10.4 Fixture Fittings, Faucets, & Accessories
Key Takeaways
- Faucets and fixture fittings must conform to ASME A112.18.1/CSA B125.1 and be installed per the manufacturer's instructions.
- Texas Board Rule 367.2(d) requires an antisiphon water closet fill valve with the critical level at least 1 inch above the flood level rim.
- A flushometer's vacuum breaker must be installed with its critical level not less than 6 inches above the flood level rim of the fixture served.
- Where a fixture has an overflow, the overflow waste must connect on the inlet side of the fixture trap.
- Slip joints are permitted only on the trap inlet, the trap outlet, and within the trap seal, and concealed slip joints require access.
10.4 Fixture Fittings, Faucets, & Accessories
Core Principle: The TSBPE review course lists two subjects under the plumbing fixtures chapter. The first is the fixtures themselves, covered in Sections 10.1 through 10.3. The second is "fixture fittings and accessories, such as p-traps, tailpieces, slip joint connections, flush valves and overflows in water closet tanks" — the trim. Trim is where the code meets the manufacturer's instruction sheet, and the review course is explicit that a Journeyman candidate must know the manufacturer's recommendations as well as the code text.
1. Standards for Faucets and Waste Fittings
| Component | Governing standard |
|---|---|
| Faucets and fixture fittings | ASME A112.18.1 / CSA B125.1 |
| Waste fittings (metallic tubular) | ASME A112.18.2 / CSA B125.2 |
| Plastic tubular waste fittings | ASTM F409 |
| Water closet fill valve (ballcock) | ASSE 1002 antisiphon |
| Flushometer valve | ASSE 1037 |
| Bath and shower valves | ASSE 1016 (see Section 8.3) |
| Dishwasher air gap fitting | ASSE 1021 |
| Hose connection vacuum breaker | ASSE 1011 |
| Wetted surfaces, lead content | Weighted average not more than 0.25 percent lead |
Every fitting must be listed and labeled and installed in accordance with the manufacturer's installation instructions. Where the instructions are more restrictive than the code, the instructions govern.
2. Supplies, Stops, and Risers
- Each fixture supply is provided with an accessible shutoff (stop) so the fixture can be isolated without shutting down the building.
- Individual fixture branch lines to lavatories, tank-type water closets, kitchen sinks, tubs, and clothes washers are a minimum of 1/2 inch nominal.
- 3/8-inch risers are permitted only for the short run from the stop to the faucet or fill valve.
- A flushometer water closet requires a 1-inch supply; a flushometer urinal requires 3/4 inch.
- Concealed supply connections must be accessible — behind an access panel, in a chase, or through a wall-hung carrier.
3. Tailpieces, Continuous Wastes, and Slip Joints
| Item | Rule |
|---|---|
| Lavatory tailpiece | Minimum 1-1/4 in |
| Sink / laundry tray tailpiece | Minimum 1-1/2 in |
| Tailpiece length | Governed by the 24-inch maximum vertical distance from fixture outlet to trap weir |
| Continuous waste | Used to join multi-compartment sink outlets to a single trap; end-outlet and center-outlet configurations are both acceptable when the trap remains centrally located |
| Slip joints | Permitted only on the trap inlet, the trap outlet, and within the trap seal — never on a concealed drain line, in a wall, or under a slab |
| Access | Where a slip joint is concealed (a tub waste and overflow, for example), an access panel or utility space at least the size of the fitting is required |
The slip-joint rule is one of the most commonly violated in remodeling. A tubular slip joint buried in a wall behind a wall-hung lavatory is a defect even if it is not leaking today.
4. Strainers and Waste Outlets
- Sinks, lavatories, and similar fixtures need a strainer or crossbar in the waste outlet, or an approved pop-up assembly.
- A shower drain requires a removable strainer not less than 3 inches in diameter, with an open area at least equal to the area of the drain it serves.
- Floor drain strainers must be removable for cleaning and, where the drain serves a food-handling area, of an approved sanitary pattern.
- Waste receptors for indirect wastes are strained and located where they are readily accessible for inspection and cleaning — never in a toilet room, closet, or inaccessible space.
5. Overflows
Where a fixture is provided with an overflow, three rules apply:
- The waste from the overflow must connect on the inlet (fixture) side of the fixture trap, so overflow water passes through the trap seal like any other waste.
- The overflow passage must be designed so that standing water in the fixture cannot rise in the overflow when the stopper is closed, and so that water cannot remain in the overflow passage after the fixture is emptied. Trapped water in an overflow becomes a stagnant, unvented reservoir.
- In a water closet tank, the overflow tube must be able to carry the full discharge of the fill valve if the valve fails to shut off, and the tank refill tube must discharge above the rim of the overflow tube — a refill tube pushed down inside the overflow is a cross-connection between the tank and the bowl.
6. Water Closet Fill Valves and Flush Valves — the Texas Rule
This is the one fixture-trim rule Texas writes into its own Board rules rather than leaving to the model code.
22 TAC 367.2(d): Water closet fill valves (ballcocks) shall be of the antisiphon, integral vacuum breaker type, with the critical level — the air inlet portion of the vacuum breaker — installed at least one (1) inch above the flood level rim of the fixture, which is the inlet of the water closet overflow tube.
The companion rule for commercial fixtures: a flushometer valve's vacuum breaker must be installed with its critical level not less than 6 inches above the flood level rim of the fixture served. That is why a flushometer's chrome vacuum breaker tube sits high above the bowl spud and why shortening it to fit a low ceiling is a violation.
Other flush-valve points:
- Flushometers must be sized and pressure-rated for the fixture; a siphon-jet closet generally needs about 20 psi residual flow pressure and a blowout closet about 25 psi.
- Manual and sensor-operated flushometers are both acceptable; sensor units still require the same vacuum breaker geometry.
- A flush tank must be fitted with an overflow, an approved fill valve, and a cover; tanks and bowls of two-piece closets must be joined with the manufacturer's gasket and hardware.
7. Appliance Connections at the Sink
| Appliance | Connection rule |
|---|---|
| Dishwasher | Protected against backflow by an air gap fitting (ASSE 1021) mounted on the counter or sink deck, or by an approved high loop where the code and the manufacturer permit; the discharge lands on a wye branch tailpiece or the disposer inlet ahead of the sink trap |
| Food waste grinder (domestic) | Discharges through a 1-1/2 inch waste to the sink trap; no separate trap is required |
| Food waste grinder (commercial) | Requires its own trap and vent and a cold water supply to the grinder |
| Clothes washer | Discharges by indirect waste into a 2-inch standpipe with its own trap; standpipe height and trap weir height are set by code (see Section 4.1) |
| Ice maker / refrigerator supply | Requires an accessible stop and, where it drains, an indirect waste with an air gap |
8. Setting the Fixture
- A water closet flange is secured to the structural floor with approved fasteners; the closet is set on an approved wax or elastomeric gasket and bolted with closet bolts, never caulked to the flange as the sole seal.
- Joints between fixtures and walls or floors are sealed watertight with an approved caulk or sealant.
- Wall-hung fixtures transfer load to a concealed structural carrier anchored to the floor (see Section 10.3), not to the wall board or partition studs.
- Fixtures must be set level and plumb, with all connections accessible for repair.
Under Texas Board rules, where must the critical level of a water closet fill valve be installed?
A lavatory has an integral overflow. Where must the overflow waste connect?
Where are slip joint connections permitted in a drainage installation?
What is the minimum installation height for the vacuum breaker on a commercial water closet flushometer valve?