Common gas piping installation
1.Construct gas header for multiple boilers using Figure 14 and the sizing tables below. Refer to the National Fuel Gas Code for other conditions.
2.Provide manual shutoff gas valve and ground joint union as shown in Figures 13 and 14 for each boiler. When gas line en- ters from top of the boilerl, the boiler internal gas piping pro- vides a drip leg. See boiler manual for details.
3.A ¾" NPT gas piping riser from header to boiler will be large enough for most jobs. Check pressure drop.
4.Size gas piping from meter outlet to entrance of gas header in accordance with Tables 1 and 2 below. For gases with other specific gravity or for different pressure drop or other pipe sizes, refer to the National Fuel Gas Code or applicable local codes.
Pipe lengths in Table 1 are equivalent length of straight pipe. Convert pipe fittings to equivalent lengths using data from Table 2.
5.Refer to page 14 of this manual and to the Ultra Boiler Manual for testing gas piping.
Figure 14 Common gas piping, with manifolded gas header
Table 1 | Capacity of gas piping for gas at 0.60 specific | Table 2 | Equivalent lengths of straight pipe |
| gravity at a pressure drop of 0.30 inches w.c. |
| for typical gas line fittings |
Part number | 15 |
