design installation and inspection for gas linespipes

2015 International
Fuel Gas Code Update
Based on the International Fuel Gas Code®
(IFGC®)

Description
▪ This seminar is designed to familiarize and
assist code officials in locating, describing and
applying the applicable code requirements of the
IFGC to determine compliance or
noncompliance.
2
2015 IFGC Design Installation & Inspection

Overview
▪ Administration
▪ Definitions
▪ General regulations
▪ Gas piping installations
▪ Chimneys and vents
▪ Specific appliances
2015 IFGC Design Installation & Inspection 3

Seminar Goal
▪ The goal of this is for you to apply the 2015
International Fuel Gas Code to the design, plan
review, installation and inspection of all fuel-gas-
related construction.

Objectives
▪ Upon completion, participants will be better able
to:
▪ Locate general topics in the 2015 IFGC.
▪ Locate applicable tables in the 2015 IFGC for specific
situations.
▪ Apply code requirements to clear-cut real world
situations.
▪ Explain the intent behind a given code requirement.
▪ Use judgment to identify borderline scenarios as
compliant or noncompliant.

Chapter 1
Scope and Administration
Module 1
6

Administration
“Due Process of Law”
▪ The responsibilities of
the various professionals
are also established:
▪ The code official reviews
the proposed work for
code compliance.
▪ As a public servant, the
code official enforces the
code in an unbiased,
proper manner.
▪ The design professional
designs a safe,
operational fuel gas
system.
▪ The contractor installs
the system in strict
accordance with the
plans and/or
manufacturer’s
installation requirements.

Applicability - 102
▪ Codes and standards referenced in Chapter 8
shall be considered part of the requirements of
this code.
▪ Provisions of this code shall apply, where
conflicts occur between the provisions of this
code and the referenced standards.

Chapter 2
Definitions
Module 2
9

Definitions
▪ APPLIANCE. Any
apparatus or device
that utilizes a fuel or
raw material to
produce light, heat,
power, refrigeration or
air conditioning.

Definitions
▪ COMBUSTIBLE
ASSEMBLY. Wall, floor,
ceiling or other assembly
constructed of one or more
component materials that are
not defined as
noncombustible.
▪ COMBUSTIBLE MATERIAL.
Any material not defined as
noncombustible.

Definitions
▪ EQUIPMENT. Apparatus and devices
other than appliances.

Definitions
▪ EXCESS FLOW
VALVE (EFV). A valve
designed to activate
when the fuel gas
passing through it
exceeds a prescribed
flow rate.

Definitions
▪ FLASHBACK
ARRESTOR CHECK
VALVE. A device that
will prevent the
backflow of one gas
into the supply system
of another gas and
prevent the passage of
flame into the gas
supply system.

Definitions
▪ NONCOMBUSTIBLE MATERIALS. Materials
tested in accordance with ASTM E 136, have at
least three of four specimens tested meeting the
following criteria:
1. The recorded temperature of the surface and interior
thermocouples shall not at any time during the test
rise more than 54ºF (30ºC) above the furnace
temperature at the beginning of the test.
2. Shall not be flaming from the specimen after the first
30 seconds.
3. If the weight loss of the specimen during testing
exceeds 50 percent, the recorded temperature of the
surface and interior thermocouples shall not at any
time during the test rise above the furnace air
temperature at the beginning of the test, and there
shall not be flaming of the specimen.

Definitions
▪ REGULATOR, PRESSURE. A device placed in
a gas line for reducing, controlling and
maintaining the pressure in that portion of the
piping system downstream of the device.

Definitions
▪ REGULATOR, SERVICE PRESSURE. For
natural gas systems, a device installed by the
serving gas supplier to reduce and limit the
service line pressure to delivery pressure.

Definitions
▪ THIRD-PARTY
CERTIFICATION AGENCY. An
approved agency operating a
product or material certification
system that incorporates initial
product testing, assessment
and surveillance of a
manufacturer's quality control
system.

Definitions
▪ THIRD-PARTY CERTIFIED. Certification
obtained by the manufacturer indicating that the
function and performance characteristics of a
product or material have been determined by
testing and ongoing surveillance by an approved
third-party certification agency.

Definitions
▪ THIRD-PARTY TESTED.
Procedure by which an
approved testing
laboratory provides
documentation that a
product, material or
system conforms to
specified requirements.

Definitions
1. ____ Third-Party
Certified
2. ____ Regulator
Service Pressure
3. ____ Excess Flow
Valve (EFV)
4. ____ Third-Party
Tested
5. ____ Flashback
Arrestor Check
Valve
6. ____ Third-Party
Certification Agency
E.
F.
A.
B.
D.
C.

Chapter 3
General Regulations
Module 3
22

General Regulations
Chapter 3
▪ Governs the approval
and installation of
equipment and
appliances.

General
Regulations/Requirements
▪ In accordance with other codes
▪ Labeling
▪ Structural safety
▪ Combustion, ventilation, dilution air
▪ Clearance reduction for required clearances

Consistency
▪ International Building Code (IBC)
▪ International Mechanical Code (IMC)
▪ International Energy Conservation Code
(IECC)
▪ International Plumbing Code (IPC)
▪ Listed Appliances
▪ Manufacturer’s Instructions

Listed and labeled – 301.3
▪ Code intends that appliances be installed and
used in a manner consistent with the nature of
their listing. This will prevent an appliance from
being used in an application other than for what
it was listed.

Label Information-301.5
▪ Allows a code official to determine which fuel
can be used, the design pressure, BTU,
clearances and approval agency.
▪ Most gas appliances are shipped for use on
natural gas and are field converted to propane
utilizing this information as well as the
Manufacturer Installation Instructions.

Label Information-301.5
▪ Required information
▪ Manufacturer’s name or
trademark
▪ Model number
▪ Serial number
▪ Hourly rating in Btu/h (W)
▪ Type of fuel
▪ Seal or mark of testing
agency
▪ Minimum clearance
requirements

Label and Listing
Trane Co.
TUE 080 A936KZ
N315TK1ZG
80,000
Natural Gas
AGA
ANSI Z21.47-2003
▪ Manufacturer: ___________________________
▪ Model number: __________________________
▪ Serial number: __________________________
▪ Hourly rating in Btu/hr (W): ________________
▪ Type of fuel: ____________________________
▪ Testing agency:__________________________
▪ Test Standard: ________________________

Flood Hazard – 301.11
▪ Section 1612 of the IBC for utilities and
attendant equipment.
▪ For structures located in flood hazard areas, the
appliance, equipment and system installations shall
be located at or above the elevation required.

Structural Integrity – 302
▪ Installation of fuel gas piping systems and
appliances must not affect:
▪ Structural integrity of building components
▪ Fire-resistive integrity of building components
▪ Cutting, notching and drilling of structural
members and penetration of assemblies must
be regulated.

Cutting and Notches in Wood
Studs

Bored Hole Requirements

Engineered wood products –
302.3.1
▪ Cuts, notches and holes bored in trusses,
structural composite lumber, structural glued-
laminated members and I-joists are prohibited
except where permitted by the manufacturer’s
recommendations or where the effects of such
alterations are considered in the design by a
registered design professional.

Structural Integrity
Identify what is wrong

Identify what is wrong.

Appliance Location - 303
Hazardous locations
(Section 303.2)
Appliances shall not be located
in hazardous locations unless
listed and approved for such
use.
Closets and alcoves
(Sections 303.5)
Furnaces and boilers installed in
closets and alcoves must be listed
for such installation
Outdoor installations
(Section 303.6)
.Appliances installed outdoors
must be listed for such installation

Prohibited Locations – 303.3
▪ Fuel-fired appliance shall not be
located in:
▪ Sleeping rooms
▪ Bathrooms
▪ Toilet rooms
▪ Storage closets
▪ Surgical rooms

Prohibited Locations
▪ Five exceptions
1. Direct-vent appliances.
2. Vented room heaters, wall furnaces, vented
decorative appliances or decorative
appliances.
3. A single wall-mounted, unvented room
heater with an input rating 6000 Btu/hr
installed in a bathroom.

Prohibited Locations
▪ Five exceptions (cont.)
4. A single-listed, wall-mounted, unvented room
heater with an input rating 10,000 Btu/hr.
5. Appliances in a dedicated enclosure in which
all combustion air is taken directly from the
outdoors.

