Gas Piping Symbols Guide
Natural gas, propane, and specialty gas piping use a specific symbol vocabulary that overlaps with general plumbing but adds shutoffs, regulators, and meter conventions worth knowing.
Gas piping appears on plumbing or mechanical drawings, sometimes on its own dedicated sheet on larger commercial projects. The symbols follow general plumbing conventions but add gas-specific items: meters, regulators, drip legs, and emergency shutoffs. Each appliance has its own connection symbol and typically a CFH (cubic feet per hour) demand rating.
Pipe Line Symbols
Service and Distribution Equipment
Valves and Fittings
Appliance Connection Notation
Each gas appliance gets a connection symbol with the demand in CFH or BTU/hr. A range might be 60,000 BTU/hr; a furnace 100,000; a water heater 40,000. The drawings list each appliance and its load.
Pipe sizing depends on cumulative demand and pipe length. The longest run plus accumulated demand drives the upstream pipe size. Sizing tables in the IFGC (or NFPA 54) determine the diameter at each segment. The drawings should show pipe sizes called out at each branch and a sizing schedule for verification.
Special Notations and Codes
Related Guides
Find Gas Piping Errors Across Your Drawings
Helonic checks gas piping symbols, sizing, and shutoff placement against IFGC requirements and architectural appliance schedules.
Try Helonic Free