G3 - Gas Technician Level 3 Piping and Tubing Systems Questions and Answers 1 — Questions and Answers
Question 1: According to the CSA B149.1 Natural Gas and Propane Installation Code, what is the required material specification for steel gas piping?
- ASTM A120
- ASTM A53/A53M (Correct answer)
- ASME B31.3
- CSA Z245
Correct answer: ASTM A53/A53M
The CSA B149.1 code specifies that steel pipes used for gas installations must comply with ASTM A53/A53M or A106 standards to ensure they meet the required strength and durability for safely conveying natural gas or propane.
Question 2: A gas technician is installing a new natural gas line for a residential furnace. The system operates at a standard pressure of 7 inches water column. Before connecting the appliance, what is the minimum required test pressure for this new piping system?
- 5 psig for 10 minutes
- 1.5 times the operating pressure for 30 minutes
- 100 psig for 15 minutes
- 15 psig for a minimum of 15 minutes (Correct answer)
Correct answer: 15 psig for a minimum of 15 minutes
As per the TSSA amendments to the CSA B149.1 code (Table 6.3), for piping systems up to 2 inches in diameter with an operating pressure up to 14 inches w.c., the minimum test pressure is 15 psig (100 kPa) for a duration of at least 15 minutes.
Question 3: Which of the following joining methods is NOT permitted for use with copper tubing in a natural gas or propane piping system?
- Brazing
- Flared fittings
- Press-connect fittings
- Soldering (Correct answer)
Correct answer: Soldering
Soldering is prohibited for joining copper tubing in gas systems because the low melting point of solder presents a significant safety hazard in the event of a fire. Approved methods like brazing, flaring, and certified press-connect fittings provide a much stronger and more heat-resistant joint.
Question 4: A G3 licensed technician is tasked with running a gas line through a solid concrete foundation wall to an outdoor appliance. What is a critical requirement for this type of installation?
- The pipe must be painted yellow for identification.
- The pipe must be sleeved and the annular space sealed.
- The pipe must be at least Schedule 80 thickness. (Correct answer)
- A union fitting must be installed inside the wall.
Correct answer: The pipe must be at least Schedule 80 thickness.
Clause 6.16.9 of the CSA B149.1 code requires that when piping or tubing passes through an exterior wall, it must be protected by a sleeve. This prevents the pipe from being damaged by the masonry and allows for movement, and the ends of the sleeve must be sealed to prevent the entry of gas, water, or insects.
Question 5: When installing an underground polyethylene (PE) gas pipe, which of the following is a mandatory requirement according to the CSA B149.1 code?
- The pipe must be buried at a minimum depth of 36 inches.
- A tracer wire must be installed with the piping. (Correct answer)
- The pipe must be encased in a sand bed at least 6 inches deep.
- Heat fusion is the only acceptable joining method.
Correct answer: A tracer wire must be installed with the piping.
Because polyethylene piping is non-metallic and cannot be located with standard pipe locators, the CSA B149.1 code mandates that it must be installed with an electrically conductive tracer wire. This allows the underground pipe to be located in the future for service or to prevent accidental damage.
Question 6: What is the primary purpose of installing a sediment trap (drip leg) in a gas piping system?
- To provide a convenient point for pressure testing.
- To automatically shut off the gas flow in an emergency.
- To collect moisture, dirt, and other foreign particles. (Correct answer)
- To regulate the gas pressure just before the appliance.
Correct answer: To collect moisture, dirt, and other foreign particles.
A sediment trap, also known as a drip leg, is installed to collect any sediment, debris, or condensate that may be present in the gas line. This prevents foreign matter from entering the appliance's sensitive gas valve and burner components, which could cause malfunction or hazardous operation.
G3 - Gas Technician Level 3 Piping and Tubing Systems Questions and Answers 1
According to the CSA B149.1 Natural Gas and Propane Installation Code, what is the required material specification for steel gas piping?