Journeyman Plumber ExamWater Supply SystemsMedium
A plumber is installing a water distribution system in a new home. The local code permits the use of PEX-A, PEX-B, and PEX-C tubing. Which type of PEX is typically manufactured using the Engel method (peroxide method) and is known for its highest degree of cross-linking and superior flexibility, even at low temperatures?
- APEX-A
- BPEX-C
- CPEX-B
- DPEX-D
Show answer & explanationAnswer & explanation
Correct answer: A. PEX-A
PEX-A is manufactured using the Engel method (peroxide method), which results in the highest degree of cross-linking among the PEX types. This gives PEX-A superior flexibility, especially at low temperatures, and allows for expansion-type fittings.
Why the other options are wrong
- B. PEX-C (electron beam method) has a lower degree of cross-linking and can be stiffer than PEX-A, also typically used with crimp or clamp fittings.
- C. PEX-B (silane method) has a lower degree of cross-linking and is less flexible than PEX-A, often used with crimp or clamp fittings.
- D. PEX-D is not a recognized standard type of PEX tubing for plumbing applications.
PEX-A Characteristics
A type of cross-linked polyethylene (PEX) tubing manufactured using the Engel method, known for its high flexibility, memory, and ability to be expanded for fittings.
- Engel method (peroxide)
- Highest degree of cross-linking
- Superior flexibility, even in cold
- Allows for expansion fittings
- Has 'shape memory'
Memory trick: PEX-A for 'Awesome' flexibility and 'Engel' method's spell!