Document Bwb4v28nMM91LjZj7RmXR5nL

TLV'$ - / ? 7J, TLVs Threshold Limit Values for Chemical Substances in Workroom Air Adopted by the American Conference of Government Industrial Hygienists for 1973 Preface Chemical Contaminants Threshold limit values refer to air borne concentrations of substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after day without adverse effect. Because of wide variation in individual rusceotibilitv, howevei, a small percentage of wuikers may experience discomfort trom some substances at concentrations at or below the threshold limit, a smaller percentage may be affected more seriously by aggravation of a pre-existing condition or by development of an occupational illness. Simple tests are now available (|. Occup. Med. 9.537, 1967; Ann. N.Y. Acad Sci., 757, Art 2:968, 1968) that may be used to detect those individuals hypersusceptible to a variety of industrial chemicals (respiratory irritants, hemolyt ic chemicals, organic isocyanates, car bon disulfide). These tests may be used to screen out by appropriate job placement the hyperreactive worker and thus in effect improve the "coverage" of the TLVs. Threshold limit values refer to timeweighted concentrations for a 7 or 8hour workday and 40-hour workweek. They should be used as guides in the control of health hazards and should not be used as fine lines between safe and dangerous concentrations (Exceptions are the substances listed in Appendices E Reprinted tilth ihv |M*mitKon U Ihe American Confer*!*.** of Governmental Indujtrul HygterwM*. and F and those substances designated with a "C" or Ceiling value, Appendix D) Time-weighted averages permit ex cursions above the limit provided they are compensated by equivalent ex cursions below the limit during the workday. In some instances it may be permissible to calculate the average conrenlralinn for a workweek rather fliar, for a workday. I he degree ot [lermissioie excursion is related to the magnitude of the threshold limit value of a particular substance as given in Appendix D. The relationship between threshold limit and permissible excursion is a rule of thumb and in certain cases may not apply. The amount by which threshold limits may be exceeded for short periods without injury to health depends upon a number of factors such as the nature of the con taminant, whether very high concentra tions -- even for short periods -- produce acute poisoning, whether the effects are cumulative, the frequency with which high concentrations occur, and the duration of such periods. All fac tors must be taken into consideration in arriving at decision as to whether a hazardous condition exists. Threshold limits are based on the best available information from industrial expertence, from experimental human and animal studies, and, when possible, from a combination of the three. The basis on which the values are established may differ from substance to substance: protection against impair ment of health may be a guiding iactoi for some, whereas reasonable freedom Journal of Occupational Medicine/Yol. 16, No. 1/January 1974 from irritation, narcosis, nuisance or othei forms of stress may form the basis for others. The amount and nature of the in formation available for establishing a TLV varies from substance to substance; consequently, the precision of the estimated TLV is also subject to variation and the latest Documentation should be ron-.ultrri in order to asses-, the rxtent of the data available lor a given substance. The committee holds to the opinion that limits based on physical irritation should be considered no less binding than those based on physical im pairment. There is increasing evidence that physical irritation may initiate, promote or accelerate physical im pairment through interaction with other chemical or biologic agents. In spite.of the fact that serious injury is not believed likely as a result of ex posure to the threshold limit con centrations, the best practice is to main tain concentrations of all atmospheric contaminants 'as low as is practical. These limits are intended for use in the practice of industrial hygiene and should be interpreted and applied only by a per son trained in this discipline. They are not intended for use, or for modification for use. (1) as a relative index of hazard or toxicity, (2) in the evaluation or air pollution nuisances, (3) in estimating the toxic potential of continuous, unin terrupted exposures, (4) as proof or disproof of an existing disease or physical condition, or (5) for adoption by countries whose working conditions differ from those in the United States of OLI 2329 39 America and where substances and processes differ. Ceiling vs Time-Weighted Average Limits. Although the time-weighted average concentration provides the most satisfactory', practical way of monitoring airborne agents for compliance with the limits, there are certain substances for which it is inappropriate. In the latter group are substances which are predominantly fast acting and whose threshold limit is more appropriately based on this particular response. Sub stances with this type of response are best controlled by a ceiling "C" limit that should not be exceeded. It is im plicit in these definitions that the manner of sampling to determine compliance with the limits for each group must dif fer; a single brief sample, that is ap plicable to a "C" limit, is not appropriate to the time-weighted limit; here, a suf ficient number of samples are needed to permit a time-weighted average con centration throughout a complete cycle of operations or throughout the work shift. Whereas the ceiling limit places a definite boundary which concentrations should not be permitted to exceed, the time-weighted average limit requires an explicit limit to the excursions that are |X.amissible above tire listed values. The magnitude of these