Half-face respirators

Half-face respirator See Half-mask respirator. 

Rubber or plastic-coated coverall (worn over underwear) with hood, chemical-resistant gloves, chemical-resistant boots, and goggles and half-face respirator (or full-face respirator). 

A spill should be promptly cleaned up using either a commercial solvent spill kit material to absorb the hquid or a preparation of equal parts of soda ash, sand, and clay cat htter, which has been recommended as an absorbent. Since the lower explosion limit concentrations are so low for so many of the commonly used ethers, all ignition sources should be promptly turned off following a spill and all except essential personnel required to leave the area. The personnel performing the clean up should wear half-face respirators equipped with organic cartridges. The resulting waste mixture from the clean up can be placed in a fume hood temporarily until removed from the laboratory for disposal as a hazardous waste. 

Since a power-assisted air-purifying (PAAP) respirator is a positive-pressure system, i.e., the air within the facepiece is atahigherpressure than the outside air, this type of unit intrinsically provides more protection than the ordinary half-face respirator. If provision is made for an escape mode of operation, i.e., the wearer can continue to breathe through the filters should the pump fail, and escape from the contaminated atmosphere. The ANSI Z88.2 standard (AmericanNational Standard Institute) would permit the use ofthis type ofrespiratorin an IDLH atmosphere. Some ofthe early models of this type of unit had some problems with the seals on the pumps, but these problems have been corrected and they represent a desirable alternative if the wearer is to remain in a contaminated atmosphere for extended periods. There have been a few problems with the pumps overheating while being used at elevated temperatures. 

Respiratory protection devices are rated as to the effectiveness of the protection provided. A typical protection factor for a full-face air purifying respirator, those with filter cartridges and no separate air supply is a factor of 100, impl3dng that the contaminant concentration inside the respirator is no more than 1/100th of the concentration in the ambient air 10 CFR 20 Appendix A contains a table of respiratory protection factors for different types of respiratory protection. As the degree of inhalation risk increases, the risk of skin contamination also increases. Therefore, half-face respirators, those without a covering for the eyes, are not commonly worn. In addition, some form of anti-contamination... 

When exhaust ventilation is not feasible, respiratory protection shall be used depending on the risk assessment disposable FPP3-type mask or full- or half-face respirators. 

Half-mask respirator A respiratory protective device that covers roughly half of the face, from under the chin to the bridge of the nose. 

Level C Full-face or half-face air-purifying respirator, splash clothing or chemical-resistant coveralls, inner and outer gloves, chemical-resistant boots with protective toe, and hard hat. 

Respirators provide protection against inhaling harmful materials. Different types of respirators may be used depending on the level of protection desired. For example, supplied-air respirators (e.g., a self-contained breathing apparatus) may be required in situations where the presence of highly toxic substances is known or suspected and/or in confined spaces where it is likely that toxic vapors may accumulate. On the other hand, a full-face or half-face air-purifying respirator may be used in situations where measured air concentrations of identified substances will be reduced by the respirator below the substance s threshold limit value (TLV) and the concentration is within the service limit of the respirator (i.e., that provided by the canister). 

PERSONAL PROTECTION wear clean body-covering clothing and protective gloves wear chemical safety goggles a closed system of local exhaust ventilation is recommended to control emissions at the source and to prevent dispersion into the general work area a half-face dust/mist respirator is needed in areas where exposure would be above the permissible exposure level in an event of a fire, wear self-contained breathing apparatus use non-sparking tools and equipment. 

Respiratory tract Dust, vapour, gas, aerosols, oxygen-deficient atmospheres Disposable filtering face piece or respirator, filtering half or full-face respirators, air-fed helmets, breathing apparatus (independent from ambient air)... 

The half-face cartridge respiratoris the type most frequently used, especially in atmospheres in which there is little or no problem of irritation or absorption ofmaterialthrough the skin. The facepiece of most of these units is molded ofa flexible plastic orsilicone rubber, which provides a seal to the face when properly adjusted. As noted earlier, facialhair between the mask and the face will prevent the seal from being effective, and it is not permitted for a person with a beard or extended sideburns in the area of the seal to be fitted with a respirator. Accommodation for individuals who wear glasses also must not break the seal to the face. The facepieces of most... 

The cost of full-face respirators is substantially more than the half-face units, typically by a factor of 4 or 5. 

A variation of the full-face respirator is the PAAP unit discussed in the previous section. In one version, the only difference is that it supplies a full-face mask instead of a half-face mask. Flowever, a useful variation is for the PAAP unit to supply air into the top of a hood which has a cape extending down to the shoulders. Some ofthesehave atransparentsection extending all the way around the upper part of the hood and provide an unusual degree offlexibility in vision and comfort, with a minimal loss in protection. This style accommodates both facial hair and glasses. 

Forother features of full-face respirators other than those covered here, the informationon half-face units in Section B.2 of this chapter will apply. 

Several types of nonemergency respirators are available for protection in atmospheres that are not immediately dangerous to life or health but could be detrimental after prolonged or repeated exposure. Other types of respirators are available for emergency or rescue work in hazardous atmospheres from which the wearer needs protection. In eitha-case, additional protection may be required if the airborne contaminant is of a type that could be absorbed through or irritate the skin. For example, the possibility of eye or skin irritation may require the use of a full-body suit and a fuU-face mask rather than a half-face mask. For some chemicals the dose from skin absorption can exceed the dose from inhalation. 

If a half-face air-purifying respirator is taken out of use, indicate it on the inspection records. The respirator must be inspected thoroughly before it is put back in use. 

Air-purifying respirators are either half-face or full-face. Half-face air-purlfying respirators are designed to cover the mouth and nose. In contrast, full-face respirators form a positive seal around the eyes, nose, and mouth. These respirators are designed to remove specific contaminants or organic vapors from the air. Concentrations of these contaminants may range from 5 to 50 times the normal exposure limit allowed by law. 

Single-use respirator Quarter-mask respirator Half-mask respirator Full-face respirator... 

A system of local or general exhaust is recommended to keep employee exposures as low as possible. Local exhaust ventilation is preferable because it controls the emissions of the contaminant at its source, preventing dispersion of it into the general work area. For conditions of use where exposure to the dust or mist is apparent, a half-face dust/mist respirator may be worn. 

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