The Longest 10 Seconds

Safety requirements for safety showers and eyewash stations

By Vince McLeod

We understand, as laboratory managers and employees, that after the chemical fume hood our next most important safety items are the safety shower and eyewash station. But do you know what constitutes a proper setup? Which requirements apply? Where do we locate them? How much flow is needed? We hope these questions are pondered and answered well before the need for using your safety shower or eyewash station arises.

Far too often, we read about serious injuries resulting from simple laboratory tasks that should have been prevented. Recently, the American Industrial Hygiene Association pages for Lab Safety Chemical Exposure Incidents posted a few prime examples.1

Several incidents have been reported in which lab workers have spilled chemicals (usually phenol, for some reason) on their clothes and bypassed the safety shower to get to a restroom to remove the contaminated clothing. Some have even put the contaminated clothing back on after rinsing it before going home. All incidents resulted in second-degree burns. A lab worker picked up a container of trifluoroacetic acid (TFAA) with her ungloved hand to move it. She was unaware that TFAA forms hydrofluoric acid upon contact with moisture. Hours later, she experienced pain in her palm and thumb and had a serious burn requiring skin grafts.

A postdoc was working with concentrated sulfuric acid and splashed some onto one of her latex gloves. The acid quickly burned a hole through the glove and resulted in a second-degree burn. Fortunately, she removed her gloves and flushed her hand for the recommended 15 minutes, reducing the impact.

What are the OSHA regulations?

29 CFR 1910.151, Medical Services and First Aid, states that “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.”2 OSHA doesn’t provide more specifics regarding what “suitable” means or what defines “immediate.” So how do we know whether we are meeting the intent of the law?

Fortunately, the American National Standards Institute (ANSI) developed and recently updated its consensus standard Z358.1, latest edition 2014. This ANSI standard is very detailed in terms of defining what is appropriate for safety showers and eyewash stations. In fact, OSHA uses this reference as a guide when inspecting facilities.3 So let’s review what is recommended for acceptable safety equipment.

Safety shower specifications

We suggest checking your facilities for the proper hardware recommended by Z358.1. Should OSHA visit and audit your labs, they will look for it. For safety showers, the showerhead must flow 20 gallons per minute (gpm) at 30 psi and produce a 20-inch diameter spray pattern at 60 inches above the surface where the user stands. The center of the sprayhead pattern should be at least 16 inches from any wall, door, or obstruction. It is recommended that the showerhead be mounted between 82 and 96 inches off the floor, with the valve no higher than 69 inches.

Eyewash station specifications

Eyewash stations target just the eyes and therefore have a lower flow requirement. ANSI Z358.1 recommends a flow of 0.4 gpm, also at 30 psi. Mount nozzles at least six inches from any obstruction and between 33 and 45 inches above the floor. Use an eyewash gauge to verify and test the flow pattern.

Requirements for both

Both safety showers and eyewash stations must provide the recommended flow for at least 15 minutes. This usually equates to having the equipment directly plumbed with hard connections to the water supply. For example, a quick calculation for the safety shower at 20 gpm for 15 minutes yields 300 gallons. Self-contained or personal wash devices are allowed but considered supplemental units that can provide immediate flushing while transiting to the permanent fixture.

If the local climate presents potential for freezing conditions, design the equipment to avoid freezing or consider the new recirculating systems to protect against that situation. An excellent white paper on these is given in the references below.4 Activation valves must open within one second and remain open until intentionally closed or turned off. That these safety devices be constructed with corrosion-resistant materials should go without saying.

The 2014 update to Z358.1 added two important criteria. The first is that tepid water is now defined as having a temperature between 60 and 100 degrees Fahrenheit (15 to 37 degrees Celsius). The second change addresses simultaneous operation for combination units. This means that if you have a drench shower combined with an eyewash station, both devices must provide adequate flows at the same time.

Finally, and most important, plan the location of the equipment. Anyone needing to flush corrosive chemicals from their eyes or skin must be able to reach the safety shower or eyewash station within 10 seconds. Travel to the unit must take less than 10 seconds, with an unencumbered and direct path. This equates to about 55 feet for most people. We strongly recommend painting or marking the floor area underneath the shower to help keep it clear. Z358.1 also recommends installing equipment in brightly lit areas and marking it with highly visible safety signs.

Maintenance and training

If you ever need to rush to the safety shower or eyewash station, the last thing you want is a drenching with nasty, sediment-laden water. ANSI recommends flushing all equipment weekly to verify proper flow and clear the plumbing of any deposits. If your facility does not have floor drains installed, remember to bring a large plastic trash can to catch the water. The weekly flushing can also provide a great training opportunity to refresh the operation and travel paths for your employees.

References:

1. Lab Safety Chemical Exposures Incidents, American Industrial Hygiene Association, Falls Church, VA. 2017. https://www.aiha.org/get-involved/VolunteerGroups/LabHSCommittee/Incident%20Pages/Lab-Safety-Chemical-Exposures-Incidents.aspx 

2. Medical Services and First Aid. US Department of Labor, Occupational Health and Safety Administration, Washington, DC. Latest edition. https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9806 

3. Understanding the ANSI Z358.1-2014 Standard for Emergency Eyewashes and Shower Equipment. Occupational Health & Safety. Sept. 2016. https://ohsonline.com/Articles/2016/09/01/Understanding-the-ANSI-Z35812014-Standard-for-Plumbed-and-Portable-Eyewash-Stations.aspx 

4. Emergency Shower and Eyewash Recirculating Loop Systems General Considerations, Whisman, Nicole. Haws Integrated. 2017. https://www.ishn.com/ext/resources/Resources/white-papers/emergency_shower_eyewash_recirculating_loop_systems_general_considerations.pdf  

Categories: Lab Health and Safety

Published In

Scientific Apps Magazine Issue Cover
Scientific Apps

Published: December 7, 2018

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