excursions may be pegged to the magnitude of the threshold limit by an appropriate factor shown in Appendix D. tt should be noted that the same factors are used by the Committee in making a judgment whether to include or exclude a sub stance for a "C" listing, "Skin" Notation. Listed substances followed by the designation "Skin" refer to the potential contribution to the overall exposure by the cutaneous route including mucuous membranes and eye, either by airborne, or more particularly, by direct contact with the substance.Vehicles cart alter skin absorption This attention-calling designation is intended to suggest appropriate measures for the prevention of cutaneous absorption so that the threshold limit is not invalidated. Mixtures. Special consideration should be given also to the application of the TIVs in assessing the health hazards which may be associated with exposure to mixtures of two or more substances. A brief discussion of basic considerations involved in developing threshold limit values for mixtures, and methods for their development, amplified by specific examples are given in Appendix C. Nuisance Particulates. In contrast to fibrogenic dusts which cause scar tissue to be formed rn lungs when inhaled in excessive amounts, so-called "nuisance" dusts have a long history of little adverse effect on lungs and do not produce significant organic disease or toxic effect when exposures are kept under reasonable control The nuisance dusts have also been called (biologically) "inert" dusts, but the latter term is inap propriate to the extent that there is no dust which does not evoke some cellular response in the lung w i inhaled in sufficient amount. However, the lungtissue reaction caused by inhalation of nuisance dusts has the following charac teristics: 1) The architecture of the air spaces remains intact 2) Collagen (scar tissue) is not formed to a significant ex tent. 3) The tissue reaction is potentially reversible. Excessive concentrations of nuisance dusts in the workroom air may seriously reduce visibility (iron oxide), may cause unpleasant deposits in the eyes, ears and nasal passages (Portland Cement dust), or cause injury to the skin or mucous membranes by chemical or mechanical action per se or by the rigorous skin cleansing procedures necessary for their removal. A threshold limit of lOmg/m*. or 30 mppef. of total dust<1% quartz is recommended for substances in these categories and for which no specific threshold limits have been assigned. This limit, for a normal workday, does not apply to brief exposures at higher con centrations. Neither does it apply to those substances which may cause physiologic impairment at tower con centrations but for which a threshold limit has not yet been adopted. Some nuisance particulates are given in Ap pendix E. Simple Asphyxiants -- "Inert" Cases or Vapors. A number of gases and vapors, when present in high con centrations in air, act primarily as simple asphyxiants without other significant physiologic effects. A TLV may not be recommended for each simple asphyxiant because the limiting factor is the available oxygen. The minimal oxygen content should be 18 percent by volume under normal atmospheric pressure (equivalent to a partial pressure, pOt of 13S mm Hg). Atmospheres deficient in Oi do not provide adequate warning and most simple asphyxiants are odorless. Several simple asphyxiants present an explosion hazard Account should be taken o( this factor in limiting the concentration ot the asphyxiant. Specific examples arc listed in Appendix F. Short-Term Limits (STLs). Because many industrial exposures are not con tinuous. 8-hour daily exposures, but are short-term, or intermittent, to which the TLVs do not necessarily apply, STLs for 5. 15, or 30 minutes for 142 substances have been put into the regulations of the Pennsylvania Department of Health (Chapter 4, Art. 432, Revised Jan. 25, 1968). These STLs represent the maximal average atmospheric concentration of a Contaminant to which a worker may be exposed for the stipulated time. The con centration represents an upper limit of exposure and assumes that there is suf ficient recovery between exposures before another is initiated. The daily average exposure including that provided by the STL shall be such that the TLV- shall not be exceeded. Similar STLs for a more restricted num ber of substances have been recom mended by the American National Stan dards Institute. This standard-setting body refers to these short-term limits as "peaks." Physical Factors. It is recognized that such physical factors as heat, ultraviolet and ionizing radiation, humidity, ab normal pressure (altitude) and the like may place added stress on the body so that the effects from exposure at a threshold limit may be altered. Most of these stresses act adversely to increase the toxic response of a substance. Although most threshold limits have built-in safety factors to guard against adverse effects to moderate deviations from normal environments, the safety factors of most .substances are not of such a magnitude as to take care of gross deviations, for example, continuous work at temperatures above 90F ot overtime extending the workweek more than 25%, might be considered gross deviations. In such instances ludgment must be exercised in the proper ad justments of the threshold limit values. Biologic Limit Values (BLVs). Other means exist and may be necessary for monitoring worker exposure other than reliance on the Threshold Limit Values for industrial air, namely, the Biologic Limit Values. These values represent limiting amounts of substances (or their effects) to which the worker may be ex- 40 TlVs for Chemical Substances in Workroom Air OLI 2330 posed without hazard to health or well being as determined in his tissues and fluids or in his exhaled breath The biologic measurements on which