Emergency Showers and Eyewash Stations

If you work with or near hazardous chemicals, you should know the appropriate safety precautions to take to work safely and avoid injury. However, accidents can happen – and when a corrosive chemical gets into your eyes or on your face or body – the first few seconds are the most critical for preventing injury. If treatment is delayed, even for a few seconds, serious injury may be caused.

That’s where emergency showers and eyewash stations come in, providing workers with on-the-spot decontamination and the ability to flush hazardous substances away, and minimize the effects of accidental exposure to chemicals.

There are different types of units available – emergency showers, eyewash stations and combination units. The type of protection selected should match the hazard, and the chemicals that are used at the workplace. Conducting a job hazard analysis will help you identify this information.

Emergency showers are designed to flush the user’s head and body. These are NOT for flushing the eyes, because the water pressure may be too great and could damage the eyes.

Eyewash stations are designed to flush the eye and face area only.

Combination units contain both an emergency shower and an eyewash station and enable any part or all of the body to be flushed. They are the most protective emergency devices and should be used wherever possible.

There are two types of emergency showers:

Plumbed Shower: An emergency shower permanently connected to a continual source of potable water

Self-Contained Shower: A stand-alone shower that contains its own flushing fluid

Key emergency shower features and specifications include:

• Hands-free valve activates in one second or less and remains open until manually closed
• Plumbed unit delivers 20 gallons of water per minute for 15 minutes at 30 pounds per square inch pressure in the required pattern
• Self-contained unit  delivers 20 gallons of water per minute for 15 minutes in the required pattern
• Height of water column is between 82 and 96-inches above the surface on which the user stands
• At 60 inches above the surface on which the user stands, the water pattern is at least 20 inches in diameter
• Center of the water pattern is at least 16 inches from any obstruction
• Easily located, accessible actuator is no more than 69 inches above the surface on which the user stands
• If provided, shower enclosure has a minimum diameter of 34 inches

There are two types of eyewash and eye/face wash stations:

Plumbed station: An eye wash unit permanently connected to a continual source of potable water

Gravity-fed (self-contained) station: A stand-alone eye wash device that contains its own flushing fluid that must be refilled or replaced after use

Key eyewash and eye/face wash station features and specifications include:

• Eyewash and eye/face wash  controlled, low velocity flow rinses both eyes and is not injurious to user
• Water flow is sufficiently high to allow user to hold eyes open while rinsing
• Spray heads are protected from airborne contaminants – covers are removed by water flow
• Plumbed eyewash delivers at least 0.4 gallons of water per minute at 30 pounds per square inch pressure for 15 minutes
• Gravity-fed (self-contained) eyewash delivers at least 0.4 gallons of water per for 15 minutes
• Plumbed eye/face wash delivers at least 3.0 gallons of water per minute at 30 pounds per square inch pressure for 15 minutes
• Gravity-fed (self-contained) eye/face wash delivers at least 3.0 gallons of water per for 15 minutes
• Water flow pattern is positioned between 33 and 53 inches from the surface on which the user stands and at least 6- inches from the wall or nearest obstruction
• Valve actuator is easy to locate and readily accessible to user
• Unit washes both eyes simultaneously and covers area indicated on test gauge at no more than 8 inches above spray heads

Flushing time

The American National Standards Institute (ANSI) Standard for Emergency Eyewash and Shower Equipment (ANSI Z358.1-2009) recommends that the affected body part must be flushed immediately and thoroughly for at least 15 minutes using a large supply of clean fluid under low pressure. Water does not neutralize contaminants — it only dilutes and washes them away. This fact is why large amounts of water is needed.

Other references recommend a minimum 20-minute flushing period if the nature of the contaminant is not known, however, the time can be modified if the identity and properties of the chemical are known. For example:

• minimum 5-minute flushing time is recommended for mildly irritating chemicals,
• at least 20 minutes for moderate-to-severe irritants,
• at least 20 minutes for non-penetrating corrosives, and
• at least 60 minutes for penetrating corrosives.
• Remember to always keep a clear, unobstructed path to the emergency shower or eyewash station at all times, and to frequently test the unit to ensure it is well maintained and operating correctly.

Water temperature

The 2009 ANSI standard recommends that the water should be “tepid”, between 16-38°C (60-100°F). Temperatures higher than 38°C (100°F) are harmful to the eyes and can enhance chemical interaction with the skin and eyes. Long flushing times with cold water (less than 16°C (60°F)) can cause hypothermia and may result in not rinsing or showering for the full recommended time (ANSI 2009). With thermal burns (injuries to the skin), the American Heart Association noted that optimal healing and lowest mortality rates are with water temperatures of 20-25°C (68-77°F).

Remember that any chemical splash should be rinsed for a minimum of 15 minutes but rinsing time can be up to 60 minutes. The temperature of the water should be one that can be tolerated for the required length of time. Water that is too cold or too hot will discourage workers from rinsing or showering as long as they should.

Install anti-scalding devices (temperature control valve or thermostatic tempering valve), constant flow meters, and other devices that will help maintain a constant temperature and flow rate. For cold or outdoor locations, emergency showers with heated plumbing are available. In hot climates, outdoor emergency showers should also have a tempering valve so that workers are not exposed to water that is too hot.

Training

Employers should inform their workers where the emergency showers or eyewash stations are and instruct them on the proper way to use them. Worker should also have access to written instructions and they should also be posted beside the emergency shower and eyewash station. Part of the training should include a “hands-on” drill on how to find equipment.

Wearing contact lenses can be dangerous, and training should include instruction in contact lens removal. Chemicals can become trapped under a contact lens and any delays caused by removing contact lenses in order to rinse eyes could cause injury.

Location of the emergency equipment

To be effective, the equipment has to be accessible. ANSI recommends that a person be able to reach the equipment in no more than 10 seconds. ANSI notes that the average person can walk 16 to 17 metres (55 feet) in 10 seconds, but this does not account for the physical and emotional state of the person.

However, the “10 second” rule may be modified depending on the potential effect of the chemical. Where a highly corrosive chemical is used, an emergency shower and eyewash station may be required within 3 to 6 metres (10 to 20 feet) from the hazard. These units should be installed in such a way that they do not become contaminated from corrosive chemicals used nearby.

The location of each emergency shower or eyewash station should be identified with a highly visible sign in the form of a symbol that does not require workers to have language skills to understand it. The location should be well lit.

The emergency shower or eyewash station should be located:

• as close to the hazard as possible
• on an unobstructed path between the workstation and the hazard. (Workers should not have to pass through doorways or weave through machinery or other obstacles to reach them)
• where workers can easily see them – preferably in a normal traffic pattern
• on the same floor as the hazard (no stairs to travel between the workstation and the emergency equipment)
• near an emergency exit where possible so that any responding emergency response personnel can reach the victim easily
• in an area where further contamination will not occur
• in an area protected from freezing when installing emergency equipment outdoors
• away from any electrical equipment that may become a hazard when wet

There must also be a drainage system for the excess water (the water may be considered a hazardous waste and special regulations may apply).

Consult your local occupational health and safety agency in your jurisdiction and check relevant legislation for any requirements to install this equipment. Currently there is no Canadian standard for the design or placement of eyewash stations or emergency showers. As a result, the American National Standards Institute (ANSI) Standard for Emergency Eyewash and Shower Equipment (ANSI Z358.1-2009) is generally used as a guide.

SOURCE:

Canadian Centre for Occupational Health and Safety, Health and Safety Report, Volume 12, Issue 5