Plumber Pipe Installation & Repair Flashcards

When transitioning from copper pipe to CPVC pipe, which fitting must be used to prevent a chemical reaction between the two materials?

Answer: A copper-to-CPVC transition fitting

Dedicated copper-to-CPVC transition fittings are required because CPVC solvent cement is incompatible with copper and direct connections can fail.

What is the maximum allowable temperature for CPVC hot water supply pipe according to most plumbing codes?

Answer: 180°F

CPVC is rated for continuous use up to 180°F, making it suitable for residential hot water supply lines.

A plumber is running PEX tubing through a wall cavity. Which tool is used to expand the PEX end before inserting an expansion fitting?

Answer: PEX expansion tool

A PEX expansion tool (used with expansion fittings) enlarges the pipe end so it can be pushed over the fitting and then contracts to form a leak-tight seal.

Under the IPC, what is the minimum pipe size for a water service line supplying a single-family residence?

Answer: 3/4 inch

The IPC requires a minimum 3/4-inch water service pipe for a single-family dwelling to ensure adequate flow and pressure.

What condition causes PVC pipe to expand and potentially crack if installed without expansion loops or offsets in long horizontal runs?

Answer: Thermal expansion

PVC has a high coefficient of thermal expansion, so long runs must include offsets or expansion loops to absorb movement and prevent cracking.

Which threading standard is used for most plumbing pipe threads in the United States?

Answer: NPT (National Pipe Taper)

NPT (National Pipe Taper) is the standard tapered thread form used on pipe and fittings throughout US plumbing systems.

When pressure testing a newly installed potable water system, what is the standard test pressure and duration specified by most plumbing codes?

Answer: 100 psi for 15 minutes

Most plumbing codes require a hydrostatic test at 100 psi held for a minimum of 15 minutes without pressure loss.