PB Heat Gas Boiler Gas Piping, A . General, B.Fuel Line Sizing, C.Gas Supply Piping Installation

GAS PIPING

4. GAS PIPING

A . GENERAL

1.All fuel piping to the boiler is to be in accordance with local codes. In the absence of local regulations refer to the National Fuel Gas Code, ANSI Z223.1/NFPA 54.

2.Size and install piping to provide a supply of gas sufficient to meet the maximum demand of all appliances supplied by the piping.

B.FUEL LINE SIZING

1.The rate of gas to be provided to the boiler can be determined by the following:

Input Rate (ft³/hr) =	Boiler Input Rate	(Btu/hr)
	Gas Heating Value	(Btu/ft³)

Obtain the gas heating value from the gas supplier.

2.As an alternative use Table 4.1 which uses typical heating values for natural gas and liquefied petroleum (LP) gas.

Table 4.1: Gas Input Rates

Boiler	Gas Input Rate* (ft³/hr)
	Natural Gas	LP Gas
Model
PI-T50	50	20
PI-T80	80	32
PI-80	80	32
PI-140	140	56
PI-199	199	79

*Natural gas input rates are based on 1000 Btu/ft³, LP input rates are based on 2500 Btu/ft³.

3.Table 4.2 shows the maximum flow capacity of several pipe sizes based on 0.3" of pressure drop.

a.The values shown are based on a gas specific gravity of 0.60 (Typical for natural gas).

b.Multiply the capacities listed by the factors indicated in Table 5.3 for gas with a specific gravity other than 0.60 to obtain the corrected capacity.

Table 4.2: Maximum Capacity of Pipe (CFH) for a Pressure Drop of 0.3" of Water

Pipe			1-1/4"	1-1/2"
Length	3/4" NPT	1" NPT	NPT	NPT
(Feet)	Pipe	Pipe	Pipe	Pipe
10	278	520	1,050	1,600
20	190	350	730	1,100
30	152	285	590	890
40	130	245	500	760
50	115	215	440	670
60	105	195	400	610

The values are based on a specific gravity of 0.60 (typical for natural gas). See Table 4.3 for capacity correction factors for gases with other specific gravities.

Table 4.3: Maximum Capacity Correction Factors for Specific Gravity other than 0.60

Specific	0.50	0.55	0.60	0.65	0.70	0.75
Gravity
Correction	1.10	1.04	1.00	0.96	0.93	0.90
Factor
Specific	0.80	0.85	0.90	1.00	1.10	1.20
Gravity
Correction	0.87	0.84	0.82	0.78	0.74	0.71
Factor
Specific	1.30	1.40	1.50	1.60	1.70	1.80
Gravity
Correction	0.68	0.66	0.63	0.61	0.59	0.58
Factor

4.The gas piping to the boiler must be a minimum of 3/4" pipe. The boiler is supplied with a 3/4" NPT x 1/2" NPT bell reducer. Do not remove the reducer.

5.Size and install the gas supply piping for no more than 0.5 inches of water pressure drop between the gas regulator and the boiler.

C.GAS SUPPLY PIPING INSTALLATION

1.Do not install any piping directly over or in front of the boiler. Locate the drop pipe adjacent to the boiler.

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