This Quick Tutorial Will Guide you Through the Steps on Gas Pope Sizing Using NFPA 54, the Longest Run Method
The Longest LengthMethod
- Add all segments of the piping to each appli ance to determine the longest run. In this example the run to the water heater is the longest at 85’. On table 4 page 11 the 90’ row is the next highest value that will cover the length of this run. We will use this row to size each segment of the system.
- Add BTU input for all appliances in the system to determine maximum load. • Section A/B = 270,000 BTU/hr input. Use table 4 – 90’ row. The 320 value will cover the 210,000 load on this segment following this column to the top, 1.25 will be the correct pipe size.
- Section B/C carries 240,000 BTU/hr after we subtract the Clothes Dryer. In table 4 –90’ row the 320 is still needed to cover this load and following this column to the top 1.25 will be the pipe size.
- Section C/D carries 100,000 BTU/hr after subtracting the Boiler. In table 4 – 90’ row 160 is needed to cover this load and following the column to the top 1” will be the pipe size.
- Each branch will be sized to the Table 4 90’ row. Branch 1, 30,000 BTU/hr will need .5”. Branch 2, 80,000 BTU/hr will need .75”. Branch 3, 45,000 will need .75” pipe. Branch 4 will need .75” pipe.
Notice
- The methos used aboce and additional information can be found in NFPA 54 Nation Fuel Gas Code