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By:
Chris Bollas
Encon Safety Products
Houston, TX
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
storage areas.
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 safety.
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.
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