G3 Piping and Tubing Systems 3

Question 1

How is residential gas piping sized?

Accepted Answer

Using pipe sizing tables based on BTU load, length, and allowable pressure drop

Answer

Piping is sized using code tables considering demand, length, and pressure drop.

Question 2

What is the difference between black iron and galvanized pipe for gas?

Accepted Answer

Black iron is approved; galvanized is not used due to flaking

Answer

Black iron is standard for gas. Galvanized zinc coating can flake and clog components.

Question 3

What is the maximum allowable pressure drop in residential gas piping?

Accepted Answer

0.5 inches water column

Answer

Maximum is 0.5 inches WC from meter outlet to furthest appliance.

Question 4

How should gas piping penetrations through walls be handled?

Accepted Answer

Pipe must be sleeved with an approved protective sleeve

Answer

CSA B149 requires protective sleeves at wall, floor, and ceiling penetrations.

Question 5

What is the purpose of an appliance shutoff valve?

Accepted Answer

To allow gas isolation for servicing or emergency shutdown of individual appliances

Answer

It allows individual appliance gas supply to be turned off without affecting others.

G3 - Gas Technician Level 3 Certification Practice Test