 5,593 1.95
5,608 1.96 6,113 2.33 8,496 4.50
5,623 1.97 6,128 2.34 8,590 4.60
5,637 1.98 6,140 2.35 8,683 4.70
5,651 1.99 6,153 2.36 8,774 4.80
5,664 2.00 6,166 2.37 8,865 4.90
5,678 2.01 6,179 2.38 8,955 5.00
5,692 2.02 6,192 2.39 9,044 5.10
5,706 2.03 6,205 2.40 9,133 5.20
5,720 2.04 6,217 2.41 9,220 5.30
5,734 2.05 6,230 2.42 9,307 5.40
5,748 2.06 6,243 2.43 9,392 5.50
5,762 2.07 6,256 2.44 9,477 5.60
5,776 2.08 6,269 2.45 9,562 5.70
5,790 2.09 6,282 2.46 9,645 5.80
5,804 2.10 6,294 2.47 9,728 5.90
5,817 2.11 6,307 2.48 9,810 6.00
5,831 2.12 6,320 2.49 9,891 6.10
5,845 2.13 6,332 2.50 9,972 6.20
5,859 2.14 6,458 2.60 10,052 6.30
5,872 2.15 6,581 2.70 10,132 6.40
5,886 2.16 6,702 2.80 10,210 6.50
5,899 2.17 6,820 2.90 10,289 6.60
5,913 2.18 6,937 3.00 10,366 6.70
5,927 2.19 7,051 3.10 10,444 6.80
5,940 2.20 7,164 3.20 10,520 6.90
5,954 2.21 7,275 3.30 10,596 7.00
5,967 2.22 7,385 3.40 10,968 7.50
5,981 2.23 7,492 3.50 11,328 8.00
5,994 2.24 7,599 3.60 11,676 8.50
6,008 2.25 7,704 3.70 12,015 9.00
6,021 2.26 7,807 3.80 12,344 9.50
6,034 2.27 7,909 3.90 12,665 10.00
6,047 2.28 8,010 4.00 13,283 11.00
6,061 2.29 8,109 4.10 13,874 12.00
6,074 2.30 8,208 4.20 14,440 13.00
6,087 2.31 8,305 4.30 14,775 13.61
6,100 2.32 8,401 4.40 14,986 14.00
V VP V VP V VP
400 0.01 2,157 0.29 3,024 0.57
566 0.02 2,193 0.30 3,050 0.58
694 0.03 2,230 0.31 3,076 0.59
601 0.04 2,261 0.32 3,102 0.60
896 0.05 2,301 0.33 3,127 0.61
981 0.06 2,335 0.34 3,153 0.62
1,060 0.07 2,369 0.35 3,179 0.63
1,133 0.08 2,403 0.36 3,204 0.64
1,201 0.09 2,436 0.37 3,229 0.65
1,266 0.10 2,469 0.38 3,254 0.66
1,328 0.11 2,501 0.39 3,279 0.67
1,387 0.12 2,533 0.40 3,303 0.68
1,444 0.13 2,563 0.41 3,327 0.69
1,498 0.14 2,595 0.42 3,351 0.70
1,551 0.15 2,626 0.43 3,375 0.71
1,602 0.16 2,656 0.44 3,398 0.72
1,651 0.17 2,687 0.45 3,422 0.73
1,699 0.18 2,716 0.46 3,445 0.74
1,746 0.19 2,746 0.47 3,468 0.75
1,791 0.20 2,775 0.48 3,491 0.76
1,835 0.21 2,804 0.49 3,514 0.77
1,879 0.22 2,832 0.50 3,537 0.78
1,921 0.23 2,860 0.51 3,560 0.79
1,962 0.24 2,888 0.52 3,582 0.80
2,003 0.25 2,916 0.53 3,604 0.81
2,042 0.26 2,943 0.54 3,625 0.82
2,081 0.27 2,970 0.55 3,657 0.83
2,119 0.28 2,997 0.56 3,669 0.84
3,690 0.85 4,423 1.22 5,050 1.59
3,709 0.86 4,442 1.23 5,066 1.60
3,729 0.87 4,460 1.24 5,082 1.61
3,758 0.88 4,478 1.25 5,098 1.62
3,779 0.89 4,495 1.26 5,114 1.63
3,800 0.90 4,513 1.27 5,129 1.64
3,821 0.91 4,531 1.28 5,144 1.65
3,842 0.92 4,549 1.29 5,160 1.66
3,863 0.93 4,566 1.30 5,175 1.67
3,884 0.94 4,583 1.31 5,191 1.68
3,904 0.95 4,601 1.32 5,206 1.69
3,924 0.96 4,619 1.33 5,222 1.70
3,945 0.97 4,636 1.34 5,237 1.71
3,965 0.98 4,653 1.35 5,253 1.72
3,985 0.99 4,671 1.36 5,268 1.73
4,005 1.00 4,688 1.37 5,283 1.74
4,025 1.01 4,705 1.38 5,298 1.75
4,045 1.02 4,722 1.39 5,313 1.76
4,064 1.03 4,739 1.40 5,328 1.77
4,081 1.04 4,756 1.41 5,343 1.78
4,103 1.05 4,773 1.42 5,359 1.79
4,123 1.06 4,790 1.43 5,374 1.80
4,142 1.07 4,806 1.44 5,388 1.81
4,162 1.08 4,823 1.45 5,403 1.82
4,181 1.09 4,840 1.46 5,418 1.83

57
Weights of galvanized sheet metal ducts
Straight runs Elbow
Weight per linear foot
Equiv.
length
in feet
Gauge size
Two
gauges
heavier than
duct
Duct
dia.
26 24 22 20 18 16 14 12
4 1.13 1.47 1.69 1.97 2.59 3.10 3.76 5.20 1.20
5 1.39 1.80 2.08 2.43 3.19 3.82 4.65 6.41 1.83
6 1.65 2.14 2.47 2.89 3.80 4.54 5.53 7.62 1.62
7 1.91 2.48 2.86 3.34 4.39 5.25 6.38 8.80 1.75
8 2.18 2.83 3.27 3.81 5.01 5.99 7.28 10.05 2.00
9 2.44 3.17 3.66 4.27 5.61 6.71 8.15 11.25 2.17
10 2.70 3.51 4.05 4.72 6.21 7.42 9.02 12.45 2.41
11 2.96 3.85 4.44 5.18 6.80 8.15 9.90 13.66 2.57
12 3.22 4.18 4.83 5.63 7.40 8.85 10.78 14.85 2.80
13 3.48 4.52 5.22 6.09 8.00 9.57 11.63 16.10 2.96
14 3.74 4.86 5.61 6.54 8.60 10.30 12.50 17.25 3.20
15 4.01 5.21 6.01 7.01 9.22 10.86 13.40 18.50 3.40
16 4.27 5.55 6.40 7.47 9.82 11.74 14.28 19.70 3.56
18 4.87 6.33 7.30 8.51 11.18 13.36 16.30 22.40 3.98
20 5.40 7.02 8.10 9.45 12.42 14.85 18.10 24.90 4.27
22 5.92 7.70 8.88 10.35 13.60 16.25 19.80 27.30 4.66
24 6.45 8.38 9.67 11.30 14.84 17.71 21.30 29.80 5.05
26 6.97 9.05 10.45 12.20 16.00 19.15 23.20 32.20 5.43
28 7.50 9.75 11.27 13.13 17.26 20.60 25.00 34.60 5.77
30 8.10 10.54 12.17 14.20 18.62 22.25 27.00 37.40 6.13
32 8.62 11.20 12.93 15.10 19.84 23.70 28.80 39.80 6.50
34 9.15 11.90 13.73 16.00 21.08 25.18 30.60 42.30 7.00
36 9.67 12.57 14.50 16.91 22.22 26.60 32.30 44.60 7.43
38 10.19 13.25 15.29 17.81 23.40 28.00 34.00 47.00 7.87
40 10.72 13.95 16.08 18.76 24.68 29.50 35.80 49.50 8.44
Lbs
Sq.
Ft.
0.90 1.30 1.50 1.75 2.30 2.70 3.28 4.53

58
Duct Data Chart
Area CFM at
Duct
Dia
Inches
Sq.
In.
Sq.
Ft.
Cir
In
Ft.
3500
FPM
Vel.
4000
FPM
Vel.
4500
FPM
Vel.
5000
FPM
Vel.
4 12.56 .087 1.05 304 348 391 435
5 19.63 .136 1.31 476 544 612 680
6 28.27 .196 1.57 686 784 882 980
7 38.48 .367 1.83 934 1066 1201 1335
8 50.26 .349 2.09 1221 1396 1570 1745
9 63.61 .442 2.35 1547 1768 1989 2210
10 78.54 .545 2.61 1910 2180 2450 2730
12 113.1 .785 3.41 2750 3140 3530 3920
14 153.9 1.06 3.66 3610 4240 4770 5300
16 201.1 1.39 4.19 4860 5560 6250 6950
18 245.5 1.76 4.70 6160 7040 7920 8800
20 314.2 2.18 5.23 7630 8720 9810 10900
22 380.1 2.64 5.75 9240 10560 11880 13200
24 452.4 3.14 6.28 10990 12560 14130 15700
26 530.9 3.68 6.80 12880 14720 16560 18400
28 615.8 4.27 7.33 14950 17080 19215 21350
30 706.9 4.91 7.85 17180 19640 22090 24550
32 804.2 5.58 8.38 19530 22320 25110 27900
34 907.9 6.30 8.90 22050 25200 28350 31500
36 1017.9 7.07 9.42 24740 28380 31810 35350
38 1134.1 7.88 9.95 27560 31500 35440 39380
40 1256.6 8.73 10.47 30545 34905 39270 43630
42 1385.4 9.62 11.00 33675 38485 43295 48105
44 1520.5 10.56 11.52 36960 42235 47515 52795
46 1661.9 11.54 12.04 40395 46165 51935 57705
48 1809.6 12.57 12.57 43980 50265 56550 62830
50 1963.5 13.64 13.09 47225 54540 61360 68175
52 2123.7 14.75 13.61 51620 58990 66365 73740
54 2290.2 15.90 14.14 55665 63620 71570 79520
56 2463.0 17.10 14.66 59865 68415 76970 85520
58 2642.1 18.35 15.18 64220 73390 82565 91740
60 2827.4 19.63 15.71 68720 78540 88360 98175

