G3 Leak Detection and Testing Procedures

Question 1

Which leak detection method is most commonly used for a quick field check of gas piping joints?

Accepted Answer

Soap bubble solution applied to joints

Answer

Soap bubble solution is the standard field method for locating gas leaks at joints and fittings, as bubbles form visibly where gas escapes.

Question 2

Before applying pressure for a leak test on a new gas piping installation, what must a technician ensure?

Accepted Answer

All open ends are capped and appliance connections are isolated

Answer

All open ends must be capped and appliance connections isolated to contain the test pressure and obtain accurate results.

Question 3

What is the minimum test pressure typically required for a pressure integrity test on a residential gas piping system according to most North American codes?

Accepted Answer

10 psi

Answer

Most codes require a minimum of 10 psi (or 1.5 times the maximum allowable operating pressure, whichever is greater) for pressure integrity tests on residential systems.

Question 4

When performing a pressure drop test, a technician notices a pressure drop of 0.5 in. W.C. over 10 minutes. What does this indicate?

Accepted Answer

A leak is present in the system

Answer

Any measurable pressure drop during a pressure drop test indicates a leak is present in the system, as a tight system should hold pressure.

Question 5

Which gas has the lowest explosive limit (LEL) making leak detection especially critical?

Accepted Answer

Propane

Answer

Propane has a lower LEL (2.1%) compared to natural gas (5%), meaning smaller concentrations of propane in air can create an explosive mixture.

G3 - Gas Technician Level 3 Certification Practice Test

G3 - Gas Technician Level 3 Certification Practice Test

G3 Leak Detection and Testing Procedures