Environment, Health and Safety Online
The site for free, objective information you can use!
The selection of appropriate protective gear is based on the hazards anticipated or recognized. Complete protection calls for assembling a set of gear including respirator, hardhat, safety glasses or faceshield (preferably both), body covering (coveralls, pants and jacket), gloves and safety boots/shoes (steel toe and shank). Omitting one item may compromise the individual's safety.
Some pieces of protective equipment, such as hardhats and boots, have specific standards for manufacture and only those items meeting these standards should be used. However, there are no such standards for chemical protective clothing. Selections must be based upon judgment.
The hardhat, a basic piece of safety equipment used in any work operations, must meet ANSI Z89.1 1986 specifications for protection. Manufacturers have adapted hardhats so that ear protection and faceshields may be easily attached. Hardhats are adjustable so a liner can be worn during cold weather. A chin strap is advantageous when work involves bending and ducking. It also helps secure the hardhat to the head when full face masks are worn.
Faceshields that attach to hardhats provide added protection. A combination that leaves no gap between the shield and the brim of the cap is best because it prevents overhead splashes from running down inside the faceshield. The faceshield must meet ANSI Z87.1‑1989 specifications.
Safety glasses must also meet ANSI Z87.1‑1989. They should be standard safety gear when the respiratory protection is a half‑face mask with no faceshield. Both safety glasses/goggles and a faceshield are advisable as long as they do not impair visibility. Safety glasses should be of the type that incorporate face shields.
Ear plugs or muffs should be issued when noise may be a problem, such as around heavy machinery and impact tools.
Footwear worn during site activities (including leather work boots and rubber boots) must meet the specifications of ANSI Z41‑1991. The material used to make the boots is not subject to any standards.
Protection against liquid hazardous chemicals requires a boot of neoprene, PVC, butyl rubber, to some other chemical resistant material.
Boots are available in two styles: pullover and shoeboot. Pullovers may be inexpensive enough to be considered disposable; otherwise they must be completely decontaminated. With chemical resistant boots, the pant leg should be outside and over the boots to prevent liquids from entering.
The hands are as susceptible to contamination as the feet. Gloves must resist puncturing and tearing as well as provide the necessary chemical resistance. Most of the materials discussed earlier can be used in gloves.
Heavy leather gloves may be worn over chemical protective gloves when doing heavy work. If they become contaminated, they should be discarded because leather is difficult to decontaminate.
Jacket cuffs should be worn over glove cuffs to prevent any liquid from spilling into the gloves. If hands are elevated above the head during work, the gloves should be sealed with tape to the coveralls or splashsuit.
When selecting gloves consider thickness and cuff length. The thicker and longer the glove the greater the protection. However, the material should not be so thick that it interferes with the necessary dexterity.
Two pair of gloves should also be considered for extra protection of the hands if the outer glove is torn or permeated. A pair of inner gloves also adds an extra layer of protection for the hands during the removal of outer gloves and other chemically protective items.
Clothing to protect the body against hazardous liquids, gases, or vapors is available in a variety of styles and materials.
If the hazard present is known to be minor or simply a nuisance, minimal protection is warranted. This may be in the form of garments of Tyvek which are disposable or Nomex which are durable. Both are available as coveralls suitable for field use. As the hazards to the body increase, so does the level of protection needed. A splash suit made of PVC is suitable for a liquid such as an acid or base or when there will be minimal contact with organic materials. Some are inexpensive enough to be disposable.
If the material is more toxic, then more protection must be utilized. Splash suits similar in design to the PVC splash suits are good barriers against toxic hazards. These are made of neoprene and butyl rubber.
Toxic vapor/gases require the most complete protection, the best being fully encapsulating suits. The suit must not allow any penetration or permeation. Zippers must be properly sealed and seams properly connected and sealed to protect against vapors. Fully encapsulating suits also require the basic safety items such as safety boots and hardhat, along with a source of breathing air.
Wearing protective clothing creates some problems, the main one being that the body is shielded from normal circulation of air. Perspiration does not evaporate, thus eliminating the body's main mechanism for cooling. A cool towel on the nape (back of the neck) will effectively cause the hypothalamus (the body's thermostat to reduce the body's temperature immediately by 2 - 4 degrees in a heat stress situation. With that gone, the body is prone to heat stress, including heat stroke, which can be fatal. Heat related problems are very common when temperature rises above 75 degrees F. Work schedules for persons wearing fully encapsulating clothing must be closely and conservatively regulated lest heat stress becomes more of a threat than the chemical hazard itself.
The best way to combat heat stress is to allow the body to cool normally. The most efficient body cooling process is by evaporation. Someone wearing protective clothing that has no ventilation perspires profusely. If the perspiration remains in contact with the skin, it has a better chance of evaporating and cooling the body surface. If the perspiration is allowed to run off the body quickly, less evaporation occurs. This happens when shorts are worn under a fully encapsulating suit.
Suit material can become very hot and cause severe burns if it contacts the wearer's bare skin. Long cotton underwear is a good solution to this problem. It clings to the body when soaked with perspiration, thus allowing the greatest amount of cooling by evaporation and also protects the body from burns caused by the suit itself.
During extended periods of work in fully encapsulating suits, some sort of "cooling" must be provided to the wearer. The best method is to schedule frequent rest periods. If this is not adequate, a cooling device should be employed. Effective cooling units are available for use with supplied‑air units. A vortex tube separates the air into cool and warm components, releasing the warm air outside the suit. When self-contained air is used for breathing, the cooling device must also be self-contained. For example, vests have been designed to carry ice packs. There are other commercial devices available to combat heat generated by fully encapsulating suits.
Many workers spend some part of their working day in a hot environment. Workers in foundries, laundries, construction projects, and bakeries, to name a few industries, often face hot conditions which pose special hazards to safety and health.
Continue to page 2
back to top
This page was updated on 22-Mar-2017
This page was updated on 22-Mar-2017