FUEL GAS

Adding or Removing Gas Appliances from Chimneys and Vents

Appliances Governed by these Code Provisions
Apply these code provisions to chimneys and vents used by gas-burning appliances. Note that similar provisions for solid and liquid fuel-burning appliances exist in IRC Chapter 18. Read the full Topic

Combustion Air for Gas Appliances From Inside and Outside the Building

Combustion Air Combining Inside and Outside Sources
1. You may combine the available volume of inside space where the appliance(s) are located with outside combustion air openings or ducts. This combination allows you to reduce the size of the outside combustion air openings or ducts. Read the full Topic

Combustion Air for Gas Appliances from Outside the Building

Combustion Air Openings Directly Outside or Ducts Run Vertically
1. Install two permanent combustion air openings between the room where the appliance(s) are located and outside the building. The outside space may be an adequately ventilated attic or crawl space or it may be outside the home. The openings may open directly to the outside or may communicate with the outside using vertical ducts. Do not use one common vertical combustion air duct for both the upper and lower duct openings. Read the full Topic

Drips and Sediment Traps

Drips (Drip Tees)
1. Install a drip (also known as a drip leg or drip tee) when the gas utility provides gas containing moisture. Wet gas is very rare in modern gas utility systems. Drips are rarely necessary.
2. Install any required drip at every point in the piping system where moisture could accumulate. Read the full Topic

Gas Appliance Clearance Reduction to Combustible Materials

Appliances Governed by these Code Provisions
1. Apply these clearance to combustible reduction provisions to gas-burning appliances and apply these provisions to related appliances such as vents and chimneys.
2. Note that similar provisions for other fuel-burning appliances exist in IRC Chapter 13. Read the full Topic

Gas Appliance Installation

1. Provide a firm and level concrete pad or other approved support pad that extends at least (≥) 3 inches above the surrounding soil for appliances mounted on the ground.
2. See Chapter 13 for other gas appliance installation requirements.

Gas Appliances and Gas Piping Systems General Requirements

Gas Types Governed by the IRC
The IRC governs natural gas (methane) and liquefi ed petroleum (LP) gas (propane and butane) in permanent systems beginning after the point of delivery by the gas supplier. The IRC does not govern liquefied natural gas systems and temporary and portable LP gas systems.

Gas Appliance Listing and Labeling
1. Use gas appliances that are listed and labeled for the intended purpose. This means that an appliance listed and labeled for one purpose may not be used for another purpose. Example: a gas cooking appliance listed and labeled only for indoor use cannot be used outdoors.

Gas Appliance Replacement Parts
1. Repair or replace defective gas appliance parts with similar parts that do not change the terms of the appliance listing. This usually means using only parts supplied and/or approved by the appliance manufacturer. Read the full Topic

Gas Appliances in Fireplaces

1. Provide a permanent opening through which combustion gasses from an unlisted gas appliance will be vented into the chimney. The opening may be provided by permanently opening the damper or by similar means. Provide a permanent opening area based on the appliance Btu per hour input rating as required in the following table. A common example of a gas appliance covered by this provision is a set of gas logs.
2. Provide a permanent opening for a listed gas appliance according to the appliance manufacturer’s instructions.

Gas Boilers

1. Refer to Section M2001.

Gas Clothes Dryers

1. Refer to Section M1502.

Gas Connections to Appliances

Gas Connection to Appliances General Requirements
1. Use any of the following gas appliance connectors to connect gas piping to gas appliances: (a) rigid metal pipes and fi tt ings, or (b) fi eld fabricated copper or aluminum tubing approved for use with gas, or (c) listed and labeled manufactured gas appliance connectors, including their associated quick-disconnect devices and convenience outlets, or (d) CSST tubing.
Read the full Topic

Gas Cooking Appliances

Appliances Governed by these Code Provisions
1. Apply these code provisions to gas cooking appliances intended for permanent installation. This does not include portable appliances with portable gas supplies such as outdoor grills.

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Gas Forced-Air Furnaces

1. Refer to Section M1602.

Gas Lighting

Gas Lighting General Installation Requirements
1. Install gaslights according to manufacturer’s instructions.
Read the full Topic

Gas Pipe Inspection, Pressure Testing, and Purging

Limitations of the Material in this Section Most readers of this book should not inspect, pressure test, leak test, or purge gas piping. Allow qualified contractors to perform these important tasks. We will discuss only some basic testing requirements in this section to give the reader a basic understanding of inspecting, testing, and purging gas piping systems. Refer to the IRC for more information. When to Inspect and Test Gas Pipe 1. Inspect and pressure test all new gas piping, new additions to existing gas pipes, and major repairs of existing gas pipes. Pressure testing of minor additions and repairs is not required if the work is inspected and tested with non-corrosive leak detection fluid. Gas Pressure Test Gases Read the full Topic

