This appendix is an excerpt from the 2021 International Fuel Gas Code® informative Appendix D, coordinated with the section numbering of the International Residential Code.
About this appendix: Appendix AD provides procedures for testing and inspecting existing gas appliance installations for safe operation.
The inspection procedures include measuring for fuel gas and carbon monoxide (CO) and will require the use of a combustible gas detector (CGD) and a CO detector. It is recommended that both types of detectors be listed. Prior to any inspection, the detectors should be calibrated or tested in accordance with the manufacturer's instructions. In addition, it is recommended that the detectors have the following minimum specifications.
Prior to entering a building, the inspector should have both a combustible gas detector (CGD) and CO detector turned on, calibrated, and operating. Immediately upon entering the building, a sample of the ambient atmosphere should be taken. Based on CGD and CO detector readings, the inspector should take the following actions:
If during the inspection process it is determined a condition exists that could result in unsafe appliance operation, shut off the appliance and advise the owner of the unsafe condition. Where a gas leak is found that could result in an unsafe condition, advise the owner of the unsafe condition and call the gas supplier to turn off the gas supply. The inspector should not continue a safety inspection on an operating appliance, venting system, and piping system until repairs have been made.
The following appliance-specific inspections are to be performed as part of a complete inspection. These inspections are performed either with the appliance in the off or standby mode (indicated by "OFF") or on an appliance that is operating (indicated by "ON"). The CO measurements are to be undertaken only after the appliance is determined to be properly venting. The CO detector should be capable of calculating CO emissions in ppm air free.
|Boilers (all categories)||400 ppm air free|
|Central Furnace (all categories)||400 ppm1 air free2, 3|
|Floor Furnace||400 ppm air free|
|Gravity Furnace||400 ppm air free|
|Wall Furnace (BIV)||200 ppm air free|
|Wall Furnace (Direct Vent)||400 ppm air free|
|Vented Room Heater||200 ppm air free|
|Vent-Free Room Heater||200 ppm air free|
|Water Heater||200 ppm air free|
|Oven/Broiler||225 ppm as measured|
|Top Burner||25 ppm as measured (per burner)|
|Clothes Dryer||400 ppm air free|
|Refrigerator||25 ppm as measured|
|Gas Log (gas fireplace)||25 ppm as measured in vent|
|Gas Log (installed in wood burning fireplace)||400 ppm air free in firebox|