Complete Solutions
(10) After a gas piping system has been installed, how many
pressure tests are required and when? Correct Answers The
first before any appliances are installed and the second after all
the appliances are installed
(10) All piping and components must be _____________ and
___________before being concealed Correct Answers
inspected and tested
(10) Critical point of acetylene? Correct Answers 28 psi at 21
degrees C (70 degrees F)
(10) Explosive limits of acetylene? Correct Answers 2.50%-
81%
(10) For piping systems over 2 psi, a line pressure regulator
must be equipped with __________ or ___________. Correct
Answers A line relief device or an overpressure protection
device
(10) How do you check for seepage at the gas meter? Correct
Answers Release a small amount of gas from the system at
static pressure (with the supply valve in the fully closed
position) then wait to see if the pressure creeps back up
(10) How is the accuracy of a regulator determined? Correct
Answers The amount of flow it can pass for a given amount of
,droop determines the accuracy of a regulator. The closer the
regulator is to setpoint, the more accurate it is.
(10) How shall movable commercial cooking appliances be
connected to gas lines and what standard covers this connection?
Correct Answers It shall be connected by a certified connector
complying with standard CAN/CSA-6.16
(10) If there is disagreement between a specification and a
drawing which is usually taken to be correct? Correct Answers
The specifications because they are prepared last
(10) In many service and line pressure regulators how can you
change the flow capacity? Correct Answers By changing the
orifice size
(10) In which applications are pilot operated regulators normally
employed other than servo regulation? Correct Answers High
capacity applications in commercial, institutional, and industrial
settings.
(10) Line pressure regulators for use on systems with an inlet
pressure over 0.5 psi must be of what type? Correct Answers
Positive shut-off type
(10) Piping may not pass under a ________ or _________
Correct Answers Footing or building wall
(10) Piping shall __________ before entry into a building unless
otherwise authorized by the authority having jurisdiction
Correct Answers Rise above grade
, (10) Purging of piping must follow engineering practices above
NPS ___ Correct Answers 4
(10) Rigging hooks should not exceed what amount of wear?
Correct Answers 5% in the throat opening not to exceed 1/4
inch or wear exceeding 10% of the original dimension
(10) Schedule 40 and Schedule 80 pipe have the same
________________. Correct Answers Outside diameter
(10) Steel gas piping must conform to which ASTM standards?
Correct Answers ASTM A53 or A106
(10) What are the four factors that may affect droop? Correct
Answers Spring rate, diaphragm rate, orifice size, and inlet
pressure
(10) What are the minimum and maximum hydrostatic relief
device pressures on liquid propane systems? Correct Answers
375 psi and 500 psi
(10) What are the three types of lifts? Correct Answers
Incidental or ordinary lift, pre-engineered lift, critical lift
(10) What are the typical upstream and manifold gas pressures
for NG and LP Correct Answers LP: 13" w.c. upstream, 11"
w.c. manifold
NG: 7" w.c. upstream, 3.5" w.c. manifold