Cookbook

ENGINEERING COOKBOOK

A Handbook
LOREN COOK COMPANY for the
2015 E. DALE STREET SPRINGFIELD, MO 65803-4637 Mechanical
417.869.6474 FAX 417.862.3820 Designer
www.lorencook.com

A Handbook
for the
Mechanical Designer

Second Edition
Copyright 1999

This handy engineering
information guide is a token of
Loren Cook Company’s appreciation
to the many ﬁne mechanical designers
in our industry.

Springﬁeld, MO

Table of Contents
Fan Basics
Fan Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Fan Selection Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Fan Laws. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fan Performance Tables and Curves . . . . . . . . . . . . . . . . . . 2
Fan Testing - Laboratory, Field . . . . . . . . . . . . . . . . . . . . . . . 2
Air Density Factors for Altitude and Temperature . . . . . . . . . 3
Use of Air Density Factors - An Example . . . . . . . . . . . . . . . 3
Classifications for Spark Resistant Construction . . . . . . . .4-5
Impeller Designs - Centrifugal. . . . . . . . . . . . . . . . . . . . . . .5-6
Impeller Designs - Axial . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Terminology for Centrifugal Fan Components. . . . . . . . . . . . 8
Drive Arrangements for Centrifugal Fans . . . . . . . . . . . . .9-10
Rotation & Discharge Designations for Centrifugal Fans 11-12
Motor Positions for Belt or Chain Drive Centrifugal Fans . . 13
Fan Installation Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 14
Fan Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . 15
Motor and Drive Basics
Definitions and Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Types of Alternating Current Motors . . . . . . . . . . . . . . . .17-18
Motor Insulation Classes. . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Motor Service Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Locked Rotor KVA/HP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Motor Efficiency and EPAct . . . . . . . . . . . . . . . . . . . . . . . . . 20
Full Load Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21-22
General Effect of Voltage and Frequency . . . . . . . . . . . . . . 23
Allowable Ampacities of Not More Than Three
Insulated Conductors . . . . . . . . . . . . . . . . . . . . . . . . .24-25
Belt Drives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Estimated Belt Drive Loss . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Bearing Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
System Design Guidelines
General Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Process Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Kitchen Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Rules of Thumb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31-32
Noise Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Table of Contents
System Design Guidelines (cont.)
Sound Power and Sound Power Level. . . . . . . . . . . . . . . . . 32
Sound Pressure and Sound Pressure Level . . . . . . . . . . . . 33
Room Sones —dBA Correlation . . . . . . . . . . . . . . . . . . . . . 33
Noise Criteria Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Design Criteria for Room Loudness. . . . . . . . . . . . . . . . . 35-36
Vibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Vibration Severity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-39
General Ventilation Design
Air Quality Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Air Change Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Suggested Air Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Ventilation Rates for Acceptable Indoor Air Quality . . . . . . . 42
Heat Gain From Occupants of Conditioned Spaces . . . . . . 43
Heat Gain From Typical Electric Motors. . . . . . . . . . . . . . . . 44
Rate of Heat Gain Commercial Cooking Appliances in
Air-Conditioned Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Rate of Heat Gain From Miscellaneous Appliances . . . . . . 46
Filter Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Relative Size Chart of Common Air Contaminants . . . . . . . 47
Optimum Relative Humidity Ranges for Health . . . . . . . . . . 48
Duct Design
Backdraft or Relief Dampers . . . . . . . . . . . . . . . . . . . . . . . . 49
Screen Pressure Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Duct Resistance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Rectangular Equivalent of Round Ducts . . . . . . . . . . . . . . . 52
Typical Design Velocities for HVAC Components. . . . . . . . . 53
Velocity and Velocity Pressure Relationships . . . . . . . . . . . 54
U.S. Sheet Metal Gauges . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Recommended Metal Gauges for Ducts . . . . . . . . . . . . . . . 56
Wind Driven Rain Louvers . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Heating & Refrigeration
Moisture and Air Relationships . . . . . . . . . . . . . . . . . . . . . . 57
Properties of Saturated Steam . . . . . . . . . . . . . . . . . . . . . . 58
Cooling Load Check Figures . . . . . . . . . . . . . . . . . . . . . . 59-60
Heat Loss Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61-62
Fuel Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Fuel Gas Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table of Contents
Heating & Refrigeration (cont.)
Estimated Seasonal Efficiencies of Heating Systems . . . . 63
Annual Fuel Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63-64
Pump Construction Types . . . . . . . . . . . . . . . . . . . . . . . . . 64
Pump Impeller Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Pump Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Pump Mounting Methods . . . . . . . . . . . . . . . . . . . . . . . . . 65
Affinity Laws for Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Pumping System Troubleshooting Guide . . . . . . . . . . . 67-68
Pump Terms, Abbreviations, and Conversion Factors . . . . 69
Common Pump Formulas . . . . . . . . . . . . . . . . . . . . . . . . . 70
Water Flow and Piping . . . . . . . . . . . . . . . . . . . . . . . . . 70-71
Friction Loss for Water Flow . . . . . . . . . . . . . . . . . . . . . 71-72
Equivalent Length of Pipe for Valves and Fittings . . . . . . . 73
Standard Pipe Dimensions . . . . . . . . . . . . . . . . . . . . . . . . 74
Copper Tube Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . 74
Typical Heat Transfer Coefficients . . . . . . . . . . . . . . . . . . . 75
Fouling Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Cooling Tower Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Evaporate Condenser Ratings . . . . . . . . . . . . . . . . . . . . . 78
Compressor Capacity vs. Refrigerant Temperature at
100°F Condensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Refrigerant Line Capacities for 134a . . . . . . . . . . . . . . . . . 79
Refrigerant Line Capacities for R-22 . . . . . . . . . . . . . . . . . 79
Refrigerant Line Capacities for R-502 . . . . . . . . . . . . . . . . 80
Refrigerant Line Capacities for R-717 . . . . . . . . . . . . . . . . 80
Formulas & Conversion Factors
Miscellaneous Formulas . . . . . . . . . . . . . . . . . . . . . . . . 81-84
Area and Circumference of Circles . . . . . . . . . . . . . . . . 84-87
Circle Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Common Fractions of an Inch . . . . . . . . . . . . . . . . . . . . 87-88
Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-94
Psychometric Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96-103

Fan Basics
Fan Types
Axial Fan - An axial fan discharges air parallel to the axis of the
impeller rotation. As a general rule, axial fans are preferred for
high volume, low pressure, and non-ducted systems.
Axial Fan Types
Propeller, Tube Axial and Vane Axial.
Centrifugal Fan - Centrifugal fans discharge air perpendicular to
the axis of the impeller rotation. As a general rule, centrifugal
fans are preferred for higher pressure ducted systems.
Centrifugal Fan Types
Backward Inclined, Airfoil, Forward Curved, and Radial Tip.
Fan Selection Criteria
Before selecting a fan, the following information is needed.
• Air volume required - CFM
• System resistance - SP
• Air density (Altitude and Temperature)
• Type of service
• Environment type
• Materials/vapors to be exhausted
• Operation temperature
• Space limitations
• Fan type
• Drive type (Direct or Belt)
• Noise criteria
• Number of fans
• Discharge
• Rotation
• Motor position
• Expected fan life in years

1

Fan Basics
Fan Laws
The simplified form of the most commonly used fan laws
include.
• CFM varies directly with RPM
CFM1/CFM2 = RPM1/RPM2
• SP varies with the square of the RPM
SP1/SP2 = (RPM1/RPM2)2
• HP varies with the cube of the RPM
HP1/HP2 = (RPM1/RPM2)3
Fan Performance Tables and Curves
Performance tables provide a simple method of fan selection.
However, it is critical to evaluate fan performance curves in the
fan selection process as the margin for error is very slim when
selecting a fan near the limits of tabular data. The perfor-
mance curve also is a valuable tool when evaluating fan perfor-
mance in the field.
Fan performance tables and curves are based on standard air
density of 0.075 lb/ft3. When altitude and temperature differ sig-
nificantly from standard conditions (sea level and 70° F) perfor-
mance modification factors must be taken into account to ensure
proper performance.
For further information refer to Use of Air Density Factors -
An Example, page 3.
Fan Testing - Laboratory, Field
Fans are tested and performance certified under ideal labora-
tory conditions. When fan performance is measured in field con-
ditions, the difference between the ideal laboratory condition and
the actual field installation must be considered. Consideration
must also be given to fan inlet and discharge connections as they
will dramatically affect fan performance in the field. If possible,
readings must be taken in straight runs of ductwork in order to
ensure validity. If this cannot be accomplished, motor amperage
and fan RPM should be used along with performance curves to
estimate fan performance.
For further information refer to Fan Installation Guidelines,
page 14.

2

Fan Basics
Air Density Factors for Altitude and Temperature
Altitude Temperature
(ft.) 70 100 200 300 400 500 600 700
0 1.000 .946 .803 .697 .616 .552 .500 .457
1000 .964 .912 .774 .672 .594 .532 .482 .441
2000 .930 .880 .747 .648 .573 .513 .465 .425
3000 .896 .848 .720 .624 .552 .495 .448 .410
4000 .864 .818 .694 .604 .532 .477 .432 .395
5000 .832 .787 .668 .580 .513 .459 .416 .380
6000 .801 .758 .643 .558 .493 .442 .400 .366
7000 .772 .730 .620 .538 .476 .426 .386 .353
8000 .743 .703 .596 .518 .458 .410 .372 .340
9000 .714 .676 .573 .498 .440 .394 .352 .326
10000 .688 .651 .552 .480 .424 .380 .344 .315
15000 .564 .534 .453 .393 .347 .311 .282 .258
20000 .460 .435 .369 .321 .283 .254 .230 .210

Use of Air Density Factors - An Example
A fan is selected to deliver 7500 CFM at 1-1/2 inch SP at an
altitude of 6000 feet above sea level and an operating tempera-
ture of 200° F. From the table above, Air Density Factors for
Altitude and Temperature, the air density correction factor is
determined to be .643 by using the fan’s operating altitude and
temperature. Divide the design SP by the air density correction
factor.
1.5” SP/.643 = 2.33” SP
Referring to the fan’s performance rating table, it is determined
that the fan must operate at 976 RPM to develop the desired 7500
CFM at 6000 foot above sea level and at an operating tempera-
ture of 200° F.
The BHP (Brake Horsepower) is determined from the fan’s per-
formance table to be 3.53. This is corrected to conditions at alti-
tude by multiplying the BHP by the air density correction factor.
3.53 BHP x .643 = 2.27 BHP
The ﬁnal operating conditions are determined to be 7500 CFM,
1-1/2” SP, 976 RPM, and 2.27 BHP.

3

Fan Basics
Classifications for Spark Resistant Construction†
Fan applications may involve the handling of potentially explo-
sive or ﬂammable particles, fumes or vapors. Such applications
require careful consideration of all system components to insure
the safe handling of such gas streams. This AMCA Standard
deals only with the fan unit installed in that system. The Standard
contains guidelines which are to be used by both the manufac-
turer and user as a means of establishing general methods of
construction. The exact method of construction and choice of
alloys is the responsibility of the manufacturer; however, the cus-
tomer must accept both the type and design with full recognition
of the potential hazard and the degree of protection required.
Construction Type
A. All parts of the fan in contact with the air or gas being han-
dled shall be made of nonferrous material. Steps must also
be taken to assure that the impeller, bearings, and shaft are
adequately attached and/or restrained to prevent a lateral
or axial shift in these components.
B. The fan shall have a nonferrous impeller and nonferrous
ring about the opening through which the shaft passes. Fer-
rous hubs, shafts, and hardware are allowed provided con-
struction is such that a shift of impeller or shaft will not
permit two ferrous parts of the fan to rub or strike. Steps
must also be taken to assure the impeller, bearings, and
shaft are adequately attached and/or restrained to prevent
a lateral or axial shift in these components.
C. The fan shall be so constructed that a shift of the impeller or
shaft will not permit two ferrous parts of the fan to rub or
strike.
Notes
1. No bearings, drive components or electrical devices shall
be placed in the air or gas stream unless they are con-
structed or enclosed in such a manner that failure of that
component cannot ignite the surrounding gas stream.
2. The user shall electrically ground all fan parts.
3. For this Standard, nonferrous material shall be a material
with less than 5% iron or any other material with demon-
strated ability to be spark resistant.

†Adapted from AMCA Standard 99-401-86
4

Fan Basics
Classifications for Spark Resistant Construction
(cont.)
4. The use of aluminum or aluminum alloys in the presence of
steel which has been allowed to rust requires special consid-
eration. Research by the U.S. Bureau of Mines and others
has shown that aluminum impellers rubbing on rusty steel
may cause high intensity sparking.
The use of the above Standard in no way implies a guarantee of
safety for any level of spark resistance. “Spark resistant construc-
tion also does not protect against ignition of explosive gases
caused by catastrophic failure or from any airstream material that
may be present in a system.”
Standard Applications
• Centrifugal Fans
• Axial and Propeller Fans
• Power Roof Ventilators
This standard applies to ferrous and nonferrous metals.
The potential questions which may be associated with fans
constructed of FRP, PVC, or any other plastic compound
were not addressed.
Impeller Designs - Centrifugal
Airfoil - Has the highest efficiency of all of the centrifugal impeller
designs with 9 to 16 blades of airfoil contour
curved away from the direction of rotation.
Air leaves the impeller at a velocity less than
its tip speed. Relatively deep blades provide
for efficient expansion with the blade pas-
sages. For the given duty, the airfoil impeller
design will provide for the highest speed of
the centrifugal fan designs.
Applications - Primary applications include general heating sys-
tems, and ventilating and air conditioning systems. Used in larger
sizes for clean air industrial applications providing significant
power savings.

5

Fan Basics
Impeller Designs - Centrifugal (cont.)
Backward Inclined, Backward Curved - Efficiency is slightly
less than that of the airfoil design. Backward
inclined or backward curved blades are single
thickness with 9 to 16 blades curved or
inclined away from the direction of rotation.
Air leaves the impeller at a velocity less than
its tip speed. Relatively deep blades provide
efficient expansion with the blade passages.
Applications - Primary applications include general heating sys-
tems, and ventilating and air conditioning systems. Also used in
some industrial applications where the airfoil blade is not accept-
able because of a corrosive and/or erosive environment.
Radial - Simplest of all centrifugal impellers and least efficient.
Has high mechanical strength and the impel-
ler is easily repaired. For a given point of rat-
ing, this impeller requires medium speed.
Classification includes radial blades and mod-
ified radial blades), usually with 6 to 10
blades.
Applications - Used primarily for material
handling applications in industrial plants. Impeller can be of rug-
ged construction and is simple to repair in the field. Impeller is
sometimes coated with special material. This design also is used
for high pressure industrial requirements and is not commonly
found in HVAC applications.
Forward Curved - Efficiency is less than airfoil and backward
curved bladed impellers. Usually fabricated at
low cost and of lightweight construction. Has
24 to 64 shallow blades with both the heel
and tip curved forward. Air leaves the impeller
at velocities greater than the impeller tip
speed. Tip speed and primary energy trans-
ferred to the air is the result of high impeller
velocities. For the given duty, the wheel is the
smallest of all of the centrifugal types and operates most effi-
ciently at lowest speed.
Applications - Primary applications include low pressure heat-
ing, ventilating, and air conditioning applications such as domes-
tic furnaces, central station units, and packaged air conditioning
equipment from room type to roof top units.

6

Fan Basics
Impeller Designs - Axial
Propeller - Efficiency is low and usually limited to low pressure
applications. Impeller construction costs are
also usually low. General construction fea-
tures include two or more blades of single
thickness attached to a relatively small hub.
Energy transfer is primarily in form of velocity
pressure.
Applications - Primary applications include
low pressure, high volume air moving applications such as air cir-
culation within a space or ventilation through a wall without
attached duct work. Used for replacement air applications.
Tube Axial - Slightly more efficient than propeller impeller design
and is capable of developing a more useful
static pressure range. Generally, the number
of blades range from 4 to 8 with the hub nor-
mally less than 50 percent of fan tip diameter.
Blades can be of airfoil or single thickness
cross section.
low and medium pressure ducted heating, ventilating, and air
conditioning applications where air distribution on the down-
stream side is not critical. Also used in some industrial applica-
tions such as drying ovens, paint spray booths, and fume
exhaust systems.
Vane Axial - Solid design of the blades permits medium to high
pressure capability at good efficiencies. The
most efficient fans of this type have airfoil
blades. Blades are fixed or adjustable pitch
types and the hub is usually greater than 50
percent of the fan tip diameter.
general heating, ventilating, and air condition-
ing systems in low, medium, and high pressure applications.
Advantage where straight through flow and compact installation
are required. Air distribution on downstream side is good. Also
used in some industrial applications such as drying ovens, paint
spray booths, and fume exhaust systems. Relatively more com-
pact than comparable centrifugal type fans for the same duty.

7

Fan Basics
Terminology for Centrifugal Fan Components
Housing

Shaft Cutoff

Impeller

Side Panel

Blast Area
Discharge
Back Plate
Outlet
Area
Blade

Inlet

Cutoff
Scroll

Shroud Impeller Frame

Bearing Inlet Collar
Support

8

Fan Basics
Drive Arrangements for Centrifugal Fans†
SW - Single Width, SI - Single Inlet
DW - Double Width, DI - Double Inlet

Arr. 1 SWSI - For belt drive Arr. 2 SWSI - For belt drive
or direct drive connection. or direct drive connection.
Impeller over-hung. Two Impeller over-hung. Bearings
bearings on base. in bracket supported by fan
housing.

