Protective Clothing

Protective Clothing for Safety

According to NOISH resources, the use of protective clothing is only one aspect of a comprehensive program for ensuring the safety and health of workers. Careful planning, work practices and engineering (isolation) and administrative (avoidance) controls should also be considered. In fact, they are required by OSHA under 29 CFR 1910.120 as a preliminary step in limiting worker exposures to hazards. If these measures do not sufficiently reduce worker exposures, OSHA mandates that personal protective equipment (PPE) be used.

Once the need for PPE is established, a careful evaluation of the hazards is necessary so that a selection can be made that minimizes the risk to the user. For chemical situations, knowing the hazard includes being aware of: the type of chemical, the physical state (liquid, solid or gas), and the physiological effect (toxic, carcinogen, asphyxiant, corrosive, etc.). Knowing the level of exposure is also important when selecting protective clothing and equipment.

EPA Levels of Protection

When response activities are conducted where atmospheric contamination is known or suspected to exist, personal protective equipment must be worn.

Personal protective equipment (PPE) is designed to prevent/reduce skin and eye contact as well as inhalation or ingestion of the chemical substance.

Protective equipment to protect the body against contact with known or anticipated chemical hazards has been divided into 4 categories by the Environmental Protection Agency (EPA).

LEVEL A

Level A protection should be worn when the highest level of respiratory, skin, eye and mucous membrane protection is needed.

Personal Protective Equipment
  • Positive pressure (pressure demand), self contained breathing apparatus (NIOSH approved), or positive-pressure supplied air respirator with escape SCBA.
  • Fully encapsulating chemical protective suit.
  • Gloves, inner, chemical resistant.
  • Gloves, outer, chemical resistant.
  • Boots, chemical resistant, steel toe and shank; (depending on suit boot construction, worn over or under suit boot.)
  • Underwear, cotton, long-john type.*
  • Hard hat (under suit).*
  • Coveralls (under suit).*
  • Two-way radio communications (intrinsically safe/non-sparking).*
* = Optional

LEVEL B

Level B protection should be selected when the highest level of respiratory protection is needed, but a lesser level of skin and eye protection. Level B protection is the minimum level recommended on initial site entries until the hazards have been further identified and defined by monitoring, sampling, and other reliable methods of analysis, and equipment corresponding with those findings utilized.

Personal Protective Equipment
  • Positive-pressure (pressure-demand), self-contained breathing apparatus (NIOSH approved), or positive-pressure supplied air respirator with escape SCBA.
  • Chemical resistant clothing (overalls and long-sleeved jacket, coveralls, hooded two-piece chemical splash suit, disposable chemical resistant coveralls.)
  • Coveralls (under splash suit).*
  • Gloves, outer, chemical resistant.
  • Gloves, inner, chemical resistant.
  • Boots, outer, chemical resistant, steel toe and shank.
  • Boot-covers, chemical resistant (disposable).*
  • Two-way radio communications (intrinsically safe).*
  • Hard hat. *
  • Faceshield.*
* = Optional

LEVEL C

Level C protection should be selected when the type of airborne substance is known, concentration measured, criteria for using air-purifying respirators met, and skin and eye exposure is unlikely. Periodic monitoring of the air must be performed.

Personal Protective Equipment
  • Full-face or half-mask, air-purifying respirator (NIOSH approved).
  • Chemical resistant clothing (one piece coverall, hooded two piece chemical splash suit, chemical resistant hood and apron, disposable chemical resistant coveralls.)
  • Gloves, outer, chemical resistant.
  • Gloves, inner, chemical resistant.
  • Boots, steel toe and shank, chemical resistant.
  • Boot-covers, chemical resistant.*
  • Cloth coveralls (inside chemical protective clothing).*
  • Two-way radio communications (intrinsically safe).*
  • Hard hat. *
  • Escape mask. *
  • Faceshield.*
* = Optional

LEVEL D

Level D is primarily a work uniform and is used for nuisance contamination only. It requires only coveralls and safety shoes/boots. Other PPE is based upon the situation (types of gloves, etc.). It should not be worn on any site where respiratory or skin hazards exist. Refer to The Office of Emergency and Remedial Response. Environmental Response, Division. See "Interim Standard Operating Safety Procedures" for full details.

The type of environment and the overall level of protection should be reevaluated periodically as the amount of information about the site increases and as workers are required to perform different tasks.

