Gas Piping Installation Inspection

Per IFGC Section 403.1 and NFPA 54 Section 5.4, gas piping must be of approved materials: black steel, galvanized steel (for exterior only), copper (where allowed by local code), or corrugated stainless steel tubing (CSST). Per IFGC Section 403.9, pipe joints must be made gas-tight using approved methods. Steel pipe joints must use threaded fittings or welded connections. CSST must be installed per manufacturer listing and ICC-ES evaluation report. White iron or cast iron fittings are prohibited per IFGC Section 403.9.3.

1. Verify all pipe materials are approved types listed in IFGC Section 403.1

2. Inspect threaded joints for proper thread engagement and use of approved thread sealant (yellow Teflon tape or pipe dope rated for gas)

3. Confirm CSST is listed, installed per manufacturer instructions, and has proper fittings

4. Check that pipe sizing matches the gas demand calculation per IFGC Table 402.4

5. Verify no prohibited materials are used (white iron, cast iron fittings, or galvanized pipe indoors)

- Galvanized pipe used indoors where it reacts with gas additives and flakes

- Improper thread sealant used (white Teflon tape instead of yellow gas-rated tape)

- CSST installed without following manufacturer-specific installation requirements

- Gas pipe undersized for the total BTU demand of connected appliances

Per IFGC Section 404.6 and NFPA 54 Section 5.7, the gas meter must be installed in an accessible location protected from physical damage. The meter must have a minimum clearance of 3 feet from ignition sources, electrical panels, and air intakes per utility company requirements. A main shutoff valve must be installed on the supply side of the meter per IFGC Section 409.1. The gas service line from the street to the meter must be installed per utility company specifications.

1. Verify the gas meter is accessible and protected from physical damage by vehicles or equipment

2. Confirm minimum clearance distances from ignition sources, electrical panels, and air intakes

3. Check the main shutoff valve upstream of the meter for proper operation and accessibility

4. Verify the meter regulator is properly set for the required delivery pressure

5. Inspect the service line entry point for proper sealing and protection from corrosion

- Gas meter located too close to electrical panels or ignition sources

- Main shutoff valve inaccessible or seized and inoperable

- Meter not protected from physical damage in driveways or parking areas

- Service line entry point not properly sealed against moisture intrusion

Per IFGC Section 411.1 and NFPA 54 Section 5.9, each gas appliance must have an accessible individual shutoff valve within 6 feet of the appliance and upstream of the connector. Flexible gas connectors must be listed per ANSI Z21.24 and must not exceed 6 feet in length for residential or 36 inches for commercial per IFGC Section 411.1.3. Connectors must not pass through walls, floors, or ceilings. Appliance input ratings must not exceed the capacity of the gas supply piping.

1. Verify each appliance has an individual shutoff valve within 6 feet and in the same room

2. Confirm flexible connectors are listed, within length limits, and not concealed in walls or floors

3. Check that connector materials are compatible with the gas type (natural gas or propane)

4. Verify appliance BTU input ratings match the gas supply pipe sizing

5. Inspect drip legs (sediment traps) at each appliance connection per IFGC Section 408.4

- Individual appliance shutoff valves missing or located in inaccessible locations

- Flexible connectors exceeding maximum length or routed through concealed spaces

- Missing sediment traps (drip legs) at appliance connections

- Old or unapproved connectors (uncoated brass) still in use

Per IFGC Chapter 5 and NFPA 54 Chapter 9, all fuel-burning appliances must have adequate combustion air supply. Per IFGC Section 304, combustion air must be provided from outdoors through openings sized per the code tables or from indoor spaces of adequate volume (50 cubic feet per 1,000 BTU/hr). Mechanical rooms with gas appliances must meet minimum volume requirements or have direct outdoor combustion air openings per IFGC Section 304.6.

