Line F Pressure test and Purge Piping Systems Flashcards
What is the minimum diameter gauge allowed to be used for a pressure test on a gas piping system?
3 inch (B149.1 - 6.22.2 (b))
Using good engineering practices, what type of fluid should be used to pressurize a piping systems 4 inches and larger that contain a combustible gas?
inert gas (B149.1 6.22.2)
What is the minimum test pressure as per code requirements for 372’ of 8” NPS schedule 80 steel pipe (yellow jacket) installed underground operating at a gas pressure of 40 psig?
100 psig (B149.1
When pressure testing a gas piping system, what is the maximum range the pressure gauge shall exceed the test pressure by?
at least by 15% but not more than 300% (B149.1 6.22.2 (b))
What is the maximum diameter purge point opening when purging NPS 2”?
1/2 inch
What is the maximum pipe size that can be purged using air or fuel gas as the purging agent if the length of the pipe is 45 feet?
2-1/2 inch (B149.1 Table 6.4)
What is the recommended pressure used when purging with nitrogen?
0.5 or 14” w.c.
What is the recommended purge velocity through the piping system?
200 ft/min
What is the reason for purging at the correct velocity through a piping system?
completely scrubs the walls, no stratification, faster than flame speed
Why is purging using an inert gas a requirement when exceeding the pipe lengths for the diameters given in Table 6.4 of the B149.1?
larger volumes of piping cannot withstand an internal explosion from a gas air mixture
What does TOE stand for in a TOE nipple?
Thread One End
During a nitrogen purge, what velocity must be maintained at the purge outlet?
200 ft/sec
When purging outdoors, what is the minimum distance from a building intake allowed?
10 feet
