Massachusetts Plumbers Journeyman Practice Exam

What is the vertical distance between the crown weir and the top of the dip of the trap in plumbing systems?

1. Air Gap (Drainage System)

2. Fixture Unit

3. Liquid Waste

4. Trap Seal

The correct answer is: Trap Seal

The vertical distance between the crown weir and the top of the dip of the trap in plumbing systems is referred to as trap seal. Trap seals are crucial because they prevent sewer gases from entering living spaces and maintain a barrier of water within the trap. This water effectively seals the trap, allowing it to fulfill its function without permitting unpleasant odors to escape into the environment. While the other options relate to plumbing systems, they do not describe this specific measurement. For example, an air gap pertains to the vertical separation between a water supply outlet and the maximum flood level of a fixture, ensuring no backflow occurs. Fixture units represent a measure of the probable demand and loading on a plumbing system based on the number and type of fixtures. Liquid waste refers to wastewater generated from various household activities, which does not directly pertain to the specific distance between parts of a trap. Therefore, trap seal is indeed the correct term for the defined vertical distance in this context.