Arr. 3 SWSI - For belt drive Arr. 3 DWDI - For belt drive
or direct drive connection. or direct connection. One
One bearing on each side bearing on each side and
supported by fan housing. supported by fan housing.

9

Fan Basics
Drive Arrangements for Centrifugal Fans (cont.)
SW - Single Width, SI - Single Inlet
DW - Double Width, DI - Double Inlet

Arr. 4 SWSI - For direct Arr. 7 SWSI - For belt drive
drive. Impeller over-hung on or direct connection.
prime mover shaft. No bear- Arrangement 3 plus base for
ings on fan. Prime mover prime mover.
base mounted or integrally
directly connected.

Arr. 7 DWDI - For belt drive Arr. 8 SWSI - For belt drive
or direct connection. or direct connection.
Arrangement 3 plus base for Arrangement 1 plus
prime mover. extended base for prime
mover.

Arr. 9 SWSI - For belt drive. Arr. 10 SWSI - For belt
Impeller overhung, two drive. Impeller overhung,
bearings, with prime mover two bearings, with prime
outside base. mover inside base.

10

Fan Basics
Rotation & Discharge Designations for
Centrifugal Fans*
Top Horizontal

Clockwise Counterclockwise
Top Angular Down

Top Angular Up

Down Blast

* Rotation is always as viewed from drive side.

11

Fan Basics
Rotation & Discharge Designations for
Centrifugal Fans* (cont.)
Up Blast

Bottom Horizontal


Bottom Angular Down

Bottom Angular Up


* Rotation is always as viewed from drive side.

12

Fan Basics
Motor Positions for Belt Drive Centrifugal Fans†

To determine the location of the motor, face the drive side of the
fan and pick the proper motor position designated by the letters
W, X, Y or Z as shown in the drawing below.


13

Fan Basics
Fan Installation Guidelines
Centrifugal Fan Conditions
Typical Inlet Conditions
Correct Installations
Limit slope to Limit slope to
15° converging 7° diverging

x
Cross-sectional Cross-sectional
area not greater area not greater Minimum of 2-1/2
than 112-1/2% of than 92-1/2% of inlet diameters
inlet area inlet area (3 recommended)

Incorrect Installations

Turbulence
Turbulence

Typical Outlet Conditions
Correct Installations
Limit slope to
7° diverging Limit slope to
15° converging

x

Cross-sectional area Cross-sectional area Minimum of 2-1/2
not greater than 105% not greater than 95% outlet diameters
of outlet area of outlet area (3 recommended)

Incorrect Installations

Turbulence Turbulence

14

Fan Basics
Fan Troubleshooting Guide
Low Capacity or Pressure
• Incorrect direction of rotation – Make sure the fan rotates in
same direction as the arrows on the motor or belt drive
assembly.
• Poor fan inlet conditions –There should be a straight, clear
duct at the inlet.
• Improper wheel alignment.
Excessive Vibration and Noise
• Damaged or unbalanced wheel.
• Belts too loose; worn or oily belts.
• Speed too high.
• Incorrect direction of rotation. Make sure the fan rotates in
assembly.
• Bearings need lubrication or replacement.
• Fan surge.
Overheated Motor
• Motor improperly wired.
• Incorrect direction of rotation. Make sure the fan rotates in
assembly.
• Cooling air diverted or blocked.
• Improper inlet clearance.
• Incorrect fan RPM.
• Incorrect voltage.
Overheated Bearings
• Improper bearing lubrication.
• Excessive belt tension.

15

Definitions and Formulas
Alternating Current: electric current that alternates or reverses
at a defined frequency, typically 60 cycles per second (Hertz) in
the U.S. and 50 Hz in Canada and other nations.
Breakdown Torque: the maximum torque a motor will develop
with rated voltage and frequency applied without an abrupt drop
in speed.
Efficiency: a rating of how much input power an electric motor
converts to actual work at the rotating shaft expressed in per-
cent.
% efficiency = (power out / power in) x 100
Horsepower: a rate of doing work expressed in foot-pounds per
minute.
HP = (RPM x torque) / 5252 lb-ft.
Locked Rotor Torque: the minimum torque that a motor will
develop at rest for all angular positions of the rotor with rated volt-
age and frequency applied.
Rated Load Torque: the torque necessary to produce rated
horsepower at rated-load speed.
Single Phase AC: typical household type electric power
consisting of a single alternating current at 110-115 volts.
Slip: the difference between synchronous speed and actual
motor speed. Usually expressed in percent slip.
(synchronous speed - actual speed)
% slip = X 100
synchronous speed
Synchronous speed: the speed of the rotating magnetic field in
an electric motor.
Synchronous Speed = (60 x 2f) / p
Where: f = frequency of the power supply
p = number of poles in the motor
Three Phase AC: typical industrial electric power consisting of 3
alternating currents of equal frequency differing in phase of 120
degrees from each other. Available in voltages ranging from 200
to 575 volts for typical industrial applications.
Torque: a measure of rotational force defined in foot-pounds or
Newton-meters.
Torque = (HP x 5252 lb-ft.) / RPM

16

Types of Alternating Current Motors
Single Phase AC Motors
This type of motor is used in fan applications requiring less
than one horsepower. There are four types of motors suitable for
driving fans as shown in the chart below. All are single speed
motors that can be made to operate at two or more speeds with
internal or external modifications.
Single Phase AC Motors (60hz)
HP Poles/
Motor Type Efficiency Slip Use
Range RPM
small direct drive
1/6 to low high 4/1550
Shaded Pole fans (low start
1/4 hp (30%) (14%) 6/1050
torque)
small direct drive
Perm-split Up to medium medium 4/1625
fans (low start
Cap. 1/3 hp (50%) (10%) 6/1075
torque)
2/3450
small belt drive
Up to medium- low 4/1725
Split-phase fans (good start
1/2 hp high (65%) (4%) 6/1140
torque)
8/850
2/3450
small belt drive
Capacitor- 1/2 to medium- low 4/1725
fans (good start
start 34 hp high (65%) (4%) 6/1140
torque)
8/850
Three-phase AC Motors
The most common motor for fan applications is the three-
phase squirrel cage induction motor. The squirrel-cage motor is
a constant speed motor of simple construction that produces rel-
atively high starting torque. The operation of a three-phase
motor is simple: the three phase current produces a rotating
magnetic field in the stator. This rotating magnetic field causes a
magnetic field to be set up in the rotor. The attraction and repul-
sion of these two magnetic fields causes the rotor to turn.
Squirrel cage induction motors are wound for the following
speeds:
Number of 60 Hz 50 Hz
Poles Synchronous Speed Synchronous Speed
2 3600 3000
4 1800 1500
6 1200 1000
8 900 750

17

Types of Alternating Current Motors
Actual motor speed is somewhat less than synchronous speed
due to slip. A motor with a slip of 5% or less is called a “normal
slip” motor. A normal slip motor may be referred to as a constant
speed motor because the speed changes very little with load
variations. In specifying the speed of the motor on the nameplate
most motor manufacturers will use the actual speed of the motor
which will be less than the synchronous speed due to slip.
NEMA has established several different torque designs to cover
various three-phase motor applications as shown in the chart.
NEMA Starting Locked Breakdown % Slip
Design Current Rotor Torque
Medium Max.
B Medium High
Torque 5%
High Max.
C Medium Medium
Torque 5%
Extra-High 5%
D Medium Low
Torque or more
NEMA
Applications
Design
Normal starting torque for fans, blowers, rotary
B pumps, compressors, conveyors, machine tools.
Constant load speed.
High inertia starts - large centrifugal blowers, ﬂy
wheels, and crusher drums. Loaded starts such as
C piston pumps, compressors, and conveyers. Con-
stant load speed.
Very high inertia and loaded starts. Also consider-
able variation in load speed. Punch presses,
D shears and forming machine tools. Cranes, hoists,
elevators, and oil well pumping jacks.
Motor Insulation Classes
Electric motor insulation classes are rated by their resistance
to thermal degradation. The four basic insulation systems nor-
mally encountered are Class A, B, F, and H. Class A has a tem-
perature rating of 105°C (221°F) and each step from A to B, B to
F, and F to H involves a 25° C (77° F) jump. The insulation class
in any motor must be able to withstand at least the maximum
ambient temperature plus the temperature rise that occurs as a
result of continuous full load operation.
18

Motor Service Factors
Some motors can be specified with service factors other than
1.0. This means the motor can handle loads above the rated
horsepower. A motor with a 1.15 service factor can handle a
15% overload, so a 10 horsepower motor can handle 11.5 HP of
load. In general for good motor reliability, service factor should
not be used for basic load calculations. By not loading the motor
into the service factor under normal use the motor can better
withstand adverse conditions that may occur such as higher than
normal ambient temperatures or voltage fluctuations as well as
the occasional overload.
Locked Rotor KVA/HP
Locked rotor kva per horsepower is a rating commonly speci-
fied on motor nameplates. The rating is shown as a code letter
on the nameplate which represents various kva/hp ratings.
Code Letter kva/hp Code Letter kva/hp
A 0 - 3.15 L 9.0 - 10.0
B 3.15 - 3.55 M 10.0 - 11.2
C 3.55 - 4.0 N 11.2 - 12.5
D 4.0 - 4.5 P 12.5 - 14.0
E 4.5 - 5.0 R 14.0 - 16.0
F 5.0 - 5.6 S 16.0 - 18.0
G 5.6 - 6.3 T 18.0 - 20.0
H 6.3 - 7.1 U 20.0 - 22.4
J 7.1 - 8.0 V 22.4 and up
K 8.0 - 9.0
The nameplate code rating is a good indication of the starting
current the motor will draw. A code letter at the beginning of the
alphabet indicates a low starting current and a letter at the end of
the alphabet indicates a high starting current. Starting current
can be calculated using the following formula:
Starting current = (1000 x hp x kva/hp) / (1.73 x Volts)

19

Motor Efficiency and EPAct
As previously defined, motor efficiency is a measure of how
much input power a motor converts to torque and horsepower at
the shaft. Efficiency is important to the operating cost of a motor
and to overall energy use in our economy. It is estimated that
over 60% of the electric power generated in the United States is
used to power electric motors. On October 24, 1992, the U.S.
Congress signed into law the Energy Policy Act (EPAct) that
established mandated efficiency standards for general purpose,
three-phase AC industrial motors from 1 to 200 horsepower.
EPAct became effective on October 24, 1997.

Department of Energy
General Purpose Motors
Required Full-Load Nominal Efficiency
Under EPACT-92
Nominal Full-Load Efficiency
Motor
Open Motors Enclosed Motors
HP
6 Pole 4 Pole 2 Pole 6 Pole 4 Pole 2 Pole
1 80.0 82.5 80.0 82.5 75.5
1.5 84.0 84.0 82.5 85.5 84.0 82.5
2 85.5 84.0 84.0 86.5 84.0 84.0
3 86.5 86.5 84.0 87.5 87.5 85.5
5 87.5 87.5 85.5 87.5 87.5 87.5
7.5 88.5 88.5 87.5 89.5 89.5 88.5
10 90.2 89.5 88.5 89.5 89.5 89.5
15 90.2 91.0 89.5 90.2 91.0 90.2
20 91.0 91.0 90.2 90.2 91.0 90.2
25 91.7 91.7 91.0 91.7 92.4 91.0
30 92.4 92.4 91.0 91.7 92.4 91.0
40 93.0 93.0 91.7 93.0 93.0 91.7
50 93.0 93.0 92.4 93.0 93.0 92.4
60 93.6 93.6 93.0 93.6 93.6 93.0
75 93.6 94.1 93.0 93.6 94.1 93.0
100 94.1 94.1 93.0 94.1 94.5 93.6
125 94.1 94.5 93.6 94.1 94.5 94.5
150 94.5 95.0 93.6 95.0 95.0 94.5
200 94.5 95.0 94.5 95.0 95.0 95.0
20

Full Load Current†
Single Phase Motors
HP 115V 200V 230V
1/6 4.4 2.5 2.2
1/4 5.8 3.3 2.9
1/3 7.2 4.1 3.6
1/2 9.8 5.6 4.9
3/4 13.8 7.9 6.9
1 16 9.2 8
1-1/2 20 11.5 10
2 24 13.8 12
3 34 19.6 17
5 56 32.2 28
7-1/2 80 46 40
10 100 57.5 50
† Based on Table 430-148 of the National Electric Code®, 1993.
For motors running at usual speeds and motors with normal
torque characteristics.

21

Full Load Current†
Three Phase Motors
A-C Induction Type-Squirrel Cage and Wound Rotor Motors*
HP 115V 200V 230V 460V 575V 2300V 4000V
1/2 4 2.3 2 1 0.8
3/4 5.6 3.2 2.8 1.4 1.1
1 7.2 4.15 3.6 1.8 1.4
1-1/2 10.4 6 5.2 2.6 2.1
2 13.6 7.8 6.8 3.4 2.7
3 11 9.6 4.8 3.9
5 17.5 15.2 7.6 6.1
7-1/2 25 22 11 9
10 32 28 14 11
15 48 42 21 17
20 62 54 27 22
25 78 68 34 27
30 92 80 40 32
40 120 104 52 41
50 150 130 65 52
60 177 154 77 62 15.4 8.8
75 221 192 96 77 19.2 11
100 285 248 124 99 24.8 14.3
125 358 312 156 125 31.2 18
150 415 360 180 144 36 20.7
200 550 480 240 192 48 27.6
Over 200 hp
2.75 2.4 1.2 0.96 .24 .14
Approx. Amps/hp
† Branch-circuit conductors supplying a single motor shall have
an ampacity not less than 125 percent of the motor full-load
current rating.
Based on Table 430-150 of the National Electrical Code®,
1993. For motors running at speeds usual for belted motors
and with normal torque characteristics.
* For conductor sizing only

22

General Effect of Voltage and Frequency
Variations on Induction Motor Characteristics
Voltage
Characteristic
110% 90%
Starting Torque Up 21% Down 19%
Maximum Torque Up 21% Down 19%
Percent Slip Down 15-20% Up 20-30%
Efﬁciency - Full Load Down 0-3% Down 0-2%
3/4 Load 0 - Down Slightly Little Change
1/2 Load Down 0-5% Up 0-1%
Power Factor - Full Load Down 5-15% Up 1-7%
3/4 Load Down 5-15% Up 2-7%
1/2 Load Down 10-20% Up 3-10%
Full Load Current Down Slightly to Up 5% Up 5-10%
Starting Current Up 10% Down 10%
Full Load - Temperature Rise Up 10% Down 10-15%
Maximum Overload Capacity Up 21% Down 19%
Magnetic Noise Up Slightly Down Slightly

Frequency
Characteristic
105% 95%
Starting Torque Down 10% Up 11%
Maximum Torque Down 10% Up 11%
Percent Slip Up 10-15% Down 5-10%
Efﬁciency - Full Load Up Slightly Down Slightly
3/4 Load Up Slightly Down Slightly
Power Factor - Full Load Up Slightly Down Slightly
Full Load Current Down Slightly Up Slightly
Starting Current Down 5% Up 5%
Full Load - Temperature Rise Down Slightly Up Slightly
Maximum Overload Capacity Down Slightly Up Slightly
Magnetic Noise Down Slightly Up Slightly

23

Insulated Conductors
Rated 0-2000 Volts, 60° to 90°C (140° to 194°F), in Raceway
or Cable or Earth (directly buried). Based on ambient air temper-
ature of 30°C (86°F).
Temperature Rating of Copper Conductor
60°C (140°F) 75°C (167°F) 90°C (194°F)
Types Types Types
TW†, UF† FEPW†, RH†, RHW†, TA,TBS, SA, SIS, FEP†, FEPB†,
THHW†, THW†, THWN†, MI, RHH†, RHW-2, THHN†,
AWG XHHW†, USE†, ZW† THHW†, THW-2, USE-2, XHH,
kcmil XHHW†, XHHW-2, ZW-2
18 — — 14
16 — — 18
14 20† 20† 25†
12 25† 25† 30†
10 30 35† 40†
8 40 50 55
6 55 65 75
4 70 85 95
3 85 100 110
2 95 115 130
1 110 130 150
1/0 125 150 170
2/0 145 175 195
3/0 165 200 225
4/0 195 230 260
250 215 255 290
300 240 285 320
350 260 310 350
400 280 335 380
500 320 380 430
600 355 420 475
700 385 460 520
750 400 475 535
800 410 490 555
900 435 520 585
1000 455 545 615
1250 495 590 665
1500 520 625 705
1750 545 650 735
2000 560 665 750