1. Calculate total BTU input of all appliances in the space and verify adequate combustion air volume

2. Inspect combustion air openings for proper sizing (1 square inch per 4,000 BTU/hr for direct outdoor air)

3. Verify combustion air openings are unobstructed and free of screens finer than 1/4 inch mesh

4. Confirm mechanical rooms have not been reduced in volume by storage or partition changes

5. Check that combustion air ducts are properly connected and sealed from the outdoors to the appliance room

- Combustion air openings blocked or covered after construction completion

- Mechanical room volume reduced by storage or added partitions

- Combustion air openings undersized for the total BTU load in the space

- Screens on combustion air openings too fine, restricting airflow

Per IFGC Chapter 5 and NFPA 54 Chapter 12, gas appliance venting must comply with the vent type required by the appliance listing. Category I appliances require Type B vent or masonry chimney with a liner. Category IV appliances (high-efficiency condensing) use listed special vent material (typically PVC or CPVC per manufacturer listing). Per IFGC Section 503.6, vent connectors must maintain proper slope (1/4 inch per foot upward) and clearances to combustibles.

1. Verify vent type matches the appliance category (Type B for Category I, PVC/CPVC for Category IV)

2. Check vent connector slope for minimum 1/4 inch per foot rise toward the chimney or vent

3. Measure clearances from single-wall vent connectors to combustibles (minimum 6 inches)

4. Inspect chimney or vent termination height and location per IFGC Section 503.6.5

5. Verify common venting configurations comply with IFGC vent sizing tables

- Improper vent material used for the appliance category (e.g., PVC on a Category I appliance)

- Vent connector sloping downward instead of upward toward the chimney

- Insufficient clearance from single-wall vent connectors to combustible materials

- Vent termination too close to windows, doors, or air intakes

Per IFGC Section 621 and NFPA 54 Section 10.3, gas appliances must have listed safety controls including automatic gas shutoff valves, flame safeguard devices, and high-temperature limit controls. Carbon monoxide detectors are required per IRC R315 in dwellings with fuel-burning appliances or attached garages. Excess flow valves must be installed per IFGC Section 409.8 where required. All safety devices must be tested to verify proper operation before system commissioning.

1. Verify all gas appliances have functioning flame safeguard devices (thermocouples or flame sensors)

2. Test high-temperature limit switches and pressure relief valves on water heaters and boilers

3. Confirm carbon monoxide detectors are installed per IRC R315 on each level and near sleeping areas

4. Check that earthquake shutoff valves are installed where required by local jurisdiction

5. Verify excess flow valves are installed at required locations per IFGC Section 409.8

- Thermocouple or flame sensor failed, allowing gas to flow without ignition confirmation

- Carbon monoxide detectors missing or installed in incorrect locations

- High-temperature limit switches bypassed or jumpered during maintenance and not restored

- Earthquake shutoff valves not installed where required by local seismic zone requirements

Per IFGC Section 406.4 and NFPA 54 Section 8.1, gas piping systems must be pressure tested before being placed in service. Test pressure must be at least 3 psig (1.5 times the working pressure for systems operating above 14 inches water column) using air, nitrogen, or carbon dioxide — never with gas. The system must hold test pressure for a minimum of 10 minutes with no detectable pressure drop. All joints must be checked with leak detection solution after the system is charged with gas.

1. Verify the pressure test is conducted at the required pressure (minimum 3 psig for standard residential systems)

2. Monitor the test gauge for a minimum of 10 minutes to confirm no pressure drop

3. Confirm the test medium is air, nitrogen, or CO2 — never gas

4. After gas is introduced, apply leak detection solution to every joint, valve, and connection

5. Use a combustible gas detector to scan all concealed connections and piping runs

- Pressure test conducted at insufficient pressure or for less than the required duration

- Small leaks at threaded joints due to improper sealant application or thread engagement

- CSST fitting connections not properly tightened to manufacturer torque specifications

- Leak testing not performed on all joints after gas is introduced to the system