Emergency showers and eyewash stations provide on-the-spot decontamination. They allow workers to flush away hazardous substances that can cause injury. Even with the best engineering and safety precautions, accidental chemical exposures still occur. As a result, it is essential to look beyond the use of goggles, face shields and procedures. Emergency showers and eyewash stations are a necessary backup to minimize the effects of accidental exposure to chemicals.
The American National Standard for Emergency Eyewash and Shower Equipment (ANSI Z358.1-2014) helps protect workers in the U.S. (as well as around the world) from eye injuries due to caustic and/or corrosive substances. This standard establishes minimum performance and use requirements for eyewash and shower equipment for the emergency treatment of the eyes or body of a person who has been exposed to hazardous materials. It covers emergency showers, eyewashes, eye/face washes and combination units. The standard includes performance and use requirements for personal wash units and drench hoses, which are considered supplemental to emergency eyewash and shower equipment.
OSHA’s regulations on this issue came before the ANSI standard; they also concern the use of emergency eyewash and shower stations. The primary regulation dealing with eyewash and shower stations can be found in 29 CFR 1910.151. It states:
“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.”
OSHA’s regulations say that a corrosive chemical is one that “destroys or irreversibly changes the structure of human tissue at the site of contact after exposure for a specified period of time.” In workplaces where corrosive chemicals are handled, OSHA requires “facilities for drenching or flushing the eyes be provided in the work area for immediate emergency use.”
Because OSHA does not define “suitable facilities” in its primary regulation, this was difficult for both employers and safety specialists to interpret properly. In 1981, the American National Standards Institute adopted the ANSI Z358.1 eyewash and shower equipment standard. The standard has since been revised in 1990, 1998, 2004 and 2009.
This standard provides various eyewash guidelines, including the proper design of eyewash stations and showers; certification and testing procedures; performance and usage guides; the maintenance of flushing equipment; and employee training.
Under the ANSI guidelines, there are three main types of emergency eyewash & shower stations. They are:
- Eyewash stations for splashes or spills where only the eyes are likely affected—this requires flushing of 0.4 gallons per minute at 30 PSI for 15 minutes.
- Eye/face wash equipment for splashes or spills where the eyes and face are affected—this requires flushing of 3.0 gallons per minute at 30 PSI for 15 minutes.
- Emergency showers for splashes or spills that affect the larger areas of the body—this requires flushing of 20 gallons per minute at 30 PSI for 15 minutes.
Types of Eyewash Stations
The ANSI Z 358.1 standard accepts two different kinds of eyewash stations: plumbed, permanent eyewash stations; and self-contained, gravity-fed portable shower and eyewash stations. Plumbed stations are permanently connected to a source of potable (tap) water, whereas portable stations are self-contained, gravity-fed units with their own flushing fluid (this must be replaced after each use). Because a portable eyewash station does not require plumbing, it delivers flushing fluid via tap water treated with bacteriostatic solution or via a sealed cartridge with a contaminant-free purified or sterile solution.
Several of the ANSI requirements for plumbed or portable eyewash stations are the same, such as:
- Required flushing of 0.4 gallons per minute (GPM) at 30 PSI for a full 15 minutes.
- Hands-free stay-open valve should activate in one second or less.
- The heads of the units (water flow pattern) must be positioned 33-53in from the surface on which the user stands and 6in minimum from the wall.
- Eyewash fluid must irrigate and flush both eyes simultaneously.
Portable eyewash stations are less expensive than plumbed units, which require the added expense of water lines. Portable stations have a few other advantages over plumbed units, as well. For one, their portability and compact size make the units easier to move and place within hazardous areas. This makes them more practical for use in the field.
Portable eyewash stations also offer flexibility to use in remodeled workspaces. Moreover, they can be mounted in smaller spaces and require less maintenance than plumbed stations.
ANSI Z358.1 requires that plumbed flushing stations “be activated weekly for a period long enough to verify operation and ensure that flushing fluid is available.” Portable equipment must “be visually checked to determine if flushing fluid needs to be changed or supplemented.” Whether plumbed or portable, both types also need to be tested annually and maintained properly.
Both portable and plumbed eyewash stations that use tap water, rather than saline solution, as the primary flushing fluid require more attention than portable, saline-solution stations. This helps avoid the growth of bacteria. In fact, the ANSI standard recommends that portable eyewash stations use a preserved, buffered pH-balanced saline solution instead of plain tap water, because tap water can cause painful damage, even to healthy eyes. Using tap water also requires more maintenance, as stated, in order to remove contaminants like mildew or sediments.
Time & Temperature
Eyewash and/or shower stations should be located on the same level as the hazard, in a well-lit area, and must be properly and clearly marked. They must be positioned within 10 seconds (about 55ft) of the hazard, along a path that is free from obstructions. This path is critical, because of the potentially impaired vision of affected/injured workers. Delaying treatment, even for a few seconds, might lead to serious injury.
The standard also states that the water temperature for the flushing fluid in an eyewash station must be tepid (approximately 60-100° F). Tepid water helps encourage worker compliance to meet the full 15 minutes of flushing; this, in turn, helps prevent further absorption of chemicals and injury to the eyes.
The most common method of delivering tepid water to the eyewash and shower station is by installing Thermostatic Mixing Valves (TMVs). These valves blend cold and hot water to provide a comfortable flushing fluid within the required temperature range.
Emergency showers are designed to flush the head and body. They are not meant to be a substitute for eyewash stations, however; the high water pressure/flow could be damaging to the eyes. Eyewash stations are designed to flush the eye and face area only, but combination units are available that contain both a shower and an eyewash.
The need for emergency showers, like eyewash stations, is based on the chemicals workers use and the tasks performed in the workplace. A job hazard analysis can provide an evaluation of potential hazards of both the job and work areas. The selection of protection—emergency shower, eyewash or both—should match the hazard(s). If the worker is in an area that might risk part or full body contact with a chemical, an emergency shower is more appropriate.
A combination unit has the ability to flush any part, or even all, of the body. It is considered to be the most comprehensive protection. Such units are appropriate in work areas where detailed information about the hazards is lacking, or where complex, hazardous operations involve many chemicals with different properties. A combination unit is useful in workplaces where there are difficulties handling workers (due to an inability to follow directions, because of intense pain or shock from an injury, for example). WMHS