Definitions of Terms
| Term | Definition |
|---|---|
| Abrasive blasting respirator | Type AE, BE, and CE supplied-air respirators designed and constructed to provide protection to the wearer's head and neck, against impact and abrasion from rebounding abrasive materials. |
| Closed-circuit apparatus | An apparatus of the type in which the exhalation is rebreathed by the wearer after the carbon dioxide has been effectively removed and a suitable oxygen concentration restored from resources composed of (1) compressed oxygen, (2) chemical oxygen, or (3) liquid-oxygen. |
| Continuous-flow airflow class | Type C supplied-air respirator which supplies respirable air at a constant flow at all times, rather than only on demand. In place of a demand or pressure-demand regulator, an airflow control valve or orifice partially controls the airflow. This means that by design, the control valve cannot be closed completely, or a continually open bypass is provided to allow air to flow around the valve and maintain the required minimum rates. |
| Demand airflow class | Provides airflow into the facepiece only on "demand" by the wearer's inhalation. |
| Dust, fume, and mist respirator | A respirator, with replaceable filters, designed as respiratory protection against dust, fume, and mist (1) having an air contamination level not less than 0.05 milligram per cubic meter or air; or (2) dust, fume, or mist having an air contamination level not less than 2 million particles per cubic foot of air. Also, designed as respiratory protection against radon daughters, and radon daughters attached to dusts, fumes, and mists. |
| Dust-only respirator | A respirator, with replaceable filters, designed as respiratory protection against dusts (1) having an air contamination level not less than 0.05 milligram per cubic meter or air; or (2) dusts having an air contamination level not less than 2 million particles per cubic foot of air. |
| Escape only respiratory device | Provides protection only during escape from hazardous atmospheres. |
| Filtering facepiece | A type of N, R, or P series disposable particulate respirator with a filter as an integral part of the facepiece or with the entire facepiece composed of the filtering medium. The unit may or may not have an exhalation valve. The unit has no replaceable parts. |
| Full facepiece | Covers from roughly the hairline to below the chin. On the average provides the greatest protection, usually seal most reliably, and provides some eye protection as well. |
| Fume respirators with replaceable filter | Designed as respiratory protection against fumes of various metals having an air contamination level not less than 0.05 milligram per cubic meter |
| Half mask | Fits over the nose, mouth, and under the chin. |
| Hood or Helmet | Loose-fitting respirators that enclose at least the head. A light, flexible device covering only the head and neck, or head, neck, and shoulders is called a hood. If rigid headgear is incorporated into the design, it is called a helmet. Blouses extend down to the waist, and some have wrist-length sleeves. The enclosure includes a system through which clean compressed air is distributed around the breathing zone. It may include a head harness and connection for a breathing tube. |
| Mist respirators with replaceable filters | Designed as respiratory protection against mist of materials having an air contamination level not less than 0.05 milligram per cubic meter or 2 million particles per cubic foot. |
| Mouthpiece respirator | Consists of a mouthpiece held in the teeth (the lips seal around it) and a clamp that closes the nostrils. Mouthpiece respirators should provide a good seal, but they eliminate communication, may cause fatigue, and provide no eye protection. Therefore, mouthpiece respirators are certified for use as escape-only respirators. |
| N100 | Particulate Filter (99.97% filter efficiency level) effective against particulate aerosols free of oil; time use restrictions may apply. |
| N95 | Particulate Filter (95% filter efficiency level) effective against particulate aerosols free of oil; time use restrictions may apply. |
| N99 | Particulate Filter (99% filter efficiency level) effective against particulate aerosols free of oil; time use restrictions may apply. |
| Obsolete | A respirator that (a) is no longer produced by the manufacturer, (b) no longer sold under private label by an approved rebrander, (c) neither the manufacturer nor private labeler has any future plans to produce, or (d) was given NIOSH or NIOSH/MSHA approval but never actively produced by the manufacturer or private labeler. NOTE: Any "obsolete" respirator in use that carries NIOSH/MSHA or NIOSH approval and has been maintained in accordance with approved designs and specifications, continues to be approved until discarded or scrapped due to physical damage, lack of maintenance, or unavailable repair parts. |
| Open-circuit demand type | An apparatus in which the pressure inside the facepiece in relation to the immediate environment is positive during exhalation and negative during inhalation and from which exhalation is vented to the atmosphere and not rebreathed. |
| Open-circuit pressure demand type | An apparatus in which the pressure inside the facepiece in relation to the immediate environment is positive during both inhalation and exhalation and from which exhalation is vented to the atmosphere and not rebreathed. |
| Oxygen-generating respirator | A respirator which supplies oxygen by means of a chemical reaction. |
| P100 | Particulate Filter (99.97% filter efficiency level) effective against all particulate aerosols. |
| P95 | Particulate Filter (95% filter efficiency level) effective against all particulate aerosols. |
| P99 | Particulate Filter (99% filter efficiency level) effective against all particulate aerosols. |
| Pesticide | (1) Any substance or mixture of substances (including solvents and impurities) intended to prevent, destroy, or repel, or mitigate any insect, rodent, nematode, fungus, weed, or other form of plant or animal life or virus, and (2) any substance or mixture of substances (including solvents and impurities) intended for use as a plant regulator, defoliant, or desiccant, as defined in the Federal Insecticide, Fungicide, and Rodenticide Act of 1947, as amended (7 U.S.C. 135-135k), excluding fumigants which are applied as gases or vapors or in a solid or liquid form as pellets or poured liquids for subsequent release as gases or vapors. |
