306A Gas Piping Systems 2

Question 1

What compound or sealant is approved for use on threaded gas pipe joints?

Accepted Answer

Pipe joint compound or Teflon tape specifically rated for gas service

Answer

Standard plumber's putty

Answer

Regular Teflon tape (white)

Answer

Silicone caulking

Question 2

Why is corrugated stainless steel tubing (CSST) sometimes preferred over black steel pipe for gas installations?

Accepted Answer

It is flexible, faster to install, and requires fewer joints, reducing potential leak points

Answer

It is less expensive

Answer

It handles higher pressures

Answer

It is required by code for all new installations

Question 3

What special requirement applies to CSST gas tubing regarding electrical grounding?

Accepted Answer

CSST must be bonded to the building's electrical grounding system to protect against lightning-induced damage

Answer

No grounding is required

Answer

CSST must be insulated from all metal components

Answer

Only the fitting ends need grounding

Question 4

What is the purpose of a gas shut-off valve at each appliance?

Accepted Answer

To allow the gas supply to be individually isolated for each appliance for maintenance, repair, or emergency

Answer

To regulate the gas flow rate

Answer

To reduce gas pressure

Answer

To filter the gas supply

Question 5

What is the maximum allowable pressure drop in a residential gas piping system from the meter to the most remote appliance?

Accepted Answer

0.25 kPa (1 inch WC)

Answer

0.5 kPa (2 inches WC)

Answer

1.0 kPa (4 inches WC)

Answer

1.75 kPa (7 inches WC)

Question 6

What is the function of a gas pressure regulator?

Accepted Answer

To reduce and maintain a constant downstream gas pressure regardless of upstream pressure fluctuations or flow rate changes

Answer

To increase gas pressure for high-demand appliances

Answer

To measure gas consumption

Answer

To filter impurities from the gas