REGULATOR TANK PRESSURE
REDUCED TO 5 PSIG (345 MBAR)
TANK
REGULATOR SECOND STAGE 5 PSIG (345 MBAR) INLET
300' (91.4m)
QUATITY 6 - 50,000 BTUH HEATERS (14,654 WATTS)
TOTAL LOAD = 300,000 BTUH (87,925 WATTS)
40'
(12.2M)
20'
(6M)
50'
(15.2M)
50'
(15.2M)
30'
(9.1M)
30'
(9.1M)
50'
(15.2M)
50'
(15.2M)
50'
(15.2M)
20'
(6M)
A
B
C
D
G
H
E
F
have an experienced gas installation agency size and
install all fuel gas piping.
Pipe sizing is critical to the proper operation of any gas
heating system. However, piping is dependent on several
factors:
1. Total gas load expressed in BTUH.
2. The gas pressure to be supplied through the piping
system. This pressure may be expressed in pounds
of pressure per square inch (P.S.I.) or (BAR) or inches
of water column or (MBAR).
3. Distance that the gas must travel to feed the
appliance furthest from the regulator.
This section will explain to you how to size piping for the
heaters through the use of pipe sizing tables and a typical
example. In all cases with this example, we will be using
only pounds of pressure, expressed as 5 psig (345 BAR)
and not inches of water column.
INSTRUCTIONS
a. Determine total gas demand for entire system, by
adding up BTU/hr. input from appliance nameplates
and adding demand for any future appliances.
b. Measure the length of piping required from outlet of
first stage regulator to the appliance furthest away.
No other length is necessary to do the sizing. In this
example the distance from first stage regulator to
appliance furthest away is 230 ft. (70.10 M)
c. Make a sketch of the piping system and installation.
See Fig. 1.
EXAMPLE
(Refer tto FFig. 2
2)
IMPORTANT: If exact length is not on chart, use next longer
length. Select the size of pipe that shows at least as much
capacity as needed for each piping section.
a. Section A to B of pipe must supply the complete gas
load of 300,000 BTUH (87930 WATTS) for the entire
building. Looking at the 5 PSIG (345 MBAR) sizing
chart, the size of pipe used in conveying gas would
need to be sized at 1/2 inch (19 MM) diameter pipe.
Note that even though furthest distance from first
stage regulator to appliance is 230 ft. (70 M), we use
the 250 ft. (76 M) length.
b. Section B to C must supply the load of 200,000
BTUH (58620 WATTS). Select 1/2 inch (12.7 MM)
pipe for Section B to C.
c. Section C to D must supply a load of 150,000 BTUH
(43960 WATTS). Select 1/2 inch (12.7 MM) pipe for
Section C to D.
d. Section D to E must supply a load of 100,000 BTUH
(29310 WATTS). Select 1/2 inch (12.7 MM) pipe.
e. Sections E to F must supply 50,000 BTUH (14650
WATTS) Select 1/2 inch (12.7 MM) pipe.
f. Sections B to C must supply 100,000 BTUH (29310
WATTS). Use 1/2 inch (12.7 MM) pipe.
g. The final section, G to H, needs only 50,000 BTUH
(14650 WATTS) for gas usage. This section would
use 1/2 inch (12.7 MM) pipe.
FIG. 1
10
