Fuel Gas Piping and Appliance Connections
Fuel Gas Piping and Appliance Connections
This domain tests fuel-gas piping, appliance connections, combustion air, and safety. Minnesota enforces a fuel gas code based on NFPA 54/ANSI Z223.1, with state amendments, so the exam expects you to size pipe by BTU load and length, install sediment traps, and bond CSST.
Core rules
- Size gas piping using the longest-length method or the adopted table, adding the input ratings of all appliances. Include the water heater, furnace, range, dryer, and any future connection.
- Install a sediment trap at the appliance connection, a shutoff valve ahead of the connector, and a union or approved connector. Appliance connectors must be listed and protected from damage.
- CSST must be bonded per the manufacturer and code, and gas piping must not be used as a grounding electrode. Provide combustion air and venting per the appliance listing.
- Test the piping with air or inert gas at the required pressure before turning on gas.
Worked example
A furnace rated 100,000 BTU/h and a water heater rated 40,000 BTU/h connect to a 1/2-inch CSST run with a developed length of 50 feet. Total load is 140,000 BTU/h. Check the adopted capacity table at 50 feet; if 1/2-inch capacity is below 140,000 BTU/h, increase to 3/4-inch. Then add a sediment trap, shutoff, and bonding.
Traps
Do not size gas pipe from the appliance outlet size alone. Do not omit the sediment trap or install it upside down. Do not bond CSST to a random pipe. Do not skip the pressure test because the appliance lights.