Prohibited Locations – 303.3
Appliance locations

Protection from Vehicle Impact –
303.4
Appliance Protected
from Vehicle Impact

Appliance Location
1. A water heater is located in a closet that is
accessed through a bathroom. All combustion
air is taken from the building interior in full
compliance with Section 304.5.
YES or NO

Appliance Location
2. A wall-mounted, unvented room heater is
installed in a bedroom with exterior walls. The
heater has a oxygen depletion safety shutoff
device and the bedroom has the volume
required by Section 304.5. The input rating of
the heater is 11,000 Btu/hr.
YES or NO

Combustion, Ventilation, and
Dilution Air – 304
▪ Gas utilization equipment requires air for
combustion, ventilation and dilution of flue gases
▪ Requirements assure:
▪ Proper air supply for the combustion and venting
process
▪ Ventilation cooling for appliances

Combustion, Ventilation, and
Dilution Air – 304

Reliability of Air Supply –
304.4
▪ Maintenance of
appropriate
relationships
▪ Choice of
appliance location
/ contaminated
atmospheres
▪ Advantages of
direct-vent
appliances

Free Area of an Opening –
304.10

Decision Tree for Combustion
Air

Indoor Combustion Air –
304.5
▪ To determine if volume of spaces meets
combustion air demand of appliances:
1. Determine type (s) of appliance (s)
2. Determine input rating for appliances
3. Determine if air change rate (ACR) is known
4. Determine volume calculation method to use
5. Calculate the required volume for each appliance.

Indoor Combustion Air –
304.5
▪ To determine if volume of spaces meets
combustion air demand:
6. Find available volume of room or rooms.
7. Determine if makeup air required for exhaust
systems, clothes dryers, etc..
8. Add the calculated volumes and compare the
total required volume to the available volume.
9. Determine if available volume is sufficient.
Determine if spaces need to be combined to
increase available volume.

Indoor Combustion Air
Calculation

Calculation
1. Calculate required volume for each boiler
(Equation 3-2).
2. Calculate required volume for each water heater
(Equation 3-1).
3. Total volumes required for all appliances
Boiler 1 5,350
Boiler 2 5,350
Water heater 1 4,500
+ Water heater 2 4,500
Total: 19,700 ft.3

Calculation
4. Determine available (actual) volume in building
▪ Basement volume 48ft. X 25ft. X 9ft. = 10,800 ft3
▪ Grade-floor volume 48ft. X 25ft. X 9ft. = 10,800 ft3
5. Louvered door opening area adequate?
▪ Determine actual louvered opening. Section 304.10
▪ 30 in. x 72 in. = 2,160 in2 x .25 = 540 in2
▪ Determine required area. Section 304.5.2
▪ (400,000 Btu/h / 1,000) x 2 = 800 in.

Calculation
▪ Combined volume (both stories) > Required
▪ Louvered door opening area: Inadequate
▪ Possible Solutions?
Adding outdoor openings in accordance with
Section 304.7 or providing metal louvers in
the door instead of wood.

Combined Indoor/Outdoor
Air – 304.7

Combined Indoor/Outdoor
Air – 304.7
▪ Required volume of room = 9,000 ft.3
▪ Actual room volume = 8,000 ft.3
▪ Ratio of available to required = 0.89
▪ Outdoor size reduction factor = 0.11
▪ Area of boiler vent connector = 56.5 in2
▪ Actual required size = 6.6 in2
▪ Minimum area must be = 9 in2

Mechanical Combustion Air
Calculation
▪ Calculate required airflow rate for combustion air
fan (304.9)

Mechanical Combustion Air
Calculation
1. Total appliance input rating:
2. Total input Btu/h / 1000 Btu/h x 0.35 CFM
= 750,000 Btu/h
= 262.5 CFM

Combustion Air Ducts – 304.11
▪ In general, combustion air ducts must:
▪ Be composed of corrosion-resistant material.
▪ Terminate in an unobstructed space.
▪ Serve a single appliance enclosure.
▪ Not serve both upper / lower combustion
openings.

Combustion Air Ducts – 304.11
▪ In general, combustion air ducts must:
(cont.)
▪ Maintain separation between openings at air
source.
▪ Not be screened where terminating in attic.
▪ Not be sloped.
▪ Duct openings to outdoors are at least 12
inches above grade.

Contaminated Atmospheres –
304.12
▪ If
▪ Indoor combustion air
is contaminated or,
▪ Contamination of
occupancy is
anticipated
▪ Then
▪ Outdoor combustion
air must be provided

Installation – 305.1
▪ Installation instructions must be available:
▪ On site
▪ At time of inspection
▪ If the code and manufacturer’s instructions
disagree:
▪ the most restrictive provision must prevail

Elevation of Ignition Source –
305.3
▪ Elevate appliances so
that the ignition source is
no less than 18 inches
above floor in:
▪ Hazardous locations.
▪ Public garages.
▪ Private garages.
▪ Repair garages.
▪ Motor fuel-dispensing
facilities.
▪ Parking garages.

Installation in Residential
Garages – 305.3.1
Elevation of Appliances Not Required

Garage Installation
Public Garages
(Section 305.4)
Private Garages
(Section 305.5)
8 feet (2438 mm) above floor 6 feet (1829 mm) above floor
Where the motor vehicles are capable of
passing under an appliance, the
appliance must be installed at the
clearance required by the manufacture
and not less than 1 foot (305 mm) higher
than the tallest vehicle garage
door opening.
If appliances are protected from motor
vehicle impact, are installed in
accordance with NFPA 30A, and the
ignition source elevation requirements of
this code are met, the 8-foot (2438 mm)
height requirement does not apply.
If appliances are protected from motor
vehicle impact and the ignition source
elevation requirements of this code are
met, the 6-foot (1829 mm) height
requirement does not apply.

Garage Installations
Public Garages

Garage Installations
Garage Space vs. Living Space

Equipment and appliances on roof
or elevated structures – 306.5

Guards – 306.6
Guards

Guards – 306.6
Roof Plan View

Condensate pumps – 307.6

Scope - 308.1
▪ For the purposes of this code, gypsum board is
identified as a combustible material, as it is in
the IMC.

Clearance Reduction -
Table 308.2
2015 IFGC,
Table
308.2,
page 30
Page 38-39

Clearance Reduction
▪ Rooms considered large in comparison with size of
equipment
▪ Assemblies listed for such appliances are also
permitted.
▪ Linear interpolation is permitted between distances in
Table 308.2.
▪ Reduced clearances below range of the table are not
permitted.
▪ Clearances shall not be reduced where reduction is
specifically prohibited by the terms of the appliance or
equipment listing.

Electrical Bonding – 310
Gas Pipe Bonding by Appliance Branch Circuit

Corrugated Stainless Steel
Tubing (CSST) – 310.1.1
CSST Bonding

Corrugated Stainless Steel
Tubing (CSST) – 310.1.1
Alternate Location for Bonding Clamp

Bonding jumper length –
310.1.1.3

Electrical Bonding—Section 310
▪ 310.1.1.4 – Bonding connections
▪ Bonding connections shall be in accordance with
NFPA 70.
▪ 310.1.1.5 – Connection devices
▪ Devices used for making the bonding connections
shall be listed in accordance with UL 467.
▪ Note: Never connect a bonding clamp to the Gas
Company service inlet pipe, Natural or LP. These are
not approved grounding electrodes or bonding
means.

Chapter 4
Gas Piping Installations
Module 4
82

Scope Includes
▪ Design
▪ Materials
▪ Components
▪ Installation
▪ Fabrication
▪ Assembly
▪ Testing
▪ Inspection
▪ Operation

Gas Piping Installation
▪ Addresses the intent to minimize hazards
associated with the use and distribution of highly
flammable fuel gas.

Piping meter identification –
401.7
▪ Multiple meter installations, one wants to be able
to properly identify and locate the valve
controlling the gas piping system to a given
tenant space.
▪ Code requires that the piping system supplied
by each meter be clearly and permanently
identifiable.

Identification - 401.9
▪ Each length of pipe or
tubing and each pipe
fitting must have the
manufacturer's
identification.

Third-party testing and
certification - 401.10
▪ All piping, tubing and fittings shall comply with
the applicable referenced standards,
specifications and performance criteria of this
code and shall be identified in accordance with
Section 401.9.
▪ Piping, tubing and fittings shall either be tested
by an approved third-party testing agency or
certified by an approved third-party certification
agency.

Pipe Sizing—402
▪ Sized to accommodate full utilization of all
the gas utilization equipment in the plan
simultaneously.

