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REGULATOR LOCK-UP AND LEAKAGE:
After the leak testing and delivery pressure tests have proven satisfactory, the regulator lock-up and leakage
test may be performed. The lock-up pressure of the final stage regulator should be slightly higher than, but
not more than, 120% of the set delivery pressure. For example, on a delivery pressure setting of 5 PSIG, the
maximum allowable lock-up pressure is 6 PSIG.
To perform the lock-up and leakage test, follow these steps:
1. With the LP tank valve fully open, shut off all appliance valves so there is no demand for gas. This
includes shutting off all pilots.
2. A slight rise in pressure will occur under these conditions. This rise should be no more than 120% of the
delivery pressure. This is the lock up pressure. NOTE: A quick rise in pressure above the allowable lock-
up point could indicate undersized piping, a worn seat disc or foreign material in the seating area. This
condition must be corrected before putting the system in service.
3. Continue the test for five minutes or more. If a creeping rise in pressure is noticed, the final stage
regulator seat is not closing off properly. The regulator must be replaced or repaired, and the system
retested, before putting the system in service.
7.2) GAS PIPE SIZING EXAMPLE
House Size: 40' x 400'
Brooder Quantity: 14
Individual Brooder Capacity: 40,000 Btu/hr
Second Stage Regulator Pressure: 14" W.C.
Operating Pressure: 11"W.C., LP gas with all brooders operating
STEP 1. Gas should be run at high pressure from the LP tank to the second stage regulator at the house.
Using the above house configuration example, calculate the gas pipe sizing. First, calculate the total distance
from the second stage regulator to the furthest brooder. In the figure above, that distance equals 202' (20' +
182'). Using Table 1, look up the row for 200' and select the smallest pipe size that has the capacity for the
flow of the end brooder (40,000). The smallest pipe size is ½" with a capacity of up to 58,000 Btu/hr over
200'.
STEP 2. Calculate the distance from the second furthest brooder to the secondary regulator. In the example,
that distance equals 174'. Using Table 1, look up the row for 174'. As 174' is not listed, you will use the next
distance up, in this case, 200'. Then select the smallest pipe size that has the capacity for the flow of both
the furthest (#7) and second furthest (#6) brooders, which combines to 80,000 Btu/hr. The smallest pipe
size is ¾" with a capacity of up to 120,000 Btu/hr over 200'. Repeat this process for each brooder until you
reach the Tee. Table 2 shows the completed example.
–16–
Form No. 43539510
May 2020
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