Journeyman Plumbers Plumbing Fixtures and Appliances Questions and Answers

Question 1

A plumber is installing a gas-fired water heater with a bottom ignition source in a residential garage. According to most plumbing codes, what is the minimum required elevation of the ignition source above the garage floor?

Accepted Answer

18 inches

Answer

To prevent the ignition of flammable vapors (such as gasoline or solvent fumes) that are heavier than air and can accumulate near the floor, plumbing and mechanical codes require the ignition source of fuel-fired appliances to be elevated. The standard minimum height is 18 inches above the floor in locations like a garage.

Question 2

Which of the following is a code-compliant method for connecting a domestic dishwasher's drainage hose to the sanitary drainage system to prevent backflow?

Accepted Answer

An approved air gap fitting installed on the countertop.

Answer

Most plumbing codes mandate that a domestic dishwasher must discharge through an approved air gap fitting to prevent contaminated water from the sink or drainage system from siphoning back into the dishwasher. The air gap provides a physical separation, making it a reliable backflow prevention method. While some jurisdictions may allow a high loop as an alternative, the air gap is the specifically listed and most protective device.

Question 3

A journeyman plumber is installing fixtures in an ADA-compliant public restroom. What is the required height range for the toilet seat above the finished floor?

Accepted Answer

17 to 19 inches

Answer

The Americans with Disabilities Act (ADA) standards require that the top of the toilet seat in an accessible restroom be between 17 and 19 inches above the finished floor. This height makes it easier for individuals with mobility impairments, particularly those transferring from a wheelchair, to use the fixture.

Question 4

A Temperature and Pressure (T&P) relief valve on a water heater must have its temperature-sensing element installed in a specific location to function correctly. Where must this element be located?

Accepted Answer

Within the top 6 inches of the tank.

Answer

The T&P valve's temperature-sensing element must be immersed in the hottest water of the tank to provide accurate protection against excessive temperatures. The hottest water is always in the top 6 inches of a storage-type water heater. Installing it elsewhere could create a thermal lag, delaying its activation and creating a safety hazard.

Question 5

In a commercial building, a floor drain is located in a mechanical room that is rarely used, making the trap seal subject to evaporation. Which device is required to maintain the trap seal?

Accepted Answer

A trap primer

Answer

A trap primer is a device that automatically supplies a small amount of water to a trap that is subject to losing its seal through evaporation, such as an infrequently used floor drain. This maintains the water seal, which is necessary to prevent sewer gases from entering the building.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Plumbing Fixtures and Appliances Questions and Answers