24

Insulated Conductors
Temperature Rating of
Aluminum or Copper-Clad Conductor
60°C (140°F) 75°C (167°F) 90°C (194°F)
Types Types
Types
TW†, UF† TA,TBS, SA, SIS, THHN†,
AWG RH†, RHW†, THHW†,
THHW†,THW-2, THWN-2, RHH†,
THW†, THWN†, XHHW†,
kcmil USE†
RHW-S, USE-2, XHH, XHHW,
XHHW-2, ZW-2
12 20† 20† 25†
10 25 30† 35†
8 30 40 45
6 40 50 60
4 55 65 75
3 65 75 85
2 75 90 100
1 85 100 115
1/0 100 120 135
2/0 115 135 150
3/0 130 155 175
4/0 150 180 205
250 170 205 230
300 190 230 255
350 210 250 280
400 225 270 305
500 260 310 350
600 285 340 385
700 310 375 420
750 320 385 435
800 330 395 450
900 355 425 480
1000 375 445 500
1250 405 485 545
1500 435 520 585
1750 455 545 615
2000 470 560 630
†Unless otherwise speciﬁcally permitted elsewhere in this Code, the overcurrent pro-
tection for conductor types marked with an obelisk (†) shall not exceed 15 amperes for
No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper, or 15 amperes for
No. 12 and 25 amperes for No. 10 aluminum and copper-clad aluminum after any cor-
rection factors for ambient temperature and number of conductors have been applied.
Adapted from NFPA 70-1993, National Electrical Code®, Copyright 1992.
25

Belt Drives
Most fan drive systems are based on the standard "V" drive
belt which is relatively efficient and readily available. The use of
a belt drive allows fan RPM to be easily selected through a
combination of AC motor RPM and drive pulley ratios.
In general select a sheave combination that will result in the
correct drive ratio with the smallest sheave pitch diameters.
Depending upon belt cross section, there may be some
minimum pitch diameter considerations. Multiple belts and
sheave grooves may be required to meet horsepower
requirements.
Drive Ratio = Motor RPM
desired fan RPM
V-belt Length Formula
Once a sheave combination is selected we can calculate
approximate belt length. Calculate the approximate V-belt
length using the following formula:
L = Pitch Length of Belt
2
L = 2C+1.57 (D+d)+ (D-d) C = Center Distance of Sheaves
4C D = Pitch Diameter of Large Sheave
d = Pitch Diameter of Small Sheave
Belt Drive Guidelines
1. Drives should always be installed with provision for center
distance adjustment.
2. If possible centers should not exceed 3 times the sum of
the sheave diameters nor be less than the diameter of the
large sheave.
3. If possible the arc of contact of the belt on the smaller
sheave should not be less than 120°.
4. Be sure that shafts are parallel and sheaves are in proper
alignment. Check after first eight hours of operation.
5. Do not drive sheaves on or off shafts. Be sure shaft and
keyway are smooth and that bore and key are of correct
size.
6. Belts should never be forced or rolled over sheaves. More
belts are broken from this cause than from actual failure in
service.
7. In general, ideal belt tension is the lowest tension at which
the belt will not slip under peak load conditions. Check belt
tension frequently during the first 24-48 hours of operation.

26

Estimated Belt Drive Loss†
100
Drive Loss, % Motor Power Output

80
60

40
30
Range of drive losses for standard belts
20 Range of drive losses for standard belts
15
10
8
6

4
3
2
1.5
1
60

100
80

200
20

400
600
30
40

300
10
4

8
3
0.8

6
2
0.4

1
0.6
0.3

Motor Power Output, hp

Higher belt speeds tend to have higher losses than lower belt
speeds at the same horsepower.
Drive losses are based on the conventional V-belt which has
been the “work horse” of the drive industry for several decades.
Example:
• Motor power output is determined to be 13.3 hp.
• The belts are the standard type and just warm to the touch
immediately after shutdown.
• From the chart above, the drive loss = 5.1%
• Drive loss = 0.051 x 13.3 = 0.7 hp
• Fan power input = 13.3 - 0.7 hp = 12.6 hp

† Adapted from AMCA Publication 203-90.

27

Bearing Life
Bearing life is determined in accordance with methods pre-
scribed in ISO 281/1-1989 or the Anti Friction Bearing Manufac-
turers Association (AFBMA) Standards 9 and 11, modified to
follow the ISO standard. The life of a rolling element bearing is
defined as the number of operating hours at a given load and
speed the bearing is capable of enduring before the first signs of
failure start to occur. Since seemingly identical bearings under
identical operating conditions will fail at different times, life is
specified in both hours and the statistical probability that a cer-
tain percentage of bearings can be expected to fail within that
time period.

Example:
A manufacturer specifies that the bearings supplied in a partic-
ular fan have a minimum life of L-10 in excess of 40,000 hours at
maximum cataloged operating speed. We can interpret this
specification to mean that a minimum of 90% of the bearings in
this application can be expected to have a life of at least 40,000
hours or longer. To say it another way, we should expect less
than 10% of the bearings in this application to fail within 40,000
hours.

L-50 is the term given to Average Life and is simply equal to 5
times the Minimum Life. For example, the bearing specified
above has a life of L-50 in excess of 200,000 hours. At least 50%
of the bearings in this application would be expected to have a
life of 200,000 hours or longer.

28

General Ventilation
• Locate intake and exhaust fans to make use of prevailing
winds.
• Locate fans and intake ventilators for maximum sweeping
effect over the working area.
• If ﬁlters are used on gravity intake, size intake ventilator to
keep intake losses below 1/8” SP.
• Avoid fans blowing opposite each other, When necessary,
separate by at least 6 fan diameters.
• Use Class B insulated motors where ambient temperatures
are expected to be high for air-over motor conditions.
• If air moving over motors contains hazardous chemicals or
particles, use explosion-proof motors mounted in or out of the
airstream, depending on job requirements.
• For hazardous atmosphere applications use fans of non-
sparking construction.*
Process Ventilation
• Collect fumes and heat as near the source of generation as
possible.
• Make all runs of ducts as short and direct as possible.
• Keep duct velocity as low as practical considering capture for
fumes or particles being collected.
• When turns are required in the duct system use long radius
elbows to keep the resistance to a minimum (preferably 2
duct diameters).
• After calculating duct resistance, select the fan having
reserve capacity beyond the static pressure determined.
• Use same rationale regarding intake ventilators and motors
as in General Ventilation guidelines above.
• Install the exhaust fan at a location to eliminate any recircula-
tion into other parts of the plant.
• When hoods are used, they should be sufﬁcient to collect all
contaminating fumes or particles created by the process.
*Refer to AMCA Standard 99; See page 4.
29

Kitchen Ventilation
Hoods and Ducts
• Duct velocity should be between 1500 and 4000 fpm
• Hood velocities (not less than 50 fpm over face area between
hood and cooking surface)
• Wall Type - 80 CFM/ft2
• Island Type - 125 CFM/ft2
• Extend hood beyond cook surface 0.4 x distance between
hood and cooking surface
Filters
• Select filter velocity between 100 - 400 fpm
• Determine number of filters required from a manufacturer’s
data (usually 2 cfm exhaust for each sq. in. of filter area maxi-
mum)
• Install at 45 - 60° to horizontal, never horizontal
• Shield filters from direct radiant heat
• Filter mounting height:
• No exposed cooking flame—1-1/2’ minimum to filter
• Charcoal and similar fires—4’ minimum to filter
• Provide removable grease drip pan
• Establish a schedule for cleaning drip pan and filters and fol-
low it diligently
Fans
• Use upblast discharge fan
• Select design CFM based on hood design and duct velocity
• Select SP based on design CFM and resistance of filters and
duct system
• Adjust fan specification for expected exhaust air temperature

30

Sound
Sound Power (W) - the amount of power a source converts to
sound in watts.
Sound Power Level (LW) - a logarithmic comparison of sound
power output by a source to a reference sound source,
W0 (10-12 watt).
LW = 10 log10 (W/W0) dB
Sound Pressure (P) - pressure associated with sound output
from a source. Sound pressure is what the human ear reacts to.
Sound Pressure Level (Lp) - a logarithmic comparison of sound
pressure output by a source to a reference sound source,
P0 (2 x 10-5 Pa).
Lp = 20 log10 (P/P0) dB
Even though sound power level and sound pressure level are
both expressed in dB, THERE IS NO OUTRIGHT CONVERSION
BETWEEN SOUND POWER LEVEL AND SOUND PRESSURE
LEVEL. A constant sound power output will result in signiﬁcantly
different sound pressures and sound pressure levels when the
source is placed in different environments.
Rules of Thumb
When specifying sound criteria for HVAC equipment, refer to
sound power level, not sound pressure level.
When comparing sound power levels, remember the lowest
and highest octave bands are only accurate to about +/-4 dB.
Lower frequencies are the most difficult to attenuate.
2 x sound pressure (single source) = +3 dB(sound pressure level)
2 x distance from sound source = -6dB (sound pressure level)
+10 dB(sound pressure level)= 2 x original loudness perception
When trying to calculate the additive effect of two sound
sources, use the approximation (logarithms cannot be added
directly) on the next page.

31

Rules of Thumb (cont.)
Difference between dB to add to highest
sound pressure levels sound pressure level
0 3.0
1 2.5
2 2.1
3 1.8
4 1.5
5 1.2
6 1.0
7 0.8
8 0.6
9 0.5
10+ 0
Noise Criteria
Graph sound pressure level for each octave band on NC curve.
Highest curve intercepted is NC level of sound source. See
Noise Criteria Curves., page 34.

Sound Power and Sound Power Level
Sound
Sound Power (Watts) Power Source
Level dB
25 to 40,000,000 195 Shuttle Booster rocket
100,000 170 Jet engine with afterburner
10,000 160 Jet aircraft at takeoff
1,000 150 Turboprop at takeoff
100 140 Prop aircraft at takeoff
10 130 Loud rock band
1 120 Small aircraft engine
0.1 110 Blaring radio
0.01 100 Car at highway speed
Axial ventilating fan (2500
0.001 90
m3h) Voice shouting
0.0001 80 Garbage disposal unit
0.00001 70 Voice—conversational level
Electronic equipment cooling
0.000001 60
fan
0.0000001 50 Ofﬁce air diffuser
0.00000001 40 Small electric clock
0.000000001 30 Voice - very soft whisper
32

Sound Pressure and Sound Pressure Level
Sound
Sound Pressure
Pressure Typical Environment
(Pascals)
Level dB
200.0 140 30m from military aircraft at take-off
Pneumatic chipping and riveting
63.0 130
(operator’s position)
20.0 120 Passenger Jet takeoff at 100 ft.
Automatic punch press
6.3 110
(operator’s position)
2.0 100 Automatic lathe shop
0.63 90 Construction site—pneumatic drilling
0.2 80 Computer printout room
0.063 70 Loud radio (in average domestic room)
0.02 60 Restaurant
0.0063 50 Conversational speech at 1m
0.002 40 Whispered conversation at 2m
0.00063 30
0.0002 20 Background in TV recording studios
0.00002 0 Normal threshold of hearing

Room Sones —dBA Correlation†
150
dBA = 33.2 Log10 (sones) + 28, Accuracy ± 2dBA
100
90
Loudness, Sones

80
70
60
50
40
30

20

10
9
50 60 70 80 90 100
Sound Level dBA
† From ASHRAE 1972 Handbook of Fundamentals

33

Noise Criteria Curves
90
Noise
Criteria
NC Curves
80
Octave Band Sound Pressure Level dB

70
70

60 65

Noise Criteria
60

50 55
50

45
40
40

30 35

30
Approximate
20 threshold of 25
hearing for
20
continuous
noise
10 15
63 125 250 500 1000 2000 4000 8000
Octave Band Mid-Frequency - Hz

34

Design Criteria for Room Loudness
Room Type Sones Room Type Sones
Auditoriums Indoor sports activities
Concert and opera halls 1.0 to 3 Gymnasiums 4 to 12
Stage theaters 1.5 to 5 Coliseums 3 to 9
Movie theaters 2.0 to 6 Swimming pools 7 to 21
Semi-outdoor amphi-
2.0 to 6 Bowling alleys 4 to 12
theaters
Lecture halls 2.0 to 6 Gambling casinos 4 to 12
Multi-purpose 1.5 to 5 Manufacturing areas
Courtrooms 3.0 to 9 Heavy machinery 25 to 60
Auditorium lobbies4.0 to 12 Foundries 20 to 60
2.0 to 6
TV audience studios Light machinery 12 to 36
Churches and schools Assembly lines 12 to 36
Sanctuaries 1.7 to 5 Machine shops 15 to 50
Schools & classrooms 2.5 to 8 Plating shops 20 to 50
Recreation halls 4.0 to 12 Punch press shops 50 to 60
Kitchens 6.0 to 18 Tool maintenance 7 to 21
Libraries 2.0 to 6 Foreman’s office 5 to 15
Laboratories 4.0 to 12 General storage 10 to 30
Corridors and halls 5.0 to 15 Offices
Hospitals and clinics Executive 2 to 6
Private rooms 1.7 to 5 Supervisor 3 to 9
Wards 2.5 to 8 General open offices 4 to 12
Laboratories 4.0 to 12 Tabulation/computation 6 to 18
Operating rooms 2.5 to 8 Drafting 4 to 12
Lobbies & waiting rooms 4.0 to 12 Professional offices 3 to 9
Halls and corridors 4.0 to 12 Conference rooms 1.7 to 5
Board of Directors 1 to 3
Halls and corridors 5 to 15
Note: Values showns above are room loudness in sones and are not fan
sone ratings. For additional detail see AMCA publication 302 - Application
of Sone Rating.

35

Design Criteria for Room Loudness (cont.)
Room Type Sones Room Type Sones
Hotels Public buildings
Lobbies 4.0 to 12 Museums 3 to 9
Banquet rooms 8.0 to 24 Planetariums 2 to 6
Ball rooms 3.0 to 9 Post offices 4 to 12
Individual rooms/suites 2.0 to 6 Courthouses 4 to 12
Kitchens and laundries 7.0 to 12 Public libraries 2 to 6
Halls and corridors 4.0 to 12 Banks 4 to 12
Garages 6.0 to 18 Lobbies and corridors 4 to 12
Residences Retail stores
Two & three family units 3 to 9 Supermarkets 7 to 21
Department stores
Apartment houses 3 to 9 6 to 18
(main floor)
Department stores
Private homes (urban) 3 to 9 4 to 12
(upper floor)
Private homes
1.3 to 4 Small retail stores 6 to 18
(rural & suburban)
Restaurants Clothing stores 4 to 12
Restaurants 4 to 12 Transportation (rail, bus, plane)
Cafeterias 6 to 8 Waiting rooms 5 to 15
Cocktail lounges 5 to 15 Ticket sales office 4 to 12
Social clubs 3 to 9 Control rooms & towers 6 to 12
Night clubs 4 to 12 Lounges 5 to 15
Banquet room 8 to 24 Retail shops 6 to 18
Miscellaneous
Reception rooms 3 to 9
Washrooms and toilets 5 to 15
Studios for sound
1 to 3
reproduction
Other studios 4 to 12
Note: Values showns above are room loudness in sones and are not fan
sone ratings. For additional detail see AMCA publication 302 - Application
of Sone Rating.

36

Vibration
System Natural Frequency
The natural frequency of a system is the frequency at which
the system prefers to vibrate. It can be calculated by the follow-
ing equation:
fn = 188 (1/d)1/2 (cycles per minute)
The static deflection corresponding to this natural frequency
can be calculated by the following equation:
d = (188/fn)2 (inches)
By adding vibration isolation, the transmission of vibration can
be minimized. A common rule of thumb for selection of vibration
isolation is as follows:
Static Deflection of Isolation
Equipment
Critical Non-critical
RPM
Installation Installation
1200+ 1.0 in 0.5 in
600+ 1.0 in 1.0 in
400+ 2.0 in 1.0 in
300+ 3.0 in 2.0 in
Critical installations are upper floor or roof mounted equipment.
Non-critical installations are grade level or basement floor.
Always use total weight of equipment when selecting isolation.
Always consider weight distribution of equipment in selection.

37

Vibration Severity
Use the Vibration Severity Chart to determine acceptability of vibration
levels measured.

Vibration Frequency - CPM

100000
20000

30000
40000
50000
10000
3600
4000
1200

3000
2000

5000
1800
1000
200

300
400
500
10.00 100
8.00
Values shown are for
6.00 filtered readings taken
4.00 on the machine structure
3.00 or bearing cap

2.00 VE
RY
SL RO RO
1.00 IG U
Vibration Displacement-Mils-Peak-to-Peak

H UG G
0.80 TL H H
0.60 Y
FA RO
0.40 IR U .6
28
G G
O H IN
VE

0.30 O /S
SM D
RY

EC
0.20 VE O .3
G

EX 14
RY O
O

TH IN
O

TR SM /S
D

EM .1 EC
0.10 O 57
0.08 EL O IN
Y TH /S
0.06 SM EC

.0
O
78
0.04 O
5
TH
IN
0.03
/S
.0

EC

Vibration Velocity - In/sec.-Peak
39
0.02 2
IN
.0 /S
19 EC
6
0.01 IN
/S
0.008 .0 EC
09
0.006 8
IN
/S
0.004 EC
.0
0.003 04
9
IN
0.002 /S
EC

0.001
1800

3600
1200

Vibration Frequency - CPM

38

Vibration Severity (cont.)
When using the Machinery Vibration Severity Chart, the
following factors must be taken into consideration:
1. When using displacement measurements only filtered
displacement readings (for a specific frequency) should be
applied to the chart. Unfiltered or overall velocity readings
can be applied since the lines which divide the severity
regions are, in fact, constant velocity lines.
2. The chart applies only to measurements taken on the
bearings or structure of the machine. The chart does not
apply to measurements of shaft vibration.
3. The chart applies primarily to machines which are rigidly
mounted or bolted to a fairly rigid foundation. Machines
mounted on resilient vibration isolators such as coil springs
or rubber pads will generally have higher amplitudes of
vibration than those rigidly mounted. A general rule is to
allow twice as much vibration for a machine mounted on
isolators. However, this rule should not be applied to high
frequencies of vibration such as those characteristic of
gears and defective rolling-element bearings, as the
amplitudes measured at these frequencies are less
dependent on the method of machine mounting.

