Page 50 - Occupational Health & Safety, July/August 2019

PROTECTIVE APPAREL
Chemical Protective Clothing:
Navigating Standards to Match Your Hazards
You should strive to select the best CPC for worker protection.
BY SUSAN LOVASIC
In the USA, general industry employers have regu- latory responsibility for selecting Personal Protec- tive Equipment under OSHA 29 CFR 1910.132. Employer assessment of workplace hazards drives
the selection of appropriate PPE. Only respiratory protection is required to be approved by a government agency in the USA—specifically by the National In- stitute for Occupational Safety and Health (NIOSH); however, other types of PPE available for consider- ation and selection may be third-party certified. It is important that safety professionals understand details of key certification standards to make informed deci- sions when matching PPE to their workplace hazards. This article will focus on chemical protective clothing (CPC) testing and National Fire Protection Associa- tion hazardous materials (hazmat) standards that can be used to assess chemical PPE.
CPC Assessments—A Sum of the Parts
The performance of CPC, in terms of chemical barrier protection, durability, and hazard scenario suitability factors, can be assessed at several levels: the material, seam, closure system, and finished garment.
The suit material’s chemical barrier protection lev- el is best quantified using the ASTM F739 permeation test, and the suit material’s physical properties should also be measured to predict durability. Likewise, the chemical barrier and physical strength of seams used to join the material to create a garment should be evaluated. For most applications, the seam should be sealed and provide a barrier level at least equivalent to the garment material.
The closure system of the garment should be con- sidered for suitability based on the hazard scenario. The suit closure area can be the weakest link in the garment, and safety professionals must consider whether it will provide effective barrier against the particles, liquids, and/or vapors in their hazards. It is very common for the closure system—most often a specialized zipper—to be covered by an extra flap of garment material that is secured in place, to provide an extra layer of protection.
In addition to tests run on materials used in gar- ments, full garment testing can be conducted to assess robustness of the garment design. These tests most of- ten check the suit’s ability to hold out a specific phase of non-hazardous chemical (particle, liquid, or gas). The chief failure mechanism for a full garment test is penetration through a void or defect or poor seal at
an interface. A “passing” rating in these full suit tests does not mean that the suit is 100 percent impervious to all hazardous chemicals of the same phase. Rather, these tests can be used to identify weaknesses in the garment design that permit leakage into the suit of challenge particle, liquid, or gas chemicals.
Full suit test methods are provided in various ASTM, ISO, and EN standards. There are a variety of tests to assess suit “liquid integrity.” These tests chiefly vary in how they expose the garment to the liquid and the surface tension, volume, and/or pressure of the test liquid water. The common methods are described as a Shower test, Jet test, Spray test, or Mist test. The liq- uid integrity test method used is based on the targeted hazard application of the suit. There are also tests to check the inward leakage of a gas/vapor or of small particles into the suit. Full garment/ensemble tests are excellent ways to assess the robustness of garment de- sign, components, and interfaces of a PPE ensemble.
Matching Certified Suits to Hazards
A common question during the CPC selection process is, “Will a certified suit be the best match for my haz- ard?” The answer to this question is, “It depends on the specific standard and your specific hazard scenario.” Each CPC standard has strengths and limitations to consider to determine whether or not a certified gar- ment would match the protection level needed.
A strength of certified CPC is that performance re- quirements were developed using a consensus process. Additionally, when the CPC is third-party certified, the certifying agency provides oversight to the CPC manufacturer. There are, however, some limitations for CPC performance standards that should be consid- ered. First, every standard has a very specific scope for how the CPC is evaluated and its intended use. Care must be taken to understand the level of protection the suit is designed to provide. Additionally, standards use a specific limited battery of hazardous chemicals to test the suit material and components. This raises the dilemma—is a third-party certified garment the best choice if it was not tested against the chemical hazards identified in your hazard assessment?
Because of this, unless certification of CPC is re- quired by your employer or government regulation, whether or not CPC is certified should not be the only question you ask. Rather, you should start with the hazard assessment and find CPC that will protect against your specific hazards. Ideally if the CPC meets
44 Occupational Health & Safety | JULY/AUGUST 2019
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