59
Material Properties
Weights and specific heats of material mean values
Material
Density
lb. per. cu. ft.
Specific heat
Btu per lb.
per deg. F.
Air .0749 0.24
Aluminum 165 0.22
Aluminum chips 48
Antimony 414 0.05
Asbestos 153 0.20
Asbestos, loose 64
Ashes, coal, dry 40 .20
Ashes, wood, dry 47
Bakelite, laminated 86 0.35
wood filler 85 0.33
asbestos filler 118 0.38
crushed 43
Baking powder 56
Bauxite, dry, crushed 43
Bone, dry, ground 75
Borax 109 0.38
Borax, dry, crushed 75
Brass 530 0.09
Brass chips 163
Brick, masonry 118 0.22
Bronze 509 0.09
Bronze, phosphor 554 0.09
Calcium, carbonate 177 0.19
Calcium chloride 134 0.16
Calcium sulphate 185 0.17
Carbide, dry, crushed 50
Carbonundum 195 0.16
Carbonundum, loose 140
Caustic soda 88
Celluloid 90 0.36
Cellulose 94 0.37
Cement, loose 94 0.20
Cereals, bulk barley,
corn
37
oats 26
rye, wheat 48
Chalk 142 0.21
Charcoal,
hard-wood 34 0.20
softwood 23 0.20
broken 12
Cinders 43 0.18

60
Weights and specific heats of material mean values (cont’d)
Material
Density
lb. per. cu. ft.
Specific heat
Btu per lb.
per deg. F.
Clay, loose, dry 63 0.22
moist 110 0.55
Coal, anthracite 98 0.31
anthracite, piled 54
bituminous 85 0.30
bituminous, piled 47
Coffee 48
Coke 75 0.20
Coke, piled 28
Coke, dry, crushed 15
Concrete, cinder 97 0.18
stone 142 0.19
Copper 556 0.09
Copper ore, crushed 190
Copper oxide 190
Cork 15 0.48
Corn meal 40
Conundum, alundum 247 0.20
Cotton, baled 93 0.32
loose 30 0.32
Dolomite 181
Duralumin 175 0.23
Earth, dry and loose 76
Earth, moist and loose 78 0.44
Emery 250
Feldspar 160 0.20
Feldspar, crushed 88
Ferrous, grind dust 125
Flour, compressed
barreled 47
loose 28
Fullers earth, dry 30
Glass, crown 160 0.16
Glass, flint 215 0.13
pyrex 140 0.20
ground 90
Granite 165 0.19
loose, piled 96
Graphite 132 0.20
Gravel, loose, plied 120
Grit blast dust 160
Gypsum
compressed 152 0.26
loose 70
Iron, gray cast 442 0.12

61
Material
Density
lb. per. cu. ft.
Specific heat
Btu per lb.
per deg. F.
Iron ore, loose 150
Lead 710 0.03
Lead oxide (red) 567 0.06
Leather 56 0.36
Lime 53-64
Limestone 163 0.22
Lucite 74
Magnesia 214 0.22
Magnesium 109 0.25
Magnesium dust 30
Manganese ore,
crushed
259
Mica 183 0.21
Monel metal 556 0.13
Natural gas 0.04475 0.526
Nickel 547 0.11
Nylon 70 0.55
Paper 58 0.32
Strawboard or
newspaper
33-44
Paraffin 56 0.69
Peat, dry 30
Phosphate, ground 75
Porcelain 150 0.26
Potash 60
Quartz 165 0.21
Quartz, ground 84
Resin 67
Rubber, India 58 0.48
compound 115
hard 75 0.33
hard sponge 30 0.40
tire reclaim, solid 74
tire reclaim, shred 27
Salt, gran, and piled 48 0.21
Saltpeter 80
Sand, dry, loose 99 0.20
Sand, wet 110
Sandstone 144 0.22
Sandstone, crushed 82
Sawdust 7-15
Shale, riprap 105
Shavings, planer 7-15 0.52
Slag, Iron 172
Slag, granulated 60

62
Material
Density
lb. per. cu. ft.
Specific heat
Btu per lb.
per deg. F.
Slate 172
Soda ash 74
Soda ash, granulated 30
Sodium carbonate 91 0.27
Sodium nitrate 141 0.28
Sodium sulphate 167 0.21
Starch 95
granulated 35
Steel 487 0.12
Sucrose 100 0.30
Sugar, bulk 55 0.28
Sulphur 126 0.17
Sulphur, crushed 50
Talc 170 0.21
Tar, bituminous 69 0.40
Tile 113 0.15
Tin 457 0.05
Tobacco 16
Water 62.4 1.0
Zinc 443 0.09
Zinc oxide 350 0.12

63
0.0001 0.0005 0.001 0.005 0.01 0.05 0.1 0.5 1 5 10 50 100 500 1,000 5,000 10,000
RAIN DROPS
SAND TAILINGS
MIST
GROUND LIMESTONE
POLLENS
FLOUR MILL DUST
FOUNDRY DUST
ASPHALT PAVING
INSECTICIDE DUST PLANT DUST
SEA FOG
SPRAY
DRIED MILK
PLANT
SPORES
CEMENT DUST
SOOT BLOWING – BOILER TUBES
BACTERIA
PARTICLE CHART
PARTICLE SIZE - MICRONS

64
0.0001 0.0005 0.001 0.005 0.01 0.05 0.1 0.5 1 5 10 50 100 500 1,000 5,000 10,000
PARTICLE CHART
PARTICLE SIZE - MICRONS
FERTILIZER PLANT
DUST & FUMES
SMELTER DUST & FUMES
SULPHURIC ACID DUST & FUMES
PAINT PIGMENTS
COAL SMOKE
OIL SMOKE PULVERIZED FUEL ASH
ATMOSPHERIC DUST
RESIN SMOKE
TOBACCO SMOKE
MAGNESIUM
OXIDE SMOKE
CONDEN-
SATION
NUCLEI
OPEN HEARTH
STEEL FURNACE FUMES
CARBON BLACK
VISIBLE TO EYE

65
ABRASION CHARACTERISTICS OF VARIOUS DUSTS
Alfafa meal N
Almonds, broken or whole N
Alum N
Alumina VA
Aluminum M
Ammonium chloride, crystalline M
Antimony VA
Apple pomace, dry N
Asbestos, shred M
Ashes, Hard Coal VA
Ashes, Soft Coal VA
Asphalt, crushed VA
Ammonium sulphate M
Bagasse M
Bakelite, powdered N
Baking powder N
Barley N
Bauxite, crushed VA
Beans, -meal etc. N
Bentonite A
Bicarbonate of Soda N
Bonemeal M
Bones, crushed, minus 1/2” M
Bones, granulated or ground, minus 1/8” M
Boneblack M
Bonechar M
Borax, powdered VA
Bran N
Brass M
Brewers grain, spent, dry N
Brick A
Buckwheat N
Calcium carbide A
Calcium carbonate A
Carbon, amorphous, graphitic M
Carbon black powder, channel M
Carbon black powder, furnace M
Carborundum VA
Casein M
Cast Iron, borings VA
Cast Iron VA
Caustic Soda M
CODE: VA – very abrasive A – abrasive
M – mildly abrasive N – less abrasive

66
Cellulose M
Cement, Portland VA
Cement, clinker VA
Chalk, crushed A
Chalk, pulverized, minus 100 mesh A
Charcoal N
Cinders, coal A
Clay, dry A
Clover seed N
Coal, bituminous A
Coal, anthracite A
Cocoa, powdered N
Cocoa beans N
Coconut, shredded N
Coffee N
Coke, bituminous A
Coke, petroleum A
Copper VA
Copra (dried coconut) N
Cork, fine ground M
Corn, cracked, shelled etc. N
Cornmeal N
Cottonseed N
Cullet (broken glass) A
Dicalcium phosphate M
Dolomite A
Ebonite, crushed N
Egg powder N
Epsom salts M
Feldspar A
Ferrous sulphate A
Fish meal N
Flaxseed N
Flour N
Flue dust, dry M
Fluorspar A
Fly ash VA
Fullers earth A
Gelatine, granulated N
Glass batch VA
Glue, ground M
Gluten mean N

67
Grains, distillery, dry N
Graphite A
Grass seed A
Gypsum N
Hops, dry N
Ice, crushed N
Ilmenite ore VA
Iron Cast VA
Iron Oxide VA
Lead A
Lead Arsenate A
Lead oxide A
Lignite A
Lime, ground VA
Lime, hydrated A
Limestone VA
Litharge A
Lucite A
Magnesite VA
Magnesium VA
Magnesium chloride A
Malt, dry N
Manganese sulphate A
Maple, hard N
Marble A
Marl A
Mica, ground M
Milk, dried, malted, powdered N
Monel metal M
Muriate or potash M
Mustard seed N
Naphthalene flakes N
Nickel VA
Oats N
Oak N
Orange peel, dry N
Oxalic acid crystals N
Peanuts N
Peas, dried N
Peas N
Phosphate rock VA
Phosphate sand VA

68
Pine N
Porcelain M
Quartz VA
Resin M
Rice N
Rubber, ground N
Rubber, hard N
Rubber, soft N
Rye N
Salt, rock A
Salt, dry, coarse A
Salt, dry, pulverized A
Saltpeter N
Sand VA
Sandstone VA
Sawdust N
Shale, crushed A
Slag, furnace, granulated VA
Slate A
Soap, chips, flakes N
Soap powder N
Soapstone talc M
Soda ash, light M
Soda ash, heavy M
Sodium Nitrate A
Sodium Phosphate A
Soybeans, meal and whole N
Starch N
Steel A
Steel chips, crushed A
Sugar N
Sugar beet pulp, dry N
Sulphur N
Talc M
Tanbark, ground M
Timothy seed N
Tin A
Titanium VA
Tobacco N
Vermiculite ore A
Wheat N
White lead A
Zinc Oxide A

69
Ignitability and Explosibility of Dust Clouds (Ref 2 & 3)
Particle Size DistributionCotton
Wood
Peat Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Dust Type 500 250 125 71 63 32 20 µm bar•m/s Class
Cotton 98 72 38 25 44 24 St. 1
Cellulose 92 71 20 3 51 66
Wood dust 90 47 7 33
Wood dust 58 57 55 43 39 80
Wood dust,
(Chipboard) 70 30 43 102 St. 2
Wood/
cardboard/jute 26
Wood/card-
board/jute/resin
Lignin dust 96 85 66 57 18 208
Paper dust 91 83 73 <10 18
Paper tissue
dust 75 58 54 52 (St. 2)
Paper ( henol-
resin treated) 100 90 25 23 190
Peat
(15% moisture) 84 58 26 3 58 157 St. 1
Peat
(22% moisture) 82 65 40 15 46 69 St. 1
Peat
(31% moisture) 87 76 43 20 38 64
Peat
(41% moisture) 88 76 40 18 39
Peat (from
bottom of sieve) 78 48 22 74 51 St. 1
Peat
(dust deposit) 66 33 11 49 144 St. 1
Paper 93 76 29 168
Particle Size Distribution
Food
Feed Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Gravy powder
(21% starch) 100 12
Citrus pellets 100 39
Dextrose,
ground 100 94 71 22 St. 2
Dextrose 38 5 4 80 18 St. 1
Fat/whey
mixture 76 11 3 330 23
Fat powder
(48% fat) 100 75 24 7 92 20 St. 2
Do. 100
Fish meal 68 23 12 320 35
Fructose
(from filter) 99 39 17 150 102
Fructose 92 15 200 28

