Plumbing Gas Piping Systems 2

Question 1

When sizing a natural gas pipe, which of the following factors is NOT used in the calculation?

Accepted Answer

Color of the pipe material

Answer

Gas pipe sizing is based on BTU demand, pipe length, and allowable pressure drop — pipe color has no engineering significance in sizing calculations.

Question 2

What unit is commonly used to measure low natural gas operating pressure in residential systems?

Accepted Answer

Inches of water column (in. WC)

Answer

Inches of water column (in. WC) is the standard unit for low residential gas pressures, where 27.7 in. WC equals 1 psi.

Question 3

Which type of fitting is NOT permitted for concealed gas piping inside a building?

Accepted Answer

Compression fitting

Answer

Compression fittings are not approved for concealed gas piping because they are mechanical connections that can loosen over time and are not reliably gas-tight.

Question 4

What material is PROHIBITED for use as interior gas piping inside a residential building?

Accepted Answer

PVC or CPVC plastic pipe

Answer

PVC and CPVC plastic pipes are not approved for interior gas service because they cannot withstand gas permeation, heat, and physical damage requirements.

Question 5

Where must a manual gas shutoff valve be installed for a new gas appliance?

Accepted Answer

Within 6 feet of the appliance in the same room, in an accessible location

Answer

Code requires an accessible manual shutoff valve within 6 feet of each gas appliance in the same room so it can be quickly reached in an emergency.

Plumbing Practice Test

Plumbing Practice Test

Plumbing Gas Piping Systems 2