Five Step Review Process
1. Determine maximum gas demand
2. Determine length to most remote outlet
3. Select correct table
4. Locate gas demand figures
5. Locate nominal size of pipe required

What You Need to Know
▪ To determine compliance:
▪ Allowable loss in pressure from point of
delivery to gas utilization equipment
▪ Maximum gas demand
▪ Length of piping and number of fittings
▪ Labeled pipe sizes
▪ Specific gravity of the gas
▪ Diversity factor

Gas Piping System
• Tables in Chapter 4 determine sizing of
gas piping.
• Variables to take into account
1. Type of fuel gas
2. Specific gravity of gas
3. Gas supply pressure
4. Pressure drop indicated
5. Piping material used
Page 35-70

Gas Piping System
▪ Table A.2.4 lists multipliers
▪ Used with Tables 402.4(1) through
402.4(22) where specific gravity of gas
is other than 0.60.
▪ Several tables are used to determine
sizing between
▪ First- and second-stage regulators
▪ Single- or second-stage regulators and
appliances
Page 146

Tables 402.4(1) through
402.4(35)
Which table would you use?
▪ A gas piping system using Schedule 40 steel
piping with an identified pressure drop of 0.5 in
wc; with a gas pressure of < 0.5 psi (< 3.4 kPa)
and conveying a gas of 0.6 specific gravity.
Table 402.4(2)

Tables 402.4(1) through
402.4(35)
Which table would you use?
▪ A gas piping system using Schedule 40 steel
piping with an identified pressure drop of 1.0 psi
(6.9 kPa), gas pressure of 2 psi(14 kPa) and
conveying a gas of 0.7 specific gravity.
Table 402.4(3) and Appendix Table A.2.4

Pipe Sizing
▪ Section 402.4 – Sizing tables and equations
▪ Includes two sizing methods and two equations to
size piping or tubing length of low-pressure gas and
for high-pressure gas.
▪ Section 402.4.1 – Longest length method
▪ Pipe size of each section of gas piping is determined
using the longest length of gas piping from the point
of delivery to the most remote outlet, and the load of
the section.

Pipe Sizing
▪ Section 402.4.2 – Branch length method
1. Pipe size of each section of the longest pipe run
from the point of delivery to the most remote outlet
shall be determined using the longest run of piping
and the load of the section.
2. The pipe size of each section of branch piping not
previously sized shall be determined using the
length of piping from the point of delivery to the most
remote outlet in each branch, and the load of the
section.

Gas System Sizing Problem
OutletB
40-galWaterHeater
45,000Btu/hr
OutletA
ClothesDryer
20,000Btu/hr
Pointof
Delivery
OutletCRange
73,000Btu/hr
OutletD
Furnace
133,000Btu/hr
15ft
15ft
20ft
10ft
25ft
12ft
5ft 5ft
Section4 Section3
Section2
15ft
Section
1
Section5
OutletB
40-galWaterHeater
45,000Btu/hr
OutletA
ClothesDryer
20,000Btu/hr
Pointof
Delivery
OutletCRange
73,000Btu/hr
OutletD
Furnace
133,000Btu/hr
15ft
15ft
20ft
10ft
25ft
12ft
5ft 5ft
Section4 Section3
Section2
15ft
Section
1
Section5
OutletB
40-galWaterHeater
45,000Btu/hr
OutletA
ClothesDryer
20,000Btu/hr
Pointof
Delivery
OutletCRange
73,000Btu/hr
OutletD
Furnace
133,000Btu/hr
15ft
15ft
20ft
10ft
25ft
12ft
5ft 5ft
Section4 Section3
Section2
15ft
Section
1
Section5

1. Determine maximum gas demand:
Outlet A: 20 cfh (ft3/h)
Outlet B: 45 cfh (ft3/h)
Outlet C: 73 cfh (ft3/h)
Outlet D: 133 cfh (ft3/h)
Maximum gas demand: 271 cfh (ft3/h)

2. Determine length to the most remote outlet:
Section 1: 15 ft.
Section 2: 25 ft.
Section 3:
Section 4:
Section 5:
Total pipe length to most remote outlet: 80 ft.
5 ft.
5 ft.
30 ft.

3. Select applicable table:
Specific gravity:
Gas pressure:
Pressure drop:
Type of material:
Special conditions:
Table Used:
0.60
10 IN WC
0.5 IN WC
Steel Pipe
NA
402.4(2)

4. Locate gas demand figures:
▪ Horizontal row showing length of piping
▪ Indicates length from point of delivery to most remote
outlet
▪ If not exact, use next longer distance
▪ Use this row for all gas demand figures

▪ Locate nominal size of pipe required:
▪ Outlet A: 20 ft3/h (from Step 1) requires 1/2-
inch pipe
▪ Outlet B: 45 ft3/h requires 1/2-inch pipe
▪ Pipe section 2: supplying A 20 ft3/h requires
1/2-inch pipe
▪ Pipe section 3: supplying A, B 65 ft3/h requires
3/4-inch pipe

5. Locate nominal size of pipe required:
▪ Outlet C:
▪ 73 ft3/h requires 3/4 inch pipe
▪ Outlet D:
▪ 133 ft3/h requires 1 inch pipe
▪ Pipe Section 4 (A,B,C):
▪ 138 ft3/h requires 1 inch pipe
▪ Pipe Section 5 (A,B,C,D):
▪ 271 ft3/h requires 1 ¼ inch pipe

Branch Length Method
▪ Determine the size of gas piping sections

▪ Determine the size of trunkline sections
▪ Determine load for each section of pipe
▪ A = 230 MBH
▪ B = 170 MBH
▪ C = 135 MBH
▪ D = 95 MBH
▪ E = 20 MBH
▪ Determine the table to use
▪ Because longest run length of pipe is between rows, use next
higher row.
= 402.4(2)

▪ Determine the size of trunk line sections
▪ Determine size for each section of pipe
▪ A = 1 ¼ inch
▪ B = 1 inch
▪ C = 1 inch
▪ D = ¾ inch
▪ E = 3/8 inch

▪ We now have the following information about the
proposed piping system:
▪ The specific gravity of the gas is 0.6.
▪ The gas pressure is 0.5 psi (3.4 kPa) or less.
▪ The pressure drop is 0.5 inch (125 Pa) wc.
▪ The material is Schedule 40 steel.
▪ The longest run length is 85 feet (25 908 mm).

▪ We determine that the table to use to determine
the size of each pipe section is Table 402.4(2).
This table lists the maximum capacity of pipe:
▪ In cubic feet of gas per hour (m3/h).
▪ For gas pressures of 0.5 psi (3.4 kPa) or less.
▪ With a pressure drop of 0.5 inch (125 Pa) wc.
▪ Based on a 0.6 specific gravity.
▪ Because the longest run length of pipe is
between rows in the table, the 90-foot (27 432
mm) rows must be chosen.

▪ Determine the load for the following branch
sections
▪ Section F:
▪ Section G:
▪ Section H:
▪ Section I:
▪ Section J:
20 ft3/h
60 ft3/h
35 ft3/h
40 ft3/h
75 ft3/h

▪ Determine the length for each branch
▪ Section F:
▪ Section G:
▪ Section H:
▪ Section I:
▪ Section J:
▪ Determine the table to use
▪ Table 402.4(13)
85 ft.
25 ft.
40 ft.
60 ft.
75 ft.

▪ Determine the size for each section of gas pipe.
Pipe Section Length (ft.) Load (MBH) Size
A 85 20 18
B 25 60 19
C 40 35 18
D 60 40 23
E 75 75 30

Hybrid Pressure System Sizing –
402.4.3

402.4.3
▪ Using IFGC Table 402.4(7), determine the
minimum required size of piping Sections A
through D. The longest run of piping from the
point of delivery to the most remote regulator is
175 feet (53 340 mm).

402.4.3
▪ Section A serves a load of 625 MBH, and in the 175-
foot row of the table, 1/2-inch pipe is shown to have
a capacity of 728 ft3/h or 728,000 Btu/h (20.6 m3/hr
or 213,356 W) for gas with a heating value of 1,000
Btu/ft3 (37.5 MJ/m3).
▪ Since Sections B, C and D all serve lesser loads
than Section A, they too can be 1/2 inch in size.
▪ Because Table 402.4(7) is based upon a pressure
drop of 3.5 psi, the available pressure at the inlets of
the “pounds-to-inches” regulators under full load
condition will be a minimum of 1.5 psig .

