Journeyman Plumbers Exam Gas Piping Systems 4

Question 1

What substance is added to natural gas to give it its distinctive odor?

Accepted Answer

Mercaptan (ethyl mercaptan)

Answer

Mercaptan (ethyl mercaptan) is the odorant added to natural gas by the utility to make odorless gas detectable by smell at very low concentrations.

Question 2

Which of the following is the correct pipe thread sealant to use on gas piping threaded joints?

Accepted Answer

Pipe dope approved for gas service

Answer

Only pipe thread compound (pipe dope) specifically listed and approved for gas service should be used on gas pipe threaded joints; standard Teflon tape alone is not sufficient.

Question 3

When a gas appliance is installed in a bedroom or bathroom, which special requirement applies?

Accepted Answer

The appliance must be direct-vent or have a sealed combustion chamber

Answer

Gas appliances in sleeping rooms and bathrooms must use direct-vent or sealed combustion systems to prevent combustion air from being drawn from the occupied space.

Question 4

What is the primary purpose of a pressure regulator on a gas system?

Accepted Answer

To reduce and stabilize supply pressure to a safe, usable level

Answer

A pressure regulator reduces the higher distribution pressure to the lower, stable pressure required by appliances and maintains that pressure under varying flow conditions.

Question 5

CSST (corrugated stainless steel tubing) installations require bonding because:

Accepted Answer

Lightning or electrical surges can arc through it and cause failures

Answer

CSST must be bonded because lightning-induced electrical surges can arc through the thin corrugated walls, potentially causing pinhole leaks and gas fires.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Gas Piping Systems 4