International Fuel Gas Code Overview: Codes are used by contractors and inspectors as a guideline for the safe installation of appliances and piping. The International Fuel Gas Codebook is the basis of many installation practices, again, for safe installations. The code is written and agreed to by engineers.

With few exceptions, the code can be overlooked. However, usually, this is at the manufacturer’s request and must be signed off on by a competent person. This is an overview of the International Fuel Gas Code. Additionally, it is also a manual we recommend to HVAC technicians to further their knowledge in HVAC.

This is mainly applicable to the installation of gas furnaces, gas-fired boilers, and other HVAC appliances which an HVAC (or plumbing) contractor may install. Some codes are simply common sense while other codes are a result of some lessons learned.

Usually, those lessons were learned the hard way and some dangerous event occurred that resulted in the generation of the code. It is important that the codes are followed as closely as possible to prevent future problems or unsafe and dangerous events from occurring. Lastly, this code applies to Natural Gas and Propane installations.

This is an overview only and not meant to replace or substitute for any Fuel-Gas Code. Additionally, always check with the local AHJ (Authority Having Jurisdiction), usually the municipality, for their requirements in meeting code compliance. Some AHJ’s have their very own code.

International Fuel Gas Code Overview (IFGC or International Fuel Gas Code)

Administration - Chapter 1

Essentially, the Administration Chapter defines what is covered under the code. This includes gas piping, gas appliances, and related accessories. It continues to define and outline the differences in types of installations and buildings. e.g. new buildings, existing buildings or structures, and new equipment and existing equipment. Lastly, this takes into account maintenance, alterations, repairs, additions, changes in occupancy, and other types of buildings.

The next sections in the admin chapter cover general provisions for Departments of Inspections. This includes appointing a code official by the Authority Having Jurisdiction. It also includes the duties and powers of a code official. It covers rulemaking, applications and permits, inspections, the right of entry, and other considerations such as record keeping. Furthermore, inspections and testing procedures for the inspector are covered including methods used, permit procedures, and record-keeping. Lastly, the Admin Chapter also covers violations and a means of appeal for violations.

Definitions - Chapter 2 | International Fuel Gas Code Overview

There are several definitions in Chapter 2 that deal with basic parlance for Fuel Gas applications and equipment. Additionally, terms and definitions of this subject matter are defined to enhance the communication of Fuel Gas installations.

General Regulations - Chapter 3

This chapter covers general regulations such as:

  • Combustion and dilution air
  • Energy efficiency
  • Labeling
  • Plumbing connections
  • Vibration isolation
  • Repair factors
  • Wind resistance
  • Flood and seismic hazards
  • Rodent proofing
  • Lastly, a referral to the Mechanical Code concerning ducts.

Structural safety is covered to include penetrations through the structure and stud cutting, notching, and boring. Furthermore, appliance location is listed to include hazardous locations and protection from motor vehicles.

Combustion air, ventilation, and dilution air are covered in the general regulations chapter. It includes an equation and illustrations to determine the proper amounts of air to satisfy the requirements. Garage installation requirements are also covered. Access to the appliance for service and repair is included. Condensate drain disposal is also covered for condensing furnaces or appliances. Furthermore, basic clearance requirements are listed along with a chart.  Lastly, the end of chapter 3 includes electrical bonding and grounding requirements for gas piping.

Gas Piping Installations - Chapter 4 | International Fuel Gas Code Overview

gas piping installation codeThe Gas Piping Installation Chapter begins by discussing the basics such as LP gas storage, existing pipe installations, meter identification, and minimum sizes. Pipe size requirements are listed next. Gas piping sizes shall be based on the maximum number of gas appliances and the combined manufacturer’s input rating on those appliances. Furthermore, an approximate gas input table is provided.

The code gives provisions for properly sizing gas piping installations. The purpose is to ensure adequate supply at maximum demand. Undersized piping will cause problems on the supply side and that can result in a dangerous situation. The code in this chapter offers equations for the proper calculation of pipe sizes. Furthermore, there are two methods of determining pipe size:

  • Longest Length Method
  • Branch Length Method

Additionally, other engineering methods of determining pipe sizing can be used provided they are approved.