39

Air Quality Method
Designing for acceptable indoor air quality requires that we
address:
• Outdoor air quality
• Design of the ventilation systems
• Sources of contaminants
• Proper air ﬁltration
• System operation and maintenance
Determine the number of people occupying the respective
building spaces. Find the CFM/person requirements in Ventila-
tion Rates for Acceptable Indoor Air Quality, page 42. Calculate
the required outdoor air volume as follows:
People = Occupancy/1000 x Floor Area (ft2)
CFM = People x Outdoor Air Requirement (CFM/person)
Outdoor air quantities can be reduced to lower levels if proper
particulate and gaseous air ﬁltration equipment is utilized.
Air Change Method
Find total volume of space to be ventilated. Determine the
required number of air changes per hour.
CFM = Bldg. Volume (ft3) / Air Change Frequency
Consult local codes for air change requirements or, in absence
of code, refer to “Suggested Air Changes”, page 41.
Heat Removal Method
When the temperature of a space is higher than the ambient
outdoor temperature, general ventilation may be utilized to pro-
vide “free cooling”. Knowing the desired indoor and the design
outdoor dry bulb temperatures, and the amount of heat removal
required (BTU/Hr):
CFM = Heat Removal (BTU/Hr) / (1.10 x Temp diff)

40

Suggested Air Changes
Air Change
Type of Space Frequency
(minutes)
Assembly Halls 3-10
Auditoriums 4-15
Bakeries 1-3
Boiler Rooms 2-4
Bowling Alleys 2-8
Dry Cleaners 1-5
Engine Rooms 1-1.5
Factories (General) 1-5
Forges 1-2
Foundries 1-4
Garages 2-10
Generating Rooms 2-5
Glass Plants 1-2
Gymnasiums 2-10
Heat Treat Rooms 0.5-1
Kitchens 1-3
Laundries 2-5
Locker Rooms 2-5
Machine Shops 3-5
Mills (Paper) 2-3
Mills (Textile) 5-15
Packing Houses 2-15
Recreation Rooms 2-8
Residences 2-5
Restaurants 5-10
Retail Stores 3-10
Shops (General) 3-10
Theaters 3-8
Toilets 2-5
Transformer Rooms 1-5
Turbine Rooms 2-6
Warehouses 2-10

41

Ventilation Rates for Acceptable Indoor Air Quality†
Outdoor Air Occupancy
Space Required
(CFM/person) (People/1000 ft2)
Auditoriums 15 150
Ballrooms/Discos 25 100
Bars 30 100
Beauty Shops 25 25
Classrooms 15 50
Conference Rooms 20 50
Correctional Facility Cells 20 20
Dormitory Sleeping Rooms 15 20
Dry Cleaners 30 30
Gambling Casinos 30 120
Game Rooms 25 70
Hardware Stores 15 8
Hospital Operating Rooms 30 20
Hospital Patient Rooms 25 10
Laboratories 20 30
Libraries 15 20
Medical Procedure Rooms 15 20
Ofﬁce Spaces 20 7
Pharmacies 15 20
Photo Studios 15 10
Physical Therapy 15 20
Restaurant Dining Areas 20 70
Retail Facilities 15 20
Smoking Lounges 60 70
Sporting Spectator Areas 15 150
Supermarkets 15 8
Theaters 15 150
†Adapted from ASHRAE Standard 62-1989 “Ventilation for Acceptable Indoor Air Qual-
ity”.

42

Heat Gain From Occupants of Conditioned Spaces1
Typical Application Sensible Heat Latent Heat
(BTU/HR)* (BTU/HR)
Theater-Matinee 200 130
Theater-Evening 215 135
Ofﬁces, Hotels, Apartments 215 185
Retail and Department Stores 220 230
Drug Store 220 280
Bank 220 280
Restaurant2 240 310
Factory 240 510
Dance Hall 270 580
Factory 330 670
Bowling Alley3 510 940
Factory 510 940
Notes:
1 Tabulated values are based on 78°F for dry-bulb tempera-
ture.
2 Adjusted total heat value for sedentary work, restaurant,
includes 60 Btuh for food per individual (30 Btu sensible and
30 Btu latent).
3 For bowling ﬁgure one person per alley actually bowling, and
all others as sitting (400 Btuh) or standing (55 Btuh).
* Use sensible values only when calculating ventilation to
remove heat.
Adapted from Chapter 26 ASHRAE “Fundamentals” Handbook, 1989.

43

Heat Gain From Typical Electric Motors†
Motor Motor
Motor Motor In,
Full Load Out, 2nd
Name- Driven
Motor Driven Driven
plate or Motor Nominal Equip-
Efﬁ- Equip- Equip-
Rated Type rpm ment in
ciency in ment in ment Out
Horse- Space
Percent Space of Space
power Btuh
Btuh Btuh
0.25 Split Ph. 1750 54 1,180 640 540
0.33 Split Ph. 1750 56 1,500 840 660
0.50 Split Ph. 1750 60 2,120 1,270 850
0.75 3-Ph. 1750 72 2,650 1,900 740
1 3-Ph. 1750 75 3,390 2,550 850
1 3-Ph. 1750 77 4,960 3,820 1,140
2 3-Ph. 1750 79 6,440 5,090 1,350
3 3-Ph. 1750 81 9,430 7,640 1,790
5 3-Ph. 1750 82 15,500 12,700 2,790
7,5 3-Ph. 1750 84 22,700 19,100 3,640
10 3-Ph. 1750 85 29,900 24,500 4,490
15 3-Ph. 1750 86 44,400 38,200 6,210
20 3-Ph. 1750 87 58,500 50,900 7,610
25 3-Ph. 1750 88 72,300 63,600 8,680
30 3-Ph. 1750 89 85,700 76,300 9,440
40 3-Ph. 1750 89 114,000 102,000 12,600
50 3-Ph. 1750 89 143,000 127,000 15,700
60 3-Ph. 1750 89 172,000 153,000 18,900
75 3-Ph. 1750 90 212,000 191,000 21,200
100 3-Ph. 1750 90 283,000 255,000 28,300
125 3-Ph. 1750 90 353,000 318,000 35,300
150 3-Ph. 1750 91 420,000 382,000 37,800
200 3-Ph. 1750 91 569,000 509,000 50,300
250 3-Ph. 1750 91 699,000 636,000 62,900

† Adapted from Chapter 26 ASHRAE “Fundamentals” Handbook, 1989.

44

Rate of Heat Gain From Commercial Cooking
Appliances in Air-Conditioned Area†
Appliance Manufacturer’s Input Rating
Gas-Burning, Heat gain
Watts Btuh
Floor Mounted Type With Hood
Broiler, unit 70,000 7,000
Deep fat fryer 100,000 6,500
Oven, deck,
4,000 400
per sq. ft of hearth area
Oven, roasting 80,000 8,000
Range, heavy duty -
64,000 6,400
Top section
Range, heavy duty - Oven 40,000 4,000
Range, jr., heavy duty -
45,000 4,500
Top section
Range, jr., heavy duty - Oven 35,000 3,500
Range, restuarant type
24,000 2,400
per 2-burner section
per oven 30,000 3,000
per broiler-griddle 35,000 3,500
Electric, Floor Mounted Type
Griddle 16,800 57,300 2,060
Broiler, no oven 12,000 40,900 6,500
with oven 18,000 61,400 9,800
Broiler, single deck 16,000 54,600 10,800
Fryer 22,000 75,000 730
Oven, baking,
500 1,700 270
per sq. ft of hearth
Oven, roasting,
900 3,070 490
per sq. ft of hearth
Range, heavy duty -
15,000 51,200 19,100
Top section
Range, heavy duty - Oven 6,700 22,900 1,700
Range, medium duty -
8,000 27,300 4,300
Top section
Range, medium duty - Oven 3,600 12,300 1,900
Range, light duty - Top section 6,600 22,500 3,600
Range, light duty - Oven 3,000 10,200 1,600
† Adapted from Chapter 26 ASHRAE “Fundamentals” Handbook, 1989

45

Rate of Heat Gain From Miscellaneous Appliances
Manufacturer’s Recommended Rate of
Electrical
Rating Heat Gain, Btuh
Appliances Watts Btuh *Sensible Latent Total
Hair dryer 1,580 5,400 2,300 400 2,700
Hair dryer 705 2,400 1,870 330 2,200
Neon sign, 30 30
per linear ft of tube 60 60
Sterilizer, instrument 1,100 3,750 650 1,200 1,850
Gas-Burning Appliances
Lab burners
3,000 1,680 420 2,100
Bunsen
Fishtail 5,000 2,800 700 3,500
Meeker 6,000 3,360 840 4,200
Gas Light, per burner 2,000 1,800 200 2,000
Cigar lighter 2,500 900 100 1,000
Adapted from Chapter 26 ASHRAE “Fundamentals” Handbook, 1989.
*Use sensible heat gain for ventilation calculation.
Filter Comparison
ASHRAE
Initial Final
ASHRAE Atmo-
Pressure Pressure
Filter Type Arrestance spheric Drop Drop
Efﬁciency Dust Spot
(IN.WG) (IN.WG)
Efﬁciency
Permanent 60-80% 8-12% 0.07 .5
Fiberglass Pad 70-85% 15-20% 0.17 .5
Polyester Pad 82-90% 15-20% 0.20 .5
2” Throw Away 70-85% 15-20% 0.17 .5
2” Pleated Media 88-92% 25-30% 0.25 .5-.8
60% Cartridge 97% 60-65% 0.3 1.0
80% Cartridge 98% 80-85% 0.4 1.0
90% Cartridge 99% 90-95% 0.5 1.0
HEPA 100% 99.97% 1.0 2.0

46

Relative Size Chart of Common Air Contaminants
0.0001 0.001 0.01 0.1 1 10 100 1000 10000

Fog Mists Rain
Yeast-Cells
Tobacco Smoke
Diameter of
Molds
Oil Smoke Human Hair
Gas Molecules Bacteria
Pollen

Virus Lung-Damaging-Particles Plant Spores

Unsettling-Atmospheric-Impurities Settling-Atmos.-Impur. Heavy Indust. Dust
Fumes Dusts
Fly-Ash
Electronic-Microscope Microscope Visible By Human Eye
X-rays Ultra-Violet Visible Infra-Red

47
0.0001 0.001 0.01 0.1 1 10 100 1000 10000

0.3
Micron
This represents a This represents a 0.3
10 micron diam. micron diameter
particle, the particle. This is the most
smallest size respirable, lung damaging
visible with the particle size.
human eye.
Relative Size Chart of Common Air Contaminants

This Dimension Represents the Diameter of a Human Hair, 100 Microns
1 Micron = 1 micrometer = 1 millionth of a meter

Optimum Relative Humidity Ranges for Health

Decrease in Bar Width Optimal
Indicates Decrease in Effect Zone

Bacteria

Viruses

Fungi

Mites

48
Respiratory
Infections1
Allergic Rhinitis
and Asthma
Chemical
Interactions
Ozone
Production
1
INSUFFICIENT DATA
Optimum Relative Humidity Ranges for Health

ABOVE 50% R.H. 10 20 30 40 50 60 70 80 90
Per Cent Relative Humidity

Optimum relative humidity ranges for health as found by E.M. Sterling in "Criteria for Human Exposure to Humidity in
Occupied Buildings." ASHRAE Winter Meeting, 1985.

Duct Design
Damper Pressure Drop
1.5

1.0
PRESSURE LOSS - Inches w.g.

0.5
0.4
0.3

0.2

0.1

0.05
0.04
0.03

0.02

0.01
0

0
0

0

0
00
0

0

00
0
10

50
30

500
400
40

0
20

10

30
20

DAMPER FACE VELOCITY -fpm
V (Velocity) = CFM
Sq. Ft. Damper Area
Adapted from HVAC Systems Duct Design, Third Edition, 1990,
Sheet Metal & Air Conditioning Contractor’s National Association .

49

Duct Design
Screen Pressure Drop
0.6
0.2
0.4
0.3

0.2
PRESSURE LOSS—inches w.g.

0.1
Insect Screen

0.05
0.04
0.03

0.02
1/2 in.
Mesh Bird Screen
0.01

0.005
0.004
0.003

0.002

0.001
50 0
00
0
0
0

00
0

00

00
0

0
30
40
50
20
10

40
30
20
10

FACE AREA VELOCITY—fpm
Adapted from HVAC Systems Duct Design, Third Edition, 1990,
Sheet Metal & Air Conditioning Contractor’s National Association .
50

Duct Design
Duct Resistance

.01 .02 .03 .04 .06 .08.1 .2 .3 .4 .6 .8 1 2 3 4 6 8 10
100,000
80,000 32

10 0 Fp

12
36 0

75 00
40

55
30 00
24 0

32 00

50 0
12
14

65 00
20

80 0
18 0

26

45

9000
22

2800
16

7000
60 0
30

00
00

0
00
60,000

0

0
00
00

00
00
00

0

0
0

00

00
0
28

0

0
r 26
40,000
m ete
30,000 8
0 Dia 24

m
uct 22

Ve
D
20,000 7
0 In.

loc
20

ity
60 18
55
10,000 50 14
8,000 5
4 12
6,000
40 10
4,000
6 9
3,000 3
CFM

32 8
2,000 30
7
28
26 6
1,000 24
800 22 5
0
600 2
18
400 4
4
300 1
200 12 3
10
100 9
80 8
60 2
7
Fp

r
m

40 ete
Ve

6 m
30 Dia /2
lo

t
uc 1-1
cit

D
In.
y

20 5
16
18
10

14
12
20

50

60

90
70
80
30

40

00
00
00

00
00

10 4
0

0
0

0
0

0
0
0

.01 .02 .03 .04 .06 .08 1 .2 .3 .4 .6 .8 1 2 3 4 6 8 10
Friction in Inches of Water per 100 Feet
Friction of Air in Straight Duct

51

Duct Design
Rectangular Equivalent of Round Ducts

500
5
400 (ab)3
d=1.265
(a + b)
300

200

10
100

0
90

90
80

80 5
7

7
70 6 0
60 60 5

55
50 50

45
40 4
3 0
3 8
34 6
Side of Duct (a)

32
30

30 8
2 6
2
2
22 4
Di
am

20 20
et
er

18
(d

16
)

14
12

10
10

9 9
8
8

7
7

6
6

5 5

4
4

3
3

2 2

1 2 3 4 5 6 8 10 20 30 40 50 60 80100

Side of Duct (b)

52

Duct Design
Typical Design Velocities for HVAC Components*
Intake Louvers Velocity (FPM)
• 7000 cfm and greater 400
Exhaust Louvers
• 5000 cfm and greater 500
Panel Filters
• Viscous Impingement 200 to 800
• Dry-Type, Pleated Media:
• Low Efficiency 350
• Medium Efficiency 500
• High Efficiency 500
• HEPA 250
Renewable Media Filters
• Moving-Curtain Viscous Impingement 500
• Moving-Curtain Dry-Media 200
Electronic Air Cleaners
• Ionizing-Plate-Type 300 to 500
• Charged-Media Non-ionizing 250
• Charged-Media Ionizing 150 to 350
500 to 600
Steam and Hot Water Coils 200 min.
1500 max
Electric Coils
• Open Wire Refer to Mfg. Data
• Finned Tubular Refer to Mfg. Data
Dehumidifying Coils 500 to 600
Spray-Type Air Washers 300 to 600
Cell-Type Air Washers Refer to Mfg. Data
High-Velocity, Spray-Type Air Washers 1200 to 1800
*Adapted from ASHRAE “Pocket Guide”, 1993

53

Duct Design
Velocity and Velocity Pressure Relationships
Velocity Velocity Pressure Velocity Velocity Pressure
(fpm) (in wg) (fpm) (in wg)
300 0.0056 3500 0.7637
400 0.0097 3600 0.8079
500 0.0155 3700 0.8534
600 0.0224 3800 0.9002
700 0.0305 3900 0.9482
800 0.0399 4000 0.9975
900 0.0504 4100 1.0480
1000 0.0623 4200 1.0997
1100 0.0754 4300 1.1527
1200 0.0897 4400 1.2069
1300 0.1053 4500 1.2624
1400 0.1221 4600 1.3191
1500 0.1402 4700 1.3771
1600 0.1596 4800 1.4364
1700 0.1801 4900 1.4968
1800 0.2019 5000 1.5586
1900 0.2250 5100 1.6215
2000 0.2493 5200 1.6857
2100 0.2749 5300 1.7512
2200 0.3017 5400 1.8179
2300 0.3297 5500 1.8859
2400 0.3591 5600 1.9551
2500 0.3896 5700 2.0256
2600 0.4214 5800 2.0972
2700 0.4544 5900 2.1701
2800 0.4887 6000 2.2443
2900 0.5243 6100 2.3198
3000 0.5610 6200 2.3965
3100 0.5991 6300 2.4744
3200 0.6384 6400 2.5536
3300 0.6789 6500 2.6340
3400 0.7206 6600 2.7157
For calculation of velocity pressures at velocities other than those
listed above: Pv = (V/4005)2
For calculation of velocities when velocity pressures are known:
V=4005 (Vp)

54

Duct Design
U.S. Sheet Metal Gauges
Steel Galvanized
Gauge No. (Manuf. Std. Ga.) (Manuf. Std. Ga.)
Thick. in. Lb./ft.2 Thick.in. Lb./ft.2
26 .0179 .750 .0217 .906
24 .0239 1.00 .0276 1.156
22 .0299 1.25 .0336 1.406
20 .0359 1.50 .0396 1.656
18 .0478 2.00 .0516 2.156
16 .0598 2.50 .0635 2.656
14 .0747 3.125 .0785 3.281
12 .1046 4.375 .1084 4.531
10 .1345 5.625 .1382 5.781
8 .1644 6.875 .1681 7.031
7 .1793 7.50 — —

Mill Std. Thick Stainless Steel
Gauge No. Aluminum* (U.S. Standard Gauge)
Thick. in. Lb./ft.2 Thick.in. Lb./ft.2
26 .020 .282 .0188 .7875
24 .025 .353 .0250 1.050
22 .032 .452 .0312 1.313
20 .040 .564 .0375 1.575
18 .050 .706 .050 2.100
16 .064 .889 .062 2.625
14 .080 1.13 .078 3.281
12 .100 1.41 .109 4.594
10 .125 1.76 .141 5.906
8 .160 2.26 .172 7.218
7 .190 2.68 .188 7.752
*Aluminum is speciﬁed and purchased by material thickness rather than gauge.

