What plumbing does an emergency eyewash station need?

OSHA's rule is short. Under 29 CFR 1910.151(c), "Where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body shall be provided within the work area for immediate emergency use." Whether a product counts depends on its hazards, so the safety data sheet is the place to start.

That rule doesn't say how much water or how warm. For that, OSHA points employers to ANSI. In a 2002 letter, OSHA wrote that "ANSI Z358.1 was not adopted by OSHA," but that it "has often referred employers to ANSI Z358.1 as a source of guidance for protecting employees who may be exposed to injurious corrosive materials." The same letter puts the temperature call on the employer: "it is the employer's responsibility to assess the particular conditions related to the eyewash/shower unit, such as water temperature, to ensure that the eyewash/shower unit provides suitable protection against caustic chemicals/materials to which employees may be exposed."

The plumbing code closes the loop. The Phoenix version of IPC Section 411.1 says "Emergency showers and eyewash stations shall conform to ISEA Z358.1." So in Phoenix, the ANSI numbers are also part of the plumbing code.

### The ANSI numbers the plumbing has to meet

Manufacturers publish summaries of the 2014 edition of the standard. Here are the figures that drive the pipe and valve choices, as Bradley and Guardian report them:

Bradley quotes the standard's definition of tepid as "A flushing fluid temperature conducive to promoting a minimum 15-minute irrigation period." The same definition gives 60 to 100 F as a suitable range. Bradley's guide says why the range matters: "At 60 degrees Fahrenheit and below hypothermia becomes a concern," and hotter water "may cause chemical interactions with the skin and result in further damage."

Flow and pressure. Size the branch so the eyewash still gets its flow when everything on that line runs. Guardian's summary says to "Connect unit to water supply capable of delivering required flow when all components are operated simultaneously." That matters most for a combination shower and eyewash, where the shower alone needs 20 GPM. A small line that's fine for a lone eyewash may not carry a shower's flow.

Tepid water. Cold water alone can work for an indoor eyewash if the line stays in the tepid range. Where a site adds hot water, the IPC is specific. Section 411.3 says "Where hot and cold water is supplied to an emergency shower or eyewash station, the temperature of the water supply shall only be controlled by a temperature-actuated mixing valve complying with ASSE 1071." It adds that where a water heater feeds the unit directly, "the water heater shall comply with ASSE 1085." Check that the valve you buy is listed to ASSE 1071.

The Phoenix problem is heat, not cold. Most guidance worries about freezing. In the Valley, the risk is a supply line that runs through a hot roof, an exterior wall or an outdoor pedestal and delivers water far above 100 F in summer. OSHA addressed this in a 1994 letter: "an installation that would be hazardous to an employee due to elevated water temperatures would constitute a violation of the OSHA standard at 1910.151(c)." For outdoor units, Bradley's checklist says to "Evaluate if the user should be protected against scalding water." Options include routing the line through conditioned space, a thermostatic valve that blends in cooler water, or a scald protection valve that bleeds off hot water. Test the temperature in July, not January.

### Backflow protection

An eyewash sits on the drinking water system, so it has to be protected from backflow like any other fixture. On a fixed bowl unit, the spray heads sit above the bowl. The risk goes up with a hand-held unit on a hose, which can end up in a sink or a bucket of chemical. Mesa's code, for example, lists "Eyewash/Emergency Shower on Flexible Hose" with acceptable protection of "AG, PVB, RPA, SVB." Check your own city's list, and treat the building's main backflow assembly as a separate question. Our page on what a cross-connection is covers the risk in general terms.

The IPC doesn't force a drain. Section 411.2 says "Waste connections shall not be required for emergency showers and eyewash stations." In practice, a missing drain doesn't stop you from installing an eyewash.

Water still comes out, though, every week during testing and for 15 minutes in a real emergency. At 0.4 GPM, a full eyewash flush is about 6 gallons. A drench shower at 20 GPM puts out about 300 gallons in 15 minutes, a figure Bradley also gives. Plan for it:

• Eyewash with a bowl. Most wall and pedestal eyewashes come with a bowl and outlet. If you connect it to the drain, it needs a trap like any fixture, and a trap that only sees weekly water can lose its seal if it sits dry.
• Emergency floor drain. The IPC fixture table lists an "Emergency floor drain" at 0 drainage fixture units with a 2 inch trap. Its trap still needs protection from drying out. See whether commercial floor drains need a trap primer.
• No drain. Use a bucket or a test kit for weekly flushes, and keep the floor near the unit free of anything that water could damage. Bradley's checklist notes that water bled off by freeze or scald valves "may be a slip hazard" and should be routed away.

Keep in mind that water from a real emergency may carry the chemical that caused it. If the area drains to a floor drain, make sure that drain goes somewhere your wastewater permit allows.

Weekly activation keeps the water fresh and proves the unit works. Bradley says plumbed eyewashes "should be activated on a weekly basis long enough to be sure flushing fluid is provided," and its checklist notes that "Activation clears sediment in the supply line." Guardian lists the same weekly step and adds an annual inspection against the standard.

A good weekly check takes a minute or two:

1. 1Remove the dust covers and open the valve. It should open in a second and stay on by itself.
2. 2Look at the stream height and pattern, and let it run until the water runs clear.
3. 3Check the temperature with a thermometer, especially in summer.
4. 4Look for leaks at the supply, valve and bowl.
5. 5Write the date on the tag or log.

If the flow is weak, check for a partly closed supply stop, a clogged strainer or flow control, or mineral scale in the nozzles. If the water runs hot, the mixing valve or the supply route is the first suspect.

Auto shop with a battery charging station. A wall eyewash near the charger, cold water only, indoors. Check that the supply line doesn't run through the hot roof space.

Pool supply or chemical storage room. Often a combination shower and eyewash. Needs a larger supply for the 20 GPM shower, a mixing valve if hot water is added, and a floor drain plan.

Outdoor chemical dock. The hardest case in Phoenix. Expect to need scald protection or a thermostatic unit, since water sitting in an exposed line can get far hotter than 100 F.

Salon or small lab using a faucet-mounted eyewash. A faucet-mounted unit can serve as the eyewash only if it meets every requirement in the table above, not just flow and temperature. That means the flow and tepid water, a valve that opens in one second or less and stays open hands free, a spot within 10 seconds of the hazard, and weekly activation. If it falls short on any of those, treat it as a supplement and put in a compliant plumbed station.

HQ Plumbing & Air runs water lines, installs mixing valves, drains and fixtures for commercial sites, and offers free estimates and upfront pricing.