402.4.3
▪ A. Load: 625,000 Btu Size: 1/2"
▪ B. Load: 350,000 Btu Size: 1/2"
▪ C. Load: 275,000 Btu Size: 1/2"
▪ D. Load: 275,000 Btu Size: 1/2"

402.4.3
▪ Determine size of piping for Sections E, F and G.
▪ Table 402.4(2) and the longest length of piping from the
regulator to the most remote outlet is used to determine
the size of piping for Sections E, F and G. In this case,
Rooftop Unit 1 is the most remote at 65 feet (40 feet +
2.5 feet) from the regulator. The minimum required size
for each section is:
▪ E. Load: 350,000 Btu Size: 11/4"
▪ F. Load: 200,000 Btu Size: 1"
▪ G.Load: 150,000 Btu Size: 1"

402.4.3
▪ Determine the size of piping for Sections H, I
and J in the same manner previously described
in Item 2.
▪ The most remote point is 35 feet (20 feet + 15
feet).
▪ H.Load: 275,000 Btu Size: 1"
▪ I. Load: 125,000 Btu Size: 3/4"
▪ J. Load: 150,000 Btu Size: 3/4"

Parallel System – 6” WC

▪ Piping arranged in parallel.
▪ Main section and individual appliance runs constructed
of CSST (2015 IFGC Table 402.4(15).
▪ Supply pressure is 6 inches (152 kPa) wc downstream of
the meter.
▪ Natural gas with specific gravity of 0.60.
▪ Chosen pressure drop 0.5 inch (125 Pa) wc.
▪ Minimum appliance supply pressure requirements is 5
inches (1.25 kPa) wc.
▪ Heating value of gas is 1,000 Btu/ft3.

▪ Sizing Section A:
▪ Size Section A based on the appliance total load
and length from the meter to the furthest
appliance.
▪ Total load = 80 + 36 + 52 + 28 + 25 = 221 ft3/h
(6.25 m3/hr).
▪ Section length = 45 + 20 + 5 = 70 feet (21 336
mm).
▪ Use Table 402.4(15).

▪ Sizing Section B:
▪ Size Section B based on the appliance total load
and length from the meter to the appliance.
▪ Total load = 80 ft3/h (2.26 m3/hr).
▪ Section length (furnace) = 45 + 15 = 60 feet (18
288 mm).
▪ Use Table 402.4(15).

▪ Sizing Section C:
▪ Size Section C based on the appliance total load
▪ Section length (water heater) = 45 + 10 = 55 feet
(16 764 mm).
▪ Use Table 402.4(15).

▪ Sizing Section D:
▪ Size Section D based on the appliance total load
▪ Section length (range) = 45 + 20 = 65 feet (19
812 mm).
▪ Use Table 402.4(15).

▪ Sizing Section E:
▪ Size Section E based on the appliance total load
appliance.
▪ Total load = 25 + 28 = 53 ft3/h (1.50 m3/hr).
▪ Section length (dryer/room heater) = 45 + 20 + 5
= 70 feet (21 336 mm).
▪ Use Table 402.4(15).

▪ Sizing Section F:
▪ Size Section F based on the appliance total load
appliance.
▪ Total load = 28 ft3/h (0.71 m3/hr)..
▪ Section length (dryer) = 45 + 20 + 5 = 70 feet
(21 336 mm).
▪ Use Table 402.4(15).

▪ Sizing Section G:
▪ Size Section G based on the appliance total load
appliance.
▪ Total load (room heater) = 25 ft3/h (0.71 m3/hr).
▪ Section length = 45 + 20 + 5 = 70 feet (21 336
mm).
▪ Use Table 402.4(15).

▪ Required Size (CSST)
▪ A
▪ B
▪ C
▪ D
▪ E
▪ F
▪ G
37
25
19
23
23
18
18

MP Regulator

Medium Pressure System

2 psi (14 kPa) Appliance
Branch Runs
▪ All piping is CSST. Each brand or manufacturer has
it’s equivalent hydraulic diameter (EHD) rating to
determine pipe size. We must know the
manufacturer to determine EHD.
▪ Piping branches run parallel.
▪ Individual CSST appliance branch runs supplied by
manifold.
▪ Supply pressure is 2 psi (14 kPa) downstream of the
meter.
▪ Chosen pressure drop is 1 psi (6.8 kPa) for Section
A [Table 402.4(18)].

Branch Runs
▪ Natural gas with specific gravity of 0.60.
▪ Heating value of gas is 1,000 Btu/ft3.
▪ Supply pressure at manifold is 8 inches wc (2.0
kPa).
▪ Chosen pressure drop is 3 inches wc (0.75 kPa)
for Sections B through G [Table 402.4(16)].
▪ Appliances need 5 inches wc (1.25 kPa)
minimum supply pressure.
▪ Pressure drop across regulator is less than 1/2
psi (3.4 kPa) at full load of this system.

Branch Runs

Medium Pressure System
▪ A
▪ B
▪ C
▪ D
▪ E
▪ F
▪ G
18
15
13
13
15
13
13

Branch Runs
▪ Sizing Section A:
▪ Size Section A based on the total load and
length from the meter to the regulator.
▪ Total load = 80 + 36 + 52 + 28 + 25 = 221 ft3/h
(6.25 m3/hr).
▪ Section length = 45 feet (13 716 mm).
▪ Use Table 402.4(18).

Branch Runs
▪ Sizing Section B:
▪ Size Section B based on the appliance load and
length from the regulator to the appliance.
▪ Appliance load = 80 ft3/h (2.26 m3/hr).
▪ Section length (furnace) = 15 feet (4568 mm).
▪ Use Table 402.4(16).

Branch Runs
▪ Sizing Section C:
▪ Size Section C based on the appliance load and
▪ Section length (water heater) = 10 feet (3048
mm).
▪ Use Table 402.4(16).

Branch Runs
▪ Sizing Section D:
▪ Size Section D based on the appliance load and
▪ Section length (range) = 20 feet (6096 mm).
▪ Use Table 402.4(16).

Branch Runs
▪ Sizing Section E:
▪ Size Section E based on the appliance total load
and length from the regulator to the furthest
appliance.
▪ Total load = 25 + 28 = 53 ft3/h (1.50 m3/hr).
▪ Section length (dryer/room heater) = 20 + 5 = 25
feet (7620 mm).
▪ Use Table 402.4(16).

Branch Runs
▪ Sizing Section F:
▪ Size Section F based on the appliance total load
and length from the regulator to the furthest
appliance.
▪ Total load (dryer) = 28 ft3/h (0.79 m3/hr).
▪ Section length = 20 + 5 = 25 feet (7620 mm).
▪ Use Table 402.4(16).

Branch Runs
▪ Sizing Section G:
▪ Size Section G based on appliance total load
and length from regulator to furthest appliance.
▪ Total load (room heater) = 25 ft3/h (0.71 m3/hr).
▪ Section length = 20 + 5 = 25 feet (7620 mm).
▪ Use Table 402.4(16).

Branch Runs

▪ Pipe shall be sized as follows:
1. Pipe size of each section of the longest pipe run
from the point of delivery to the most remote
outlet shall be determined using the longest run
of piping and the load of the section.
2. Pipe size of each section of branch piping not
previously sized shall be determined using the
length of piping from the point of delivery to the
most remote outlet in each branch and the load
of the section. 2.25 kPa) wc.

▪ Given:
▪ Natural gas.
▪ Specific gravity 0.60.
▪ Pressure drop 0.5 inches (0.75 kPa) wc for steel
pipe and 3 inches (76 mm) wc for CSST.
▪ Supply pressure 9 inches (2.25 kPa) wc.

▪ Required Size 40”
Steel Pipe
▪ A
▪ B
▪ C
▪ D
▪ E
▪ F
▪ G
▪ H
▪ I
▪ J
▪ K
▪ L
▪ M
▪ N
1 ¼”
1 ¼”
1”
1”
¾”
¾”
3/8”
13
23
15
18
15
18
13

Piping Materials - 403

403.5.2 – Copper and copper
alloy tubing
▪ Copper tubing shall comply with Standard Type
K or L of ASTM B 88 or ASTM B 280.
▪ Copper and copper alloy tubing shall not be
used if the gas contains more than an average
of 0.3 grains of hydrogen sulfide per 100
standard cubic feet of gas (0.7 milligrams per
100 liters).
▪ Contact the local natural gas company for
number of grains per 100 liters.

403.5.4 – Corrugated stainless
steel tubing
▪ ANSI/LC 1/CSA 6.26 provides material and
performance criteria; and installation
requirements for CSST gas distribution piping
systems.
▪ Choice of material and design is up to the
designer of the system.
▪ Material can be used as manifold, traditional or
parallel.