70
Food
Med-
ian
Explos.
KSt < 63 µm
Fructose 81 400 27
Barley
grain dust 79 51 25 8 3 240
Do. 100 83
Oats grain dust 64 24 8 295 14 St. 1
Wheat
grain dust 48 30 80 112 St. 1
Wheat
grain dust 100 81 50 32 25 125 St. 2
Coffee
(from filter) 100 99 89 <10 90
Coffee (refined) 100 11
Cocoa bean
shell dust 100 68
Cocoa/sugar
mixture 53 20 500 43 St. 1
Potato granulate 100 21
Potato flour 86 53 26 17 65 69
Lactose
(from filter) 83 60 47 22 29
Lactose
(from cyclone) 97 70 41 23 81 St. 2
Maize seed waste
(9% moisture) 98 67 40 23 16 165 117
Milk powder 34 18 165 90
Milk powder 98 15 8 235 75
Milk powder (low
fat spray dried) 100 100 99 60 17 46 109
Milk powder (full
fat spray dried) 30 88 83 St. 1
Whey
fat emulator 62 7 2 400 38
Olive pellets 100 74
Rice flour 100 57
Rye flour 94 76 58 15 29 79
Soy bean flour 85 63 50 20 110 St. 1
Potato starch 100 43
Potato starch 100 50 17 32 (89)
Maize starch 99 98 94 <10 128
Maize starch 94 81 60 16 158 St. 1
Rice starch
(hydrolyzed) 29 15 120 190 (St. 2)
Rice starch 99 74 54 18
Rice starch 86 62 52 18 190 (St. 2)
Wheat starch 84 50 20 132 (St. 2)
Tobacco 81 64 29 49 12
Tapioca pellets 61 42 44 53 St. 1

71
Food
Med-
ian
Explos.
KSt < 63 µm
Tea
(6% moisture) 100 68
Tea (black from
dust collector) 64 48 26 16 76 59 St. 1
Meat flour 69 52 31 21 62 106 St. 1
Wheat flour 50
Wheat flour 97 60 32 25 57 87
Wheat flour 550 60 34 25 56 42
Milk sugar 99 92 77 10 75
Milk sugar 98 64 32 27 82 St. 1
Sugar (Icing) 88 70 52 19
Particle Size DistributionCoal
Coal
products Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Activated Carbon 99 80 55 18 44
Activated Carbon 88 64 22 No Ignition
Activated Carbon
(16% moisture) 84 65 38 46 67
Brown coal 83 69 40 20 41 123
Brown coal (from
electrostatic filter) 75 60 27 55 143 St. 1
Brown coal (dust
from grinding) 71 56 38 30 60 107
Brown coal/
anthracite (80-20) 66 43 24 40 108
Brown coal/
anthracite (20-80) 91 85 80 <10 1
Brown coal coke 93 18 13 290 115 St. 1
Brown coal
(graphitized) 82 55 35 28 No Ignition
Charcoal 99 88 67 14 10 St. 1
Charcoal 95 85 58 19 117
Charcoal 36 >500 No Ignition
Asphalt 83 54 32 29 117
Bituminous coal 97 93 85 <10 55
Bituminous coal
(Petchora) 76 65 46 37 38 86
Bituminous coal
(high volat.) 99 4 59

72
Particle Size DistributionOther
natural
organic
Med-
ian
Explos.
KSt < 63 µm
Cotton seed
expellers 66 24 10 245 35 St. 1
Dextrin 57 26 5 55 109 St. 1
Wheat gluten
(after mill) 78 28 13 48 105
Blood flour 93 61 27 5 57 85
Hops, malted 52 14 9 490 90
Leather dust
(from collector) St. 2
Linen
(containing oil) 63 21 300 17
Lycopodium 100 91
Oil shale dust 99 79 50 20 35
Oil shale dust 71 50 39 32 No Ignition
Grass dust 96 26 200 47
Walnut shell
powder St. 1
Particle Size DistributionPlastics
Resins
Rubber Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Acryinitrate-
Butadiene-
Styrene-
Co-polym. 79 37 24 200 147 (St. 2)
Epoxy Resin (or
powder coating) 100 82 58 28 55 147 (St. 2)
Cellulose-2
5-Acetate 100 89 53 19 180
Polyester resin
with glass 92 91 89 80 72 14 (St. 2)
Rubber (dust
from grinding) 78 43 12 80 138
Resin (from
filter) 97 44 40 108
Epoxy resin
60% resin +
36% TO2 99 67 43 23 155
Epoxy resin 95 60 36 26 129 St. 1
Epoxy resin
with Al 90 46 34 208
Melamin resin 99 84 55 18 110 St. 1
Melamin resin 66 24 13 57 172 St. 1
Phenol resin 100 99 94 <10 129 (St. 2)
Phenol Formal-
dehyde resin) 100 98 81 50 30 60 St. 1
Polyamid resin 95 84 64 15 105

73
Particle Size DistributionPlastics
Resins
Rubber Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Polymethacrylate 56 100 33 199
Silicon resin 91 59 39 20 13 100 80
Caoutohouc 58 40 20 95 192
Polystyrene
(Copolymer) 32 11 155 110
Polystyrene
(Hard-foam) 30 10 5 760 23
Polyurethane 100 90 3 (156)
Polyvinylacetate
(Copolymer) 83 50 20 86 St. 1
Polyvinylalcohol 74 55 44 26 128 (St. 2)
Polyvinylalcohol 57 29 9 56 83 St. 1
Polyvinylchloride 100 <10 168
Polyvinylchloride 46 15 125 68
Polyvinylchloride
(Em., 97.5% PVC) 97 73 26 25 42
Polyvinylchloride
(Em., 97% PVC) 60 31 14 51 63
Polyvinylchloride
(Susp.) 66 23 105 45 St. 1
Polyvinylchloride
(Susp.) 30 137 No Ignition
Urea-
formaldehyde
(mold.-form) 99 91 75 13 136 St. 1
Melamine-
formaldehyde
(mold.-form) 93 86 70 14 189 St. 1
El. stat. coating
powder (Epoxy) 100 70 29 100 (St. 2)
El. stat. coating
powder
(Polyurethane) 100 66 22 29 89 St. 1
Shellac 100 33 144 (St. 2)
Wax
(NN Ethylene
distearmide) 100 95 10 269 (St. 2)
Particle Size DistributionPharmaceutical
Cosmetics
Pesticide Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Acetyl salicylic
acid 100 217 (St. 2)
Amino
phenazone 100 98 <10 238
Ascorbic acid.
L(+)- 93 75 61 14 48 (St. 2)
Ascorbic acid 92 38 15 39 111 (St. 2)

74
Particle Size DistributionPharmaceutical
Cosmetics
Pesticide Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Coffein 100 165 (St. 2)
Cysteine hydrate 100 98 94 <10 40
L-Crystin 100 95 69 15 142
Digitalis leaves 59 42 46 73
Dimethylamino-
phenazone 100 <10 337
2-Ethoxybenza-
mide 100 214 (St. 2)
Fungicide
(Captan) 100 99 93 5 St. 1
Fungicide (Org.
zinc comp.) 99 96 <10 154
Fungecide
(Maneb) 98 97 93 <10
Methionine 100 99 95 <10 143
Methionine 100 98 87 <10 128
Sodium –
L(+) ascorbate 97 67 45 23 119 St. 1
Paracetamole 100 156 (St. 2)
Pesticide 99 98 98 <10 151
Particle Size DistributionIntermediate
products
Auxiliary
Materials Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Adipinic acid 98 92 <10 97 (St. 2)
Aging protective 100 67 <32 256 (St. 2)
Anthracene 89 20 7 235 231
Anthrachinone 100 <10 364
Anthrachinone 100 90 75 12 91
Azodicarbonamide 100 <10 176
Benzoic acid (St. 2)
Betaine
hydrochloride 93 85 78 <10 114 (St. 2)
Betaine
monohydrate 34 4 710 63 St. 1
Diphenol ketylene 98 80 60 15 270
Calcium acetate 74 41 25 17 92 9 St. 1
Casein 99 65 40 24 115
Sodium caseinate
(from filter) 100 99 77 17 117
Carboxy methyl
cellulose 97 89 <15 184
Carboxy methyl
cellulose 50 20 12 71 127 St. 1
Methyl cellulose 96 87 30 22 157

75
products
Auxiliary
Med-
ian
Explos.
KSt < 63 µm
Ethyl cellulose 66 40 40 162
Chloroacetamide 98 79 33 13 3 170 St. 1
Cyanoacrylicacid
methylester 69 20 260 269 (St. 2)
Dicyandiamide 99 98 97 <10 9
1.3-Diethyldiph-
enyl urea 98 93 83 <10 163 (St. 2)
1.3-Diethyldiph-
enyl urea 8 1300 116 (St. 2)
Dimethyl
terephtalate 60 27 247
Diphenyl urethane 93 49 27 128 218 (St. 2)
Diphenyl urethane 31 1100 51 (St. 2)
Emulgator (50%
CH, 30% fat) 89 50 11 71 167
Ferrocene 71 33 95 267
Fumac acid 100 75 24 15 11 215 (St. 2)
Epoxy resin
hardener 97 85 60 17 64
Urea 4 2 <1 2900 St. 1
Hexamethylene
tetramine 100 69 42 27 286
Hexamethylene
tetramine 100 30 9 155 224
Cellulose ion
exchange resin <10 91 (St. 2)
Cellulose ion
exchange resin 27 9 112 112
Condensation
product (phenol) 92 74 50 20 171 (St. 2)
D(-)-Mannite 61 24 13 67 54 St. 1
Melamine 98 95 88 <10 1 St. 1
Melamine
peroxide 61 56 46 24 73 St. 1
Melamine
phosphate 100 79 22 St. 1
Melamine
phtalate 99 89 65 16 52 St. 1
Metal soap
(Ba/Pb-stearate) 100 48 180 (St. 2)
Metal soap
(Zn-behenate) 100 80 119 (St. 2)
Methacrylamide 42 580 113
Naphtalene 89 66 35 12 95 178
Naphtalic acid
anhydride 97 69 16 90

