Fixtures, Fixture Fittings, and Water Heaters
Fixture Requirements and Clearances
Fixture questions test spacing, clearance, accessibility, and the water and drainage connections each fixture needs. Know the required clearances in front of and beside fixtures, the difference between a water closet compartment and a bathroom, and which fixtures must be accessible in public facilities. Traps include confusing minimum fixture counts with fixture spacing and forgetting that fixture substitutions must provide equivalent performance.
Traps, Tailpieces, and Connections
Every fixture except certain listed exceptions needs a trap, and each trap needs a vent. Know the trap seal depth and the maximum distance from a fixture outlet to its trap. Understand slip joints, tailpieces, and the requirement that a fixture drain connect to the drainage system through an approved trap.
Water Heaters
Water heater questions focus on relief valve discharge, seismic strapping, combustion air, and temperature control. The temperature-and-pressure relief valve discharge must terminate in a safe, visible location and must not be trapped or reduced in size. Know the difference between a temperature relief valve and a pressure relief valve, and why both functions are combined in one device on a tank.
Worked Example
A tank water heater installed in a garage must be elevated or protected from vehicle impact, and its relief discharge must run by gravity to a safe place of disposal. If the discharge pipe runs uphill, the installation fails regardless of valve quality.