Journeyman Plumber ExamWater Supply SystemsEasy
A plumber is installing a water distribution system in a new commercial office building. The system requires a reduced pressure zone (RPZ) backflow preventer. Which of the following is an essential requirement for the installation location of an RPZ assembly?
- AIt must be installed in a horizontal position to ensure proper drainage.
- BIt must be readily accessible for testing and maintenance.
- CIt must be installed upstream of any shutoff valve.
- DIt must be protected from freezing, but not necessarily from flooding.
Show answer & explanationAnswer & explanation
Correct answer: B. It must be readily accessible for testing and maintenance.
All backflow prevention assemblies, especially RPZs which require annual testing, must be installed in a location that is readily accessible for inspection, testing, and maintenance. This is a fundamental code requirement to ensure their continued functionality.
Why the other options are wrong
- A. While many RPZs can be installed horizontally, some models allow vertical installation. 'Must be horizontal' is not a universal requirement.
- C. The RPZ is installed downstream of the main shutoff valve for the system it protects, not upstream, as it needs to protect the potable water supply from the building's system.
- D. RPZs must be protected from both freezing and flooding, as water discharge from the relief valve must be able to drain freely.
RPZ Installation Requirements
Proper installation of an RPZ backflow preventer is critical for its function and compliance, including specific requirements for orientation, location, and protection.
- Must be accessible for testing and maintenance.
- Must be protected from freezing and flooding.
- Discharge port must have adequate air gap/drainage.
Memory trick: RPZ Readiness Requires Reach-ability.