55

Duct Design
Recommended Metal Gauges for Duct
Rectangular Duct Round Duct
Greatest U.S. B&S Galv. Steel Aluminum
Diameter
Dimension ga. ga. U.S. ga. B&S ga.
to 30 in. 24 22 to 8 in. 24 22
31-60 22 20 9-24 22 20
61-90 20 18 25-48 20 18
91-up 18 16 49-72 18 16

Wind Driven Rain Louvers†
A new category of product has emerged recently called a
wind-driven rain louver. These are architectural louvers designed
to reject moisture that are tested and evaluated under simulated
wind driven rain conditions. Since these are relatively new prod-
ucts, several different test standards have emerged to evaluate
the performance of these products under severe wind and rain
weather conditions. In addition, manufacturers have developed
their own standards to help evaluate the rain resistance of their
products. Specifying engineers should become familiar with the
differences in various rain and pressure drop test standards to
correctly evaluate each manufacturer’s claims. Four test stan-
dards are detailed below:
Dade Co. Power Plant AMCA 500 HEVAC
Test Test Test* Test
Wind Velocity 16-50 22 13.5
0
m/s (mph) (35 - 110) (50) (30)
Rain Fall Rate 220 38-280 100 75
mm/h (in./h) (8.8) (1.5 to 10.9) (4) (3)
Wet Wall Water
0.08
Flow Rate 0 0 0
(1.25)
L/s (gpm)
Airﬂow Through 6.35 (1,250) 6.35 (1,250) 3.6 (700)
Louver 0 Free Area Free Area Free Core
m/s (fpm) Velocity Velocity Area Velocity
†Table from AMCA Supplement to ASHRAE Journal, September 1998.
*AMCA Louver Engineering Committee at this writing is currently updating
AMCA 500-L to allow testing of varying sizes, wind speed, and rainfall
intensity and is developing a Certiﬁed Ratings Program for this product
category.

56

Moisture and Air Relationships
ASHRAE has adopted pounds of moisture per pound of dry air
as standard nomenclature. Relations of other units are
expressed below at various dewpoint temperatures.
Equiv. Lb H20/lb Parts per Grains/lb Percent
Dew Pt., °F dry air million dry aira Moisture %b
-100 0.000001 1 0.0007 —
-90 0.000002 2 0.0016 —
-80 0.000005 5 0.0035 —
-70 0.00001 10 0.073 0.06
-60 0.00002 21 0.148 0.13
-50 0.00004 42 0.291 0.26
-40 0.00008 79 0.555 0.5
-30 0.00015 146 1.02 0.9
-20 0.00026 263 1.84 1.7
-10 0.00046 461 3.22 2.9
0 0.0008 787 5.51 5.0
10 0.0013 1,315 9.20 8.3
20 0.0022 2,152 15.1 13.6
30 0.0032 3,154 24.2 21.8
40 0.0052 5,213 36.5 33.0
50 0.0077 7,658 53.6 48.4
60 0.0111 11,080 77.6 70.2
70 0.0158 15,820 110.7 100.0
80 0.0223 22,330 156.3 —
90 0.0312 31,180 218.3 —
100 0.0432 43,190 302.3 —
a7000 grains = 1 lb
bCompared to 70°F saturated
Normally the sensible heat factor determines the cfm required
to accept a load. In some industrial applications the latent heat
factor may control the air circulation rate.
Latent heat1 Btu/h
Thus cfm =
(W1 - W2) x 4840

Adapted from “Numbers,” by Bill Hollady & Cy Otterholm 1985.

57

Properties of Saturated Steam†
Speciﬁc Volume Speciﬁc Enthalpy
Temperature Pressure
Sat. Vapor Sat. Liquid Sat. Vapor
°F PSIA
Ft3/lbm Btu/lbm Btu/lbm
32 0.08859 3304.7 -0.0179 1075.5
40 0.12163 2445.8 8.027 1079.0
60 0.25611 1207.6 28.060 1087.7
80 0.50683 633.3 48.037 1096.4
100 0.94924 350.4 67.999 1105.1
120 1.6927 203.26 87.97 1113.6
140 2.8892 123.00 107.95 1122.0
160 4.7414 77.29 127.96 1130.2
180 7.5110 50.22 148.00 1138.2
200 11.526 33.639 168.09 1146.0
212 14.696 26.799 180.17 1150.5
220 17.186 23.148 188.23 1153.4
240 24.968 16.321 208.45 1160.6
260 35.427 11.762 228.76 1167.4
280 49.200 8.644 249.17 1173.8
300 67.005 6.4658 269.7 1179.7
320 89.643 4.9138 290.4 1185.2
340 117.992 3.7878 311.3 1190.1
360 153.010 2.9573 332.3 1194.4
380 195.729 2.3353 353.6 1198.0
400 247.259 1.8630 375.1 1201.0
420 308.780 1.4997 396.9 1203.1
440 381.54 1.21687 419.0 1204.4
460 466.87 0.99424 441.5 1204.8
480 566.15 0.81717 464.5 1204.1
500 680.86 0.67492 487.9 1202.2
520 812.53 0.55957 512.0 1199.0
540 962.79 0.46513 536.8 1194.3
560 1133.38 0.38714 562.4 1187.7
580 1326.17 0.32216 589.1 1179.0
600 1543.2 0.26747 617.1 1167.7
620 1786.9 0.22081 646.9 1153.2
640 2059.9 0.18021 679.1 1133.7
660 2365.7 0.14431 714.9 1107.0
680 2708.6 0.11117 758.5 1068.5
700 3094.3 0.07519 822.4 995.2
705.47 3208.2 0.05078 906.0 906.0
†Based on “1967 ASME Steam Tables”
58

Occupancy Lights Refrigeration Air Quantities CFM/Sq.Ft.
Classification Sq. Ft/Person Watts/Sq.Ft. Sq.Ft/Ton‡ East-South-West North Internal
Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi
Apartment, High Rise 325 100 1.0 4.0 450 350 0.8 1.7 0.5 1.3 — —
Auditoriums, Churches, Theaters 15 6 1.0 3.0 400 90 — — — — 1.0 3.0
Educational Facilities
30 20 2.0 6.0 240 150 1.0 2.2 0.9 2.0 0.8 1.9
Schools, Colleges, Universities
Factories-Assembly Areas 50 25 3.0† 6.0† 240 90 — — — — 2.0 5.5
Light Manufacturing 200 100 9.0† 12.0† 200 100 — — — — 1.6 3.8
Heavy Manufacturingo 300 200 15.0† 60.0† 100 60 — — — — 2.5 6.5
Hospitals-Patient Rooms* 75 25 1.0 2.0 275 165 0.33 0.67 0.33 0.67 — —
Public Areas 100 50 1.0 2.0 175 110 1.0 1.45 1.0 1.2 0.95 1.1
Cooling Load Check Figures

Hotels, Motels, Dormitories 200 100 1.0 3.0 350 220 1.0 1.5 0.9 1.4 — —

59
Libraries and Museums 80 40 1.0 3.0 340 200 1.0 2.1 0.9 1.3 0.9 1.1
Office Buildings* 130 80 4.0 9.0† 360 190 0.25 0.9 0.25 0.8 0.8 1.8
Private Offices* 150 100 2.0 8.0 — — 0.25 0.9 0.25 0.8 — —
Cubicle Area 100 70 5.0* 10.0* — — — — — — 0.9 2.0
Residential -Large 600 200 1.0 4.0 600 380 0.8 1.6 0.5 1.3 — —
Medium 600 200 0.7 3.0 700 400 0.7 1.4 0.5 1.2 — —
Restaurants - Large 17 13 15 2.0 135 80 1.8 3.7 1.2 2.1 0.8 1.4
Medium 150 100 1.5 3.0 1.1 1.8 0.9 1.3

Occupancy Lights Refrigeration Air Quantities CFM/Sq.Ft.
Classification Sq. Ft/Person Watts/Sq.Ft. Sq.Ft/Ton‡ East-South-West North Internal
Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi
Beauty & Barber Shops 45 25 3.0* 9.0* 240 105 1.5 4.2 1.1 2.6 0.9 2.0
Dept. Stores-Basement 30 20 2.0 4.0 340 225 — — — — 0.7 1.2
Main Floor 45 16 3.5 9.0† 350 150 — — — — 0.9 2.0
Upper Floors 75 40 2.0 3.5† 400 280 — — — — 0.8 1.2
Clothing Stores 50 30 1.0 4.0 345 185 0.9 1.6 0.7 1.4 0.6 1.1
Drug Stores 35 17 1.0 3.0 180 110 1.8 3.0 1.0 1.8 0.7 1.3
Discount Stores 35 15 1.5 5.0 345 120 0.7 2.0 0.6 1.6 0.5 1.1
Shoe Stores 50 20 1.0 3.0 300 150 1.2 2.1 1.0 1.8 0.8 1.2

60
Malls 100 50 1.0 2.0 365 160 — — — — 1.1 2.5
Refrigeration for Central Heating and Cooling Plant
Urban Districts 285
College Campuses 240
Cooling Load Check Figures (cont.)

Commercial Centers 200
Residential Centers 375
Refrigeration and air quantities for applications listed in this table of cooling load check figures are based on all-air system and normal
outdoor air quantities for ventilation except as noted.
Notes: ‡Refrigeration loads are for entire application.
†Includes other loads expressed in Watts sq.ft.
oAir quantities for heavy manufacturing areas are based on supplementary means to remove excessive heat.
*Air quantities for hospital patient rooms and office buildings (except internal areas) are based on induction (air-water) system.

Heat Loss Estimates
The following will give quick estimates of heat requirements in a
building knowing the cu.ft. volume of the building and design con-
ditions.
Masonry Wall Insulated Steel Wall
Indoor Temp (F)
Type of Structure
60° 65° 70° 60° 65° 70°
BTU/Cubic Foot BTU/Cubic Foot
Single Story
3.4 3.7 4.0 2.2 2.4 2.6
4 Walls Exposed
Single Story
2.9 3.1 3.4 1.9 2.0 2.2
One Heated Wall
Single Floor
One Heated Wall 1.9 2.0 2.2 1.3 1.4 1.5
Heated Space Above
Single Floor
Two Heated Walls 1.4 1.5 1.6 0.9 1.0 1.1
Heated Space Above
Single Floor
2.4 2.6 2.8 1.6 1.7 1.8
Two Heated Walls
2 Story 2.9 3.1 3.4 1.9 2.1 2.2
3 Story 2.8 3.0 3.2 1.8 2.0 2.1
Multi-Story
4 Story 2.7 2.9 3.1 — — —
5 Story 2.6 2.8 3.0 — — —

The following correction factors must be used and multiplied by
the answer obtained above.
Corrections for Corrections for “R” Factor
Outdoor Design (Steel Wall)
Temperature Multiplier “R” Factor Multiplier
+50 .23 8 1.0
+40 .36 10 .97
+30 .53 12 95
+20 .69 14 .93
+10 .84 16 .92
+ 0 1.0 19 .91
-10 1.15
-20 1.2
-30 1.46

61

Heat Loss Estimates (cont.)
Considerations Used for Corrected Values
1—0°F Outdoor Design (See Corrections)
2—Slab Construction—If Basement is involved multiply final
BTUH by 1.7.
3—Flat Roof
4—Window Area is 5% of Wall Area
5—Air Change is .5 Per Hour.
Fuel Comparisons**
This provides equivalent BTU Data for Various Fuels.
1,000,000 BTU = 10 Therms or
Natural Gas
1,000,000 BTU = (1000 Cu. Ft.)
1,000,000 BTU = 46 Lb. or
Propane Gas
1,000,000 BTU = 10.88 Gallon
No. 2 Fuel Oil 1,000,000 BTU = 7.14 Gallon
Electrical Resistance 1,000,000 BTU = 293 KW (Kilowatts)
Municipal Steam 1,000,000 BTU = 1000 Lbs. Condensate
Sewage Gas 1,000,000 BTU = 1538 Cu.Ft. to 2380 Cu.Ft.
1,000,000 BTU = 46 Lb. Propane or
LP/Air Gas 1,000,000 BTU = 10.88 Gallon Propane or
1,000,000 BTU = 690 Cu.Ft. Gas/Air Mix
Fuel Gas Characteristics
Natural Gas 925 to 1125 BTU/Cu.Ft. .6 to .66 Specific Gravity
Propane Gas 2550 BTU/Cu.Ft. 1.52 Specific Gravity
*Sewage Gas 420 to 650 BTU/Cu.Ft. .55 to .85 Specific Gravity
*Coal Gas 400 to 500 BTU/Cu.Ft. .5 to .6 Specific Gravity
*LP/Air Mix 1425 BTU/Cu.Ft. 1.29 Specific Gravity
* Before attempting to operate units on these fuels, contact manufacturer.
** Chemical Rubber Publishing Co., Handbook of Chemistry and Physics.

62

Estimated Seasonal Efficiencies of Heating Systems
Seasonal
Systems
Efficiency
Gas Fired Gravity Vent Unit Heater 62%
Energy Efficient Unit Heater 80%
Electric Resistance Heating 100%
Steam Boiler with Steam Unit Heaters 65%-80%
Hot Water Boiler with HYD Unit Heaters 65%-80%
Oil Fired Unit Heaters 78%
Municipal Steam System 66%
INFRA Red (High Intensity) 85%
INFRA Red (Low Intensity) 87%
Direct Fired Gas Make Up Air 94%
Improvement with Power Ventilator
4%
Added to Gas Fired Gravity Vent Unit Heater
Improvement with Spark Pilot Added
1/2%-3%
to Gas Fired Gravity Vent Unit Heater
Improvement with Automatic Flue Damper and
8%
Spark Pilot Added to Gravity Vent Unit Heater
Annual Fuel Use
Annual fuel use may be determined for a building by using one of
the following formulas:
Electric Resistance Heating
H/(∆T x 3413 x E) xDx24x CD = KWH/YEAR
Natural Gas Heating
H/(∆T x 100,000 x E) x D x 24 x CD= THERMS/YEAR
Propane Gas Heating
H/(∆T x 21739 x E) x D x 24 x CD= POUNDS/YEAR
H/(∆T x 91911 x E) x D x 24 x CD= GALLONS/YEAR
Oil Heating
H/(∆T x 140,000 x E) x D x 24 x CD = GALLONS/YEAR
Where: ∆T = Indoor Design Minus Outdoor Design Temp.
H = Building Heat Loss
D = Annual Degree Days
E = Seasonal Efficiency (See Above)
CD = Correlation Factor CD vs. Degree-Days
63

Annual Fuel Use (cont.)
1.2
1.0
Factor CD

+o
0.8
CD
0.6
0.4 -o

0.2
00

00

00

00
0
20

40

60

80
Degree Days
Pump Construction Types
The two general pump construction types are:
Bronze-fitted Pumps
• cast iron body
• brass impeller
• brass metal seal assembly components
Uses: Closed heating/chilled water systems, low-temp
fresh water.
All-Bronze Pumps
• all wetted parts are bronze
Uses: Higher temp fresh water, domestic hot water, hot
process water.
Pump Impeller Types
Single Suction - fluid enters impeller on one side only.
Double Suction - fluid enters both sides of impeller.
Closed Impeller - has a shroud which encloses the pump vanes,
increasing efficiency. Used for fluid systems free of large parti-
cles which could clog impeller.
Semi-Open Impeller - has no inlet shroud. Used for systems
where moderate sized particles are suspended in pumped fluid.
Open Impeller - has no shroud. Used for systems which have
large particles suspended in pumped fluid, such as sewage or
sludge systems.
64

Pump Bodies
Two basic types of pump bodies are:
Horizontal Split Case - split down centerline of pump horizontal
axis. Disassembled by removing top half of pump body. Pump
impeller mounted between bearings at center of shaft. Requires
two seals. Usually double suction pump. Suction and discharge
are in straight-line conﬁguration.
Vertical Split Case - single-piece body casting attached to cover
plate at the back of pump by capscrews. Pump shaft passes
through seal and bearing in coverplate. Impeller is mounted on
end of shaft. Suction is at right angle to discharge.
Pump Mounting Methods
The three basic types of pump mounting arrangements are:
Base Mount-Long Coupled - pump is coupled to base-mount
motor. Motor can be removed without removing the pump from
piping system. Typically standard motors are used.
Base Mount-Close Coupled - pump impeller is mounted on
base mount motor shaft. No separate mounting is necessary for
pump. Usually special motor necessary for replacement. More
compact than long-coupled pump.
Line Mount - mounted to and supported by system piping. Usu-
ally resilient mount motor. Very compact. Usually for low ﬂow
requirements.