Piping Material
▪ Identify any code violations apparent in the
installation

403.6 – Plastic pipe and tubing fittings
and Section 404.17.1 – Plastic pipe
▪ The installation of plastic pipe and tubing is
limited to areas that are both outside the building
and underground because of the potential
hazard associated with the use of a material that
has lower resistance to physical damage and
heat as compared to metallic pipe.

403.9.2 – Number of threads
2015 IFGC,
Table
403.9.2,
page72

Tubing joints – 403.10.2
Press Copper Fitting

Piping System Installation - 404
▪ Prohibited locations
▪ Piping in concealed locations
▪ Underground penetration prohibited
▪ Protection against physical damage
▪ Piping in solid floors
▪ Conduit with both ends terminating indoors
▪ Minimum burial depth
▪ Individual outdoor appliances

403.10.4 – Metallic Fittings
▪ Metallic fittings shall comply with the following:
1. Threaded fittings in sizes larger than 4 inches (102
mm) shall not be used except where approved.
2. Fittings used with steel or wrought-iron pipe shall be
steel, copper alloy, malleable iron or cast iron.
3. Fittings used with copper or copper alloy pipe shall
be copper, or copper alloy.
4. Fittings used with aluminum-alloy pipe shall be of
aluminum alloy.

5. Cast-iron fittings:
5.1. Flanges shall be permitted.
5.2. Bushings shall not be used.
5.3. Fittings shall not be used in systems containing
flammable gas-air mixtures.
5.4. Fittings in sizes 4 inches (102 mm) and larger shall
not be used indoors except where approved.
5.5. Fittings in sizes 6 inches (152 mm) and larger shall
not be used except where approved.

6. Aluminum-alloy fittings. Threads shall not form
the joint seal.
7. Zinc aluminum-alloy fittings. Fittings shall not
be used in systems containing flammable gas-
air mixtures.

6. Special fittings. Fittings such as couplings,
proprietary-type joints, saddle tees, gland-type
compression fittings, and flared, flareless or
compression-type tubing fittings shall be used
within the fitting manufacturer's pressure
temperature recommendations; used within the
service conditions anticipated with respect to
vibration, fatigue, thermal expansion or contraction;
installed or braced to prevent separation of the joint
by gas pressure or external physical damage; and
shall be approved.

9. Where pipe fittings are drilled and tapped in the field,
the operation shall be in accordance with all of the
following:
9.1. The operation shall be performed on systems having
operating pressures of 5 psi (34.5 kPa) or less.
9.2. The operation shall be performed by the gas supplier or the
gas supplier's designated representative.
9.3. The drilling and tapping operation shall be performed in
accordance with written procedures prepared by the gas
supplier.
9.4. The fittings shall be located outdoors.
9.5. The tapped fitting assembly shall be inspected and proven
to be free of leakage.

404.2 CSST Piping Systems
▪ CSST piping systems shall be installed in
accordance with their listing and the
manufacturer’s installation instructions.

Sample installation instructions for
CSST gas piping

404.5 – Fittings in concealed
locations
▪ Fittings installed in concealed locations shall be
limited to the following types:
1. Threaded elbows, tees and couplings.
2. Brazed fittings.
3. Welded fittings.
4. Fittings listed to ANSI LC-1/CSA 6.26 or ANSI LC-4.

404.5 – Fittings in concealed
locations

Underground penetration
prohibited – 404.6
Above Grade Entrance/Exit

404.7 – Protection against
physical damage
▪ Intended to minimize the possibility that nails or
screws will be driven into the gas pipe.
▪ Where piping will be concealed within light-
frame construction assemblies, the piping shall
be protected against penetration by fasteners in
accordance with Sections 404.7.1 through
404.7.3

404.7 – Protection against
physical damage

404.7.1 – Piping through bored
holes or notches
▪ Is located less than 11/2 inches (38 mm) from the
framing member face to which wall, ceiling or floor
membranes will be attached,
▪ Pipe shall be protected by shield plates that cover
the width of the pipe and the framing member and
that extend not less than 4 inches (51 mm) to each
side of the framing member.
▪ Shield plates shall cover the framing member and
extend not less than 4 inches (51 mm) above the
bottom framing member and not less than 4 inches
(51 mm) below the top framing member.

404.7.2 – Piping installed in other
locations
▪ Is less than 11/2 inches (38 mm) from the
framing member face to which wall, ceiling or
floor membranes will be attached, the piping
shall be protected by shield plates that cover the
width and length of the piping.
▪ Located less than 11/2 inches (38 mm) from the
nearest edge of the face of the framing member
to which the membrane will be attached, the
piping shall be protected by shield plates that
cover the width and length of the piping.

404.7.3 – Shield plates
▪ Shield plates shall be of steel material having a
thickness of not less than 0.0575 inch (1.463
mm) (No. 16 gage).

Piping in Solid Floors – 404.8

Conduit with both ends terminating
indoors – 404.8.2 & 404.14.2
Piping Under Slab Between Interior Points

Protective coatings and
wrapping - 404.11.2
▪ Pipe protective coatings and wrappings
approved for the application and shall be
factory applied.
▪ Exception: Where installed in accordance with the
manufacturer's instructions, field application of
coatings and wrappings shall be permitted for
pipe nipples, fittings and locations where the
factory coating or wrapping has been damaged or
necessarily removed at joints.

Minimum burial depth – 404.11.2
▪ A depth of 12 inches (305 mm) below grade is
considered sufficient to avoid possible harm to
the underground piping system from the use of
hand tools.

Prohibited devices -404.18
▪ Excess flow valves
and other devices are
allowed to be installed
in gas piping provided
that the piping system
has been designed
for such restrictions.

Piping System Installation—
Section 404
▪ Section 404.12.1 – Individual outside appliances
▪ Individual lines to outdoor lights, grills and other
appliances shall be installed not less than 8 inches
(203 mm) below finished grade, provided that such
installation is approved and is installed in locations
not susceptible to physical damage.
▪ Section 404.18 – Pipe cleaning
▪ The use of a flammable or combustible gas to clean
or remove debris from a piping system shall be
prohibited.

Inspection, Testing and Purging -
406
▪ All piping installation must be inspected and
pressure tested.
▪ Includes:
▪ Visual inspection
▪ Pressure test
▪ Leakage test verifies connection to appliances
are gas-tight.

Appliance isolation – 406.3.4
▪ Since the minimum required test pressure
exceeds the maximum inlet pressure for most
appliances, the appliance must not be
connected to the piping system during pressure
testing.

Purging – 406.7

Combustible Gas Indicator
Section 406.7.1.4
▪ Combustible gas
indicator shall be listed
and calibrated in
accordance with the
manufacturer’s
instruction and display
a volume scale from
zero to 100 percent in
1 percent or smaller
increments.

GAS LINE PURGING CHECKLIST
FOR THE FOLLOWING TWO CONDITIONS
BASED ON IFGC SECTION 406.7.1
1. Design operating
pressure greater than
2 psig.
2. Pipe being purged
contains one or more
sections of pipe or
tubing meeting the
size and length
criteria of Table
406.7.1.1.

2015 IFGC,
Table
406.7.1.1
page 77

▪ PROCEDURE
▪ Removal from Service
▪ Placing in Service
▪ Appliance/Equipment Purge

▪ PROCEDURE
▪ Appliance/Equipment Purge

Piping support design and
installation – 407.2
▪ All materials and devices used to hang or
support gas piping must be constructed of metal.
▪ Piping is allowed to rest upon and be supported
by building structural components.

Sediment Trap - 408.4

Shutoff Valves - 409

Appliance shutoff valves located
at manifold – 409.5 and 409.5.3
▪ Appliance shutoff valves are now permitted to be
located within 50 feet (15 240 mm) of the
appliance on a remote manifold.

Shutoff valve for laboratories –
409.6
Master Shutoff Valve for Laboratories

410.2 – MP regulators

Gas Flow Controls
▪ Medium Pressure (MP) gas regulators
Hybrid Pressure System

Gas Flow Controls
▪ Medium Pressure (MP) gas regulators
Low-pressure (Single) System

Venting of regulators – 410.3
Gas Pressure Regulator

Vent piping – 410.3.1
▪ Regulator relief vents and breather vents must
be connected to vent piping constructed of the
same materials as allowed for gas distribution.
▪ The text addresses the practice of joining
multiple vents to a manifold piping arrangement.