Gas Pipe Installation and Protection

Code Provisions Versus Manufacturer’s Instructions
1. Apply the IRC if manufacturer’s installation instructions are less strict than the IRC. Apply manufacturer’s instructions if they are stricter than the IRC. Read the full Topic

Gas Pipe Materials

Materials Permitted for Use as Gas Pipes in Buildings
1. You may use Schedule 40 or thicker steel or wrought iron pipe for gas pipes. Black steel is one of the most common types of gas pipe. Read the full Topic

Gas Pipe Sizing

Limitations of the Material in this Section
Determining the correct size of gas pipes requires knowledge of the type(s) of gas pipes to be installed, the length of each part of the gas pipe system (trunks and branches), the Btu/hour input ratings of all gas appliances to be installed and the appliance location in the home, the type of gas (natural or LP), the gas supply inlet pressure, and the number of bends and fittings in the piping system. This knowledge is beyond most readers of this book; therefore, we will not discuss how to determine gas pipe sizes. Leave calculation of correct gas pipe size calculations to qualified contractors. Read the full Topic

Gas Pipe Support

Gas Pipe Support Materials and Installation
1. Support gas pipes with pipe hooks, metal straps, metal bands, metal brackets, or other suitable hangers. Use gas pipe supports made of material that is compatible with the gas piping material and will not cause corrosion by galvanic action. Example: do not use copper pipe supports with steel gas pipe. Use gas pipe supports that are strong enough to support the gas piping without allowing excessive gas pipe sagging and without straining fi tt ings, joints, and valves. Use gas pipe supports that allow for natural expansion and contraction of gas piping material. Read the full Topic

Gas Piping General Installation, Modification, and Identification

Gas Piping Governed by the IRC
1. Apply IRC gas piping provisions beginning at the outlet connection of the gas provider’s gas meter and apply the provisions beginning at the second stage regulator of a liquefied petroleum (LP) gas system.

 

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Gas Piping System Grounding and Bonding

Gas Piping System Use as a Grounding Electrode
1. Do not use gas pipes as a grounding electrode and do not use gas pipes as part of the grounding electrode system. Read the full Topic

Gas Pressure Regulators

Gas Pressure Regulators General Requirements
1. Install a gas pressure regulator before a gas appliance when the appliance operates at a lower gas pressure than the supply pressure.
2. Install gas pressure regulators where they are accessible. Ready access to gas pressure regulators is not required. Removing access panels or moving the appliance to access the valve is acceptable. Read the full Topic

Gas Sauna Heaters

1. Refer to Section M1902.

Gas Shutoff Valves

Gas Shutoff Valve Access for Appliances
1. Install accessible gas shutoff valves for appliances. Ready access to gas shutoff valves is not required. Removing access panels or moving the appliance to access the valve is acceptable.
2. Do not locate gas shutoff valves in concealed locations. A concealed location requires damaging a building component (such as drywall) to gain access. Read the full Topic

Gas Vent Draft Hoods and Dampers

Draft Hoods
1. Install draft hoods according to manufacturer’s instructions. Do not alter a manufacturer supplied draft hood except as specifi ed by the manufacturer.
2. Install draft hoods and draft control devices in the same room as the appliance and so that there will be no difference in pressure between the hood or control device and the combustion air supply.
3. Install draft hoods with its opening at least (≥) 6 inches from any surface or with the clearance required by manufacturer’s instructions, whichever is greater. Surfaces do not include the appliance itself and the vent att ached to the draft hood.

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Gas Vent Roof Termination

Gas Vent Roof Flashing and Cap
1. Use manufacturer recommend components when extending a gas vent through a roof. These usually include fl ashing, a roof jack or thimble, a storm collar, and a listed cap.

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Masonry Chimney Size Table When Chimney Used as Vent for Multiple Gas Appliances Using Type B Vent Connector

Appliances and Appliances Covered by this Table
1. Apply this table to Category I gas appliances and natural draft appliances that would be classified as Category I appliances if they were classifi ed. These appliances include most draft hood water heaters and most fan-assisted gas furnaces. Do not apply this table to Category II, III, & IV gas appliances, wall furnaces that use Type BW vents, decorative gas appliances, and other appliances not listed for use with a Type B vent.
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Masonry Chimney Size Table: When Chimney Used as Vent for Multiple Gas Appliances Using Single Wall Vent Connector

Appliances and Appliances Covered by this Table
1. Apply this table to Category I gas appliances and natural draft appliances that would be classified as Category I appliances if they were classifi ed. These appliances include most draft hood water heaters and most fan-assisted gas furnaces. Do not apply this table to Category II, III, & IV gas appliances, wall furnaces that use Type BW vents, decorative gas appliances, and other appliances not listed for use with a Type B vent.
2. Use this table for installations involving two or more gas appliances connected to one masonry chimney flue using single wall vent connectors. The values in the table are appliance input ratings in thousands of Btu/hour.
3. Do not use this table if the chimney is exposed to the outside on one or more sides below the roof line. This means that the all chimney walls must be entirely within the home or attic until the chimney protrudes above the roof.
4. Do not use this table when the chimney serves only one gas appliance. You may use Section G2427.5 when the chimney serves only draft hood type gas appliances. You must use other approved engineering methods to determine if a chimney may serve as a vent for one fan-assisted appliance.