76
products
Auxiliary
Med-
ian
Explos.
KSt < 63 µm
2-Naphtol 100 96 94 <10 137
Sodium amide (St. 2)
Sodium cyclamate 97 52 13 5 2 250 St. 1
Sodium hydrogen
cyanamide 95 90 28 8 40 47
Sodium lingo
sulphonate 100 63 20 58 St. 1
Oil Adsorber
(hydrophobic
cellulose) 65 51 31 21 65 42
Paraformaldehyde 89 65 41 23 175 (St. 2)
Paraformaldehyde 86 58 37 27 222
Pectin 86 61 21 59 162
Pectinase 91 47 20 34 177
Pentaerythrite 100 98 86 <10 120
Pentaerythrite
(from filter) 90 33 6 3 85 188
Pentaerythrite 86 47 36 20 12 135 158
Phtalic acid
anahydride (St. 2)
Polyethylene
oxide 99 83 53 29 14 115 (St. 2)
Polysaccharide 100 78 23 St. 1
Propyleneglycol
alginate 57 24 115 82
Salicylic acid (St. 2)
Saponin 93 77 65 13 150 St. 1
Lead stearate 99 96 90 80 <10
Lead stearate 90 12 152
Calcium stearate 99 92 84 <10
Calcium stearate 92 80 <10 99
Calcium stearate 100 43 25 145 155
Magnesium stearate (St. 2)
Sodium stearate 92 67 45 22 123 St. 1
Zinc stearate (St. 2)
Zinc stearate 95 86 72 13
Stearin/Lead 99 95 75 15 111
Stearin/Calcium 100 89 64 16 133
Stearic acid 12 1300 34 (St. 2)
Terephthalic acid
dinitrile 100 78 260
2.2-Thiodiacetic
acid 48 27 18 75 72 St. 1
Thio urea 56 1 460 8 St. 1
Trimellitic
anhydride 4 1250 33
Trisodium citrate 36 2 1 800 St. 1

77
products
Auxiliary
Med-
ian
Explos.
KSt < 63 µm
Tyrosine
(final product) 100 99 48 10 (St. 2)
Tyrosine
(raw product) 99 96 91 74 15 (St. 2)
Viscose flock 100 94 13 St. 1
Tartaric acid 100 5 1 480 St. 1
Zinc cyanamide 99 96 94 <10
Zinc cyanamide 47 34 27 14 600 (53) No. ign.
Zinc pyridine
thione 100 St. 1
Technical/
Chemical
Med-
ian
Explos.
KSt < 63 µm
Organic dyestuff
(blue) 99 98 95 <10 73
Organic dyestuff
(red) <10 249
Organic dyestuff
(red) 65 33 23 52 237 (St. 2)
Organic dyestuff
(Azo. yellow) 100 98 95 <10 288 (St. 2)
Organic dyestuff
(brown) St. 1
Organic dyestuff
(Pthalocyanine) 96 86 <10 73 St. 1
Fushsin base 74 45 26 36 115
Bituminous
hydrocarbon 23 11 260 63
Light protection
agent 97 92 83 <10 214
Light protection
agent 100 93 <15 310
Soap 65 111
Surfacer (Epoxy
based) 100 77 24 St. 1
Surfacer
(Polyester based) 100 85 19 St. 1
Washing agent
(Na-sulph.) 88 14 275 267 (St. 2)
Wax raw material
(Alkylaryl
sulphonate) (St. 1)
Wax raw material
(Olefin
sulphonate) 60 28 105 115

78
Metal
Alloys Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Aluminum
powder 94 88 79 <10 515
Aluminum
powder 98 70 45 22 400
Aluminum
powder 99 64 47 22 1100
Aluminum
powder 94 60 17 29 415 (St. 3)
Aluminum grit 100 96 23 320
Aluminum grit 99 16 2 41 100
Aluminum grit 92 26 6 170
Aluminum
shavings 80 35 20 190
Aluminum
shavings 79 29 17 240
Aluminum/Iron
(50:50) 93 68 48 21 230
Aluminum/
Magnesium 47 130 52 St. 1
Aluminum/
Nickel 95 86 <10 300
Aluminum/
Nickel (50:50) 37 18 90
Bronze powder 97 60 18 31 St. 1
Calcium/
Aluminum
(30:70) 68 46 22 420
Calcium/Silicon
(from cyclone) 94 75 48 21 200 (St. 2)
Calcium/Silicone 87 55 28
Iron (from
dry filter) 98 82 67 12 50
Iron Carbonyl 96 <10 111 (St. 1)
Ferrochromium 96 82 73 <10 86
Ferromanganese 99 97 90 <10 84
FeSiMg
(22:45:26) 99 77 57 17 169
Ferrosilicon
(22:78) 97 70 47 21 87
Hard metal
(TiC, TiN, WC,
VC, Mo) 100 95 68 40 43 St. 1
Co-Al-Ti
(62:18:20) 92 61 41 25 134
Magnesium 100 70 28 508
Magnesium 99 1 240 12 (St. 2)
FeSiMg
(24:47:17) 99 70 47 21 267

79
Metal
Alloys Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Manganese
(electrolyt.) 82 70 57 16 157
Manganese
(electrolyt.) 70 41 33 69
Molybdenum 100 96 92 <10
Niobium (6% Al) 87 44 24 9 3 250 St. 1
Silicon 99 98 97 <10 126
Silicon
(from filter) 100 99 <10 116
Silicon
(from cust extr.) 90 70 57 16 100
Steel (100 Cr6)
dust 100 74 (82) (St. 2)
Tantalum/Niobium 97 90 80 <10 37
Titanium 98 55 24 30
Titanium
(pre-oxidized) 77 46 26 35
TiTiO2
(dust deposit) 61 40 28 12 6 310 (St. 3)
Zinc (from
zinc coating) 91 72 53 19 85 St. 1
Zinc (from
zinc coating) 93 70 21 93
Zinc (dust
from collector) 99 <10 125 (St. 2)
Zinc (dust
from collector) 97 91 72 10 176 St. 1
Inorganic
Products Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
NH4NO3/
Dicyanimide
(66:34) 60 42 35 50 21
Graphite
(99.5% C) 100 97 7 71
Carbon fibers
(99% C) St. 1
Molybdenum
disulphide 92 75 53 19 37 St. 1
Petroleum coke 93 75 59 15 47 St. 1
Petroleum coke 83 51 22 14 71 3
Petroleum coke
(calcinated) 94 86 64 47 22 14
Phosphorous
(red) 100 92 59 18 526
Soot 99 5 85

80
Inorganic
Products Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Soot
(from filter) <10 88
Sulphur 97 85 71 12
Sulphur 96 70 51 20 151 (St. 2)
Sulphur 86 23 40
Sulphur 53 7 120
Titanium carbide (St. 2)
Titanium hydride St. 1
Titanium
monoxide (St. 2)
Other
Med-
ian
Explos.
KSt < 63 µm
Flyash (from
electrofilter) 100 99 92 6 35 No. Ign.
Ash concentrate 87 61 48 21 91
Bentonite/
Asphalt/Coal/
Org. (15:45:35:5) 90 55 54 St. 1
Bentonite/Coal
(50:50) 98 86 69 41 42 St. 1
Bentonite der.
+ org. comp. 89 45 23 35 123
Pb and Ca
stearate mixture 98 70 35 (St. 2)
Break liner
(grinding dust) 98 95 89 <10 71
Brush dust
(Al-brushes) 99 74 30 25 360
CaC/Diamide
lime/Mg
(72:18:10) 99 93 87 80 8 30
Mud from
settling chamber 99 91 62 45 23 96
Dust from
polishing (Al) 44 26 150 18
Dust from
polishing (Zn) 60 35 15 2 190 St. 1
Dust from
polishing (brass) St. 1
Dust from
grinding (Al) 100 85 (214) (St. 2)
Dust from
grinding (Zn) 100 67 (24) St. 1
Dust from
grinding cardbd. 70 64 44 25 10 160 St. 1

81
Other Materials Weight %<Size (µm)
Med-
ian
Explos.
KSt < 63 µm
Dust from
grinding polyester 98 95 93 <10 153
Dust from
grinding polyester 97 84 60 41 25 237
Dust from
grinding (Ti) 89 64 37 18 4 170 (St. 2)
Dust from
grinding +
polishing
(polyester) 99 96 91 <10
Blasting dust
(light metals) 100 82 242 (St. 2)
Immersion
polishing agent 46 600 11 St. 1
Textile fibers
(nat. + synth.) St. 1
Toner 100 <10 196
Toner 100 <10 137
Toner 100 96 48 21 134
Toner 100 95 30 23 145
Toner/iron
powder 58 37 60 169
Toner/resin 98 78 55 18
Zinc stearate/
Bentonate
(90:10) (St. 2)
Zinc stearate/
Bentonate
(20:80) (St. 1)
Explosion Classes
St. 1 = 200 kst or less
St. 2 = 300 kst or less
Equations per NFPA 68, Sec. 7-1.1.1, p. 68-27
Av = a*Vˆ(2/3)*Kstˆb*Predˆc
where
a = 0.000571 eˆ(2*Pstat)
b = 0.978 eˆ(-0.105* Pstat)
c = -0.687 eˆ(.226*Pstat)
Variables: Pstat (bars) – Vent Release Pressure
Pred (bars) – Max. Press. During Venting
Kst (bar*m/sec) – Deflagration Index
V (mˆ3) – Volume of Vessel
Av (mˆ2) – Required Vent Area
See Reference #3