Excess Flow Valves - 410.4

Flashback arrestor check valve -
410.5

Appliance Connections - 411
▪ Choice of connection type to use
must take into consideration:
▪ Appliance movement
▪ Vibration
▪ Ambient conditions
▪ Susceptibility to physical damage

Connecting appliances- 411.1

Connecting appliances- 411.1
▪ New requirement for appliances to be connected
to a piping system and listed outdoor gas hose
connectors in compliance with ANSI Z21.54
used to connect portable outdoor appliances.
The gas hose connection shall be made only in
the outdoor area where the appliance is used,
and shall be to the gas piping supply at an
appliance shutoff valve, a listed quick-disconnect
device or listed gas convenience outlet.

Commercial cooking appliances
– 411.1.1
▪ Connectors listed to ANSI Z21.69 are required
for all commercial cooking appliances that are
moved from cleaning/sanitation purposes.
▪ Connectors are designed to tolerate repeated
movement to allow for cleaning operations or
relocation.

Connector Installation
Connector Installation

411.1.2 – Protection against
damage
▪ Between the shutoff valve and appliance, a
means of disconnecting the piping must be
provided by a union fitting or similar
arrangement.
▪ Most manufacturers require that a sediment trap
be installed at the point of connection to the gas
supply (see Section 408.4).
▪ In accordance with the CSST manufacturer’s
instructions, CSST can connect directly to fixed-
in-place, nonmovable appliances.

411.1.3 – Connector installation

Prohibited locations and
penetrations – 411.1.3.3
216
Connector Piping Downstream of Shutoff Valve

Suspended low-intensity infrared
tube heaters – 411.3
Connector Piping Downstream of Shutoff Valve

415.1 – Interval of support
2015 IFGC,
Table
415.1,
page 84

Overpressure Protection
Devices—Section 416
▪ 416.2.1 – Pressure under 14 inches w.c.
▪ 416.2.2 – Pressure over 14 inches w.c.
▪ 416.2.3 – Device capability
▪ 416.2.4 – Failure detection

416.2.5 – Relief valve
1. The line pressure regulator for which the relief
valve is providing overpressure protection has
failed wide open.
2. The gas pressure at the inlet of the line
pressure regulator for which the relief valve is
providing overpressure protection is not less
than the regulator’s normal operating inlet
pressure

416.3 – Devices
1. Pressure relief valve.
2. Monitoring regulator.
3. Series regulator installed upstream from the line
regulator and set to continuously limit the pressure on
the inlet of the line regulator to the maximum values
specified by Section 416.2.1.
4. Automatic shutoff device installed in series with the line
pressure regulator and set to shut off when the
pressure on the downstream piping system reaches the
maximum values specified by Section 416.2.1. This
device shall be designed so that it will remain closed
until manually reset.

Overpressure Protection
Devices—Section 416
▪ 416.3.1 – Construction and installation
▪ 416.3.2 – External control piping
▪ 416.3.3 – Setting

Chapter 5
Chimneys and Vents
Module 5
223

Chimneys and Vents
▪ Code provides requirements for:
▪ Installation
▪ Maintenance
▪ Repair
▪ Approval
▪ Of residential and commercial
▪ chimney and venting systems.

Purpose of Venting
▪ Venting Systems
▪ Convey products of combustion to the outdoors

General Requirements
▪ Every fuel-burning appliance is required to be
vented except as allowed by Section 501.8
▪ Venting method must be designed for particular
type of appliance
▪ Venting material and method of installation
depend on characteristics of gas utilization
equipment

Operating Characteristics
▪ Positive or non-positive pressure in the venting
system
▪ Temperature of vent gases and possibility of
condensation

Sizing of venting
systems/General
▪ Minimize condensation. (It is essential to operate closer
to maximum than minimum capacity, and also to use the
smallest allowable vent size).
▪ Maintain the required draft in Category I and II appliance
venting systems.
▪ Assure that products of combustion are conveyed to the
outdoors.
▪ Prevent damage due to possible condensation from flue
gases.
▪ Avoid overheating the equipment and surrounding
building materials.

Sizing of venting
systems/General

Types of Venting Systems
▪ Type B Gas Vent
▪ Type BW Gas Vent
▪ Type L Vent
▪ Chimney
▪ Single-Wall Metal Pipe
▪ Plastic Pipe and Stainless Steel special vents

502.7.1
– Door
swing

Type of venting system to
be used
2015 IFGC,
Table
503.4,
page 90

503.4.1 –
Plastic piping

501.11 – Masonry chimneys
▪ Manufacturer’s instructions for gas-fired
appliances specify very limited conditions under
which the appliance is allowed to vent to a
masonry chimney.
▪ The conditions include: size; state or condition;
location and construction of a chimney.

Existing Chimneys and Vents –
501.15

501.3 and 503.5.3 – Masonry
chimneys

503.5.7.1 – Solid fuel-burning
appliances
▪ Each appliance or fireplace must be provided with a
dedicated independent chimney, or a dedicated
independent flue in multiple-flue chimney
constructions.
▪ Appliances and fireplaces cannot share a common
chimney or flue-way with any other appliance or
fireplace.
▪ If multiple appliances are vented together, a greater
potential exists for a chimney fire or the discharge of
combustion byproducts back into the building.

Decorative shrouds
▪ Decorative shrouds are
intended to conceal
chimney and vent
terminations to improve
the appearance of a
building.
▪ Only specific listed/tested
assemblies are allowed
Page 98

Vent System Performance
Factors

503.6.9.3 – Category II, III and IV
appliance

503.6.10 – Gas vents serving
appliances on more than one floor
▪ A common gas vent shall be permitted in
multiple-story installations to vent Category I gas
utilization equipment located on more than one
floor level.
▪ Section 503.6.10.1 requires the appliances and
venting system to be located in a space that
does not communicate with living space.

503.8 – Venting system
termination location

503.10 – Vent connectors for
Category I appliances
▪ Provide clean, outdoor air to the appliance (see
Section 304.12); and
▪ Limit the length of wet time in the vent. The
duration of wet time and attendant corrosion in a
vent may be minimized in three ways:
▪ Use a double-wall, Type B gas vent for the entire
system, including connectors.
▪ Use the smallest vent size allowed by the tables.

503.7.4 – Limitations of use
▪ Single-wall metal pipe shall be used only for
runs directly from the space in which the
appliance is located through the roof or exterior
wall to the outdoor atmosphere.

Passage through ceilings, floors
or walls – 503.10.8

504.3.4 – Combined connectors
Common Vent System
Offset
All
single wall
fittings
and
pipe

504.3.5, 504.3.6 and 504.3.7 –
Offsets
▪ Evaluation of a common vent system
▪ Connectors are manifolded before the Type B
vent. Ten-percent common vent capacity
reduction (
▪ Offset in the common vent at ceiling, using two,
45-degree (0.79 rad) elbows. Ten-percent
common vent capacity reduction
▪ Because the connector manifold is actually part of
the common vent, it must be constructed of the
same materials as the common vent (i.e., Type B
vent)

504.3.5, 504.3.6 and 504.3.7 –
Offsets
▪ Connector length limit
▪ Connectors are necessary for chimney and
vent systems that serve multiple appliances.
To reduce friction loss and flue gas heat loss,
and to conserve available draft, connectors
must be kept to a minimum length

Connector Length Limit

Connector Length Limit
A:Actual connector length
Max. allowed
B:Actual connector length
Max. allowed
C: Actual connector length
Max. allowed
= 2.5
= 4.5
= 4.5
= 6.0
= 9.5
= 9.0

504.3.3 – Length alternative
▪ Maximum capacity of the vent connector shall be
reduced by 10 percent for each additional
multiple of maximum connector length permitted
by Section 504.3.2.
▪ Minimum capacity for the fan-assisted appliance
shall be determined by using Table 504.2(1) for
Type B, double-wall connectors and Table
504.2(2) for single-wall connectors.

Length Alternative

Length Alternative
1. Determine maximum allowable vent connector
length
▪ Use Table 504.3.2
▪ 5 inch connector diameter
▪ 7 ½ feet.
225

Length Alternative
2. Determine absolute maximum allowable vent
connector length
▪ Use Section 503.10.9
▪ 5 inch connector diameter
▪ 20 feet.
195

Length Alternative
3. Evaluate steps 1 and 2
▪ Apply the more restrictive criteria, or
▪ Apply connector length alternative provisions of
Section 504.3.3
30

Length Alternative
4. Extend the vent connector maximum length to
15 feet, a 10-percent capacity reduction is
applied to the maximum input capacity of
176,000 Btu/h in Table 504.3(1).
[176,000 x 0.90] = 158,400 Btu/h
▪ The 158,400 Btu/h (46,129 W) is greater than the
boiler input of 135,000 Btu/h.
▪ The boiler input exceeds the minimum required input
of 59,000 Btu/h in Tables 504.2(1) (see 504.3.3,
Condition 2).
(A/B x C) + D
(2.5/5 x 30) + 195 =
(1/2 x 30) + 195 =
15 + 195 = 210

Common Vent offsets – 504.3.5
Offset in Attic to Avoid Streetside Roof Penetration

Common vertical vent offset –
504.3.5

504.3.6 – Elbows in vents
▪ Each and every fitting that creates a change in
direction (elbow) causes a capacity reduction
penalty to be applied to the common vent.
▪ Not greater than 45 degrees (0.79 rad) is a 5-
percent penalty.
▪ Greater than 45 degrees (0.79 rad) is a 10-
percent penalty.

