ILM 110205g , 080105cA, 080106c Gas Piping Flashcards
What types of gas piping materials can be used?
Black iron, plastic (polyethelene), copper
What schedule of black iron pipe is most commonly used for gas connections?
Schedule 40
NPS stands for
Nominal Pipe Size
Which 3 fittings cannot be used in a gas piping system?
- Street tee
- Street elbow
- Close nipple
NPT stands for ______ and what is the included angle on a perfect thread?
National Pipe Thread
60 degree
What is the approximate number of threads to be cut for a nominal pipe size of ½”?
10 1/2
What tool is used to remove the internal burr from cut pipe?
Reamer
Why is removing the internal burr so important?
To ensure a smooth flow. If the burr is not removed, pipe pressure loss, turbulence and catching foreign material is a possibility.
After securing the pipe to the pipe vise, what steps are followed to thread the pipe?
Measure
mark
cut
clean die threads
ream
thread and oil.
Bushings reduce pipe sizes, what is not permitted when using bushings?
Nesting
How is Teflon tape applied to the thread? What is the purpose of the Teflon tape?
Teflon tape is used as a lubricant to be applied to the male threads, clockwise with a 50% overlap
leaving the first 2 threads bare.
What should not be in contact with the pipe when using a pipe wrench to tighten a fitting together?
Hook jaw
What is the purpose of a dirt pocket?
They are designed to collect scale, filings and foreign
materials that may be present in the gas line before they reach the appliance.
What is the purpose of a nipple chuck?
To hold short pieces of pipe without damaging existing threads
Can gas materials be reused?
Yes if they are deemed to be in acceptable condition
List three approved gas leak detectors.
Soapy water solution
methane gas leak detector
clocking the meter
What should not be used to check for gas leaks?
Flame
What is cutting oil used for?
Keep the die or tool cool
List the following uses for the below copper types: K, L, M, G
K,L,G - gas
M - water
What material can be used above ground and doesn’t require fittings to change direction?
CSST -corrugated stainless steel tubing
Under the general gas code information, who is responsible for the safe operation and startup of any appliance?
The installer
Describe thread engagement?
A short length of pipe that is used in the makeup of the
fitting or is threaded into the fitting is called the thread engagement.
Where can aluminum tubing be used?
Pilot gas from gas valve to pilot burner
For any appliance to be approved for installation, it requires what on the appliance?
Rating plate
What is the purpose of a regulator and what is it called when the flow of gas is completely stopped by the regulator?
The regulator is a piece of equipment that reduces and maintains a set pressure while compensating for volume in a gas system.
It is known as lock up when gas is completely stopped by the regulator.
What is installed in a regulator to restrict the volume of gas escaping from the regulator vent in case the diaphragm ruptures?
Ball check leak limiting device
What is the minimum clearance required for the service side of a furnace?
2’ or 24 “
A regulator must be installed with a manual _______ valve located upstream of the regulator
to accommodate maintenance and service requirements.
shut off
In which direction is an orifice drilled and how many sizes smaller of a bit would you use?
Drilled in the direction of gas flow with a bit 2 sizes smaller.
If a heat exchanger is found to be defective, what must be done to the heat exchanger in a
residential situation?
Replaced
How far must a regulator vent terminate from a mechanical air intake?
10’ or 3m
What is the only type of copper fitting that can be used on gas line connections?
Flare fitting
What are the 3 main elements of a regulator?
What is the purpose of each element?
Restricting element - limits gas flow
Measuring element - measures outlet (downstream) pressure
Loading element - raise or lower outlet pressure
What must be done to an appliance that was previously installed in Calgary and is now
being installed at 6750’?
Derate 9% 6750 – 4500 =2250
(Derate 4% for every 1000’ or 1% for every 250’)