82
Misc. Ref.
Weight of rolled steel
Thickness Weight
MSG
no.
Sheet
equiv-
alent
inches
Order limit
inches
Pounds
per
square
foot
Order limit
pounds
MSG
no.
8 .1644 .1716 to .1570 6.675 7.187 to 6.563 8
9 .1495 .1569 to .1420 6.250 6.562 to 5.938 9
10 .1345 .1419 to .1271 5.625 5.937 to 5.313 10
11 .1196 .1270 to .1121 5.000 5.312 to 4.688 11
12 .1046 .1120 to .0972 4.375 4.687 to 4.063 12
13 .0897 .0971 to .0822 3.750 4.062 to 3.438 13
14 .0747 .0821 to .0710 3.125 3.437 to 2.969 14
15 .0673 .0709 to .0636 2.812 2.968 to 2.657 15
16 .0598 .0635 to .0568 2.500 2.656 to 2.375 16
17 .0538 .0567 to .0509 2.250 2.374 to 2.125 17
18 .0478 .0508 to .0449 2.000 2.124 to 1.875 18
19 .0418 .0448 to .0389 1.750 1.874 to 1.625 19
20 .0359 .0388 to .0344 1.500 1.624 to 1.438 20
21 .0329 .0343 to .0314 1.375 1.437 to 1.313 21
22 .0299 .0313 to .0284 1.250 1.312 to 1.188 22
23 .0269 .0283 to .0255 1.125 1.187 to 1.063 23
24 .0239 .0254 to .0225 1.000 1.062 to .938 24
25 .0209 .0224 to .0195 .875 .937 to .813 25
26 .0179 .0194 to .0172 .750 .812 to .719 26
27 .0164 .0171 to .0157 .688 .718 to .657 27
28 .0149 .0156 to .0142 .625 .656 to .594 28
29 .0135 .0141 to .0128 .562 .593 to .532 29
Weights of steel plate
Thick-
ness
Weight
per
sq. ft.
lbs.
Thick-
ness
Weight
per
sq. ft.
lbs.
Thick-
ness
Weight
per
sq. ft.
lbs.
3/16 7.65 7/16 17.86 11/16 28.03
1/4 10.20 1/2 20.40 3/4 30.60
5/16 12.74 9/16 22.95 7/8 35.70
3/8 15.29 5/8 25.50 1 40.89

83
Standard Sieve Series*
Sieve OpeningTyler
Inch/Mesh
U.S. Standard
Inch/Sieve # Inches Microns
3 1/2 3 1/2 0.223 5660
4 4 0.187 4760
5 5 0.157 4000
6 6 0.132 3660
7 7 0.111 2830
8 8 0.0937 2380
9 10 0.0787 2000
10 12 0.0661 1680
12 14 0.0555 1410
14 16 0.0469 1190
16 18 0.0394 1000
20 20 0.0331 840
24 25 0.0280 710
28 30 0.0232 590
32 35 0.0197 500
35 40 0.0165 420
42 45 0.0138 350
48 50 0.0117 297
60 60 0.0098 250
65 70 0.0083 210
80 80 0.0070 177
100 100 0.0059 149
115 120 0.0049 125
150 140 0.0041 105
170 170 0.0.35 88
200 200 0.0029 74
250 230 0.0024 62
270 270 0.0021 53
325 325 0.0017 44
400 400 0.0015 37
*Sieve analysis is limited in its usefulness in industrial ventilation
and dust collection because it does not register particles in the
submicron range.

84
Right Triangle Trig Formulas
A, B, C = Angles a,b,c = Distances
sin A = _a_, cos A = _b_, tan A = _a_
c c b
cot A = _b_, sec A = _c_, cosec A = _c_,
a b a
Given a and b, Find A, B, and c
______ _______
tan A = _a_ = cot B, c = √a2
+ b2
= a√ 1 + _b2
b a2
Given a and c, Find A, B, b
________ _______
sin A = _a_ = cos B, b = √(c+a) (c-a) = a√ 1 - _a2
c c2
Given A and a, Find B, b, c
B = 90°-A, b = a cot A, c = _a_
sin A
Given A and b, Find B, a, c
B = 90°-A a = b tan A, c = _b_
cos A
Given A and c, Find B, a, b
B = 90°-A, a = c sin A, b = c cos A

85
Given A,B and a, Find b, C, and c
b = a sin B , C = 180° - (A + B), c = a sin C
sin A sin A
Given A,a and b, Find B, C, and c
sin B = b sin A , C = 180° - (A + B), c = a sin C
a sin A
Given a,b and C, Find A, B, and c
A + B = 180° - C, c = a sin C
sin A
tan 1/2 (A – B) = (a – b) tan 1/2, (A + B)
a + b
Given a, b and c, Find A, B, and C
__________
s = a + b + c , sin 1/2 A = √(s – b)(s – c)
2 bc
__________
sin 1/2 B = √(s –a)(s – c) , C = 180° - (A + B)
ac
Given a, b and c, Find Area
________________
s = a + b + c , Area = √s(s – a)(s – b)(s – c)
2
Area = bc sin A , Area = a²sin B sin C
2 2 sin A

86
Surface and volume of Solids
Cylinder
(Right or Oblique, Circular or Elliptic)
Perimeter or base, Pb; perpendicular height, h, Lateral Surface = Pbh
Perimeter, P, perpendicular to sides; lateral length L, Lateral Surface = PL
Area of base, B; perpendicular height, h, Volume = Bh
Area of section perpendicular to sides A, lateral length L, Volume = AL
Pyramid or Cone
(Right or Oblique, Regular or Irregular)
___
Area of base, B, perpendicular height, h, Volume = 1/3 √Bh
= 1/3 the volume of prism or cylinder of same base and
perpendicular height or 1/2 the volume of hemisphere of
same base and perpendicular height.
Frustum of Any Pyramid or Cone
(Parallel Ends)
Areas of base, B, and top, T; perpendicular
height, h, ___
Volume = 1/3h (B + T + √BT)
Sphere
Area = 4πr²
Volume = 1/2/³π
Radius, r,
Spherical Segment
Radius, r; length of chord, c; height, h, Curved Surface = 2πrh = π/4(4h²+c²)
Volume = π/3 h² (3r-h)=π/24 h (3c²+4h²)

87
Conversion Tables
Decimal and metric equivalents of common fractions of an inch
U.S. inch U.S. inch
Frac-
tion
Decimal
Mm Frac-
tion
Decimal
Mm
1/32 0.03125 0.794 17/32 0.53125 13.494
1/16 0.06250 1.588 9/16 0.56250 14.288
3/32 0.09375 2.381 19/32 0.59375 15.081
1/8 0.12500 3.175 5/8 0.62500 15.875
5/32 0.15625 3.969 21/32 0.65625 16.669
3/16 0.18750 4.763 11/16 0.68750 17.463
7/32 0.21875 5.556 23/32 0.71875 18.256
1/4 0.25000 6.350 3/4 0.75000 19.050
9/32 0.28125 7.144 25/32 0.78125 19.844
5/16 0.31250 7.938 13/16 0.81250 20.638
11/32 0.34375 8.731 27/32 0.84375 21.431
3/8 0.37500 9.525 7/8 0.87500 22.225
13/32 0.40625 10.319 29/32 0.90625 23.019
7/16 0.43750 11.113 15/16 0.93750 23.813
15/32 0.46875 11.906 31/32 0.96875 24.606
1/2 0.50000 12.700 1 1.00000 25.400
Conversion ratios
Multiply by to obtain
Diam. circle 3.1416 Circumference circle
Diam. circle 0.8862 Side of equal square
Diam. sphere cubed 0.5236 Volume of sphere
Circular mils 0.7854 Square mils
U.S. gallons 0.8327 Imperial gallons (Brit.)
U.S. gallons 0.1337 Cubic feet
U.S. gallons 8.330 Pounds of water (20°C)
Cubic feet 62.427 Pounds of water (4°C)
Feet of water (4°C) 0.4336 Pounds per sq. inch
In. of mercury (0°C) 0.4912 Pounds per sq. inch
Knots 1.1516 Miles per hour
To obtain divide into

88
Pressure equivalents
1 Atmosphere =
= 14.696 lb. per sq. in. = 2116.3 lb. per sq. ft.
= 33.96 ft. of water = 407.52 in. water
= 29.92 in. of mercury = 760 mm. mercury
= 234.54 oz. per sq. in. = 10.340 mm. water
1 in. water =
= 0.0735 in. mercury = 1.876 mm. mercury
= 0.002456 atmospheres = 0.5774 oz. per sq. in.
= 25.4 mm. of water = 0.08333 ft. of water
1 in. mercury =
= 25.4 mm. mercury = 7.86 oz. per sq. in.
= 0.03342 atmospheres = 345.6 mm. water
= 13.61 in. water = 1.134 ft. water
1 mm. mercury =
= 0.3094 oz. per sq. in. = 0.001316 atmospheres
= 0.5357 in. water = 0.04464 ft. water
= 13.61 mm. water = 0.03937 in. mercury
1 lb. per sq. in. =
= 144 lb. per sq. ft. = 16 oz. per sq. in.
= 51.71 mm. mercury = 2.036 in. mercury
= 27.70 in. water = 2.309 ft. water
= 0.06895 megabars (or megadynes) per sq. cm.
= 0.0703 kg. per sq. cm.
1 oz. per sq. in. =
= 1.733 in. water = 0.1441 ft. water
= 0.1272 in. mercury = 3.23 mm. mercury
1 in. of water resistance lowers wt. per cu. ft. of air by 1/4 or 1%
1 in. of mercury represents 900 ft. difference in elevation at sea level to 4,000 ft.
1 in. of mercury represents 1,000 ft. difference in elevation at 4,000 to 6,000 ft. elevation
1 in. of water represents 66 ft. difference in elevation at sea level to 4,000 ft.
1 in. of water represents 74 ft. difference in elevation at 4,000 to 6,000 ft. elevation
1,000 ft. difference in elevation at seal level represents 1.11 in. of mercury
1,000 ft. difference in elevation at 4,000 ft. represents 1 in. of mercury
1,000 ft. difference in elevation at sea level represents 15.2 in. water
1,000 ft. difference in elevation at 4,000 ft. represents 13.6 in. water
1 gm. per sq. cm. = 0.394 in. water = 0.02896 in. mercury

