Model 4
1500 - 6000 MBTU/hr
Rev. 03-08
Section B2-21
Gas Supply Pipe Sizing
- For proper operation of a single unit or multiple units, we
recommend that the gas pipe be sized to allow no more than 0.3" w.c. pressure
drop from the source (gas header or utility meter) to the final unit location. The gas
supplier (utility) should be consulted to confirm that sufficient volume and normal
pressure are provided to the building at the discharge side of the gas meter or
supply pipe (for installations of new boilers into an existing building, gas pressure
should be measured with a manometer to ensure sufficient pressure is available).
A survey of all connected gas using devices should be made. If appliances other
than the boiler are connected to the gas supply line, then a determination should be
made of how much flow volume (cfh = cubic feet per hour) will be demanded at
one time and the pressure drop requirements when all appliances are operating.
The total length of gas piping and all fittings must be considered when sizing the gas
piping. Total equivalent length should be calculated from the utility meter or source
to the final connection. As a minimum guideline, gas piping Tables B2 - 16 through
B2 - 20 should be used. The data in these tables is from the NFPA source book,
2006 edition.