504.3.7 – Elbows in connectors
▪ Each fitting above and beyond the two “free”
elbows causes a capacity reduction penalty to
be applied to the connector.
▪ Not greater than 45 degrees (0.79 rad) is a 5-
percent penalty.
▪ Greater than 45 degrees (0.79 rad) is a 10-
percent penalty.

504.2.8 – Vent area and diameter
504.3.17 – Vertical vent maximum
size
▪ 87.9 square inches (0.06 m2) is larger than the area of a
10-inch (254 mm) vent and smaller than the area of a
12-inch (305 mm) vent, therefore a 10-inch (254 mm)
vent is the largest size vent to which the 4-inch (102 mm)
draft hood could connect.

504.2.9 and 504.3.20 – Chimney
and vent location
▪ Indicate that the sizing tables in Section 504 are
not to be used for chimneys and vents exposed
to the outdoors below the roof line. Provisions
are included for enclosing Type B vents to
prevent them from being exposed to wind and
outdoor temperatures.

Tables 504.2(1) and 504.2(4)
▪ Central furnaces
(forced air types)
▪ Low pressure boilers
▪ Water heaters
▪ Duct furnaces
▪ Unit heaters
▪ Vented room heaters
▪ Floor furnaces
▪ Conversion burners

504.2.2 – Minimum size
▪ Total vent height is a minimum of 10 feet (3048
mm);
▪ Vents for appliance draft hood outlets or flue
collars 12 inches (305 mm) in diameter or less
are not reduced more than one size;
▪ Vents for appliance draft hood outlets or flue
collars greater than 12 inches (305 mm) in
diameter are not reduced more than two sizes;

504.2.2 – Minimum size
▪ Maximum capacity listed in the tables for a fan-
assisted appliance is reduced by 10 percent;
and
▪ For other than fan-assisted appliances, the draft
hood outlet is greater than 4 inches (102 mm) in
diameter. A 3-inch-diameter (76 mm) vent
cannot connect to a 4-inch-diameter (102 mm)
draft hood outlet.

Vent offsets – 504.2.3
▪ To create a lateral (horizontal) run of vent or a
vent connector, one or two elbows are
necessary.
▪ Tables account for two 90-degree changes in
direction.

504.2.6 – Multiple input rate
appliances

504.2.7 – Liner system sizing and
connections
▪ Corrugated metal vent systems installed with
bends or offsets shall have their maximum
capacity
▪ Corrugated metal liners are constructed of
semirigid piping having a higher flow resistance
▪ Chimney lining systems for chimneys serving
gas-fired appliances include stainless steel and
aluminum piping

504.2.8 – Vent area and diameter
▪ Maximum capacity of a venting system must be
based on the component of the system having
the least capacity; likewise, the minimum Btu/h
(W) input required for proper vent system
operation must be based on the largest
component of the system, because the largest
component will naturally have the highest
minimum input requirement

504.2.9 – Chimney and vent
locations
▪ Chimneys that have one or more walls exposed
to the outdoors and unenclosed exterior vents
can develop condensation and weak draft
problems in cold weather.
▪ Chimney lined with a listed liner is to be sized as
if it was a Type B vent

504.2.14 – Table interpolation
▪ Interpolated maximum vent capacity = (A/B x C) + D
▪ Interpolated minimum vent capacity = E - (A/B x F)
A. = Difference between the design height entry and the next
lower height entry in the applicable table.
B. = Difference between the closest consecutive height entries in
the applicable table.
C. = Difference between the maximum capacity column
consecutive entries in the applicable table.
D. = Lower capacity entry in the applicable table.
E. = Higher capacity entry in the applicable table.
F. = Difference between the minimum capacity column entries in
the applicable table.

Height entries - 504.2.17 and
504.3.28
▪ Tables 504.2(1) through 504.2(6)
▪ Actual height of a vent falls between entries in the
height column
▪ Either interpolation shall be used or the lower
appliance input rating
▪ FAN MAX and NAT MAX column values and the
higher appliance input rating shall be used for
the FAN MIN column values.

Height entries - 504.2.17
and 504.3.28
▪ Consider a single, Category I appliance with an
8 inch B-vent height of 18 feet.
▪ The lateral offset is 5 feet and the B-vent is
directly connected to the appliance.
▪ What are the values for FAN MAX, NAT MAX
and FAN MIN?
Refer to Table 504.2(1).
For FAN MAX and NAT MAX, use the values for the 15-foot
(5486 mm) vent height with the 5-foot (1524 mm) lateral offset.
Therefore, FAN MAX = 620 Btu/h
(182 W/hr) and NAT MAX = 403 Btu/h (118 W/hr).
For FAN MIN, use the value for the 15-foot (5486 mm) vent
height with the 5- foot (1524 mm) lateral offset. Therefore, FAN
MIN = 76 Btu/h (25 W/hr).

Height entries - 504.2.17
and 504.3.28
▪ Consider a single, Category I appliance with an
8 inch B-vent height of 18 feet.
▪ The lateral offset is 5 feet and the B-vent is
directly connected to the appliance.
▪ What are the values for FAN MAX, NAT MAX
and FAN MIN?
Refer to Table 504.2(1).
• For FAN MAX, the value for 15 feet (5486 mm) vent height
with 5 foot (1524 mm) lateral offset is 620 Btu/h (182 W/hr)
and the value for 20-foot (6096 mm) vent height with 5-foot
(1524 mm) lateral offset is 697 Btu/h (204 W/hr).
• FAN MAX = [((18 feet - 15 feet)/ (20 feet - 15 feet)) x (697
Btu/h - 620 Btu/h)] + 620 Btu/h = 666 Btu/h
• For NAT MAX, the value for 15 feet (5486 mm) vent height
with 5 foot (1524 mm) lateral offset is 403 Btu/h (118 W/hr)
and the value for 20 feet (6096 mm) with 5 foot (1524 mm)
lateral offset is 460 Btu/h (135 W/hr). NAT MAX = [((18 feet -
15 feet)/ (20 feet - 15 feet)) x (460 Btu/h - 403 Btu/h)] + 403
Btu/h = 437 Btu/h
• For FAN MIN, the value for 15 feet (5486 mm) vent height
with 5 foot (1524 mm) lateral offset is 76 Btu/h (22 W/hr) and
the value for 20 feet (6096 mm) with 5 foot (1524 mm) lateral
offset is 73 Btu/h (21 W/hr). FAN MIN = 76 Btu/h - [((18 feet -
15 feet)/ (20 feet - 15 feet)) x (76 Btu/h – 73 Btu/h)] = 74 Btu/h

Table Interpolation

Table Interpolation
▪ Step 1: Find the maximum vent capacity (MAX)
at the first height entry greater than
▪ 121/2 feet, [i.e., 15 feet ].
▪ Step 2: Find the maximum vent capacity (MAX)
at the next height entry lower than
▪ 121/2 feet, [i.e., 10 feet ].

Table Interpolation
▪ Step 3: Determine the difference between the
two maximum vent capacities.
▪ Step 4: Determine the maximum vent capacity
for a 121/2-foot-high (3810 mm) vent.

Sizing Venting System: Two or
More Appliances – 504.3
▪ A common vent is a vent for two or more
appliances on the same floor level
▪ Must be designed to vent products of
combustion when:
▪ Any one
▪ Any combination, and
▪ All of the connected appliances operate

Sizing Venting System: Two or
More Appliances
▪ Connector, for purposes of designing a common
vent
▪ Is that part of the vent piping between the
appliance outlet and its junction with the rest
of the system
▪ For each connector the correct size must be
found

Vent fitting – 504.3.9
Common Vent Fittings

Tee and wye fittings – 504.3.9.1
▪ This code section requires tees and wyes used
in common vent systems to be constructed of
the same materials as the common vent.