89
Weights and measures
Time Measure
Troy Weight 60 seconds 1 minute
24 grains 1 pwt. 60 minutes 1 hour
20 pwt. 1 ounce 24 hours 1 day
12 ounces 1 pound 7 days 1 week
Used for weighing gold, silver and jewels 28, 29, 30 or 31 days 1 cal. month
30 days 1 month in comp. interest
Cloth Measure 365 days 1 year 366 days lp. yr.
21/8 inches 1 nail
4 nails 1 quarter Miscellaneous
4 quarters 1 yard 3 inches 1 palm
4 inches 1 hand
Cubic Measure 6 inches 1 span
1,728 cubic inches 1 cubic foot 18 inches 1 cubit
27 cubic feet 1 cubic yard 21.8 inches 1 Bible cubit
128 cubic feet 1 cord (wood) 2-1/2 feet 1 military pace
40 cubic feet 1 ton (shipping)
2,150.42 cubic inches 1 standard bu. Measure of Volume
231 cubic inches 1 U.S. standard gal. 1 cubic centimeter .061 cu. inch foot
1 cubic foot about 4/5 of a bushel 1 cubic inch 16.39 cubic cent.
1 cubic decimeter 0.0353 cubic foot
Dry Measure 1 cubic foot 28.317 cubic dec.
2 pints 1 quart 1 cubic meter 1.308 cubic yards
8 quarts 1 peck 1 cubic yard 0.7646 cubic meter
4 pecks 1 bushel 1 stere 0.2759 cord
36 bushels 1 chaldron 1 cord 3.624 steres
1 liter 0.908 qt. dry 1.0567 qt. liq.
Mariners’ Measure 1 quart dry 1.101 liters
6 feet 1 fathom 1 quart liquid 0.9463 liter
120 fathoms 1 cable length 1 dekaliter 0.3785 dekaliter
71/2 cable lengths 1 mile 1 peck 0.881 dekaliter
5,280 feet 1 statute mile 1 hektoliter 2.8375 bushels
6,080.2 feet 1 nautical mile 1 bushel 0.3524 hektoliter
Surveyors’ Measure Approximate Metric Equivalents
7.92 inches 1 link 1 decimeter 4 inches
25 links 1 rod 1 liter 1.06 quarts liquid, 0.9 qt. dry
4 rods 1 chain 1 meter 1.1 yards
10 sq. chains or 160 sq. rods 1 acre 1 kilometer 5/8 of a mile
640 acres 1 sq. mile 1 hektoliter 2-5/8 bushels
36 sq. miles (6 miles sq.) 1 township 1 hectare 2-1/2 acres
1 kilogram 2-1/5 pounds
1 stere or, cubic meter 1/4 of a cord
1 metric ton 2,204.6 pounds

90
Weights and measures (cont’d)
Temperatures Hat and energy units
Fahrenheit 1 ton (refrig.) = 200 Btu/min.
Milk Freezes 30° above Zero
Water Freezes 32° above Zero Apothecaries’ weight
Olive Oil Freezes 36° above Zero 1 scruple = 20 grains 1 ounce = 8 drams
Wines Freeze 20° above Zero 1 dram = 3 scruples 1 pound = 12 ounces
Vinegar Freezes 28° above Zero Grain = 0.0648 9.
Alcohol Boils at 173° above Zero Oz. = 28.3495 9.
Water Boils at 212° above Zero Lb. = 0.4536 kg.
Eggs Hatch 104° above Zero Ton (sht.) = 907.1848 kg.
Petrol. (av.) Boils at 360° above Zero Ton (sht.) = 0.9072 ton (met.)
Blood Heat 98.4° above Zero Ton (lg.) = 1.0160 ton (met.)
Mineral lubricating oil has specific gravity of 0.88 to 0.94
Linear measure
1 foot = 12 inches 1 stat mile = 8 furlongs Pressure
1 yard = 3 feet 1 stat mile = 5,280 feet 1 kg. per sq. cm. = 14.223 lb. per sq. in.
1 rod = 5-1/2 yards 1 naut mile = 6,080 ft. 1 lb. per sq. in. = 0.0703 kg. per sq. cm.
1 furlong = 40 rods 1 league = 3 miles 1 kg. per sq. m. = 0.2048 lb. per sq. ft.
1 lb. per sq. ft. = 4.8824 kg. per sq. m.
Circular measure 1 kg. per sq. cm. = 0.9678 normal atmosphere
1 minute = 60 seconds 1 radian = 57.296 deg.
1 deg. = 60 minutes 1 quadrant = 90 deg. Heat and Energy units
1 circle = 4 quadrants =
2 πradians or 360 deg.
1,000 w/hr.
Square measure 1.3410 h.p.-hr.
144 sq. in. = 1 sq. ft. 160 sq. rods = 1 acre 2,655,217 ft.-lb.
9 sq. ft. = 1 sq. yd. 43,560 sq. ft. = 1 acre 3,600,000 joules
30-1/4 sq. yd. = 1 sq. rod 640 acres = 1 sq. mile 3,413 Btu.
860 kg.-cal.
Liquid measure 1 kw.-hr. 367,098 kg.-m.
1 pint = 4 gills 1 barrel = 31-1/2 gallons 0.235 lb. carbon oxidized
1 quart = 2 pints 1 hogshead = 2 barrels with perfect efficiency
1 gallon = 4 quarts 1 Imp. gal. = 1.2 gal (U.S.) 3,518 lb. water evap. from
and at 212°F.
Volume 22.76 lb. of water raised from
1 cu. foot = 7.48 gallons 62 to 212°F.
1 gallon = 231 cu. inches
1 gal./hr. = 2.135 oz./min.
Avoirdupois weight
1 dram = 27.3437 grains
1 ounce = 16 drams
1 pound = 16 ounces
1 quarter = 25 pounds
1 hundredweight = 4 quarters
1 short ton = 2,000 pounds
1 long ton = 2,240 pounds
1 pound = 7,000 grains

91
Heat and Energy units (cont’d)
0.7457 kw.-hr.
1,980,000 ft.-lb.
2,545 Btu.
1 h.p. – hr. 273,745 kg.-m.
0.1849 lb. carbon oxidized with perfect efficiency
2.622 lb. water evap. from and at 212°F.
14,520 Btu
1.1085 lb. anthracite oxidized (varies)
2.315 lb. dry wood oxidized (varies)
1 lb. carbon 26.4 cu. ft. manufactured gas (varies)
oxidized 12.9 cu. ft. natural gas (varies)
with perfect 14.255 kw.-hr.
efficiency 5.709 h.p.-hr.
11,300,000 ft.-lb.
14.97 lb. of water evap. from and at 212°F.
0.2844 kw.-hr.
0.3814 h.p.-hr.
1 lb. water 970.2 Btu
evaporated 104,400 kg.-m.
from and 1,023,500 joules
at 212°F. 756,500 ft.-lb.
0.0668 lb. of carbon oxidized with perfect efficiency
1 kg.-cal. = 3.9685 Btu
1 Btu = 0.2520 kg.-cal.
1 kg.-cal. per kilogram = 1.8000 Btu per lb.
1 Btu per pound = 0.5555 kg.-cal. per kg.
1 kg.-cal. per liter = 112.37 Btu per cu. ft.
1 Btu per cu. ft. = 0.0089 kg.-cal. per lb.
1 kg.-cal. per cu. m. = 0.1124 Btu per cu. ft.
1 Btu per cu. ft. = 8.8987 kg.-cal. per cu. m.

92
Metric Conversions
Atmospheres – atm (Standard at sea-level pressure)
x 101.325 = Kilopascals (kPa) absolute
x 14.696 = Pounds-force per square inch absolute (psia)
x 76.00 = Centimeters of mercury (cmHg) at 0°C
x 29.92 = Inches of mercury (inHg) at 0°C
x 33.96 = Feet of water (ftH2O) at 68°F
x 1.01325 = Bars (bar) absolute
x 1.0332 = Kilograms force per square centimeter (kg/cm²) absolute
x 1.0581 = Tons force per square foot (tonf/ft²) absolute
x 760 = Torr (torr) (= mmHg at 0°C)
Barrels, Liquid, U.S. – bbl
x 0.11924 = Cubic meters (m³)
x 31.5 = U.S. gallons (U.S. gal) liquid
Barrels, Petroleum – bbl
x 42 = U.S. gallons (U.S. gal) oil
Bars – bar
x 100 = Kilopascals (kPa)
x 14.504 = Pounds-force per square inch (psi)
x 1.0197 = Kilograms-force per square centimeter (kg/cm²)
x 0.98692 = Atmospheres (atm) sea-level standard
x 1.0443 = Tons-force per square foot (tonf/ft²)
x 750.06 = Torr (torr) (= mmHg at 0°C)
British Thermal Units – Btu (See note)
x 1055 = Joules (J)
x 778 = Foot-pounds-force (ft • lbf)
x 0.252 = Kilocalories (kcal)
x 107.6 = Kilogram-force-meters (kgf • m)
x 2.93 x 10-4
= Kilowatt-hours (kW • h)
x 3.93 x 10-4
= Horsepower-hours (hp • h)
British Thermal Units per Minute – Btu/min (See note)
x 17.58 = Watts (W)
x 12.97 = Foot-pounds-force per second (ft • lbf/s)
x 0.02358 = Horsepower (hp)
Centares
x 1 = Square meters (m²)
Centimeters – cm
x 0.3937 = Inches (in)

93
Metric Conversions (cont’d)
Centimeters of Mercury – cm/Hg at 0°C
x 1.3332 = Kilopascals (kPa)
x 0.013332 = Bars (bar)
x 5.362 = Inches of water (inH2O) at 68°F
x 0.013595 = Kilograms force per square centimeter (kg/cm²)
x 27.85 = Pounds-force per square foot (lbf/ft²)
x 0.013158 = Atmospheres (atm) standard
x 10 = Torr (torr) (= mmHg at 0°C)
Centimeters per Second – cm/s
x 1.9685 = Feet per minute (ft/min)
x 0.03281 = Feet per second (ft/s)
x 0.03600 = Kilometers per hour (km/h)
x 0.6000 = Meters per minute (m/min)
x 0.02237 = Miles per hour (mph)
Cubic Centimeters – cm³
x 3.5315 x 10-5
= Cubic feet (ft³)
x 6.1024 x 10-2
= Cubic inches (in³)
x 1.308 x 10-6
= Cubic yards (yd3
)
x 2.642 x 10-4
= U.S. gallons (U.S. gal)
x 2.200 x 10-4
= Imperial gallons (imp gal)
x 1000 x 10-3
= Liters (l)
Cubic Feet - ft³
x 2.832 x 104
= Cubic centimeters (cm³)
x 1728 = Cubic inches (in³)
x 0.03704 = Cubic yards (yd³)
x 7.481 = U.S. gallons (U.S. gal)
x 6.229 = Imperial gallons (imp gal)
x 28.32 = Liters (l)
Cubic Feet per Minute – cfm
x 472.0 = Cubic centimeters per second (cm³/s)
x 1.699 = Cubic meters per hour (m³/h)
x 0.4720 = Liters per second (l/s)
x 0.1247 = U.S. gallons per second (U.S. gps)
x 62.30 = Pounds of water per minute (lbH2O/min) at 68°F
Cubic Feet per Second – cfs
x 0.02832 = Cubic meters per second (m³/s)
x 1.699 = Cubic meters per minute (m³/min)
x 448.8 = U.S. gallons per minute (U.S. gpm)
x 0.6463 = Million U.S. gallons per day (U.S. gpd)

