Florida Home Inspector Practice Test

If a plumbing vent extends too far above the roof line, what is the primary risk involved?

1. Water Pollution

2. Frost Closure

3. Reduced Pressure

4. Ventilation Failure

The correct answer is: Frost Closure

When a plumbing vent extends too far above the roof line, frost closure becomes a primary concern. Plumbing vents are designed to release gases and allow air into the plumbing system, which helps prevent negative pressure that can cause drainage issues. If a vent pipe is situated excessively high, it may be exposed to lower temperatures, especially in colder climates, leading to frost accumulation inside the vent. This frost can block the vent, resulting in a failure to equalize pressure within the system. When frost closure occurs, the flow of air becomes restricted, which can hinder the system's ability to function properly. Without adequate venting, negative pressure can build up, leading to siphoning of traps and allowing sewer gases to enter living spaces. Therefore, maintaining the appropriate height for plumbing vents is crucial for ensuring proper ventilation and system integrity.