Sanitary Fixtures
Domain 9 tests fixture types, fixing heights, trap and water-seal requirements, venting, and the connection of fixtures into the drainage system.
Fixtures and traps
- Water closet (EWC or IWC), wash basin, kitchen sink, urinal, bidet, bathtub and floor trap.
- Every fixture needs a trap with a water seal of at least 50 mm; wet areas take a floor trap or gully trap.
- Use P-traps with a cleaning access; avoid S-traps, which siphon their own seal.
- Vitreous china per IS 2556; fix with brackets and silicone, not grout alone.
Heights and connections
- Wash basin about 800 mm and kitchen sink about 900 mm above finished floor; set the WC pan level and seal it to the floor.
- Branch to the stack with a fall, and vent the branch to protect the trap seal.
- Keep access panels for concealed traps and cisterns.
Worked example
A wash basin smells and gurgles when the WC is flushed. Reasoning: gurgling means the trap seal is being siphoned because the branch is unvented or the stack is partly blocked, and the smell follows the empty trap. Clear the stack first, then fit an anti-siphon valve or re-vent the basin trap rather than simply refilling the trap each day.
Traps
No trap or a dry trap; double trapping; sealing a trap with grout so it cannot be cleaned; bedding a WC pan on dry mortar without a seal.