Eyewash & Shower Safety
Encon Safety Products
When a corrosive chemical comes in contact with eyes or skin, tissue damage begins immediately. While the rate and extent of this damage depends upon the chemical involved, the most important step in halting the damage is the same: The affected area must be irrigated immediately with copious amounts of water for a minimum of 15 minutes.
When done properly, irrigation improves the medical prognosis and reduces the risk of long-term tissue damage. If delayed or cut short, however, first aid treatment (irrigation) is less effective, and the full extent of the injury becomes problematic.
Proper irrigation is made easier by emergency shower and eyewash equipment. This equipment is specially designed to wash chemicals from the whole body, the eyes and face, or specific areas. Although emergency shower and eyewash stations have been part of the workplace for more than 70 years, it wasn't until 1981 that a comprehensive industry standard was developed. Through the coordinated efforts of the Industrial Safety Equipment Association, industry, labor, government, and the medical community, a consensus standard was approved, culminating in the creation of the ANSI Standard Z358.1, first issued in 1981. This standard is on its newly released third issue and is now referred to as ANSI Standard Z358.1-1998.
The "standard" is valued by planners, hygienists, and safety specialists as the source tool to outline the types of emergency shower and eyewash equipment, provide uniform minimum requirements for equipment performance, and provide information regarding installation, testing, maintenance, and training.
Types of Equipment
Each type of equipment outlined in the standard is designed to perform a specific function; one piece of equipment is not a substitute for another. The types of equipment covered include:
- Emergency showers
- Eyewash stations
- Eye/facewash stations
- Hand-held drench hoses
- Combination equipment
Emergency showers. Emergency showers
are designed to provide a deluge large enough to encompass the
whole body. Emergency showers should be selected when large volumes
of potentially injurious materials are present, i.e., chemical
Emergency showers shall deliver a pattern of potable water at least 50.8 cm (20 inches) across, flowing at a rate of at least 75.7 liters (20 gallons) per minute at a velocity low enough so as not to be injurious to the user. The diameter ensures the entire body receives a direct, fresh supply of water.
Emergency showers are not to be considered or used for irrigating chemicals from the face and eyes, due to the delicate nature of these tissues and the potentially high velocity and volume of water an emergency shower may produce.
Emergency eyewash stations. Emergency eyewash stations are specifically designed to provide a controlled flow of water to both eyes simultaneously. To maintain a soft, controlled flow to the eyes, regulation of the volume and pressure from the station is required. Eyewash stations require an uninterrupted, 15-minute supply of water. As a general rule, select a plumbed unit if plumbing is available. Plumbed units are recommended because of the greater volume of water available to the user-between 7.5 and 13.25 liters (2.0 and 3.5 gallons) per minute.
Emergency eye/facewash stations. An enhancement of the eyewash station is the eye/facewash station, a product designed to irrigate the eyes and face simultaneously. An eye/facewash station delivers a substantially greater volume of water (minimum 11.4 lpm/3.0 gpm) than an eyewash station and does so to irrigate the larger target area. In planning equipment selection, one should recognize the probability that when a chemical splash affects the eyes, it will also affect the face. With this in mind, eye/facewash stations are strongly recommended when selecting plumbed chemical splash irrigation equipment.
Drench hoses. Drench hoses have been part of emergency stations for many years. They are particularly common in laboratories and provide first aid capability in conjunction with eyewash/eye-facewash equipment. Drench hoses are used:
- to spot drench an affected area when a full shower is not required.
- to irrigate exposures when the victim is unconscious or unable to stand, and
- to irrigate under clothing prior to the removal of clothes.
It is important to note that drench hoses serve as a
secondary piece of equipment to emergency showers and eyewash
stations but do not replace them.
