Download Chemical Protection: In and Out of the Lab

Chemical Protection: In and Out of the Lab
You’ve suited up for a day in the lab. Lab coat? Check. Safety glasses? Check.
Gloves? Check. Hazmat suit? Ummmm….hazmat suit?
That’s right. Chemicals such as acids, bases, solvents and more are common in labs
and other controlled environments. And even if you don’t directly handle dangerous chemicals in your lab, chances are good that dangerous chemicals are present
somewhere in your facility or on your campus. That’s why it’s important to include
personal protective equipment (PPE) that provides chemical protection in your
overall PPE program.
Chemical protection apparel is designed specifically to block harmful chemicals
from reaching the skin. From chemical resistant gloves and simple sleeve protectors
to safety goggles and fully encapsulated hazmat suits, there is a variety of PPE that
provides chemical protection for workers in labs.
Risk Assessment and Hazard Analysis
The first step in selecting the appropriate chemical protection PPE is a thorough
analysis of the hazards in the environment – both within and outside the lab. In addition to the lab, consider other areas of the facility, such as shipping/receiving and
production environments. The goal in a hazard analysis is to identify all the possible
ways someone could be hurt while working.
Once hazards are identified, the next step is to attempt to remove the hazards or minimize their potential via engineering or process changes. When such changes aren’t
possible, it’s time to turn to PPE to protect workers. However, before that is done, the
other key step is a risk assessment. Here, it is important to understand how likely the
hazard is to occur and what the consequences are if the exposure does happen.
Consider this example: A trained laboratory technician is working with sulfuric acid
in a lab, using 10ml of chemical at a time to create a dilute acid solution to be used in
a different experiment later in the day. In this case, while the technician is working
with acid, the quantity is small and only the tech’s hands and forearms are entering the area of potential exposure. A safety professional assessing this hazard may
decide that even though a splash is possible, the tech’s whole body is not exposed
and the volume of chemical is minimal. A recommendation for chemical resistant
gloves and sleeve protectors may provide reasonable protection. The safety professional might even conservatively recommend a chemical apron but not require a full
coverall in this particular application. In fact, two different lab safety professionals
may make different recommendations on the same chemical and task based on their
knowledge of other lab conditions that could affect safety.
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Penetration Data vs. Permeation Data
Understanding chemical resistance data of PPE is important in the PPE selection
process. Remember to look at both permeation and penetration data.
Chemical penetration data is determined via a test method (ASTM F903) intended
to measure the resistance of the material to liquid chemicals. The use of penetration data is appropriate when the chemical does not present a gas or vapor hazard
and only liquid splash protection is required. The test requires the chemical to be
held against the material (at saturation) for 60 minutes. If, at the end of the 60 minute
period, the liquid has not come through the material, then the material “passes” the
test. If anything comes through, even one tiny droplet, then the material “fails” the
test. Often, penetration results are much easier to understand than permeation data.
Permeation data, on the other hand, tells how molecules of the chemical come
through the material. Molecule permeation is more like exposure to a gas or vapor.
It does not indicate whether a liquid splash will come through the material or not.
Selection based on permeation data alone will often drive lab purchasers to choose
a garment that is more expensive and less comfortable than what they would
choose if they considered liquid penetration data.
The Bottom Line
Use practical observations of the tasks being performed when
thinking about the use of PPE. While both chemical penetration and
chemical permeation data are crucial, the best choice for chemical
protection PPE can not be made based only on what chemical is
being used.
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