Cumberland VariFlame VF-16-ONG, Owner'S Manual

Page: 32 / 64

Chapter 4: Installation
Pipe sizing guidelines
You must calculate the Heating Value Required (HVR) and Equivalent Length of Pipe (ELOP) for your
installation.
• Using a system schematic, label each piping section of the system starting at the meter or regulator.
A different pipe section starts where the gas demand of the system changes, usually at a junction.
• Determine the Heating Value Required (HVR) in BTUH (BTU's per hour) for each section of pipe.
HVR = (number heaters supplied by pipe section) X (heat output per heater)
• Determine the Equivalent Length Of Pipe (ELOP) required for sufficient gas service. ELOP =
(length from meter to most remote heater) + (Minor loss equivalents of the system)
IMPORTANT: Use the ELOP value from this equation for size determination of all pipe sections.
• Use the ELOP and the HVR of each pipe section to determine the required pipe size for either natu-
ral gas (NG) (Table 1) or liquid propane (LP) (Table 2) from the table 'Maximum Capacity Of Pipe'.
Determining the correct pipe size
EXAMPLE: Four 40,000 BTUH (12 kW) heaters will be installed on the gas pipe line in the 'Arbitrary
Piping System' diagram below. NOTE: Values given in English and Metric equivalent units.
Figure 4-9 Example Piping System
• Determine the HVR value for each pipe section of the system.
Pipe Section
No. Of
Heaters
HVR Calculation HVR Value
BTUH kW BTUH kW
a-b 4
4 x 40,000
4 x 12
160,000
48
b-c 2
2 x 40,000
2 x 12
80,000
24
c-e
1
1 x 40,000
1 x 12
40,000
12
b-d 1
1 x 40,000
1 x 12
40,000
12
32 PNEG-2091 VariFlame™ Heater