Pool and Spa Heaters

1. Refer to Section M2006.

Single Wall Vents for Gas Appliances

Single Wall Gas Vent Description
A single wall gas vent is constructed of at least (≥) 0.0304 in. (approximately 23 gage) galvanized steel, or other approved corrosion resistant, non-combustible material, and serves as the vent for a gas appliance. Do not apply these provisions to single wall vent connectors used to connect a gas appliance to a listed venting system such as a Type B vent.

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Type B Gas Vent Size for One Appliance General Installation Requirements and Examples

Application of these Tables
Use these tables to determine the size of Type B gas vents that serve only one Category I draft hood or fan-assisted gas appliance. Do not use these tables for: (a) Type BW vents, and (b) vents for decorative gas fireplaces, and (c) vents for gas appliances not listed for use with Type B vents, and (d) vents for appliances listed only for connection to chimneys, and (e) for factory-built chimneys, and (f) Category II, III, and IV gas appliances. Do not use these tables when connecting a single Category I appliance to a chimney. Use the tables in Section G2428.3 for this purpose.

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Type B Gas Vent Size Table for Multiple Appliances Using Single Wall Vent Connector

Appliances and Appliances Covered by this Table
1. Apply this table to Category I gas appliances and natural draft appliances that would be classified as Category I appliances if they were classified. These appliances include most draft hood water heaters and most fan-assisted gas furnaces. Do not apply this table to Category II, III, & IV gas appliances, wall furnaces that use Type BW vents, decorative gas appliances, and other appliances not listed for use with a Type B vent.
Read the full Topic

Type B Gas Vent Size Table for One Appliance Using Type B Vent Connector

Appliances and Appliances Covered by this Table
1. Apply this table to Category I gas appliances and natural draft appliances that would be classified as Category I appliances if they were classifi ed. These appliances include most draft hood water heaters and most fan-assisted gas furnaces. Do not apply this table to Category II, III, and IV gas appliances, wall furnaces that use Type BW vents, decorative gas appliances, and other appliances not listed for use with a Type B vent.
2. Use this table for installations involving one gas appliance directly connected to one vent or using a Type B vent connector. The values in the table are appliance input ratings in thousands of Btu/hour.

Unvented Gas Room Heaters

Unvented Room Heater Description
Unvented room heaters provide supplemental heat to a single room or adjacent rooms. If they have no fan, they provide heat by natural movement of the heated air and by thermal radiation. Because these heaters become very hot, proper installation is important to prevent fires. Because they are unvented, proper installation is important to prevent carbon monoxide poisoning.

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Vent Connectors for Category I Gas Appliances

Vent Connectors in Unconditioned Space
1. Use Type B or Type L vent connectors with Category I gas appliances when the vent connectors are located in unconditioned areas, such as attics, crawl spaces, garages, and basements. You may use single wall pipe for a vent connector in an unconditioned garage or basement if the local 99 percent winter design temperature is at least (≥) 5º F. You may not use single wall pipe as a vent connector in any attic or crawl space.

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Vent Termination for Mechanical Draft and Direct Vent Appliances

Appliances Governed by these Code Provisions
1. Apply these code provisions to gas vent systems using mechanical draft (positive pressure) venting appliances such as internal and external power exhausters and draft inducers.
2. Apply these code provisions to direct vent gas appliances.
3. Do not apply these code provisions to Category I gas appliances including those with internal fan-assisted draft such as most medium efficiency gas furnaces.

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Vented Gas Floor Furnaces

1. Refer to Section M1408.

Vented Gas Room Heaters

Refer to Section M1410.

Vented Gas Wall Furnaces

1. Refer to Section M1409.

Venting Gas Appliances Using a Masonry Chimney

Masonry Chimney Used for Gas Appliance Venting General Requirements
1. Construct the chimney according to IRC Chapter 10 using approved clay flue liners, listed chimney lining systems, or other approved materials that will resist deterioration by vent gasses at temperatures of at least (≥) 1,800º F.
2. You may use a chimney liner that is approved only as a gas appliance vent in masonry chimney if the liner is approved for: Read the full Topic

Vents for Gas Appliances General Requirements

Appliances Governed by these Code Provisions
1. Apply these code provisions to chimneys and vents used by gas-burning appliances.
2. Note that similar provisions for solid and liquid-fuel appliances are in IRC Chapter 18.

Read the full Topic