Reasons to upgrade to a higher level (D is lowest, A is highest):
  • Known or suspected presence of dermal hazards
  • Occurrence or likely occurrence of gas or vapor emission
  • Change in work task that will increase contact or potential contact with hazardous materials
  • Request of the individual performing the task


Reasons to downgrade:
  • New information indicating that the situation is less hazardous than was originally thought
  • Change in site conditions that decreases the hazard
  • Change in work task that will reduce contact with hazardous materials


Selection of Material

The selection of appropriate protective gear is based on the hazards anticipated or recognized. Protective clothing protects primarily because of the material from which it is made.

In selecting the protective material, the following should be considered: (From EHSO)
  • CHEMICAL RESISTANCE, which is the most important. When clothing contacts a hazardous material, it must maintain its structural integrity and protective qualities.
  • STRENGTH, which is based on resistance to tears, punctures, and abrasions, as well as tensile strength.
  • FLEXIBILITY, clothing easy to move in and work in. Flexibility is especially important in glove materials.
  • THERMAL LIMITS affect the ability of clothing to maintain its protective capacity in temperature extremes. Thermal limits also affect mobility in cold weather and transfer of heat to the wearer in hot weather.
  • CLEANABILITY, difficult and expensive if protective clothing is not cleanable. Some materials are nearly impossible to clean adequately under any circumstances. Disposable clothing is sometimes used.
  • LIFESPAN, which is the ability to resist aging, especially in severe conditions over time. This should be balanced against the initial cost of the garment.


Chemical Resistance. Protective material must be able to resist degradation, penetration, and permeation by the contaminant. Any of these actions may result upon contact, depending on factors such as concentration and contact time.

Degradation is the result of a chemical reaction between the contaminant and the protective material. Damage to the material may be slight or as severe as complete deterioration. The reaction may cause the material to shrink or swell, become brittle or very soft, or completely change its chemical and physical structure. Changes such as these may enhance or restrict permeation or allow penetration by the contaminant.

Penetrability. A chemical penetrates a protective garment because of its design and construction imperfections, not because of the inherent material from which it is made. Stitched seams, button holes, porous fabric, and zippers can provide an avenue for the contaminant to penetrate the garment. A well designed and constructed protective suit with self-sealing zippers and lapped seams made of a nonporous degradation-resistant material prevents penetration, but as soon as the suit is ripped or punctured it loses its ability to prevent penetration. A material may also be easily penetrated once degraded.

Permeability. The ability of a protective material to resist permeation is an inherent property. A contaminant in contact with the protective material establishes a concentration gradient. The concentration is high on the contact surface and low inside. Because the tendency is to establish equilibrium, diffusion and other molecular forces "drive" the contaminant into the material.

When the contaminant passes through the material to the inside surface, it condenses there. The process of permeation continues as long as the concentration remains greater at the contact surface. The permeation rate is based on several factors. Rate is inversely proportional to the thickness of the material and directly proportional to the concentration of the contaminant.

The amount or degree of permeation is related to the exposure conditions, especially contact time, which ultimately dictates how much of the contaminant permeates the protective material. Thus a conscious effort should be made to avoid prolonged exposure or contact with any hazardous contaminant, even when wearing protective clothing. No material resists permeation by all agents.

Decontamination. Once a contaminant contacts a protective material, the garment must be decontaminated. With many materials, it is impossible to completely remove all contamination. Materials such as butyl rubber and Viton, which can be effectively decontaminated and cleaned, are also expensive. In some situations disposable clothing may be advantageous.

Chemical Resistance Charts. Tables are available indicating relative effectiveness of various protective materials against generic classes of chemicals (for specific chemicals). Most tables only reflect ability to resist degradation. A protective material may resist degradation by a contaminant, but still be very permeable to it. Such charts are useful when used with discretion and when the seriousness of the hazard is properly evaluated. If a chemical is extremely toxic, then any activity involving it should be re-evaluated.

Permeability data are available from manufacturers and independent testing laboratories. If there is a question about permeability of a material in contact with a specific contaminant, a sample swatch of the material should be tested by a recognized laboratory for permeability to that chemical.

Other Useful Resources

Protective Clothing for Avian Flu

A Guide for Evaluating the Performance of Chemical Protective Clothing

Control Technologies and Personal Protective Equipment
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