MODULE 10 EXERCISE
1. Above ground piping of which size must be welded, unless authority having jurisdiction allows threaded
joints ?
a. 1 ½”
b. 2 “
c. 1 ¼”
d. 2 ½”
2. What is the pressure and time required for testing piping with working pressure up to and including 2 psig,
when pipe length is less than 200 ft?
a. 15 psig, 60 min
b. 15 psig, 15 min
c. 50 psig, 60 min.
d. 60 psig, 60 min.
3. Determine which statement is wrong:
a. bushings shall not be nested
b. a dirt pocket is not required at the bottom of on the final drop for a clothes dryer
c. a flexible metal connector may be used to connect a range, and the maximum length is 2 feet.
d. piping having a diameter of less than NPS 1/2” shall not be used underground
4. What is the normal purge velocity for a large pipe?
a. 100 ft/min
b. 150 ft/min
c. 200 ft/min
d. 250 ft/min
5. When using an approved purging assembly to purge a gas line under 2 psig, how long you need to purge if
the pipe size is 1” and the length is 100’?
a. 15 seconds
b. 40 seconds
c. 84 seconds
d. 100 seconds
6. When plastic pipe is used underground, what is the minimum size of what material should be used to tape
along the pipe for tracing purpose?
a. 6-AWG, steel
b. 6-AWG, copper
c. 16-AWG, copper
d. 16-AWG, steel
6. What diameter and length of dirt pocket is required when a drop line is 3” in diameter?
a. D-3”, L-3”
b. D-1”, L-3”
c. D-3/4”, L-3”
d. D-2”, L-3”
7. When sizing a branch line, what is the minimum of job fabricated welded fittings that can be used a 6”
supply header?
a. 2”
b. 3”
c. 3/4”
d. 1/2”
8. What is the minimum diameter of a pressure gauge needed to perform leak test on gas piping?
a.
b.
c.
d.
2”
2-3/4”
3”
3-1/2”
9. Should a high pressure leak test be performed if a section of more than 20 feet is added to an existing
gas piping system?
a. yes
b. no
c. soap test only
d. dial and soap test
10. Determine which statement is right:
a. you can purge a new line through the burner system into combustion chamber
b. you can crack the piping union open to purge a piping system
c. for very long, large pipes, instead of completely purge with nitrogen, you can purge the piping by
injecting a mass of inert gas, called slug, and then flush the slug with the fuel gas
d. if you mix natural gas and air in a ratio between 4% to 14% then it is not combustible
11. What are the minimum required air changes per hour when welding is taking place in the shop?
a. 1
b. 2
c. 3
d. 4
12. What is the pressure and time required for testing piping of 3 inches in diameter with working pressure of
40 psig, when pipe length is less than 200 ft?
a. 15 psig, 60 min
b. 60 psig, 180 min
c. 50 psig, 180 min.
d. 60 psig, 60 min.
13. An appliance under 400,000 Btuh maybe purged:
a) in the combustion chamber at the pilot burner
b) at the pilot valve train outlet by flaring off the gas
c) at the main burner outlet by flaring off the gas
d) at the main burner train inlet by flaring off the gas
14. What is the required minimum distance a purge line may terminate from either a building or air intake
when purging a piping system to outdoors?
a) 5 feet
b) 10 feet
c) 15 feet
d) 20 feet
15. Fittings used for steel piping maybe made from :
a) brass or iron
b) steel and plastic
c) copper and malleable iron
d) malleable iron and steel
16. What is the allowable maximum distance piping supports should be spaced on a 4 inch gas line?
a) 15 feet
b) 20 feet
c) 10 feet
d) 35 feet
17. Underground copper tubing shall be
a) type GP or type L
b) type K or type L externally coated with PVC
c) type K or type GP externally coated with PVC
d) type ACR or type K
19. Propane piping in industrial building shall be identified by
a) yellow paint or bands
b) red paint or red bands
c) black paint
d) green paint and yellow bands
20. When is it necessary to purge every branch supply line in a piping system
a) never
b) always
c) only when the supply pressure is greater than 14 inches
d) only when the pipe is 2 1/2 NPS or greater
21. Underground piping laid under commercial driveway must be buried a minimum of
a) 6 inches
b) 15 inches
c) 24 inches
d) 30 inches
22. Underground piping can be joined
a) only by welding
b) by welding or approved compression fitting
c) only by brazing
d) approved flared fitting
23. What is the equivalent length of a 2 inch NPS, Schedule 40, 90 degree threaded elbow?
a) 2.07 feet
b) 2.41 feet
c) 5.17 feet
d) 11.05 feet
24. When a piping system extends from one building to another
a) a shut off valve must be installed where the pipe exits the building
b) a shut off valve must be installed before the pipe enters the building
c) two shut off valves are required : at the exit of the first building and before the entrance of the second
building
d) one shut off valve at the meter location is required
25. When is it permissible to use maleable bushings to reduce piping size?
a) never
b) only when the piping is not concealed
c) only when the pipe size is less than 2 1/2 NPS
d) only when the reduction is two pipe sizes
26. A barbeque is installed as a permanent structure. The maximum length of hose to be used is:
a) 6 feet
b) 10 feet
c) 30 feet
d) 50 feet
27. A piping outlet disconnected from an appliance
a) must be fitted with a plugged valve, cap or plug.
b) must be fitted with valve and nipple
c) must be fitted with nipple and elbow
d) must be removed and purged
28. An appliance with an input of 300 Mbtu/h is to be connected to a copper system with a length of 125 feet
at P=2.0 psig( natural gas, 1.0 psig pressure drop). What is the diameter of the copper line?
a) 3/4"
b) 1/2"
c) 1"
d) 3/8"
29. A manual shut off valve must be:
a) plug, ball or eccentric type
b) gate, ball or eccentric type
c) ball, plug or globe type
d) lubricated plug, ball or gate type
30. The maximum length of a hose used for a portable appliance
a) shall be 10'
b) shall not exceed 50'
c) shall be 6'
d) shall not exceed 30'
31. The person doing the purging shall
a) be a G1 certificate holder
b) be a competent person
c) perform with the permission of the authority having jurisdiction
d) remain in constant attendance
32. The minimum depth of a drip pocket is
a) 1"
b) 2"
c) 3"
d) 4"
33. What is the minimum pressure and time required to test a piping or tubing system of 300 feet length,
before an appliance , which will operate at pressure less than 14"WC, is connected?
a) 25 psig for 30 minutes
b) 1.5 hours at the appliance manifold pressure
c) 15 psig for 24 hours
d) 15 psig for 60 minutes