| Powered air-purifying respirator (PAPR) | A device equipped with a facepiece, hood, or helmet, breathing tube, canister, cartridge, filter, canister with filter, or cartridge with filter, and a blower. |
| Pressure-demand airflow class | Very similar to the demand class except that the regulator admission valve is held slightly open until the pressure in the facepiece reaches a preset pressure point, then closes. (maintains a slight positive pressure in the facepiece at all times). All pressure-demand devices have a special exhalation valve that maintains about 1.5 inches H2O positive back pressure in the facepiece, and opens only when the pressure exceeds that value. This combination of modified regulator and special exhalation valve is designed to maintain positive pressure in the facepiece at all times. |
| Private label | Private labeled products are labeled as belonging to a company or interest that is not the manufacturer. Private labeled products will carry the same approval number that was issued to the manufacturer. |
| Quarter mask | Covers the mouth and nose, and the lower sealing surface rests between the chin and mouth. |
| R100 | Particulate Filter (99.97% filter efficiency level) effective against all particulate aerosols; time use restrictions may apply. |
| R95 | Particulate Filter (95% filter efficiency level) effective against all particulate aerosols; time use restrictions may apply. |
| R99 | Particulate Filter (99% filter efficiency level) effective against all particulate aerosols; time use restrictions may apply. |
| Replaceable filter | A filter attached to the respirator by mechanisms that allow replacement after excessive resistance, sorbent exhaustion, hygiene considerations, or physical damage renders it unsuitable for further use. |
| Service Time | The length of time required for an air-purifying element to reach a specific effluent concentration. Service time is determined by the type of substance being removed, the concentration of the substance, the ambient temperature, the specific element being tested (cartridge or canister), the flow rate resistance, and the selected breakthrough value. The service time for a self-contained breathing apparatus (SCBA) is the period of time, as determined by the NIOSH certification tests, in which adequate breathing gas is supplied. Current service time ratings are 3 minutes, 5 minutes, 10 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 3 house, 4 hours, and other service times as prescribed by the Institute. |
| Single use respirator | A respirator that has no replaceable filter and is not cleanable. This type of respirator is entirely discarded after excessive resistance, sorbent exhaustion, hygiene considerations, or physical damage renders it unsuitable for further use. |
| Supplied-air "Hose mask" respirator (Type A) | For entry into and escape from atmospheres not immediately dangerous to life or health, which consists of a motor-driven or hand-operated blower that permits the free entrance of air when the blower is not operating and a strong large-diameter hose having a low resistance to airflow. |
| Supplied-air "Hose mask" respirator (Type AE) | A Type A supplied-air respirator equipped with additional devices designed to protect the wearer's head and neck against impact and abrasion from rebounding abrasive material, and with shielding material such as plastic, glass, woven wire, sheet metal, or other suitable material to protect the window(s) of facepieces, hoods, and helmets which do not unduly interfere with the wearer's vision and permit easy access to the external surface of such window(s) for cleaning. |
| Supplied-air respirator (SAR) | An airline respirator |
| Supplied-air respirator (Type B) | A hose mask respirator, for entry into and escape from atmospheres not immediately dangerous to life or health, which consists of a strong large diameter hose with low resistance to airflow through which the user draws inspired air by means of his lungs alone, a harness to which the hose is attached, and a tight-fitting facepiece. |
| Supplied-air respirator (Type BE) | A Type B supplied-air respirator equipped with additional devices designed to protect the wearer's head and neck against impact and abrasion from rebounding abrasive material, and with shielding material such as plastic, glass, woven wire, sheet metal, or other suitable material to protect the window(s) of facepieces, hoods, and helmets which do not unduly interfere with the wearer's vision and permit easy access to the external surface of such window(s) for cleaning. |
| Supplied-air respirator (Type C) | An airline respirator, for entry into and escape from atmospheres not immediately dangerous to life or health, which consists of a source of respirable breathing air, a hose, a detachable coupling, a control valve, orifice, a demand valve or pressure demand valve, and arrangement for attaching the hose to the wearer and a facepiece, hood, or helmet. |
| Supplied-air respirator (Type CE) | A Type C supplied-air respirator equipped with additional devices designed to protect the wearer's head and neck against impact and abrasion from rebounding abrasive material, and with shielding material such as plastic, glass, woven wire, sheet metal, or other suitable material to protect the window(s) of facepieces, hoods, and helmets which do not unduly interfere with the wearer's vision and permit easy access to the external surface of such window(s) for cleaning. |
| Type A particulate respirators - Asbestos-containing dusts and mists (30 CFR 11) |
Respirators, with replaceable filters, designed as respiratory protection against asbestos-containing dusts and mists, however, no longer permitted for use under the OSHA asbestos standard, 1910.1001. |
| Type H particulate respirators - Dusts, Fumes, Mists and Radionuclides (30 CFR 11) |
Respirators, with replaceable filters, designed as respiratory protection against dusts, fumes and mists having an air contamination level less than 0.05 milligram per cubic meter, and against |
| Type R particulate respirators - Radon daughters (30 CFR 11) |
Respirators, with replaceable filters, designed as respiratory protection against radon daughters, and radon daughters attached to dusts, fumes, and mists. |
- CEL Data last Updated: N/A
- Page last reviewed: December 13, 2024
- Page last updated: December 13, 2024
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Content source:
- National Institute for Occupational Safety and Health (NIOSH)
- Page maintained by: National Personal Protective Technology Laboratory