3.3 Water Conservation, Temperature-Limiting Devices, Flushing Devices & Emergency Fixtures
Key Takeaways
Table 604.4 maximums: water closets 1.6 gallons per flush, urinals 1.0 gallon per flush, showerheads 2.5 gpm at 80 psi, private lavatories 2.2 gpm, and public non-metering lavatories 0.5 gpm at 60 psi.
Individual shower and tub-shower valves must be balanced-pressure, thermostatic or combination valves (ASSE 1016 or ASME A112.18.1), with a limit stop field-adjusted to 120°F (IPC 412.3).
Bidet water is limited to 110°F by an ASSE 1070 device (IPC 408.3); public hand-washing lavatories deliver tempered water through an ASSE 1070 device (IPC 419.5).
Bathtub and whirlpool valves are limited to 120°F by an ASSE 1070 device or an ASSE 1082/1084 water heater, unless a combination tub/shower valve is used (IPC 412.5).
Emergency showers and eyewash stations meet ISEA Z358.1, and where hot and cold water are supplied, the temperature may be controlled only by an ASSE 1071 mixing valve (IPC 411).
Maximum flow rates (IPC 604.4 and Table 604.4)
| Fixture or fitting | Maximum flow or quantity |
|---|---|
| Lavatory, private | 2.2 gpm at 60 psi |
| Lavatory, public (metering) | 0.25 gallon per metering cycle |
| Lavatory, public (other than metering) | 0.5 gpm at 60 psi |
| Shower head (a hand-held shower spray counts as a shower head) | 2.5 gpm at 80 psi |
| Sink faucet | 2.2 gpm at 60 psi |
| Urinal | 1.0 gallon per flushing cycle |
| Water closet | 1.6 gallons per flushing cycle |
Exceptions (604.4): blowout-design water closets using no more than 3-1/2 gallons per flush; vegetable sprays; clinical sinks using no more than 4-1/2 gallons per flush; service sinks; and emergency showers.
Lower-flow products such as 1.28-gallon water closets or 1.5-gpm lavatory faucets are allowed, since the table sets maximums. The table itself does not list lower values. Table 604.3 is a different table: it gives the minimum flow and pressure the distribution system must deliver to each outlet (see Section 8.2).
Why temperature limits exist
Scald injury depends on temperature and contact time. Burn research commonly cited by the plumbing industry shows that water around 140°F can cause a serious burn in seconds, while 120°F water takes several minutes of contact. Water heaters often store water hotter than is safe at the outlet. The code therefore requires a limiting device at, or serving, the fixture for showers, tubs, bidets, public lavatories and similar fixtures.
Temperature limits by fixture
| Fixture | Code section | Maximum | Device |
|---|---|---|---|
| Individual shower and tub-shower | 412.3 | 120°F (limit stop field-adjusted to manufacturer instructions) | Balanced-pressure, thermostatic or combination valve meeting ASSE 1016/ASME A112.1016/CSA B125.16 or ASME A112.18.1/CSA B125.1, installed at the point of use |
| Multiple (gang) showers on one tempered supply | 412.4 | 120°F | ASSE 1069 or CSA B125.3 automatic temperature control valve, or individual ASSE 1016 valves at each head |
| Bathtub and whirlpool bathtub | 412.5 | 120°F | ASSE 1070 limiting device, or an ASSE 1082 or 1084 water heater, unless a combination tub/shower valve under 412.3 is used |
| Bidet | 408.3 | 110°F | ASSE 1070 |
| Public hand-washing lavatories and group wash fixtures | 419.5 | Tempered water (85°F to 110°F) | ASSE 1070 |
| Head shampoo sinks | 412.10 | 120°F | ASSE 1070, an ASSE 1082 water heater, or an ASSE 1062 device; integral check valves required |
| Footbaths and pedicure baths | 423.3 | 120°F | ASSE 1070 or an ASSE 1082 water heater |
| Emergency shower or eyewash with hot and cold supply | 411.3 | Tepid (Z358.1) | Controlled only by an ASSE 1071 mixing valve; a water heater supplying the station directly must meet ASSE 1085 |
"Tempered water" is defined in IPC Chapter 2 as water between 85°F and 110°F. Under 607.1.2, tempered water is controlled by an ASSE 1070 device set no higher than 110°F, an ASSE 1017 thermostatic mixing valve, or an ASSE 1082 or ASSE 1084 water heater. Neither option replaces the protective shower valves required by 412.3.
