Ceiling exposure limit

Value is a PEL C, ie, permissible exposure limit ceiling exposure limit. 

Ceiling exposure limit The maximum allowed concentration of a contaminant to which a worker may be exposed, set by legislation. 

Peak-above-ceiling exposure limit The short-term exposure peak permitted above the OSHA standard ceiling exposure level. 

Peak limit A pollutant or noise level that exceeds the ceiling exposure limit, but is allowed for a specific limited time during the work shift. 

Ceiling Exposure limit that specifies the concentration of vapor, dust, or aerosol that should not be exceeded at any time during the workday. In some instances, a time limit for exposure to the ceiling value is established and is indicated in parentheses. A [Skin] notation indicates that percutaneous absorption of the material is a potential hazard and may contribute to the overall exposure. 

Threshold limit value (TLV) The concentration of an airborne substance to which an average person can be repeatedly exposed without adverse effects. TLVs may be expressed in three ways 1) TLV-TWA (Time weighted average), based on an allowable exposure averaged over a normal 8-hour workday or 40-hour workweek 2) TLV-STEL (Short-term exposure limit) or maximum concentration for a brief specified period of time, depending on a specific chemical (TWA must still be met) and 3) TLV-C (Ceiling Exposure Limit) or maximum exposure concentration not to be exceeded under any circumstances. TWA must still be met. 

These exposure results were within the limits of the OSHA standards for TWA, celling, and peak exposure and the ACGIH TLV standard of 5 ppm. The peak exposures determined sometimes exceeded the ACGIH Short Term Exposure Limit maximum of 20 ppm and the NIOSH 2 ppm for 1-hour ceiling exposure limit. 

TLV-C—Ceiling Exposure Limit or maximum exposure concentration not to be exceeded under any circumstances. 

TLV-C Ceiling Exposure Limit the concentration that should not be exceeded even momentarily. 

The major hazard with caustic solutions is hodily contact [13]. Both NaOH and KOH are very strong alkalis and are corrosive to human tissue. A concentration of 1 mg m of NaOH in the air, as mist or dust, can cause mild watering of the eyes. A concentration of 2mgm is taken as an average or a ceiling exposure limit. The National Institute of Occupational Safety and Health (NIOSH) now lists 10 mg m as immediately dangerous to life or health (changed from 250 mg m c. 1995). Those who work with these materials must also be alert to delayed symptoms, as minor contact may not produce immediate effects. 

CEILING EXPOSURE LIMIT An airborne concentration that is not to be exceeded at any time during the working day. 

PEL = personal exposure limit LEL = lower exposure limit UEL = upper exposure Ceiling limit is the concentration that should not be exceeded during any part of the working exposure relative vs -butyl acetate = 1, Relative to air = 1. 

Safety. Chlorosulfuric acid is a strong acid and the principal ha2ard is severe chemical bums when the acid comes into contact with body tissue. The vapor is also ha2ardous and extremely irritating to the skin, eyes, nose, and respiratory tract. Exposure limits for chlorosulfuric acid have not been estabhshed by OSHA or ACGIH. However, chlorosulfuric acid fumes react readily with moisture in the air to form hydrochloric and sulfuric acid mists, which do have estabhshed limits. The OSHA 8-h TWA limits and ACGIH TLV—TWA limits are sulfuric acid = 1 mg/m hydrochloric acid = 5 ppm or 7 mg/m (ceiling limit). 

Workplace. The Occupational Safety and Health Administration (OHSA) has estabUshed workplace permissible exposure limits (PEL) for chromium metal and three forms of chromium compounds. OSHA s PEL for chromic acid and chromates is 0.1 mg/m 3 both a ceiling, ie, no exposure above this concentration is allowed, and an 8-h time-weighted average (TWA). Chromium metal and insoluble chromium salts have an 8-h TWA PEL of 1.0 mg/m Cr, and the same standard is 0.5 mg/m Cr for soluble Cr(III) and Cr(II) compounds (144). 

Ceiling Rcconiincndcd Exposure Limit (CREL) Exposure limit which should not be exceeded at any time. 

Reeuinincndcd Exposure Limit (REL) NlOSH-rccommendcd exposure limit for an 8- or lO-h timc-wcightcd-averagc exposure and/or ceiling,... 

The TLV may be expressed as a Time Weighted Average (TWA), as a Short-Term Exposure Limit (STEL), or as a ceiling limit (CL). 

Threshold Limit Value (TLV)—An American Conference of Governmental Industrial Hygienists (ACGIH) concentration of a substance to which most workers can be exposed without adverse effect. The TLV may be expressed as a Time Weighted Average (TWA), as a Short-Term Exposure Limit (STEL), or as a ceiling limit (CL). 

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. 

NOISH Recommended exposure limit guidelines for occupational exposure TWA Ceiling (15 minutes) IDLH... 

TLVs established by the ACGIH, including short-term exposure limits (TLV-STELs) and ceiling concentrations (TLV-Cs),... 

TIN-TWA Threshold limit value, time-weighted average for 8-h exposures, with ceiling concentrations shown as C, and with skin absorption hazard as S. The OSHA permissible exposure limit (PEL) is the lower of the TWA or the ceiling limit. 

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. 

Threshold Limit Value Airborne concentrations of substances devised by the ACGIH that represent conditions under which it is believed that nearly all workers maybe exposed day after day with no adverse effect. TLV s are advisory exposure guidelines, not legal standards, based on evidence from industrial experience, animal studies, or human studies when they exist. There are three different types of TLV s Time Weighted Average (TLV-TWA) Short Term Exposure Limit (TLV-STEL) and Ceiling (TLV-C). (See also PEL)... 

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