Gas pipe capacity by size & length
Gas pipe capacity depends on the size and the longest run: capacity falls as the run gets longer. The table shows a planning CFH capacity for Schedule-40 metallic pipe at a 40 ft reference length and about a 0.5 in WC drop, as labeled NFPA-54-style bands. ⚠️ Gas work must be done by a licensed professional — your local code governs. Use them with the gas pipe size and pressure-drop tools.
| Nominal size | Capacity at 40 ft (CFH) | ≈ BTU/hr (nat gas) |
|---|---|---|
| 1/2 in | ~95 CFH | ~95,000 |
| 3/4 in | ~190 CFH | ~190,000 |
| 1 in | ~205 CFH | ~205,000 |
| 1-1/4 in | ~435 CFH | ~435,000 |
| 1-1/2 in | ~650 CFH | ~650,000 |
| 2 in | ~1,250 CFH | ~1,250,000 |
Labeled NFPA-54-style planning bands for Schedule-40 metallic pipe at ~0.5 in WC drop; capacity falls roughly as 1/√(length ÷ 40). ⚠️ Gas work must be done by a licensed professional — your local code governs.