65

Afﬁnity Laws for Pumps
Speciﬁc To
Impeller
Speed Gravity Correct Multiply by
Diameter
(SG) for
New Speed
Flow
Old Speed
2
Constant Variable Constant Head New Speed
Old Speed
3
BHP New Speed
(or kW) Old Speed

Flow New Diameter
Old Diameter
2
Variable Constant Head New Diameter
Old Diameter
3
BHP New Diameter
(or kW) Old Diameter
BHP New SG
Constant Variable
(or kW) Old SG
Adapted from ASHRAE “Pocket Handbook”, 1987.

66

Pumping System Troubleshooting Guide
Complaint: Pump or System Noise
Possible Cause Recommended Action
Shaft misalignment • Check and realign
Worn coupling • Replace and realign
• Replace, check manufacturer’s
Worn pump/motor bearings lubrication recommendations
• Check and realign shafts
• Check foundation bolting or
proper grouting
Improper foundation • Check possible shifting
or installation because of piping expansion/
contraction
• Realign shafts
Pipe vibration and/or strain • Inspect, alter or add hangers
caused by pipe expansion/ and expansion provision to
contraction eliminate strain on pump(s)
• Check actual pump perfor-
mance against speciﬁed and
reduce impeller diameter as
Water velocity required
• Check for excessive throttling
by balance valves or control
valves.
Pump operating close to or • Check actual pump perfor-
mance against speciﬁed and
beyond end point of perfor-
reduce impeller diameter as
mance curve required
• Check expansion tank connec-
tion to system relative to pump
suction
• If pumping from cooling tower
sump or reservoir, check line
Entrained air or low suction
size
pressure • Check actual ability of pump
against installation require-
ments
• Check for vortex entraining air
into suction line
67

Pumping System Troubleshooting Guide (cont.)
Complaint: Inadequate or No Circulation
Possible Cause Recommended Action
Pump running backward
• Reverse any two-motor leads
(3 phase)
Broken pump coupling • Replace and realign
• Check motor nameplate wiring
Improper motor speed
and voltage
• Check pump selection (impeller
Pump (or impeller diameter)
diameter) against specified sys-
too small
tem requirements
Clogged strainer(s) • Inspect and clean screen
• Check setting of PRV fill valve
System not completely filled • Vent terminal units and piping
high points
Balance valves or isolating • Check settings and adjust as
valves improperly set required
• Vent piping and terminal units
• Check location of expansion
tank connection line relative to
Air-bound system
pump suction
• Review provision for air elimina-
tion
• Check pump suction inlet con-
ditions to determine if air is
Air entrainment
being entrained from suction
tanks or sumps
• Check NPSH required by pump
• Inspect strainers and check
Low available NPSH
pipe sizing and water tempera-
ture

68

Pump Terms, Abbreviations and Conversion Factors
Abbrevia-
Term Multiply By To Obtain
tion
Length l ft 0.3048 m
Area A ft2 0.0929 m2
Velocity v ft/s 0.3048 m/s
Volume V ft3 0.0283 m3

Flow rate 0v
gpm 0.2272 m3/h
gpm 0.0631 L/s
psi 6890 Pa
Pressure P psi 6.89 kPa
psi 14.5 bar
Head (total) H ft 0.3048 m
NPSH H ft 0.3048 m
Output power water hp
Po 0.7457 kW
(pump) (WHP)
Shaft power Ps BHP 0.7457 kW
Input power (driver) Pi kW 1.0 kW
Efﬁciency, %
Pump Ep — — —
Equipment Ee — — —
Electric motor Em — — —
Utilization Eu — — —
Variable speed Fv — — —
drive
System Efﬁciency
SEI — — —
Index (decimal)
rpm 0.1047 rad/s
Speed n
rpm 0.0167 rps
Density ρ lb/ft3 16.0 kg/m3
Temperature ° °F-32 5/9 °C

69

Common Pump Formulas
Formula for I-P Units
Head H=psi x 2.31/SG* (ft)
Output power Po = Qv x H x SG*/3960 (hp)

Shaft power Ps = Qv x H x SG* (hp)
39.6 x Ep
Input power Pi = Ps x 74.6/Em (kw)
Utilization
QD= design flow
QA= actual flow
HD= design head
ηµ = 100 Q
Q
D
A
HD
HA
HA= actual head
*SG = specific gravity
Water Flow and Piping
Pressure drop in piping varies approx as the square of the
flow:
h2 Q2 2
=
h1 Q1
The velocity of water flowing in a pipe is
gpm x 0.41
v=
d2
Where V is in ft/sec and d is inside diameter, in.
Nom 1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3 4
size
ID in. 0.622 0.824 1.049 1.380 1.610 2.067 2.469 3.068 4.02
d2 0.387 0.679 1.100 1.904 2.59 4.27 6.10 9.41 16.21

Quiet Water Flows
Nom size 1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3 4
Gpm 1.5 4. 8. 14 22 44 75 120 240
Six fps is a reasonable upper limit for water velocity in pipes.
The relationship between pressure drop and flow rate can also
be expressed:
Q2 2 h2
h2 = h1 x or Q2 = Q1 x
Q1 h1

70

Water Flow and Piping (cont.)
Example: If design values were 200 gpm and 40 ft head and
actual ﬂow were changed to 100 gpm, the new head
would be:
100 2
h2 = 40 = 10 ft
200
gpm x ft head x sp gr
Pump hp =
3960 x % efficiency

Typical single suction pump efﬁciencies, %:
1/12 to 1/2 hp 40 to 55
3/4 to 2 45 to 60
3 to 10 50 to 65
double suction pumps:
20 to 50 60 to 80

Friction Loss for Water Flow
Average value—new pipe. Used pipe add 50%
Feet loss / 100 ft—schedule 40 pipe
1/2 in. 3/4 in. 1 in. 1-1/4 in.
US
v hF v hF v hF v hF
Gpm
Fps FtHd Fps FtHd Fps FtHd Fps FtHd
2.0 2.11 5.5
2.5 2.64 8.2
3.0 3.17 11.2
3.5 3.70 15.3
4 4.22 19.7 2.41 4.8
5 5.28 29.7 3.01 7.3
6 3.61 10.2 2.23 3.1
8 4.81 17.3 2.97 5.2
10 6.02 26.4 3.71 7.9
12 4.45 11.1 2.57 2.9
14 5.20 14.0 3.00 3.8
16 5.94 19.0 3.43 4.8

71

Friction Loss for Water Flow (cont.)
1-1/2 in. 2 in. 2-1/2 in. 1-1/4 in.
US
v hF v hF v hF v hF
Gpm
Fps FtHd Fps FtHd Fps FtHd Fps FtHd
18 2.84 2.8 3.86 6.0
20 3.15 3.4 4.29 7.3
22 3.47 4.1 4.72 8.7
24 3.78 4.8 5.15 10.3
26 4.10 5.5 5.58 11.9
28 4.41 6.3 6.01 13.7
30 4.73 7.2 6.44 15.6
35 5.51 9.6 7.51 20.9
40 6.30 12.4 3.82 3.6
45 7.04 15.5 4.30 4.4
50 4.78 5.4
60 5.74 7.6 4.02 3.1
70 6.69 10.2 4.69 4.2 3 in.
80 7.65 13.1 5.36 5.4 v hF
100 6.70 8.2 Fps FtHd
120 8.04 11.5 5.21 3.9
140 9.38 15.5 6.08 5.2
160 6.94 6.7
180 7.81 8.4
200 8.68 10.2
Adapted from “Numbers”, Bill Holladay and Cy Otterholm, 1985

72

Equivalent Length of Pipe for Valves and Fittings
Screwed fittings, turbulent flow only, equipment length in feet.
Pipe Size
Fittings
1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3
Standard 3.6 4.4 5.2 6.6 7.4 8.5 9.3 11
90° Ell
Long rad.
90° Ell 2.2 2.3 2.7 3.2 3.4 3.6 3.6 4.0
Standard .71 .92 1.3 1.7 2.1 2.7 3.2 3.9
45° Ell
Tee
1.7 2.4 3.2 4.6 5.6 7.7 9.3 12
Line flow
Tee 4.2 5.3 6.6 8.7 9.9 12 13 17
Br flow
180° 3.6 4.4 5.2 6.6 7.4 8.5 9.3 11
Ret bend
Globe 22 24 29 37 42 54 62 79
Valve
Gate .56 .67 .84 1.1 1.2 1.5 1.7 1.9
Valve
Angle 15 15 17 18 18 18 18 18
Valve
Swing 8.0 8.8 11 13 15 19 22 27
Check
Union or .21 .24 .29 .36 .39 .45 .47 .53
Coupling
Bellmouth .10 .13 .18 .26 .31 .43 .52 .67
inlet
Sq mouth .96 1.3 1.8 2.6 3.1 4.3 5.2 6.7
inlet
Reentrant 1.9 2.6 3.6 5.1 6.2 8.5 10 13
pipe
2
Sudden (V1 - V2)
enlargement Feet of liquid loss =
2g
where V1 & V2 = entering and leaving velocities
and g = 32.17 ft/sec2
Adapted from “Numbers”, Bill Holladay and Cy Otterholm, 1985

73

Standard Pipe Dimensions
Schedule 40 (Steel)
Diameter Area ft2/
Nominal Volume Weight
Size Outside Inside lin ft. gal/lin ft. lb/lin ft
in. in. Inside
1/8 0.405 0.269 0.070 0.0030 0.244
1/4 0.540 0.364 0.095 0.0054 0.424
3/8 0.675 0.493 0.129 0.0099 0.567
1/2 0.840 0.622 0.163 0.0158 0.850
3/4 1.050 0.824 0.216 0.0277 1.13
1 1.315 1.049 0.275 0.0449 1.68
1-1/4 1.660 1.380 0.361 0.0777 2.27
1-1/2 1.900 1.610 0.422 0.1058 2.72
2 2.375 2.067 0.541 0.1743 3.65
2-1/2 2.875 2.469 0.646 0.2487 5.79
3 3.500 3.068 0.803 0.3840 7.57
4 4.500 4.026 1.054 0.6613 10.79
5 5.563 5.047 1.321 1.039 14.62
6 6.625 6.065 1.587 1.501 18.00
Copper Tube Dimensions
(Type L)
Diameter Cross-sect Volume
Nominal Weight
Area sq.in. gal/lin ft.
size Outside in. Inside in. lb/lin ft
Inside
1/4 0.375 0.315 0.078 0.00404 0.126
3/8 0.500 0.430 0.145 0.00753 0.198
1/2 0.625 0.545 0.233 0.0121 0.285
5/8 0.750 0.666 0.348 0.0181 0.362
3/4 0.875 0.785 0.484 0.0250 0.455
1 1.125 1.025 0.825 0.0442 0.655
1-1/4 1.375 1.265 1.26 0.0655 0.884
1-1/2 1.625 1.505 1.78 0.0925 1.14
2 2.125 1.985 3.10 0.161 1.75
2-1/2 2.625 2.465 4.77 0.247 2.48
3 3.125 2.945 6.81 0.354 3.33
4 4.125 3.905 12.0 0.623 5.38

74

Typical Heat Transfer Coefficients
Controlling fluid and U free U forced
Type of Exchanger
apparatus convection convection
Air - flat plates Gas to gasa 0.6 -2 2-6
Air - bare pipes Steam to aira 1-2 2-10
Air - fin coil Air to watera 1-3 2-10
Air - HW radiator Water to aira 1-3 2-10
Oil - preheater Liquid to liquid 5-10 20-50
Air - aftercooler Comp air to waterb 5-10 20-50
Oil - preheater Steam to liquid 10-30 25-60
Brine - flooded chiller Brine to R12, R22 30-90
Brine - flooded chiller Brine to NH3 45-100
Brine - double pipe Brine to NH3 50-125
Water - double pipe Water to NH3 50-150
Water - Baudelot
Water to R12, R22 60-150
cooler
Brine to R12, R22,
Brine - DX chiller NH3 60-140
Brine - DX chiller E glycol to R12, R22 100-170
Water to R12,
Water - DX Baudelot 100-200
R22,R502
Water - DX Shell & Water to R12, R22,
NH3 130-190
tube
Water - shell & int
Water to R12, R22 160-250
finned tube
Water - shell & tube Water to water 150-300
Condensing vapor to
Water - shell & tube 150-800
water

Notes: U factor = Btu/h - ft2 •°F
Liquid velocities 3 ft/sec or higher
a At atmospheric pressure
b At 100 psig
Values shown are for commercially clean equipment.
Adapted from “Numbers”, Bill Holladay and Cy Otterholm, 1985.

75

Fouling Factors
Recommended minimum fouling allowances (f)a for water ﬂowing
at 3 ft/secb or higher:
Distilled water 0.0005
Water, closed system 0.0005
Water, open system 0.0010
Inhibited cooling tower 0.0015
Engine jacket 0.0015
Treated boiler feed (212°F) 0.0015
Hard well water 0.0030
Untreated cooling tower 0.0033
Steam:
Dry, clean and oil free 0.0003
Wet, clean and oil free 0.0005
Exhaust from turbine 0.0010
Non-ferrous Ferrous
Brines:
tubes tubes
Methylene chloride none none
Inhibited salts 0.0005 0.0010
Non-inhibited salts 0.0010 0.0020
Inhibited glycols 0.0010 0.0020
Vapors and gases:
Refrigerant vapors none
Solvent vapors 0.0008
Air, (clean) centrifugal compressor 0.0015
Air, reciprocating compressor 0.0030
Other Liquids:
Organic solvents (clean) 0.0001
Vegetable oils 0.0040
Quenching oils (ﬁltered) 0.0050
Fuel oils 0.0060
Sea water 0.0005

aInsert factor in: 1 where f1 and f2 are the
U=
1 + f1 + f2 + 1 surface fouling factors.
h1 h2
bLower velocities require higher f values.
76

Cooling Tower Ratings†
Temperatures °F
Hot Water Cold Water Wet Bulb Capacity Factor
90 80 70 0.85
92 82 70 1.00
95 85 70 1.24
90 80 72 0.74
92 82 72 0.88
95 85 72 1.12
95 85 74 1.00
95 85 76 0.88
95 85 78 0.75
95 85 80 0.62
Hot water - Cold water = Range
Cold water - Wet bulb = Approach
The Capacity Factor is a multiplier by which the capacity at any
common assumed condition may be found if the rating at some
other point is known.
Factors are based on a Heat Rejection Ratio of 1.25 (15,000 Btu/
hr • ton) and gpm/ton ﬂow rate.
Example: at 95-85-80, the capacity is 0.62/0.85 or 0.73 that
of the rating at 90-80-70.
Capacity is reduced as the ﬂow rate per ton is increased.
If the refrigerant temperature is below 40°F, the heat rejection will
be greater than 15,000 btu/hr • ton.
Evaporation will cause increasing deposit of solids and fouling
of condenser tube unless water is bled off. A bleed of 1% of the
circulation rate will result in a concentration of twice the original
solids (two concentrations), and 0.5% bleed will result in three
concentrations.
Horsepower per Ton†
at 100°F Condensing Temperature
Vapor enters Compressor at 65°F
Refrig. Temp., F 40 20 0 -20 -40
Practical Avg. 0.87 1.20 1.70 2.40 3.20
†Adapted from “Numbers”, Bill Holladay and Cy Otterholm, 1985

77

Evaporate Condenser Ratings†
An Evaporative Condenser rated at a condensing temperature
of 100°F and a wet bulb temperature of 70°F will have rating fac-
tors under other conditions, as follows:
Cond. Entering Air Wet Bulb Temp., °F
Temp.,
55° 60° 65° 70° 75° 78°
°F
90 0.96 0.86 0.75 0.63 0.50 0.41
95 1.13 1.03 0.91 0.80 0.67 0.59
100 1.32 1.22 1.11 1.00 0.87 0.79
105 1.51 1.41 1.31 1.20 1.08 1.00
110 1.71 1.62 1.52 1.41 1.29 1.22
115 1.93 1.85 1.75 1.65 1.54 1.47
120 2.20 2.11 2.02 1.93 1.81 1.75
Compressor Capacity Vs. Refrigerant
Temperature at 100°F Condensing†
Heat
Refrig. Rejection Capacity, % Based on
Temp. °F
Ratioa 50°F 40°F 20°F 0°F
50 1.26 100
40 1.28 83 100
30 1.31 69 83
20 1.35 56 67 100
10 1.39 45 54 80
0 1.45 36 43 64 100
-10 1.53 28 34 50 78
-20 1.64 22 26 39 61
-30 1.77 15 18 27 42
-40 1.92 10 12 18 28
aFor sealed compressors.

