Page 24 - Occupational Health & Safety, May 2019

PROTECTIVE APPAREL
Chemical Protective Clothing Selection— Finding the Best Match for Your Hazard
You should strive to gather permeation data for the CPC you plan to use.
BY SUSAN LOVASIC
Safety professionals deal with many work- place hazards, and most employ the “Hi- erarchy of Controls” shown in Figure 1 to reduce/eliminate hazards. If possible, elimi- nate the hazard completely or substitute a safer option. Next, apply engineering controls to minimize worker contact. If that is not 100 percent effective, then ad- ministrative controls such as work practices are modi- fied to minimize potential contact. After all these steps are completed, then personal protective equipment (PPE) options are selected for any residual risk.
Selection of PPE is the responsibility of USA gen- eral industry employers under OSHA 29 CFR 1910.132, Personal Protective Equipment. Employer assessment of workplace hazards drives the selection of appropriate PPE. This article will focus on PPE se- lection against chemical hazards.
Hazard Assessments
For proper selection of chemical protective clothing (CPC) as PPE, there are several questions to be con- sidered during the hazard assessment. First, what is the hazardous chemical’s name, Chemical Abstracts Service (CAS) Registry number, and the chemical’s physical state (solid, liquid, gas)? Many industries use their own chemical names or acronyms. It is best to use the CAS # so that you and the CPC manufacturer are discussing the same chemical. Additionally, is the chemical a mixture and what are the components? A hazardous component could breach the barrier mate- rial when part of a mixture when it would not do so in pure form.
Second, how is the chemical a skin hazard? Will it cause skin irritation or burn? Can the chemical be absorbed through the skin and cause acute or chronic
health effects? It is important to consider that some materials, such as asbestos or lead, are not listed as skin hazards, but if these particles get onto the work- er’s skin or clothing, they can be transferred and be- come inhalation or ingestion hazards in or away from the workplace.
Finally, consider the potential exposure scenario. This is best done by direct observation of the work. What are the work practices? Is chemical exposure expected to occur frequently or only when something fails in the process or when a specific non-routine work task (e.g., line break) is conducted? Consider how much of the chemical could be released and in what direction. The exposure scenario should con- sider likelihood of contact with the chemical and if contact occurs, the amount, duration, and direction.
Once the chemical hazard assessment has been completed, then CPC selection can begin. There are three key aspects of CPC that should be considered: fabric, seam, and garment design. This article will fo- cus chiefly on barrier properties of fabric used in CPC.
There may be other special hazards to consider, such as flammable/explosive environment, extreme heat or cold, physical hazards, etc. These special needs are not covered in this article, but if they apply to your workplace, they must be addressed. Also, remember that CPC is often an element of a protective ensemble. You must validate that the wearer is fully protected from all hazards, including respiratory.
Chemical Barrier Assessments
of CPC Materials
A material’s chemical resistance can be measured sev- eral ways: degradation, penetration, and permeation. Permeation is the most accurate option, but we will discuss the other two, as well.
Degradation is usually reported only for chemical glove materials and is rarely reported for chemical suit materials. Degradation assesses the compatibility of the material with the chemical, rather than measuring its barrier properties. Degradation occurs when there is a change in the exposed material, such as did the material swell or become brittle or lose weight? If the material shows degradation due to the chemical, then it is clearly not a candidate to provide barrier. How- ever, if the material shows no degradation, that result does not prove the material will provide any barrier to that chemical.
Penetration testing is another way CPC materials
20 Occupational Health & Safety | MAY 2019
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