NIOSH Ceiling Limit

NIOSH Ceiling Limit (NIOSH CL) NIOSH-recommended l5-min e.xposure limit, which should not be exceeded. 

Recommended Exposure Limit (REL) was developed by the National Institute for Occupational Safety and Health (NIOSH) and defines the highest allowable airborne concentration that is not expected to injure a worker expressed as a ceiling limit of time-weighted average for an eight- to ten-hour work day. 

Ceiling Limits and Approximate Safety Factors Recommended by NIOSH for Several Airborne Chemicals... 

Exposure limits The Occupational Safety and Health Administration (OSHA), the National Institute for Occupational Safety and Health (NIOSH), and the American Conference of Industrial Hygienists (ACGIH) recommend permissible exposure limits (PELs) for acetic anhydride as 5 ppm as a ceiling limit. ... 

The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit for halothane as a waste anesthetic gas of 2 ppm (16.2 mg m ) as a 60 min ceiling limit that should not be exceeded during any part of the workday. 

Non-enforceable guidelines have also been established for formaldehyde. The American Conference of Governmental and Industrial Hygienists (ACGIH) has established a ceiling limit for occupational exposure (Threshold Limit Value [TLV]) of 0.4 ppm. NIOSH has a recommended exposure limit for occupational exposure (8-hour TWA) of 0.016 ppm, and a 15-minute ceiling limit of 0.1 ppm. 

Detection Limit (NIOSH) ceiling 5 ppm/15 min (OSHA) carcinogenicity Recognized Human Carcinogen (ACGIH), Animal Sufficient Evidence, Human Sufficient Evidence (IARC), Cancer Suspect Agent (OSHA). 

TLV Values, In the United States, the equivalent of the MAK value is the threshold limit value (TLV). The TLV value is that concentration of a substance in the air to which virtually all workers can be exposed daily without any harmful effects. This value is subdivided into TLV-TWA (time-weighted average eoncentra-tion), TLV-STEL (short-term exposure limit), and TLV-C (ceiling limit). TLV-TWA applies to a normal 8-h working day or a 40-h week, TLV-STEL is the maximum concentration for an exposure time of 15 min, and TLV-C is the concentration that should at no time be exceeded. The TLV values published by the ACGIH are recommendations, whereas the PEL values (permissible exposure limit) specified by OSHA (Occupational Safety and Health Administration) are enforced by law. The safety limits are recommended to OSHA by NIOSH (National Institute of Occupational Safety and Health). Solvent TLV values for the USA and several European countries are listed in Table 13. 

If applicable, exposure limits are listed in this section of the MSDS. The OSHA permissible exposure limit (PEL) is a legal, regulated standard. Other limits may also be listed. These include recommended exposure limits (REL) from the National Institute for Occupational Safety and Health (NIOSH) and threshold limit values (TLV) from the American Conference of Governmental Industrial Hygenists (ACGIH). Sometimes, short-term exposure and/or ceiling limits are shown. The ceiling limit should never be exceeded. 

EPA has established that hydrogen sulfide is a regulated toxic substance and is a hazardous substance as defined under the Federal Water Pollution Control Act. OSH A has established an acceptable ceiling concentration of 20 parts per million (ppm) for hydrogen sulfide in the workplace, with a maximum level of 50 ppm allowed for 10 minutes maximum duration if no other measurable exposure occurs. NIOSH has set a maximum Recommended Exposure Limit (REL) ceiling value (10 minutes) of 10 ppm. A complete listing of federal and state regulations and recommendations are found in Chapter 7. 

Both ACGIH (1996) and NIOSH (1999) based their ceiling and short-term exposure limits, respectively, on one of the studies used for development of the AEGL-1. The value for both agency limits of 4.7 ppm was based on symptoms described during chronic exposures of workers in several studies and specifically on El Ghawabi et al. (1975). In 1993, the ACGIH value was reduced from 10 ppm to minimize the potential for irritation to the respiratory... 

Also included are recommended exposure limits (RELs) pubhshed by NIOSH (1997) and/or threshold limit values (TLVs) published by the American Conference of Govermnental Industrial Hygienists (ACGIH). Unless noted otherwise, the NIOSH RELs are TWA concentrations for up to a 10-h workday during a 40-h workweek. The short-term exposure limit (STEL) is a 15-min TWA that should be exceeded at any time during the workday. Recommended ceiling values are concentrations that should never be exceeded at any time during the day. 

Exposure limits (ppm) Potential occupational carcinogen. NIOSH REL TWA 1, 15-min ceiling 1, IDLH 85 OSHA PEL TWA 2, 15-min ceiling 10 ACGIH TLV TWA 2 (proposed). 

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