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| First Stage Regulator
Manifold Construction
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1 Shut-Off Valve
2 Regulator
3 Union
4 Reducing Bushing
5 Tee |
First Stage Regulator
Manifold Construction
Install the regulators with
vents pointing down, be sure that the regulator manifold is adequately supported.
All threaded piping
upstream of the first stage regulator must be schedule 80. All pipe fittings must be 250
PSI min.
For pipe and fitting
specifications, see NFPA 58 (1998 edition 3-2.10).
Downstream of the first
stage regulator, schedule 40 pipe and 125 PSI fittings are acceptable.
The shutoff valve
immediately upstream of the regulator should be at least of the same size as the regulator
inlet.
The fittings and shutoff
valve downstream of the regulator should be at least of the same size as the regulator
outlet. It is essential that these fittings are not smaller than the regulator outlet,
this will act as a restriction, reducing regulator capacity.
As the manifold is
constructed, special care must be taken at Fitting 5. This fitting must be large enough to
handle the volume of gas created through both regulators. The inside area of Fitting 5
must be at least as large as the added inside areas of each side of the manifold.
Example:
Assume that two LV4403TR4 First Stage Regulators are used in a manifold. These regulators
have 1/2" outlet connections. The chart below, Characteristics of Steel Pipe, shows
that 1/2" Schedule 40 pipe has an inside area of .304 in˛. Since two regulators are
used, the required inside area is .304 + .304 = .608 in˛. The chart shows that the next
larger size pipe with at least this .608 in2 area is the 1" pipe,
with an inside area of .864 in˛. For this example, 1/2" x 1" Reducing Bushings
must be installed at Point 4 and a 1" tee is required at Point 5. The downstream pipe
must be at least 1".
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