In this chapter, the code also has requirements for allowable pressure drop. Under maximum demand, the supply pressure cannot drop below the manufacturer’s minimum pressure requirements for any appliance in the piping system. This is the minimum allowable pressure for an appliance to safely operate. Additionally, the Fuel Gas Code also has restrictions, with some exceptions, on the maximum allowable pressure in any gas piping installed in buildings.

Gas Piping Installations Chapter 4 - Tables | International Fuel Gas Code Overview

There are several tables in the Gas Piping Installations Chapter to help determine the proper size. The table title lists the type of pipe used. Horizontally are the pipe size and vertically are the lengths of piping. Cross-referencing the table from pipe size to pipe length will give the capacity of the piping in cubic feet of gas per hour. It is important to note that at the top of every page lists a given inlet pressure, type of gas (Natural or LP Gas), the calculated pressure drop, and the specific gravity of the gas.

Furthermore, in each table, the sizing requirements are different based on that information. It is important to take this into account when properly sizing piping and piping branches taking different piping types into account.

Furthermore, after the sizing tables, the code discusses piping materials. This includes standard requirements, materials not allowed for use, and limitations on the installation of various piping materials. Lastly, included are details defining the number of minimum threads on piping, protective coatings on piping, and other pertinent installation requirements.

Additionally, requirements for methods of joining pipes are detailed and listed for various types of piping and fittings. Furthermore, regulator venting requirements are also included in this section after the pipe sizing tables.

Gas Piping Installations Chapter  4 - Piping System Installation

Section 404 in Chapter 4 of the Fuel-Gas Code lists requirements for Piping Systems Installation requirements. This code section includes installation of piping systems in prohibited locations, piping installations inside walls, piping inside solid flooring, and corrosion resistance among additional requirements. Additionally, Section 404 of the Fuel-

IFGC Fuel Gas Code

This piping has no sleeve or protection from the masonry at the penetration

Gas Code includes:

  • Minimum burial depth when piping is buried
  • Above ground outdoor piping
  • Trenches
  • Piping underground beneath buildings
  • Outdoor closures
  • Plastic pipe and limitations
  • Connections and Tracer requirements
  • Testing of piping

Furthermore, section 405 includes requirements for piping bends and changes in direction.

Moving forward, Section 406 includes requirements for inspection, testing, and purging of piping systems. Section 407 in Chapter 4 of the Fuel-Gas Code lists requirements for piping support. Section 408 and 409 deal with Drips and Sloped Piping and Shutoff Valves, respectively. Furthermore, Chapter 4 concludes with several other code requirements for:

  • Flow controls
  • Appliance and Manufactured Home Connections
  • Liquefied Petroleum Vehicle Dispensing Facilities
  • Compressed Natural Gas Vehicle Dispensing Facilities
  • Supplemental and Standby Gas Supply
  • Table and Requirements for Piping Support Intervals (Section 415)
  • Lastly, Overpressure Protection Devices

Chimneys and Vents - Chapter 5

Venting the byproducts of combustible gas is very important to the health of the occupants of any building. Therefore, it makes perfect sense to have a Chapter on Chimneys and Venting in the Fuel-Gas Code. It is important that a competent person install or repair and venting system or chimney. That being said, there is a part of the scope of Chapter 5 that covers equipment not required to be vented. Before making that decision the code and the manufacturer should be consulted. Chapter 5 covers proper sizing, materials approved for use, and passageways for vents among other requirements. Furthermore, a basic list of the sections in chapter 5 include:

  • Vents (502)
  • Venting of Appliances (503) with a table and illustrations included in the code
  • Sizing of Category 1 Appliance Venting Systems (504) with a table that covers sizing for various types of vents such as masonry or B-vent…etcetera
  • Direct-Vent, Integral Vent, Mechanical Vent, and Ventilation/Exhaust Hood Venting (505)
  • Lastly, Factory Built Chimneys (506) with sizing tables included for various venting materials and methods

International Fuel Gas Code Overview

Specific Appliances - Chapter 6

Chapter 6 of the Fuel-Gas Code covers specific appliances such as gas logs and wall furnaces. Furthermore, a listing of the sections in Chapter 6 includes:

  • International Fuel Gas Code OverviewDecorative Appliances for Installation in Fireplaces (602)
  • Log Lighters (603)
  • Vented Gas Fireplaces (604)
  • Vented Gas Fireplace Heaters (605)
  • Incinerators and Crematories (606)
  • Commercial-Industrial Incinerators (607)
  • Vented Wall Furnaces (608)
  • Floor Furnaces (609)
  • Duct Furnaces (610)
  • Non-recirculating Direct-Fired Industrial Air Heaters (611)
  • Recirculating Industrial IR Heaters (612)
  • Clothes Dryers (613)
  • Clothes Dryer Exhaust (614)
  • Sauna Heaters (615)
  • Engine and Gas Turbine Powered Equipment (616)
  • Pool and Spa Heaters (617)
  • Forced-Air Warm Air Furnaces (618)
  • Conversion Burners (619)
  • Unit Heaters (620)
  • Unvented Room Heaters (621)
  • Vented Room Heaters (622)
  • Cooking Appliances (623)
  • Water Heaters (624)
  • Refrigerators (625)
  • Gas-Fired Toilets (626)
  • Air Conditioning Equipment (627)
  • Illuminating Appliances (628)
  • Small Ceramic Kilns (629)
  • Infrared Radiant Heaters (630)
  • Boilers (631)
  • Equipment Installed in Existing Unlisted Boilers (632)
  • Stationary Fuel-Cell Power Systems (633)
  • Chimney Damper Opening Area (634) table included
  • Lastly, in Chapter 5, Gaseous Hydrogen Systems (635)

outdoor gas piping protected from vehivles

The yellow posts protect the gas piping from damage from vehicles

Gaseous Hydrogen Systems - Chapter 7 | International Fuel Gas Code Overview

For installations of gaseous hydrogen systems, the IFGC or International Fuel Gas Code has its own Chapter for these systems. Additionally, the IFGC refers you to the International Fire Code for additional requirements for gaseous hydrogen systems. Chapter 7 of the IFGC covers:

  • General Definitions for Gaseous Hydrogen Systems (702)
  • Basic General Requirements for Gaseous Hydrogen Systems (703)
  • Piping, Use, and Handling (704)
  • Testing of Hydrogen Piping Systems (705)
  • Location of Gaseous Hydrogen Systems (706)
  • Operation and Maintenance of Gaseous Hydrogen Systems (707)
  • Lastly, Design of Liquefied Hydrogen Systems Associated with Hydrogen Vaporization Operations (708)

Referenced Standards - Chapter 8

Chapter 8 simply lists the standard reference where the code originated for a basis of code. Referenced Organizations include:

  • ANSI or American National Standards Institute
  • ASME or American Society of Mechanical Engineers
  • ASTM is a group of scientist and engineers that help develop standards with technical issues
  • CGA or Compressed Gas Association
  • CSA is a testing, training, and laboratory services group for industry including manufacturing and construction
  • DOT or Department of Transportation
  • ICC or International Code Council
  • MSS or Manufacturers Standardization Society of Valves and Fittings
  • NFPA or National Fire Protection Association
  • Lastly, UL or United Laboratories, Inc

International Fuel Gas Code Overview

Sizing and Capacities of Gas Piping - Appendix A

Appendix A offers general gas piping considerations and includes several tables concerning gas piping capacities in relation to size with valves and fittings installed. Since valves and fittings create friction and turbulence these need to be taken into account when factoring the size for the capacity of gas piping. Higher pressure considerations along with pressure drop considerations are included. Additionally, several equations and tables can be referenced in Appendix A.

Sizing of Venting Systems Serving Appliances Equipped with Draft Hoods, Category 1 Appliances, and Appliances Listed for Use with Type B Vents - Appendix B

Appendix B offers information and illustrations for proper venting of appliances. This includes combining venting systems for several appliances utilizing a common vent.

International Fuel Gas Code Overview

Exit Terminals of Mechanical Draft and Direct Draft Systems - Appendix C

Basic information and an illustration of proper exit terminals for gas venting systems.

Recommended Safety Procedure for Safety Inspection of an Existing Appliance Installation - Appendix D

The basic procedure for a safety inspection of an existing appliance.

International Fuel Gas Code Overview

Finally, this completes the index for the International Fuel Gas Code.

High Performance HVAC Heating Cooling

International Fuel Gas Code Overview