The capacity of a typical compressor is reduced as the evaporat-
ing temperature is reduced because of increased speciﬁc volume
(cu ft/lb) of the refrigerant and lower compressor volumetric efﬁ-
ciency. The average 1 hp compressor will have a capacity of
nearly 12,000 btu/h, 1 ton, at 40°F refrigerant temperature,
100°F condensing temperature. A 10° rise/fall in condensing
temperature will reduce/increase capacity about 6%.
†Adapted from “Numbers”, Bill Holladay and Cy Otterholm, 1985

78

Refrigerant Line Capacities for 134a†
Tons for 100 ft. - Type L. Copper, Suction Lines, ∆t = 2°F
Saturated Suction Temp. °F/ Discharge Liquid
∆p Lines∆t 1°F Lines
Size 0 10 20 30 40
0 ∆t 1°F
O.D. 1.00 1.19 1.41 1.66 1.93
1/2 0.14 0.18 0.23 0.29 0.35 0.54 2.79
5/8 0.27 0.34 0.43 0.54 0.66 1.01 5.27
7/8 0.71 0.91 1.14 1.42 1.75 2.67 14.00
1-1/8 1.45 1.84 2.32 2.88 3.54 5.40 28.40
1-3/8 2.53 3.22 4.04 5.02 6.17 9.42 50.00
1-5/8 4.02 5.10 6.39 7.94 9.77 14.90 78.60
2-1/8 8.34 10.60 13.30 16.50 20.20 30.80 163.00
2-5/8 14.80 18.80 23.50 29.10 35.80 54.40 290.00
3-1/8 23.70 30.00 37.50 46.40 57.10 86.70 462.00
3-5/8 35.10 44.60 55.80 69.10 84.80 129.00 688.00
4-1/8 49.60 62.90 78.70 97.40 119.43 181.00 971.00
5-1/8 88.90 113.00 141.00 174.00 213.00
6-1/8 143.00 181.00 226.00 280.00 342.00
Refrigerant Line Capacities for R-22†
Saturated Suction Temp. °F/ Discharge Liquid
∆p Lines∆t 1°F Lines
Size -40 -20 0 20 40
0 ∆t 1°F
O.D. 0.79 1.15 1.6 2.2 2.9
1/2 0.40 0.6 0.8 3.6
5/8 0.32 0.51 0.76 1.1 1.5 6.7
7/8 0.52 0.86 1.3 2.0 2.9 4.0 18.2
1-1/8 1.1 1.7 2.7 4.0 5.8 8.0 37.0
1-3/8 1.9 3.1 4.7 7.0 10.1 14.0 64.7
1-5/8 3.0 4.8 7.5 11.1 16.0 22.0 102
2-1/8 6.2 10.0 15.6 23.1 33.1 45.6 213
2-5/8 10.9 17.8 27.5 40.8 58.3 80.4 377
3-1/8 17.5 28.4 44.0 65.0 92.9 128 602
3-5/8 26.0 42.3 65.4 96.6 138 190 896
4-1/8 36.8 59.6 92.2 136 194 268 1263
5-1/8 60.0 107 164 244 347 478
*Tables are based on 105°F condensing temperature.
Refrigerant temperature has little effect on discharge line size.
Steel pipe has about the same capacity as Type L. copper 1/8”
larger.
†Adapted from ASHRAE Refrigeration Handbook 1998.
79

Discharge
Saturated Suction Temp. °F/ Liquid
Lines ∆t
∆p Lines
1°F
Size -40 -20 0 20 40
0 ∆t 1°F
∆p 0.92 1.33 1.84 2.45 3.18
1/2 0.08 0.14 0.22 0.33 0.49 0.63 2.4
5/8 0.16 0.27 0.42 0.63 0.91 1.2 4.5
7/8 0.43 0.70 1.1 1.7 2.4 3.1 11.8
1-1/8 0.87 1.4 2.2 3.4 4.8 6.3 24.1
1-3/8 1.5 2.5 3.9 5.8 8.4 10.9 42.0
1-5/8 2.4 4.0 6.2 9.2 13.3 17.2 66.4
2-1/8 5.0 8.2 12.8 19.1 27.5 35.6 138
2-5/8 8.8 14.5 22.6 33.7 48.4 62.8 244
3-1/8 14.1 23.2 36.0 53.7 77.0 99.8 389
3-5/8 21.0 34.4 53.5 79.7 114 148 579
4-1/8 29.7 48.5 75.4 112 161 208 817
5-1/8 53.2 86.7 135 200 287 371
6-1/8 85.6 140 216 321 461 596
Tons for 100 ft. - Type L. Copper
R-717 (Ammonia)
∆p
Tons for 100 Ft.
∆p -40 -20 0 20 40
IPS
Sch
3 2
0.31 0.49 0.73 1.06 1.46
3/4 80 2.6 3.8
1 2.1 3.4 5.2 7.6 13.9 106
1-1/4 40 3.2 5.6 8.9 13.6 19.9 36.5 229a
1-1/2 4.9 8.4 13.4 20.5 29.9 54.8 349a
2 9.5 16.2 26.0 39.6 57.8 106 811
2-1/2 15.3 25.9 41.5 63.2 92.1 168 1293
3 27.1 46.1 73.5 112 163 298 2288
4 55.7 94.2 150 229 333 600 4662
5 101 170 271 412 601 1095
6 164 276 439 668 972 1771
aSchedule 80
†Adapted from ASHRAE Refrigeration Handbook 1998.

80

Miscellaneous Formulas
OHMS Law
Ohms = Volts/Amperes (R = E/I)
Amperes = Volts/Ohms (I = E/R)
Volts = Amperes x Ohms (E = IR)
Power—A-C Circuits
746 x Output Horsepower
Efficiency =
Input Watts
Three-Phase Kilowatts = Volts x Amperes x Power Factor x 1.732
1000
Three-Phase Volt-Amperes = Volts x Amperes x 1.732

Three-Phase Amperes = 746 x Horsepower
1.732 x Volts x Efficiency x Power Factor
Three-Phase Efficiency = 746 x Horsepower
Volts x Amperes x Power Factor x 1.732

Three-Phase Power Factor = Input Watts
Volts x Amperes x 1.732
Single-Phase Kilowatts = Volts x Amperes x Power Factor
1000
Single-Phase Amperes = 746 x Horsepower
Volts x Efficiency x Power Factor
Single-Phase Efficiency = 746 x Horsepower
Volts x Amperes x Power Factor
Single-Phase Power Factor = Input Watts
Volts x Amperes
Horsepower (3 Ph) = Volts x Amperes x 1.732 x Efficiency x Power Factor
746
Volts x Amperes x Efficiency x Power Factor
Horsepower (1 Ph) =
746
Power —D-C Circuits
Watts = Volts x Amperes ( W = EI)

Amperes = Watts (I = W/E)
Volts
Horsepower = Volts x Amperes x Efficiency
746

81

Miscellaneous Formulas (cont.)
Speed—A-C Machinery
Synchronous RPM = Hertz x 120
Poles
Percent Slip = Synchronous RPM - Full-Load RPM x 100
Synchronous RPM

Motor Application
Torque (lb.-ft.) = Horsepower x 5250
RPM
Horsepower = Torque (lb.-ft.) x RPM
5250
Time for Motor to Reach Operating Speed (seconds)

Seconds = WK2 x Speed Change
308 x Avg. Accelerating Torque

Average Accelerating Torque = [(FLT + BDT)/2] + BDT + LR1
3
WK2 = Inertia of Rotor + Inertia of Load (lb.-ft.2)
FLT = Full-Load Torque BDT = Breakdown Torque
LRT = Locked Rotor Torque

WK2 (Load) x Load RPM2
Load WK2 (at motor shaft) =
Motor RPM2
Shaft Stress (P.S.I.) = HP x 321,000
RPM x Shaft Dia.3

Change in Resistance Due to Change in Temperature
(K + TC)
RC = RH x
(K + TH)
(K + TH)
RH = R C x
(K + TC)

K = 234.5 - Copper
= 236 - Aluminum
= 180 - Iron
= 218 - Steel
RC = Cold Resistance (OHMS)
RH = Hot Resistance (OHMS)
TC = Cold Temperature (°C)
TH = Hot Temperature (°C)
82

Vibration
D = .318 (V/f) D = Displacement (Inches Peak-Peak)
V = π(f) (D) V = Velocity (Inches per Second Peak)
A = .051 (f)2 (D) A = Acceleration (g’s Peak)
A = .016 (f) (V) f = Frequency (Cycles per Second)
Volume of Liquid in a Tank
Gallons = 5.875 x D2 x H
D = Tank Diameter (ft.)
H = Height of Liquid (ft.)
Centrifugal Applications
Afﬁnity Laws for Centrifugal Applications:
Flow1 RPM1
=
Flow2 RPM2

Pres1 (RPM1)2
=
Pres2 (RPM2)2

BHP1 (RPM1)3
=
BHP2 (RPM2)3
For Pumps
GPM x PSI x Specific Gravity
BHP =
1713 x Efficiency of Pump
BHP = GPM x FT x Specific Gravity
3960 x Efficiency of Pump
For Fans and Blowers
Tip Speed (FPS) = D(in) x RPM x π
720

Temperature: °F = °C 9 + 32 °C = (°F - 32) 5
5 9
BHP = CFM x PSF
33000 x Efficiency of Fan

BHP = CFM x PIW
CFM x PSI
BHP =
1 ft. of water = 0.433 PSI
1 PSI = 2.309 Ft. of water
Specify Gravity of Water = 1.0
83

Where:
BHP = Brake Horsepower
GPM = Gallons per Minute
FT = Feet
PSI = Pounds per Square Inch
PSIG = Pounds per Square Inch Gauge
PSF = Pounds per Square Foot
PIW = Inches of Water Gauge
Area and Circumference of Circles
Diameter Area Area Circumference
(inches) (sq.in.) (sq. ft.) (feet)
1 0.7854 0.0054 0.2618
2 3.142 0.0218 0.5236
3 7.069 0.0491 0.7854
4 12.57 0.0873 1.047
5 19.63 0.1364 1.309
6 28.27 0.1964 1.571
7 38.48 0.2673 1.833
8 50.27 0.3491 2.094
9 63.62 0.4418 2.356
10 78.54 0.5454 2.618
11 95.03 0.6600 2.880
12 113.1 0.7854 3.142
13 132.7 0.9218 3.403
14 153.9 1.069 3.665
15 176.7 1.227 3.927
16 201.0 1.396 4.189
17 227.0 1.576 4.451
18 254.7 1.767 4.712
19 283.5 1.969 4.974
20 314.2 2.182 5.236
21 346.3 2.405 5.498
22 380.1 2.640 5.760
23 415.5 2.885 6.021
24 452.4 3.142 6.283

84

Area and Circumference of Circles (cont.)
25 490.9 3.409 6.545
26 530.9 3.687 6.807
27 572.5 3.976 7.069
28 615.7 4.276 7.330
29 660.5 4.587 7.592
30 706.8 4.909 7.854
31 754.7 5.241 8.116
32 804.2 5.585 8.378
33 855.3 5.940 8.639
34 907.9 6.305 8.901
35 962.1 6.681 9.163
36 1017.8 7.069 9.425
37 1075.2 7.467 9.686
38 1134.1 7.876 9.948
39 1194.5 8.296 10.21
40 1256.6 8.727 10.47
41 1320.2 9.168 10.73
42 1385.4 9.621 10.99
43 1452.2 10.08 11.26
44 1520.5 10.56 11.52
45 1590.4 11.04 11.78
46 1661.9 11.54 12.04
47 1734.9 12.05 12.30
48 1809.5 12.57 12.57
49 1885.7 13.09 12.83
50 1963.5 13.64 13.09
51 2043 14.19 13.35
52 2124 14.75 13.61
53 2206 15.32 13.88
54 2290 15.90 14.14
55 2376 16.50 14.40
56 2463 17.10 14.66
57 2552 17.72 14.92

85

58 2642 18.35 15.18
59 2734 18.99 15.45
60 2827 19.63 15.71
61 2922 20.29 15.97
62 3019 20.97 16.23
63 3117 21.65 16.49
64 3217 22.34 16.76
65 3318 23.04 17.02
66 3421 23.76 17.28
67 3526 24.48 17.54
68 3632 25.22 17.80
69 3739 25.97 18.06
70 3848 26.73 18.33
71 3959 27.49 18.59
72 4072 28.27 18.85
73 4185 29.07 19.11
74 4301 29.87 19.37
75 4418 30.68 19.63
76 4536 31.50 19.90
77 4657 32.34 20.16
78 4778 33.18 20.42
79 4902 34.04 20.68
80 5027 34.91 20.94
81 5153 35.78 21.21
82 5281 36.67 21.47
83 5411 37.57 21.73
84 5542 38.48 21.99
85 5675 39.41 22.25
86 5809 40.34 22.51
87 5945 41.28 22.78
88 6082 42.24 23.04
89 6221 43.20 23.30
90 6362 44.18 23.56
91 6504 45.17 23.82
86

92 6648 46.16 24.09
93 6793 47.17 24.35
94 6940 48.19 24.61
95 7088 49.22 24.87
96 7238 50.27 25.13
97 7390 51.32 25.39
98 7543 52.38 25.66
99 7698 53.46 25.92
100 7855 54.54 26.18
Circle Formula
A(in2) = π r (in)2 = π d(in)2 Where: A = Area
4 C = Circumference
A(ft2) = π r (in) = π d(in)
2 2 r = Radius
144 576 d = Diameter
C(ft) = π d (in)
12
Common Fractions of an Inch
Decimal and Metric Equivalents
Fraction Decimal mm Fraction Decimal mm
1/64 0.01562 0.397 17/64 0.26562 6.747
1/32 0.03125 0.794 9/32 0.28125 7.144
3/64 0.04688 1.191 19/64 0.29688 7.541
1/16 0.06250 1.588 5/16 0.31250 7.938
5/64 0.07812 1.984 21/64 0.32812 8.334
3/32 0.09375 2.381 11/32 0.34375 8.731
7/64 0.10938 2.778 23/64 0.35938 9.128
1/8 0.12500 3.175 3/8 0.37500 9.525
9/64 0.14062 3.572 25/64 0.39062 9.922
5/32 0.15625 3.969 13/32 0.40625 10.319
11/64 0.17188 4.366 27/64 0.42188 10.716
3/16 0.18750 4.763 7/16 0.43750 11.113
13/64 0.20312 5.159 29/64 0.45312 11.509
7/32 0.21875 5.556 15/32 0.46875 11.906
15/64 0.23438 5.953 31/64 0.48438 12.303
1/4 0.25000 6.350 1/2 0.50000 12.700

87

Common Fractions of an Inch (cont.)
Decimal and Metric Equilavents
Fraction Decimal mm Fraction Decimal mm
33/64 0.51562 13.097 49/64 0.76562 19.447
17/32 0.53125 13.494 25/32 0.78125 19.844
35/64 0.54688 13.891 51/64 0.79688 20.241
9/16 0.56250 14.288 13/16 0.81250 20.638
37/64 0.57812 14.684 53/64 0.82812 21.034
19/32 0.59375 15.081 27.32 0.84375 21.431
39.64 0.60938 15.478 55/64 0.85938 21.828
5/8 0.62500 15.875 7/8 0.87500 22.225
41/64 0.64062 16.272 57/64 0.89062 22.622
21/32 0.65625 16.669 29/32 0.90625 23.019
43/64 0.67188 17.066 59/64 0.92188 23.416
11/16 0.68750 17.463 15/16 0.93750 23.813
45/64 0.70312 17.859 61/64 0.95312 24.209
23/32 0.71875 18.256 31/32 0.96875 24.606
47/64 0.73438 18.653 63/64 0.98438 25.004
3/4 0.75000 19.050 1/1 1.00000 25.400
Conversion Factors
Multiply Length By To Obtain
centimeters x .3937 = Inches
fathoms x 6.0 = Feet
feet x 12.0 = Inches
feet x .3048 = Meters
inches x 2.54 = Centimeters
kilometers x .6214 = Miles
meters x 3.281 = Feet
meters x 39.37 = Inches
meters x 1.094 = Yards
miles x 5280.0 = Feet
miles x 1.609 = Kilometers
rods x 5.5 = Yards
yards x .9144 = Meters

88

Conversion Factors (cont.)
Multiply Area By To Obtain
acres x 4047.0 = Square meters
acres x .4047 = Hectares
acres x 43560.0 = Square feet
acres x 4840.0 = Square yards
circular mils x 7.854x10-7 = Square inches
circular mils x .7854 = Square mils
hectares x 2.471 = Acres
hectares x 1.076 x 105 = Square feet
square centimeters x .155 = Square inches
square feet x 144.0 = Square inches
square feet x .0929 = Square meters
square inches x 6.452 = Square cm.
square meters x 1.196 = Square yards
square meters x 2.471 x 10-4 = Acres
square miles x 640.0 = Acres
square mils x 1.273 = Circular mils
square yards x .8361 = Square meters
Multiply Volume By To Obtain
cubic feet x .0283 = Cubic meters
cubic feet x 7.481 = Gallons
cubic inches x .5541 = Ounces (fluid)
cubic meters x 35.31 = Cubic feet
cubic meters x 1.308 = Cubic yards
cubic yards x .7646 = Cubic meters
gallons x .1337 = Cubic feet
gallons x 3.785 = Liters
liters x .2642 = Gallons
liters x 1.057 = Quarts (liquid)
ounces (fluid) x 1.805 = Cubic inches
quarts (fluid) x .9463 = Liters

89

Multiply Force & Weight By To Obtain
grams x .0353 = Ounces
kilograms x 2.205 = Pounds
newtons x .2248 = Pounds (force)
ounces x 28.35 = Grams
pounds x 453.6 = Grams
pounds (force) x 4.448 = Newton
tons (short) x 907.2 = Kilograms
tons (short) x 2000.0 = Pounds
Multiply Torque By To Obtain
gram-centimeters x .0139 = Ounce-inches
newton-meters x .7376 = Pound-feet
newton-meters x 8.851 = Pound-inches
ounce-inches x 71.95 = Gram-centimeters
pound-feet x 1.3558 = Newton-meters
pound-inches x .113 = Newton-meters
Multiply Energy or Work By To Obtain
Btu x 778.2 = Foot-pounds
Btu x 252.0 = Gram-calories
Multiply Power By To Obtain
Btu per hour x .293 = Watts
horsepower x 33000.0 = Foot-pounds per
minute
horsepower x 550.0 = Foot-pounds per
second
horsepower x 746.0 = Watts
kilowatts x 1.341 = Horsepower
Multiply Plane Angle By To Obtain
degrees x .0175 = Radians
minutes x .01667 = Degrees
minutes x 2.9x10-4 = Radians
quadrants x 90.0 = Degrees
quadrants x 1.5708 = Radians
radians x 57.3 = Degrees
Pounds are U.S. avoirdupois.
Gallons and quarts are U.S.