Combination equipment. Combination equipment refers to multiple-use stations with a common plumbing unit, i.e., combination shower/eyewash. Combinations of shower, eyewash, eye/facewash, and drench hose equipment are available in a variety of configurations. When combination stations are used, the water line must be at least 3.2 cm (1 1/4") in diameter in order to readily supply multiple pieces of equipment. When planning system requirements, it is important to note that it is a standards requirement to be able to operate both shower and eyewash devices simultaneously.
Use of Equipment
Location. The location of the emergency equipment is critical to its ability to successfully serve its purpose. Because of the destructive capability of many chemicals, a recommended location for shower/eyewash equipment is within 10 seconds travel time from the identified hazard.
Specific distance references have been removed from the 1998 standard, and it is incumbent upon the planner to select a location based on the suspected time of travel of a person with compromised vision. (To help you develop a frame of reference, the average adult walking four miles an hour can travel 50 feet in 10 seconds. With compromised vision and no assistance the travel distance will be greatly reduced.) Assure there are no stairways, changes in floor levels, potential trip hazards, and doors that could be locked unknowingly between the emergency equipment and the work area. It is also recommended that the equipment should be readily accessible on paths of access and egress from the work area.
Water temperature. The ANSI Z358.1-1998 standard now addresses the subject of temperature. The standard refers to "tepid" temperatures, those being moderately warm or lukewarm. Medical references support tepid temperatures in first aid treatment for a majority of chemical exposures, and providing water at a temperature conducive to use is considered an integral part of providing suitable first aid facilities.
One could reasonably support a "tepid" range from 78 °F to 92 °F. Temperatures above 100 °F, have proven to be harmful to the eyes and can enhance chemical interaction with body tissues.
Controls. Commonly referred to as activation devices, pull rods, and push plates, these controls are required to cause water flow. Key characteristics of activation devices to consider are user visibility and durability. Stay-open valve devices are specified in the ANSI standard, with the purpose of assuring continuous flow while the hands remain free to remove clothing or hold the eyelids open. Actuation of the device shall provide water within one second to meet ANSI requirements.
Visibility. Equipment visibility is an important factor. Locating equipment on normal access and egress paths in the laboratory helps reinforce the location to potential users, who will pass the equipment in day-to-day work. Increasing the recognition factor of emergency equipment can be achieved by various means. The use of high-visibility signs that can be seen anywhere within the area being served by the first aid equipment is required. Another method is to paint the floors, walls, or emergency equipment itself in a bright color contrasting from the environment, but this can be expensive and will require ongoing maintenance. The area around the emergency shower/eyewash station shall be well lit to help the user identify the area and assist in conducting first aid activities.
Water disposal. How to dispose of chemically contaminated water is a growing concern. Can a chemical, even in diluted state, be released into the sewer system without violating local codes? This question can only be answered at each school.
Training. Although the steps involved in training personnel on how to use emergency shower/eyewash stations are quite simple, training is often overlooked. The standard requires personnel to know how, when, where, and how long to use emergency shower/eyewash equipment, and what they should do after the initial irrigation is completed.
Testing, inspection, and maintenance. Testing the equipment regularly is the best preventive maintenance program available. According to the ANSI standard, plumbed emergency equipment shall be tested weekly to verify flow and proper operation. Testing also clears the water lines, allowing any dirt or pipe scale to pass. Broken or worn parts should be repaired or replaced immediately. An annual inspection of emergency equipment is now required per the ANSI standard to assure equipment conformance.
Summary. The purpose of emergency shower/eyewash equipment is to reduce and eliminate chemical incident injuries. Proper equipment selection, location, utilities, training, and scheduled inspections can make the difference in how well first aid is performed.
You hope that emergency shower and eyewash stations are only tested and are never used. But in case of emergency, proper planning can minimize the impact of a chemical exposure and protect the school, teachers and students from unnecessary hardship.
Flinn Scientific would like to thank Chris Bollas for writing
and allowing us to reproduce this article on eyewash and shower
Chris Bollas is Operations Manager of Encon Safety Products, Inc., a supplier of eyewash and safety shower equipment. Encon products can be purchased through Flinn Scientific.