94
Cubic Inches - In³
x 1.6387 x 10-5
= Cubic meters (m³)
x 16.387 = Cubic centimeters (cm³)
x 0.016387 = Liters (l)
x 5.787 x 10-4
= Cubic feet (ft³)
x 2.143 x 10-5
= Cubic yards (yd³)
x 4.329 x 10-3
= U.S. gallons (U.S. gal)
x 3.605 x 10-3
= Imperial gallons (imp gal)
Cubic Meters - m³
x 1000 = Liters (l)
x 35.315 = Cubic feet (ft³)
x 61.024 x 10³ = Cubic inches (in³)
x 1.3080 = Cubic yards (yd³)
Cubic Meters per Hour - m³/h
x 2.778 x 10-4
= Cubic meters per second (m³/s)
Cubic Meters per Second – (m³/s)
x 3600 = Cubic meters per hour (m³/h)
x 15.85 x 10³ = U.S. gallons per minute (U.S. gpm)
Cubic Yards - yd³
x 7.646 x 105
= Cubic centimeters (cm³)
x 27 = Cubic feet (ft³)
x 46,656 = Cubic inches (in³)
Degrees Angular (°)
x 0.017453 = Radians (rad)
x 60 = Minutes (‘)
x 3600 = Seconds (“)
x 1.111 = Grade (gon)
Degrees per Second, Angular (°/s)
x 0.017453 = Radians per second (rad/s)
x 0.16667 = Revolutions per minute (r/min)
x 2.7778 x 10-3
= Revolutions per second (r/s)
Drams (dr)
x 1.7718 = Grams (g)
x 27.344 = Grains (gr)
x 0.0625 = Ounces (oz)

95
Fathoms
x 1.8288 = Meters (m)
x 6 = Feet (ft)
Feet – ft
x 0.3048 = Meters (m)
x 30.480 = Centimeters (cm)
x 12 = Inches (in)
x 0.3333 = Yards (yd)
Feet of Water – ftH2O, at 68°F
x 0.02984 = Bars (bar)
x 0.02945 = Standard atmospheres
Feet per Minute – ft/min
x 0.5080 = Centimeters per second (cm/s)
x 0.0051 = Meters per second (mps)
Feet per Second per Second – ft/s²
x 0.3048 = Meters per second per second (m/s²)
x 30.48 = Centimeters per second per second (cm/s²)
Foot-Pounds-Force – ft • lbf
x 1.356 = Joules (J)
x 1.285 x 10-3
= British thermal units (Btu) (see note)
x 3.239 x 10-4
= Kilocalories (kcal)
x 0.13825 = Kilogram-force-meters (kgf • m)
x 5.050 x 10-7
x 3.766 x 10-7
= Kilowatt-hours (kW • h)

96
Gallons U.S. – U.S. gal
x 3.7854 = Liters (l)
x 3.7854 x 10-3
x 231 = Cubic inches (in³)
x 4.951 x 10-3
x 8 = Pints (pt) liquid
x 4 = Quarts (qt) liquid
x 8.328 = Pounds of water at 60°F in air
x 8.337 = Pounds of water at 60°F in vacuo
Gallons, Imperial – imp gal
x 4546 = Cubic centimeters (cm³)
x 4.546 x 10-3
x 5.946 x 10-3
x 10.000 = Pounds of water at 62°F in air
Gallons, per Minute, U.S. – U.S. gpm
x 0.22715 = Cubic meters per hour (m3
/h)
x 8.021 = Cubic feet per hour (cfh)
x 2.228 x 10-3
= Cubic feet per second (cfs)
Grains – gr av. or troy
x 0.0648 = Grams (g)
Grains per Cubic Foot
x 2288.1 = milligrams per cubic meter (mg/m3
)
Grains per U.S. Gallon – gr/U.S. gal at 60°F
x 17.12 = Grams per cubic meter (g/m³)
x 17.15 = Parts per million by weight in water
x 142.9 = Pounds per million gallons
Grains per Imperial Gallon – gr/imp gal at 62°F
x 14.25 = Grams per cubic meter (g/m3
)
x 14.29 = Parts per million by weight in water
Grams – g
x 0.035274 = Ounces (oz) av.
x 0.032151 = Ounces (oz) troy
x 2.2046 x 10.3 = Pounds (lb)

97
Grams-Force – gf
x 9.807 x 10-3
= Newtons (N)
Grams – Force per Centimeter – gf/cm
x 98.07 = Newtons per meter (N/m)
x 5.600 x 10-3
= Pounds-force per inch (lbf/in)
Grams per Cubic Centimeter – g/cm3
x 62.43 = Pounds per cubic foot (lb/ft³)
x 0.03613 = Pounds per cubic inch (lb/in³)
Grams per Liter – g/l
x 58.42 = Grains per U.S. gallon (gr/U.S. gal)
x 8.345 = Pounds per 1000 U.S. gallons
x 0.06243 = Pounds per cubic foot (lb/ft³)
x 1002 = Parts per million by mass
Hectares – ha
x 1.000 x 104
= Square meters (m²)
x 1.0764 x 105
= Square feet (ft²)
Horsepower – hp
x 745.7 = Watts (W)
x 0.7457 = Kilowatts (kW)
x 33,000 = Foot-pounds-force per minute (ft • lbf/min)
x 550 = Foot-pounds-force per second (ft • lbf/s)
x 42.43 = British thermal units per minute (Btu/min) (see note)
x 10.69 = Kilocalories per minute (kcal/min)
x 1.0139 = Horsepower (metric)
Horsepower – hp boiler
x 33,480 = British thermal units per hour (Btu/h) (see note)
x 9.809 = Kilowatts (kW)
Horsepower-Hours – hp • h
x 0.7457 = Kilowatt-hours (kW • h)
x 1.976 x 106
= Foot-pounds-force (ft • lbf)
x 2545 = British thermal units (Btu) (see note)
x 2.732 x 105
= Kilogram-force-meters (kgf • m)
Inches – in
x 2.540 = Centimeters (cm)

98
Inches of Mercury – inHg at 0°C
x 0.03386 = Bars (bar)
Inches of Water – in H2O at 68°F
x 2.487 x 10-3
= Bars (bar)
x 2.535 x 10-3
= Kilograms-force per square centimeter (kg/cm²)
x 0.5770 = Ounces-force per square inch (ozf/in²)
x 2.454 x 10-3
= Standard atmospheres
Joules – J
x 0.9484 x 10-3
= British thermal units (Btu) (see note)
x 0.2390 = Calories (cal) thermochemical
x 0.7376 = Foot-pounds-force (ft • lbf)
x 2.778 x 10-4
= Watt-hours (W • h)
Kilograms – kg
x 2.2046 = Pounds (lb)
x 1.102 x 10-3
= Tons (ton) short
Kilograms-force – kgf
x 9.807 = Newtons (N)
x 2.205 = Pounds-force (lbf)
Kilograms-Force per Meter – kgf/m
x 0.6721 = Pounds-force per foot (lbf/ft)
Kilograms-Force per Square Centimeter – kg/cm²
x 0.9807 = Bars (bar)
x 2048 = Pounds-force per square foot (lb/ft²)
Kilograms-Force per Square Millimeter – kgf/mm²
x 9.807 = Megapascals (MPa)
x 1.000 x 106
= Kilograms-force per square meter (kgf/m²)

99
Kilometers per Hour – km/h
x 0.53996 = International knots (kn)
Kilometers per Hour per Second – km • h-1
• s-1
x 0.2778 = Meters per second per second (m/s²)
x 27.78 = Centimeters per second per second (cm/s²)
x 0.9113 = Feet per second per second (ft/s²)
Kilometers per Second – km/s
x 37.28 = Miles per minute (mi/min)
Kilopascals – kPa
x 103 = pascals (Pa) or newtons per square meter (N/m²)
x 0.1450 = Pounds-force per square inch
x 0.2953 = Inches of mercury (inHg) at 32°F
Kilowatts – kW
x 4.425 x 104
= Foot-pounds-force per minute (ft • lbf/min)
x 737.6 = Foot-pounds-force per second (ft • lbf/s)
x 1.3410 = Horsepower (hp)
Kilowatt-Hours – kW • h
x 3.6 x 106
= Joules (J)
x 2.655 x 106
= Foot-pounds-force (ft • lbf)
x 3413 = British thermal units (Btu) (see note)
x 860 = Kilocalories (kcal)
x 3.671 x 105
= Kilogram-force meters (kgf • m)
x 1.3410 = Horsepower-hours (hp • h)
Knots – kn (International)
x 0.5144 = Meters per second (m/s)
Liters – l
x 61.024 = Cubic inches (in³)
x 1.308 x 10-3

100
Liters per Minute – l/min
x 0.01667 = Limits per second (l/s)
x 5.885 x 10-4
x 4.403 x 10-3
= U.S. gallons per second (U.S. gal/s)
x 3.666 x 10-3
= Imperial gallons per second (imp gal/s)
Liters per Second – l/s
x 10-3
= Cubic meters per second (m3
/s)
x 60 = Liters per minute (l/min)
x 13.20 = Imperial gallons per minute (imp gpm)
Megapascals – Mpa
x 106
= Pascals (Pa) or newtons per square meter (N/m²)
x 10³ = Kilopascals (kPa)
x 0.1020 = Kilograms-force per square millimeter (kgf/mm²)
Meters – m
x 3.281 = Feet (ft)
x 39.37 = Inches (in)
x 1.0936 = Yards (yd)
Meters per Minute – m/min
Meters per Second – m/s
x 0.0600 = Kilometers per minute (km/min)
x 0.03728 = Miles per minute (mi/min)
Micrometers - µm (micron)
x 0.000001 = Meters (m)
Miles – mi
x 1.6093 x 10³ = Meters (m)
x 1.6093 = Kilometers (km)
x 5280 = Feet (ft)
x 1760 = Yards (yd)

101
Miles per Hour – mph
x 88 = Feet per minute (R/min)
x 0.8690 = International knots (kn)
Miles per Minute – mi/min
x 1.6093 = Kilometers per minute (km/min)
x 2682 = Centimeters per second (cm/s)
x 88 = Feet per second (ft/s)
x 60 = Miles per hour (mph)
Minutes, Angular – (‘)
x 2.909 x 10-4
= Radians (rad)
Newtons – N
x 0.10197 = Kilograms-force (kgf)
x 0.2248 = Pounds-force (lbf)
x 7.233 = Poundals
x 105
= Dynes
Ounces – oz av.
x 28.35 = Grams (g)
x 2.835 x 10-5
= Tonnes (t) metric ton
x 16 = Drams (dr) av.
x 0.06250 = Pounds (lb) av.
x 0.9115 = Ounces (oz) troy
x 2.790 x 10-5
= Tons (ton) long
Ounces – oz troy
x 31.103 = Grams (g)
x 480 = Grains (gr)
x 20 = Pennyweights (dwt) troy
x 0.08333 = Pounds (lb) troy
x 1.0971 = Ounces (oz) av.
Ounces – oz U.S. fluid
x 0.02957 = Liters (l)
x 1.8046 = Cubic inches (in)
Ounces-Force per Square Inch – ozf/in²
x 43.1 = Pascals (Pa)
x 4.395 = Grams-force per square centimeter (gf/cm²)