90

Multiply By To obtain
acres x 0.4047 = ha
atmosphere, standard x *101.35 = kPa
bar x *100 = kPa
barrel (42 US gal. petroleum) x 159 =L
Btu (International Table) x 1.055 = kJ
Btu/ft2 x 11.36 = kJ/m2
Btu⋅ft/h⋅ft2⋅°F x 1.731 = W/(m⋅K)
Btu⋅in/h⋅ft2⋅°F x 0.1442 = W/(m⋅K)
(thermal conductivity, k)
Btu/h x 0.2931 = W
Btu/h⋅ft2 x 3.155 = W/m2
Btu/h⋅ft2⋅°F x 5.678 = W/(m2⋅K)
(heat transfer coefﬁcient, U)
Btu/lb x *2.326 = kJ/kg
Btu/lb⋅°F (speciﬁc heat, cp) x 4.184 = kJ/(kg⋅K)
bushel x 0.03524 = m3
calorie, gram x 4.187 = J
calorie, kilogram (kilocalorie) x 4.187 = kJ
centipoise, dynamic viscosity,µ x *1.00 = mPa⋅s
centistokes, kinematic viscosity, v x *1.00 = mm2/s
dyne/cm2 x *0.100 = Pa
EDR hot water (150 Btu/h) x 44.0 =W
EDR steam (240 Btu/h) x 70.3 =W
fuel cost comparison at 100% eff.
cents per gallon (no. 2 fuel oil) x 0.0677 = $/GJ
cents per gallon (no. 6 fuel oil) x 0.0632 = $/GJ
cents per gallon (propane) x 0.113 = $/GJ
cents per kWh x 2.78 = $/GJ
cents per therm x 0.0948 = $/GJ
ft/min, fpm x *0.00508 = m/s
* Conversion factor is exact.

91

ft/s, fps x 0.3048 = m/s
ft of water x 2.99 = kPa
ft of water per 100 ft of pipe x 0.0981 = kPa/m
ft2 x 0.09290 = m2
ft2⋅h⋅°F/Btu (thermal resistance, R) x 0.176 = m2⋅K/W
ft2/s, kinematic viscosity, v x 92 900 = mm2/s
ft3 x 28.32 = L
ft3 x 0.02832 = m3
ft3/h, cfh x 7.866 = mL/s
ft3/min, cfm x 0.4719 = L/s
ft3/s, cfs x 28.32 = L/s
footcandle x 10.76 = lx
ft⋅lbf (torque or moment) x 1.36 = N⋅m
ft⋅lbf (work) x 1.36 =J
ft⋅lbf / lb (speciﬁc energy) x 2.99 = J/kg
ft⋅lbf / min (power) x 0.0226 =W
gallon, US (*231 in3) x 3.7854 =L
gph x 1.05 = mL/s
gpm x 0.0631 = L/s
gpm/ft2 x 0.6791 = L/(s⋅m2)
gpm/ton refrigeration x 0.0179 = mL/J
grain (1/7000 lb) x 0.0648 =g
gr/gal x 17.1 = g/m3
horsepower (boiler) x 9.81 = kW
horsepower (550 ft⋅lbf/s) x 0.746 = kW
inch x *25.4 = mm
in of mercury (60°F) x 3.377 = kPa
in of water (60°F) x 248.8 = Pa
in/100 ft (thermal expansion) x 0.833 = mm/m
in⋅lbf (torque or moment) x 113 = mN⋅m
in2 x 645 = mm2
*Conversion factor is exact.
92

in3 (volume) x 16.4 = mL
in3/min (SCIM) x 0.273 = mL/s
in3 (section modulus) x 16 400 = mm3
in4 (section moment) x 416 200 = mm4
km/h x 0.278 = m/s
kWh x *3.60 = MJ
kW/1000 cfm x 2.12 = kJ/m3
kilopond (kg force) x 9.81 =N
kip (1000 lbf) x 4.45 = kN
kip/in2 (ksi) x 6.895 = MPa
knots x 1.151 = mph
litre x *0.001 = m3
micron (µm) of mercury (60°F) x 133 = mPa
mile x 1.61 = km
mile, nautical x 1.85 = km
mph x 1.61 = km/h
mph x 0.447 = m/s
mph x 0.8684 = knots
millibar x *0.100 = kPa
mm of mercury (60°F) x 0.133 = kPa
mm of water (60°F) x 9.80 = Pa
ounce (mass, avoirdupois) x 28.35 = g
ounce (force of thrust) x 0.278 = N
ounce (liquid, US) x 29.6 = mL
ounce (avoirdupois) per gallon x 7.49 = kg/m3
perm (permeance) x 57.45 = ng/(s⋅m2⋅Pa)
perm inch (permeability) x 1.46 = ng/(s⋅m⋅Pa)
pint (liquid, US) x 473 = mL
pound
lb (mass) x 0.4536 = kg
lb (mass) x 453.6 = g
lbƒ(force or thrust) x 4.45 =N
*Conversion factor is exact.
93

lb/ft (uniform load) x 1.49 = kg/m
lbm/(ft⋅h) (dynamic viscosity, µ) x 0.413 = mPa⋅s
lbm/(ft⋅s) (dynamic viscosity, µ) x 1490 = mPa⋅s
lbƒs/ft2 (dynamic viscosity, µ) x 47 880 = mPa⋅s
lb/min x 0.00756 = kg/s
lb/h x 0.126 = g/s
lb/h (steam at 212°F) x 0.284 = kW
lbƒ/ft2 x 47.9 = Pa
lb/ft2 x 4.88 = kg/m2
lb/ft3(density, p) x 16.0 = kg/m3
lb/gallon x 120 = kg/m3
ppm (by mass) x *1.00 = mg/kg
psi x 6.895 = kPa
quart (liquid, US) x 0.946 =L
square (100 ft2) x 9.29 = m2
tablespoon (approx.) x 15 = mL
teaspoon (approx.) x 5 = mL
therm (100,000 Btu) x 105.5 = MJ
ton, short (2000 lb) x 0.907 = mg; t (tonne)
ton, refrigeration (12,000 Btu/h) x 3.517 = kW
torr (1 mm Hg at 0°C) x 133 = Pa
watt per square foot x 10.8 = W/m2
yd x 0.9144 =m
yd2 x 0.836 = m2
yd3 x 0.7646 = m3
* Conversion factor is exact.
Note:
In this list the kelvin (K) expresses temperature intervals.
The degree Celsius symbol (°C) is often used for this pur-
pose as well.

94

15.
0
50

Vol
.028

.
ASHRAE Psychrometric Chart No.1 IR
60

C
Normal Temperature A .026

UF
Barometric Pressure: 29.921 Inches of Summary RY 45
D

T
Copyright 1992 F .024
O 80°

per
D F 55
American Society of Heating, Refrigeration N 40 -° 80° .022
U FW

LB
and Air-Conditioning Engineers, Inc. PO E et B
R

%
ulb
R U .020
Pyschometric Chart

Tem

dry

90
PE 35 p
AT
U R .018

air
T E 50
B M 70°

%
) - 30 TE .016
14.

70
(h
5
Y N
.014

95
LP IO 45
A 25 AT
TH R 60° % .012
U 50
EN T

14.
.010
0
20 SA 40
50° .008
15 30%

13.

40° ity .006

5
umid 35
tive H .004
Rela

13.
10%

0

12.
.002

5
Humidity Ratio (W) - Pounds moisture per pound dry air

30
40 50 60 70 80 90 100 110
Reduced from ASHRAE Psychrometric Chart No. 1 Dry Bulb Temp F°

INDEX
A
Affinity Laws for Centrifugal Applications 83
For Fans and Blowers 83
For Pumps 83
Affinity Laws for Pumps 66
Air Change Method 40
Air Density Factors for Altitude and Temperature 3
Air Quality Method 40
Airfoil Applications 5
Allowable Ampaciites of Not More Than Three
Insultated Conductors 24–25
Alternating Current 16
Annual Fuel Use 63–64
Appliance Gas-Burning, Floor Mounted Type 45
Area and Circumference of Circles 84–87
Axial Fan Types 1
B
Backdraft or Relief Dampers 49
Backward Inclined, Backward Curved
Applications 6
Bearing Life 28
Belt Drive Guidelines 26
Belt Drives 26
Breakdown Torque 16
C
Cell-Type Air Washers 53
Centrifugal Fan Types 1
Centrifugal Fan Conditions
Typical Inlet Conditions 14
Typical Outlet Conditions 14
Change in Resistance Due to Change in Temperature 82
Circle Formula 87
Classifications for Spark Resistant Construction 4–5
Construction Type 4
Notes 4–5
Standard Applications 5
Closed Impeller 64

96

INDEX
Common Fractions of an Inch 87
Compressor Capacity Vs. Refrigerant Temperature at 100°F
Condensing 78
Conversion Factors 88–94
Cooling Load Check Figures 59–60
Cooling Tower Ratings 77
Copper Tube Dimensions (Type L) 74
D
Damper Pressure Drop 49
Decimal and Metric Equivalents 87–88
Dehumidifying Coils 53
Design Criteria for Room Loudness 35–36
Double Suction 64
Drive Arrangements for Centrifugal Fans 9–10
Arr. 1 SWSI 9
Arr. 10 SWSI 10
Arr. 2 SWSI 9
Arr. 3 DWDI 9
Arr. 3 SWSI 9
Arr. 4 SWSI 9
Arr. 7 DWDI 10
Arr. 7 SWSI 9
Arr. 8 SWSI 10
Arr. 9 SWSI 10
Duct Resistance 51
E
Efficiency 16
Electric Coils 53
Electric, Floor Mounted Type 45
Electrical Appliances 46
Electronic Air Cleaners 53
Equivalent Length of Pipe for Valves and Fittings 73
Estimated Belt Drive Loss 27
Estimated Seasonal Efficiencies of Heating Systems 63
Evaporate Condenser Ratings 78
Exhaust Louvers 53

97

INDEX
F
Fan Basics
Fan Selection Criteria 1
Fan Types 1
Impeller Designs - Axial 7
Fan Installation Guidelines 14
Centrifugal Fan Conditions 14
Fan Laws 2
Fan Performance Tables and Curves 2
Fan Selection Criteria 1
Fan Testing - Laboratory, Field 2
Fan Troubleshooting Guide 15
Excessive Vibration and Noise 15
Low Capacity or Pressure 15
Overheated Bearings 15
Overheated Motor 15
Fan Types 1
Axial Fan 1
Centrifugal Fan 1
Filter Comparison 46
Filter Type 46
For Pumps 83
Forward Curved Applications 6
Fouling Factors 76
Frequency Variations 23
Friction Loss for Water Flow 71–72
Fuel Comparisons 62
Fuel Gas Characteristics 62
Full Load Current 21–22
Single Phase Motors 21
Three Phase Motors 22
G
Gas-Burning Appliances 46
General Ventilation 29

98

INDEX
H
Heat Gain From Occupants of Conditioned Spaces 43
Typical Application 43
Heat Gain From Typical Electric Motors 44
Heat Loss Estimates 61–62
Considerations Used for Corrected Values 62
Heat Removal Method 40
High-Velocity, Spray-Type Air Washers 53
Horizontal Split Case 65
Horsepower 16
Horsepower per Ton 77
I
Impeller Designs - Axial
Propeller 7
Tube Axial 7
Vane Axial 7
Impeller Designs - Centrifugal 5–6
Airfoil 5
Backward Inclined, Backward Curved 6
Forward Curved 6
Radial 6
Inadequate or No Circulation 68
Induction Motor Characteristics 23
Intake Louvers 53
K
Kitchen Ventilation 30
Fans 30
Filters 30
Hoods and Ducts 30
L
Locked Rotor KVA/HP 19
Locked Rotor Torque 16

99

INDEX
M
Miscellaneous Formulas 81–84
Moisture and Air Relationships 57
Motor and Drive Basics Definitions and Formulas 16
Motor Application 82
Motor Efficiency and EPAct 20
Motor Insulation Classes 18
Motor Positions for Belt or Chain Drive 13
Motor Service Factors 19
N
Noise Criteria 32
Noise Criteria Curves 34
O
OHMS Law 81
Open Impeller 64
Optimum Relative Humidity Ranges for Healt 48
P
Panel Filters 53
Power —D-C Circuits 81
Power —A-C Circuits 81
Process Ventilation 29
Propeller Applications 7
Properties of Saturated Steam 58
Pump Bodies 65
Pump Construction Types
All-Bronze Pumps 64
Bronze-fitted Pumps 64
Pump Impeller Types 64
Pump Mounting Methods 65
Base Mount-Close Coupled 65
Base Mount-Long Coupled 65
Line Mount 65
Pump or System Noise 67
Pump Terms, Abbreviations, and Conversion Factors 69
Pumping System Troubleshooting Guide 67–68
Pyschometric Chart 95

100

INDEX
Q
Quiet Water Flows 70
R
RadialApplications 6
Rate of Heat Gain Commercial Cooking Appliances in
Air-Conditioned Area 45
Rate of Heat Gain From Miscellaneous Appliances 46
Rated Load Torque 16
Recommended Metal Gauges for Ducts 56
Rectangular Equivalent of Round Ducts 52
Refrigerant Line Capacities for 134a 79
Refrigerant Line Capacities for R-22 79
Relief or Backdraft Dampers 49
Renewable Media Filters 53
Room Sones —dBA Correlation 33
Room Type 35–36
Auditoriums 35
Churches and schools 35
Hospitals and clinics 35
Hotels 36
Indoor sports activities 35
Manufacturing areas 35
Miscellaneous 36
Offices 35
Public buildings 36
Residences 36
Restaurants, cafeterias, lounges 36
Retail stores 36
Transportation 36
Rotation & Discharge Designations 11–12
Rules of Thumb 31–32

101

INDEX
S
Screen Pressure Drop 50
Single Phase AC 16
Single Phase AC Motors 17
Single Suction 64
Sound 31
Sound Power 31
Sound Power Level 31
Sound Power and Sound Power Leve 32
Sound Pressure and Sound Pressure Leve 33
Speed—A-C Machinery 82
Spray-Type Air Washers 53
Standard Pipe Dimenions Schedule 40 (Steel) 74
Standard Pipe Dimensions 74
Steam and Hot Water Coils 53
Suggested Air Changes 41
Synchronous speed 16
T
Terminology for Centrifugal Fan Components 8
Three Phase AC 16
Three-phase AC Motors 17
Time for Motor to Reach Operating Speed (seconds) 82
Torque 16
Tube Axial Applications 7
Types of Alternating Current Motors 17–18
Three-phase AC Motors 17
Types of Current Motors ??–18
Typical Design Velocities for HVAC Components 53
Typical Heat Transfer Coefficients 75
U
U.S. Sheet Metal Gauges 55
Use of Air Density Factors - An Example 3

102

INDEX
V
Vane Axial
Applications 7
V-belt Length Formula 26
Velocity and Velocity Pressure Relationships 54
Ventilation Rates for Acceptable Indoor Air Quality 42
Vertical Split Case 65
Vibration 37, 83
System Natural Frequency 37
Vibration Severity 38–39
Vibration Severity Chart 38
Voltage 23
Volume of Liquid in a Tank 83
W
Water Flow and Piping 70–71
Wind Driven Rain Louvers 56

103

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