Height and Rise Measurements –
504.3.11 & 504.3.12
▪ Least total height
▪ Vertical distance from highest appliance outlet
to lowest discharge opening of vent cap
▪ Least total height is used for vent sizing for all
connected appliances on one floor level.

Size B vent system
▪ Rise Measurement - Rise (R)
▪ Vertical distance from the draft hood outlet or
flue collar to the level where the vent gas
streams merge

Size B vent system
FAN
NAT

Size B vent system
▪ Find each connector size
▪ Correct Table:
▪ Least total height and vent rise
▪ Vent height:
▪ Water heater rise:
▪ Furnace rise:
▪ Vent connector size
▪ Water heater:
▪ Furnace:
Table 504.3(1)
15 feet
1 foot
3 feet
4 inch
5 inch

Size B vent system
▪ Find common vent size
▪ Total Btu/h input:
▪ Combined input rating:
▪ Size of common vent:
164,000 Btu/h
5 inch

Flue gases must leave the
structure – 503.6.4
Top Location Rules

Gas Vent Termination
▪ Determine which diagram shows correct vent
termination requirement
45
5'
6'
12
18

Venting System
▪ Given the following
information, size the entire
venting system.
▪ Water heater 40,000 Btu/h
▪ Natural draft
▪ 3-inch draft hood
▪ Furnace 80,000 Btu/h
▪ Fan assisted
▪ 4 inch flue collar

Sizing of Venting Systems
for Two or More Appliances
A. Diameter for the water heater connector.
4 inches
B. Diameter for the furnace connector.
4 inches
C. Percent capacity reduction for common vent.
20 percent, Sections 504.3.5 and 505.3.6

D. Diameter of common vent.
5 inches, (159,000 Btu/h ´ 0.80 =
127,200 Btu/h)
E. Maximum allowable horizontal connector length.
6 feet or in accordance with Sections 504.3.2 and
503.10.9 the MAX Length allowed is 12.75' (75%
´ 17' = 12.75)

F. Maximum allowable length of common vent
offset.
7.5
G. Is interpolation necessary?
No

▪ A two-appliance, FAN + NAT system, combining a water
heater (NAT) equipped with a draft hood with a fan-
assisted, Category I furnace (FAN).
▪ Single-wall vent connectors are used for the water
heater. Add a double-wall vent connector for the furnace.
▪ Vent height is 35 feet (10 668 mm).
▪ Furnace connector rise is 4 feet (1219 mm).
▪ Water heater connector rise is 2 feet (610 mm).
▪ Furnace input is 75,000 Btu/h (21 983 W).
▪ Water heater input is 42,000 Btu/h (12 310 W).

Sizing of Venting Systems for
Two or More Appliances

▪ Determine the venting system sizing for the two
appliances.
▪ Find the size of the common vent based on least
total height and the combination of connected
appliances

A. Furnace Connector
Material:
Size:
B. Water Heater Connector
Material:
Size:
C. Common Vent Size:
▪ Type B
▪ 4 inches, [Table 504.3(1)]
▪ Single-wall
▪ 4 inches, [Table 504.3(2)]
▪ 4 inches (10% reduction
for offset, 132,000 Btu/h ´
0.9 = 118,800 Btu/h)

D. Interpolation Necessary?
E. Any Noted Violations?
No

Direct-vent terminations

Direct Vent Appliances

503.3.3 – Mechanical draft systems
503.8 – Venting system termination
location
▪ Must be listed and installed in accordance with
its appliance manufacturer’s instructions;
▪ Must be located a minimum of 7 feet (2134 mm)
above the level of adjacent walkways;
▪ Must be a minimum of 3 feet (914 mm) higher than
any air intake area within 10 feet (3048 mm); and
▪ The vent system must terminate:
▪ 4 feet (1219 mm) below;
▪ 4 feet (1219 mm) horizontally from; or
▪ 1 foot (304.8 mm) above any door, operable window
or gravity air intake into any building.

503.3.3 – Mechanical draft systems
503.8 – Venting system termination
location

Commercial cooking appliance
vented by exhaust hoods
Solenoid Valve Interlock Method

Mechanical Draft Venting System
Terminations

Chapter 6
Specific Appliances
Module 6
318

Specific Appliances
▪ Provides requirements for all aspects of specific
appliances
▪ Special requirements for installation and location
▪ Assures for installation in accordance with
manufacturer’s installation instructions

Scope
▪ Approval
▪ Design
▪ Installation
▪ Construction
▪ Maintenance
▪ Alteration
▪ Repair

Appliances
▪ Standards
▪ Typical Application
▪ Prohibited Installations
▪ Major code enforcement issues

Appliances
▪ Decorative Gas-Fired Appliances for Installation
in Vented Fireplaces (Section 602)
▪ Vented Gas Fireplaces (Section 604)
▪ Vented Gas Fireplace Heaters (Section 605)
▪ Vented Wall Furnaces (Section 608)

Appliances
▪ Floor Furnaces (Section 609)
▪ Non-recirculating Direct-Fired Industrial Air
Heaters (Section 611)
▪ Recirculating Direct-Fired Industrial Air Heaters
(Section 612)
▪ Cloths Dryers (Section 613)
▪ Clothes Dryer exhaust (Section 614)

TABLE 614.8.4.1 Dryer
Exhaust Duct Fitting
Equivalent Length
2015 IFGC,
Table
614.8.4.1,
page 126

Projection required – 614.6.3
▪ Section 614.6.3
requires clothes dryer
exhaust ducts to be
protected from
penetration by
fasteners such as
drywall screws and
trim nails

614.8.4.3 – Dryer exhaust duct
power ventilator length
▪ The maximum length of the exhaust duct shall
be determined by the dryer exhaust duct power
ventilator manufacturer’s installation instructions.

Length identification – 614.6.6
▪ Requires a label or
tag to be placed by
the point of
connection to a
concealed clothes
dryer exhaust duct
system.

Common exhaust systems for clothes
dryers located in multistory structures
▪ Provides 11 provisions for the construction of a
multistory common exhaust shaft to serve
clothes dryers on multiple floors.
▪ The shaft in which the duct is installed shall be
constructed and fire-resistant rated as required by the
IBC.
▪ Dampers shall be prohibited in the exhaust duct.
▪ Rigid metal ductwork shall be installed within the shaft
to convey the exhaust.

▪ The ductwork within the shaft shall be designed and
installed without offsets.
▪ The exhaust fan motor design shall be in accordance
with Section 503.2 of the IMC.
▪ The exhaust fan motor shall be located outside of the
airstream.

▪ The exhaust fan shall run continuously, and shall be
connected to a standby power source.
▪ The exhaust fan operation shall be monitored in an
approved location and shall initiate an audible or
visual signal when the fan is not in operation.
▪ Makeup air shall be provided for the exhaust system.

▪ A cleanout opening shall be located at the base of the
shaft to provide access to the duct to allow for
cleaning and inspection.
▪ Screens shall not be installed at the termination.

Appliances
▪ Forced-Air Warm-Air Furnaces (Section 618)
▪ Unit Heaters (Section 620)
▪ Unvented Room Heaters (Section 621)
▪ Cooking Appliances (Section 623)

Appliances
▪ Water Heaters
(Section 624)
▪ Air Conditioning
Equipment (Section
627)
▪ Illuminating
Appliances (Section
628)
▪ Boilers (Section 631)

Outdoor Decorative Appliances–
636.1
▪ Permanently, fixed-in-
place outdoor
decorative appliances
must be tested in
accordance with ANSI
Z21.97 and installed
in accordance with
the manufacturer’s
instructions.

Review and Final Questions
335

Final Reflection
This slide will help the learner to reflect on the day
and what they will take back to the job and apply.
▪ What? What happened and what was observed
in the training?
▪ So what? What did you learn? What difference
did this training make?
▪ Now what? How will you do things differently
back on the job as a result of this training?

337
International Code Council is a Registered Provider with The American
Institute of Architects Continuing Education Systems. Credit earned on
completion of this program will be reported to CES Records for AIA
members. Certificates of Completion for non-AIA members are available on
request.
This program is registered with the AIA/CES for continuing professional
education. As such, it does not include content that may be deemed or
construed to be an approval or endorsement by the AIA of any material of
construction or any method or manner of handling, using, distributing, or
dealing in any material or product. Questions related to specific materials,
methods, and services will be addressed at the conclusion of this
presentation.

338
Copyright Materials
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Copyright laws. Reproduction, distribution, display and use of
the presentation without written permission of the speaker is
prohibited.
© International Code Council 2015

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