102
Parts per Million by Mass – mass (weight) in water
x 0.9991 = Grams per cubic meter (g/m³) at 15°C
x 0.0583 = Grains per U.S. gallon (gr/U.S. gal) at 60°F
x 0.0700 = Grains per imperial gallon (gr/imp gal) at 62°F
x 8.328 = Pounds per million U.S. gallons at 60°F
Pascals – Pa
x 1 = Newtons per square mater (N/m²)
x 1.450 x 10-4
= Pounds-force per square inch (psi)
x 1.0197 x 10-5
x 10-3
= Kilopascals (kPa)
Pennyweights – dwt troy
x 1.5552 = Grams (g)
x 24 = Grains (gr)
Poises – P
x 0.1000 = Newton-seconds per square meter (N • s/m²)
x 100 = Centipoises (cP)
x 2.0886 x 10-3
= Pound-force-seconds per square foot (lbf • s/ft²)
x 0.06721 = Pounds per foot second (lb/ft • s)
Pounds-Force – lbf av.
x 0.4536 = Kilograms-force (kgf)
Pounds – lb. av.
x 453.6 = Grams (g)
x 16 = Ounces (oz) av.
x 256 = Drams (dr) av.
x 7000 = Grains (fr)
x 5 x 10-4
= Tons (ton) short
Pounds per Cubic Foot
x 7000 = Grams/cubic ft.
x 1.6x107
= Mg/cubic meter
Pounds – lb troy
x 373.2 = Grams (g)
x 12 = Ounces (oz) troy
x 240 = Pennyweights (dwt) troy
x 5760 = Grains (gr)
x 13.166 = Ounces (oz) av.
x 3.6735 x 10-4
= Tons (ton) long
x 4.1143 x 10-4
= Tons (ton) short
x 3.7324 x 10-4
= Tonnes (t) metric tons

103
Pounds-Mass of Water at 60°F
x 0.45398 = Liters (l)
x 0.01603 =Cubic feet (ft³)
Pounds of Water per Minute at 60°F
x 7.576 = Cubic centimeters per second (cm³/s)
x 2.675 x 10-4
Pounds per Cubic Foot – lb/ft³
x 16.018 = Kilograms per cubic meter (kg/m³)
x 0.016018 = Grams per cubic centimeter (g/cm³)
x 5.787 x 10-4
= Pounds per cubic inch (lb/in³)
Pounds per Cubic Inch – lb/in³
x 2.768 x 104
= Kilograms per cubic meter (kg/m³)
x 27.68 = Grams per cubic centimeter (g/cm³)
x 1728 = Pounds per cubic foot (lb/ft³)
Pounds-Force per Foot – lbt/fl
x 1.488 = Kilograms-force per meter (kgf/m)
x 14.88 = Grams-force per centimeter (gf/cm)
Pounds-Force per Square Foot – lbf/ft²
x 47.88 = Pascals (Pa)
x 4.882 x 10-4
x 6.944 x 10-3
= Pounds-force per square inch (psi)
Pounds-Force per Square Inch – psi
Quarts – qt dry
Quarts – qt liquid

104
Quintals – obsolete metric mass term
x 100 = Kilograms (kg)
x 220.46 = Pounds (lb) U.S. av.
x 101.28 = Pounds (lb) Argentina
x 129.54 = Pounds (lb) Brazil
x 101.41 = Pounds (lb) Chile
x 101.47 = Pounds (lb) Mexico
x 101.43 = Pounds (lb) Peru
Radians – rad
x 57.30 = Degrees (°) angular
Radians per Second – rad/s
x 57.30 = Degrees per second (°/s) angular
Stokes – St
x 10-4
= Square meters per second (m²/s)
x 1.076 x 10-3
= Square feet per second (ft²/s)
Tons-Mass – tonm long
x 2240 = Pounds (lb) av.
x 1.1200 = Tons (ton) short
Tonnes – t metric ton, millier
x 2204.6 = Pounds (lb)
Tonnes-Force – tf metric ton-force
Tons – ton short
x 907.2 = Kilograms (kg)
x 0.9072 = Tonnes (t)
x 2000 = Pounds (lb) av.
x 32000 = Ounces (oz) av.
x 0.8929 = Tons (ton) long
Tons of Water per 24 Hours at 60°F
x 83.33 = Pounds of water per hour (lb/h H2O) at 60°F
x 1.338 = Cubic feet per hour (cfh)

105
Watts - W
x 44.25 = Foot-pounds-force per minute (ft – lbf/min)
x 0.7376 = Foot-pounds-force per second (ft – lbf//s)
x 1.341 x 10-3
= Horsepower (hp)
Watt-Hours – W • h
x 3600 = Joules (J)
x 3.413 = British thermal units (Btu) (see note)
x 2655 = Foot-pounds-force (ft • lbf)
x 1.341 x 10-3
x 367.1 = Kilograms-force-meters (kgf • m)
NOTE: Significant Figures The precision to which a given conversion factor is know, and its application, determine
the number of significant figures which should be used. While many handbooks and standards give factors contained
in this table to six or more significant figures, the fact that different sources disagree, in many cases, in the fifth or
further indicates that four or five significant figures represent the precision for these factors fairly. At present the
accuracy of process instrumentation, analog or digital, is in the tenth percent region at best, thus needing only three
significant figures. Hence this table is confined to four or five significant figures. The advent of the pocket calculator
(and the use of digital computers in process instrumentation) tends to lead to use of many figures as the calculator will
handle. However, when this exceeds the precision of the data, or the accuracy of the application, such a practice is
misleading and timewasting.

106
Temperature Conversions
°C °F °C °F °C °F °C °F °C °F °C °F
10000 18032 430 806 200 392.0 77 170.6 34 93.2 -9 15.8
9500 17132 420 788 195 383.0 76 168.8 33 91.4 -10 14.0
9000 16232 410 770 190 374.0 75 167.0 32 89.6 -11 12.2
8500 15332 400 752 185 365.0 74 165.2 31 87.8 -12 10.4
8000 14432 395 743 180 356.0 73 163.4 30 86.0 -13 8.6
7500 13532 390 734 175 347.0 72 161.6 29 84.2 -14 6.8
7000 12632 385 725 170 338.0 71 159.8 28 82.4 -15 5.0
6500 11732 380 716 165 329.0 70 158.0 27 80.6 -16 3.2
6000 10832 375 707 160 320.0 69 156.2 26 78.8 -17 1.4
5500 9932 370 698 155 311.0 68 154.4 25 77.0 -18 -0.4
5000 9032 365 689 150 302.0 67 152.6 24 75.2 -19 -2.2
4500 8132 360 680 145 293.0 66 150.8 23 73.4 -20 -4.0
4000 7232 355 671 140 284.0 65 149.0 22 71.6 -21 -5.8
3500 6332 350 662 135 275.0 64 147.2 21 69.8 -22 -7.6
3000 5432 345 653 130 266.0 63 145.4 20 68.0 -23 -9.4
2500 4532 340 644 125 257.0 62 143.6 19 66.2 -24 -11.2
2000 3632 335 635 120 248.0 61 141.8 18 64.4 -25 -13.0
1500 2732 330 626 115 239.0 60 140.0 17 62.6 -26 -14.8
1000 1832 325 617 110 230.0 59 138.2 16 60.8 -27 -16.6
950 1742 320 608 105 221.0 58 136.4 15 59.0 -28 -18.4
900 1652 315 599 100 212.0 57 134.6 14 57.2 -29 -20.2
850 1562 310 590 99 210.2 56 132.8 13 55.4 -30 -22.0
800 1472 305 581 98 208.4 55 131.0 12 53.6 -31 -23.8
750 1382 300 572 97 206.6 54 129.2 11 51.8 -32 -25.6
700 1292 295 563 96 204.8 53 127.4 10 50.0 -33 -27.4
650 1202 290 554 95 203.0 52 125.6 9 48.2 -34 -29.2
600 1112 285 545 94 201.2 51 123.8 8 46.4 -35 -31.0
590 1094 280 536 93 199.4 50 122.0 7 44.6 -36 -32.8
580 1076 275 527 92 197.6 49 120.2 6 42.8 -37 -34.6
570 1058 270 518 91 195.8 48 118.4 5 41.0 -38 -36.4
560 1040 265 509 90 194.0 47 116.6 4 39.2 -39 -38.2
550 1022 260 500 89 192.2 46 114.8 3 37.4 -40 -40.0
540 1004 255 491 88 190.4 45 113.0 2 35.6 -50 -58.0
530 986 250 482 87 188.6 44 111.2 1 33.8 -60 -76.0
520 968 245 473 86 186.8 43 109.4 0 32.0 -70 -94.0
510 950 240 464 85 185.0 42 107.6 -1 30.2 -80 -112.0
500 932 235 455 84 183.2 41 105.8 -2 28.4 -90 -130.0
490 914 230 446 83 181.4 40 104.0 -3 26.6 -100 -148.0
480 896 225 437 82 179.6 39 102.2 -4 24.8 -125 -193.0
470 878 220 428 81 177.8 38 100.4 -5 23.0 -150 -238.0
460 860 215 419 80 176.0 37 98.6 -6 21.2 -200 -328.0
450 842 210 410 79 174.2 36 96.8 -7 19.4 -250 -418.0
440 824 205 401 78 172.4 35 95.0 -8 17.6 -273 459.4
°C = Degrees Centigrade (Celsius scale). 1 unit is 1/100 of the difference between the temperature of melting ice and boiling water at standard
temperature and pressure.
°F = Degrees Fahrenheit. 1 unit is 1/180 of the difference between the temperature of melting ice and boiling water at standard temperature
and pressure.
°C = 5/9 (°F-32) °F = 9/5 °C + 32
Absolute Zero = 0°K = -273.16°C = -459.69°F
°K = Degrees Kelvin (Absolute temperature). This scale is based on the average kinetic energy per molecule of a perfect gas and uses the same
ske degrees as the Centigrade scale. Zero (0°K) on the scale is the temperature at which a perfect gas has lost all of its energy.

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