Related rules:
- 613.1: temperature-actuated mixing valves installed to reduce water temperatures to defined limits must meet ASSE 1017. These are typically source (master) mixing valves.
- 607.1.1: a water heater thermostat may serve as the temperature-limiting means only if the water heater complies with ASSE 1082 or ASSE 1085.
- 412.7: ASSE 1062 temperature-actuated, flow-reduction devices may limit an individual fitting to 120°F, but they cannot replace the shower valves of 412.3 or the bathtub limiting devices of 412.5.
- 604.11: ASSE 1066 in-line pressure-balancing valves for individual fittings also cannot replace 412.3 shower valves.
- 501.6: water from tankless water heaters for domestic use must not exceed 140°F.
Comparing the ASSE standards
| Standard | What it is | Where it goes |
|---|---|---|
| ASSE 1016 | Individual shower/tub-shower valve (balanced-pressure, thermostatic or combination) | Point of use, in the shower valve |
| ASSE 1017 | Temperature-actuated mixing valve for a hot water distribution system | At the source or on a branch |
| ASSE 1069 | Automatic temperature control mixing valve | Gang showers |
| ASSE 1070 | Water temperature limiting device | Point of use: tubs, bidets, public lavatories, shampoo sinks, pedicure baths |
| ASSE 1071 | Temperature-actuated mixing valve for plumbed emergency equipment | Emergency showers and eyewash stations |
An ASSE 1017 master valve at the water heater does not satisfy 412.3. Every individual shower still needs its own point-of-use ASSE 1016 (or ASME A112.18.1) valve. A balanced-pressure valve reacts to pressure changes in the supply lines; a thermostatic valve reacts to outlet temperature.
Flushing devices (IPC 415)
- 415.1: water closets, urinals, clinical sinks and other fixtures that depend on trap siphonage need a flushometer valve, flushometer tank or flush tank. 415.1.1: one flushing device may not serve more than one fixture.
- 415.2: flushometer valves and tanks meet ASSE 1037. Their vacuum breakers meet ASSE 1001 and must be accessible. Flushometer valves must be the water-conservation type, must complete their cycle automatically, and need a way to regulate flow. They must not be used where the water pressure is below the minimum required for normal operation.
- 415.3.1: flush tanks need an antisiphon fill valve meeting ASSE 1002, with the fill valve backflow preventer at least 1 inch above the full opening of the overflow pipe.
- 415.3.2: the flush tank overflow discharges to the water closet or urinal and is sized to prevent flooding at the maximum supply rate.
- 415.4: flush pipes and fittings must be nonferrous.
Emergency showers and eyewash stations (IPC 411; ISEA Z358.1)
- 411.1: they must conform to ISEA Z358.1.
- 411.2: a waste connection is not required.
- 411.3: where hot and cold water are supplied, the temperature is controlled only by an ASSE 1071 temperature-actuated mixing valve. A water heater that supplies the station directly must meet ASSE 1085.
- ISEA Z358.1 requires tepid water, defined as 60°F to 100°F, for a 15-minute flushing period. Its minimum flow rates are 20 gpm for a plumbed drench shower, 0.4 gpm for an eyewash, and 3.0 gpm for an eye/face wash. The IPC exempts emergency showers from the Table 604.4 flow limits.
Other fixture rules
- 416.1: a food waste disposer must not increase the drainage fixture unit load. 416.4: disposers need a water supply.
- 417: garbage can washers need protected water supply and a trapped waste with a removable basket.
- 418: laundry trays need a waste outlet of at least 1-1/2 inches with a strainer or crossbar.
Under IPC 408.3, what is the maximum discharge temperature for a bidet, and what device standard limits it?
120°F; ASSE 1016
105°F; ASSE 1017
115°F; ASSE 1071
110°F; ASSE 1070
What is the maximum flow rate in IPC Table 604.4 for a public lavatory faucet that is not the metering type?
2.2 gpm at 60 psi
0.5 gpm at 60 psi
0.25 gallon per cycle
1.5 gpm at 60 psi
A hospital laboratory has an emergency eyewash station supplied with both hot and cold water. Under IPC 411.3, how must the water temperature be controlled?
Only by an ASSE 1071 temperature-actuated mixing valve
By an ASSE 1070 limiting device set no higher than 110°F
By the water heater thermostat set no higher than 100°F
By an ASSE 1016 balanced-pressure valve like those used for showers
Sections you finish are checked off in the contents.