CBI Plumbing & Mechanical Inspection

Question 1

What is the purpose of a plumbing trap?

Accepted Answer

To hold water that creates a seal preventing sewer gases from entering the building through drain openings

Answer

To catch dropped items like jewelry

Answer

To filter debris from wastewater

Answer

To increase water pressure

Question 2

What is the minimum slope required for horizontal drain pipes?

Accepted Answer

1/4 inch per foot for pipes 3 inches or smaller; 1/8 inch per foot for pipes larger than 3 inches

Answer

Level (no slope required)

Answer

1 inch per foot for all pipes

Answer

2 inches per foot for all pipes

Question 3

What is a plumbing vent and why is it necessary?

Accepted Answer

A pipe extending to the roof that allows air into the drainage system to maintain proper flow and prevent siphoning of traps

Answer

A ventilation fan in the bathroom

Answer

An air conditioning duct

Answer

A window in the bathroom

Question 4

What should an inspector verify during an HVAC rough-in inspection?

Accepted Answer

Correct ductwork sizing, proper support, sealed connections, refrigerant line insulation, and compliance with mechanical code

Answer

Only the thermostat location

Answer

Whether the HVAC brand is approved

Answer

Only the exterior condenser placement

Question 5

What is the purpose of a water heater temperature and pressure (T&P) relief valve?

Accepted Answer

To release water and pressure if the tank overheats or becomes over-pressurized, preventing a tank explosion

Answer

To regulate the temperature of hot water at faucets

Answer

To test water quality

Answer

To drain the tank for maintenance

Question 6

Where must a water heater T&P relief valve discharge line terminate?

Accepted Answer

To the exterior of the building or to an approved indirect waste receptor, within 6 inches of the floor

Answer

Into the drain system

Answer

Back into the water heater

Answer

Into the attic space