Beckett CG10 Install a Drip Leg in Gas Supply Piping, Gas Trains Gas Leaks and Exposion Hazards

Section: Connect Gas Piping

Figure 7. Typical Gas Piping Layout

ABBREV.	ITEM DESCRIPTION
HGPS	HIGH GAS PRESSURE SWITCH
LGPS	LOW GAS PRESSURE SWITCH
MSC	MAIN SHUTOFF COCK
MLTC	MAIN LEAK TEST COCK
PG	PRESSURE GAUGE
S	STRAINER
SSOV1	SAFETY SHUTOFF VALVE #1
TC	TEST COCK
U	UNION
2PRV	TWO POSITION REGULATING VALVE

	LGPS
METER		HGPS

REGULATOR PG U

GAS UTILITY PIPING

										BURNER
DRIP LEG	S	MSC	U	SSOV1	TC	2PRV	TC	MLTC	U	TC
	(IF USED)
FACILITY PIPING					GAS TRAIN					BURNER

Table 1. Gas supply piping capacity

Schedule 40 metallic pipe with 0.50 psi or less inlet pressure and 0.30” W.C. pressure drop

Maximum capacity in cubic feet of gas per hour (CFH). Natural gas with 0.60 specific gravity. Pipe size (inches) IPS

Pipe Length (ft.)	0.75”	1.0”	1.25”	1.5”	2.0”	2.5”	3.0”	4.0”
10	278	520	1050	1600	3050	4800	8500	17500
20	190	350	730	1100	2100	3300	5900	12000
30	152	285	590	800	1650	2700	4700	9700
40	130	245	500	760	1450	2300	4100	8300
50	115	215	440	670	1270	2000	3600	7400
60	105	195	400	610	1150	1850	3250	6800
70	96	180	370	560	1050	1700	3000	6200
80	90	170	350	530	990	1600	2800	5800
90	84	160	320	490	930	1500	2600	5400
100	79	150	305	460	870	1400	2500	5100
125	72	130	275	410	780	1250	2200	4500
150	64	120	250	380	710	1130	2000	4100
175	59	110	225	350	650	1050	1850	3800
200	55	100	210	320	610	980	1700	3500

Install a Drip Leg in Gas

Supply Piping

Foreign matter could lodge in gas valve cutoff seals, resulting in gas leak-through, explosion or fire.

Install a full-size drip leg or dirt pocket in the piping directly ahead of the main shutoff valve to capture foreign matter.

Gas Trains

Gas Leaks and Exposion

Hazards

Provide Over-pressure Protection

CSD-1 requires that if gas pressure entering the building exceeds the rating of any gas train component an overpressure protection device must be installed.

Standard – An Underwriters Laboratories (UL) listed gas train is standard for the CG10 gas burner. This configuration also meets CSD-1 requirements. See Figure 8 for typical component layout.

Propane (LP) – When the correct propane restrictor is added to a burner’s gas pipe assembly it changes the burner’s gas pressure drop so that the propane pressure drop is equal to the natural gas pressure drop of the same BTU firing rate. That is why the Manifold to Furnace Pressure Drop curves of Figures 12 and

13 are correct for both propane and natural gas. That is also why a gas train adjusted for the burner’s natural gas requirements will be correctly adjusted for its propane requirements. R. W. Beckett provides the same pressure regulating safety shutoff valve in the gas train (usually a Honeywell V4944B) for both natural gas and propane. The valve is marked for natural gas due to

its primary usage in a pressure range normally used

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