Fixtures, Fixture Fittings, and Water Heaters
Fixtures and clearance
A water closet needs about 15 in from centerline to a side wall and 30 in of clear width, with working space in front. Accessible fixtures follow ICC A117.1: clear floor space, insulated or protected supply and drain pipes under lavatories, and lever handles. Fixture flow rates trace to the 1992 Energy Policy Act: 1.6 gpf water closets, 1.0 gpf urinals, 2.5 gpm showerheads at 80 psi, and 2.2 gpm lavatory and kitchen faucets. Check District amendments for stricter numbers.
Water heaters
- A temperature and pressure relief valve is required, set to open at 210 F or 150 psi, installed in the manufacturer-designated port, with no valve or plug between the tank and the valve.
- The discharge pipe must match the valve outlet size, drain by gravity, terminate not more than 6 in above the floor or a waste receptor, and must not be threaded, capped, trapped, or reduced.
- A pan with a drain is required where leakage would cause damage; the pan drain runs to an indirect waste.
- Gas heaters need combustion air and venting per the fuel gas code; electric heaters need a disconnecting means.
- A closed system needs an expansion tank; a check valve or PRV on the supply creates that closed system.
Worked example
An inspector rejects a T&P discharge running 20 ft across a basement and ending 3 ft above a floor drain with a threaded cap on the end. Three defects, one fix: the termination is too high (6 in maximum above the receptor), the pipe is capped or threaded (prohibited because it invites plugging), and the long horizontal run traps water. Re-pipe with a short, continuously falling run to within 6 in of the drain.
Traps that cost marks
Capping or plugging the T&P; installing a shutoff between tank and valve; discharging the T&P directly into the drainage system instead of indirectly; and sizing a pan drain too small to carry a tank failure.