Red Seal Plumbing Practice Exam

Which best describes a dual check valve backflow preventer?

1. For industrial applications

2. For public water systems

3. Used when a hazard is minor in a residential application

4. Used for major hazards only

The correct answer is: Used when a hazard is minor in a residential application

A dual check valve backflow preventer is a mechanical device that ensures the flow of water in a piping system only goes in one direction, preventing any backflow and contamination of the water supply. The key feature of a dual check valve backflow preventer is that it has two independently acting check valves, providing an extra layer of protection compared to a single check valve backflow preventer. Option A, "For industrial applications", is incorrect because a dual check valve backflow preventer can be used in a variety of settings, including residential and commercial applications. Option B, "For public water systems", is incorrect because a dual check valve backflow preventer can be used in both public and private water systems. Option D, "Used for major hazards only", is incorrect because a dual check valve backflow preventer is effective at preventing backflow, regardless of the severity of the hazard