the BLVs are based can furnish two kinds of information useful in the control of worker exposure (1) measure of the in dividual worker's over-all exposure; (2) measure of the worker's individual and characteristic response. Measurements of response furnish a superior estimate of (he physiologic status of the worker, and may be made of (a) changes in amount of some critical biochemical constituent, (b) changes in activity of a critical en zyme, (c) changes in some physiologic function. Measurement of exposure may be made by (1) determining in blood, urine, hair, nails, in body tissues and fluids, the amount of substance to which the worker was exoosed; (2) deter mination of the amount of the metabolite(s) of the substance in tissues and fluids; (3) determination of the amount of the substance in the exhaled breath. The biologic limits may be used as an adjunct to the TLVs for atr, or in place of them The U S, National In stitute for Occupational Safety and Health is proposing a senes of these BLVs which will be issued from time to lime as part of the Criteria Documents for recommended mdustiidl oil stan dards Unlisted substances. There are a num ber of reasons why a substance does not appear in the Threshold Limit list; either insufficient information is available or it has not been, brought to the attention of the Threshold Limits Committee from which a limit can be developed, or it is a substance that could be included in the Appendices E and F pertaining to Nuisance Particulates and Simple Asphyxiants. Substances appearing in these appendices serve as examples only; the appendices are not intended to be inclusive. "Notice of Intent" At the beginning of each year, proposed actions of the Com mittee for the forthcoming year are issued in the form of a "Notice of In tended Changes " This Notice provides not only an opportunity for comment, but solicits suggestions of substances to be added td the list. The suggestions should be accompanied by sub stantiating evidence. The list of Intended Changes follows the Adopted Values in the TLV booklet, legal Status. By publication in the Federal Rcgisier (Vol. 36, No. 105, May 29, 1971) the Threshold Limit Values are now official federal standards for in dustrial air Reprint Permission. This publication may be reprinted provided that written permission is obtained from the Secretary-Treasurer of the Conference and that it be published in its entirety Adopted Values See Documentation for basis of TLVs Substance ppm*1 Abate .............................. Acetaldehyde .................. 100 Acetic acid...................... 10 CAcetic anhydride . 5 Acetone . ............. 1,000 Acetonitrile..................... 40 2-Acelylaminofluorene -- Skin............ ....... Acetylene......................... Acetylene dichloride, see 1, 2-Dichloroeihylene... F Acetylene tetrabromide.... Acrolein........................... Acrylamide--Skin ......... 1 0,1 Acrylonitrile--Skin ......... Aldrin--Skin .................. Allyl alcohol--Skin.......... Allyl chloride................... * Allyl glycidyl ether (ACE) Allyl propyl disulfide... , Alundum (AhOj)............ 4-Aminodiphenyl--Skin 20 _ 2 1 S 2 _ 2-Aminoethanol, see Ethanolamine................ 2-Aminopvndine.............. Ammonia............... ......... Ammonium chloride. lump 0.5 25 Ammonium *ulfamate (Ammate).................... n-Amyl acetate................ sec-Amyl acetate............. Aniline--Skin.................... _ 100 12S 5 Anisidine (o, p<i$Omer*) -- Skin............................... Antimony & compounds 01 (as Sb)......................... ANTU (alpha naphthyl -- . thiourea)....................... Argon............................... Arsenic & compounds (as As)................................ F _ Arsine............................... 0.05 Asphalt (petroleum) fumes............................ Azinphos methyl -- Skin -- Barium (soluble com pounds) ........................ CBenzene (benzol) -- Skin Benzidine -- Skin........... p-Benzoquinone, see 25 Quinone...................... Benzoyl peroxide............. Benzyl chloride................ Beryllium........................... Biphenyl, see Diphenyl... -- 1 -- Bismuth telluride............. _ * Bismuth telluride (Se- doped).......................... Boron oxide................. . _ Boron tnbromide .......... C Boron influoririe . , 1 1 Bromine ......................... 0,1 Bromine pentafluoude 01 mg/M1h) Substance ppm1'! mg/Mlb* 10 iao 25 20 2,400 70 A* -- 14 0.25 0.3 45 0.25 3 5 22 12 E A1b 2 18 10 10 525 650 19 0.5 05 0.3 -- 0.5 0.2 5 0.2 0.5 80 Alb 5 '5 0.002 10 5 10 10 3 0.7 0.7 Bromoform -- Skin..... Butadiene (1, 3- 0.5 butadiene) ................. 1,000 Butane............. . . 500 Butanethiol, see Butyl mercaptan.................... 2-Bulanone ................... 200 2-Butoxy ethanol (Butyl Cellosolve) -- Skin ... 50 Butyl acetate (n-buly! acetate)...................... 150 sec-Buly! acetate............. 200 tert-Butyl acetate.............. 200 Butyl alcohol................... sec-Butyl alcohol .......... tert-Butyl alcohol............. CButylam.ne -- Skin......... 100 150 100 5 Ctert-Butyl chromate (as CrOl) -- Skin ............ __ n-Butyl glycidyl ether (BCE).......................... 50 Butyl mercaptan ............. 05 p-tert-Bulyltoluene........... 10 Cadmium (Metal dust and soluble salts) :............. _ *CCadmium oxide fume (as Cd)............................... j* nrlwiifFr Calcium arsenate............ -- Calcium oxide................. -- Camphor (Synthetic)........ 2 Carbaryl (Sevin')............ -- Carbon black.................. -- Capital tellers refer to Appendices. *1973 Addition **$ce Notice of Intended Changes. Substance |ppm Carbon dioxide................ 5.000 f Carbon disulfide -- Skin. 20 Carbon monoxide........ . 50 Carbon tetrachloride -- Skin............................... 10 Cellulose (paper fiber).... -- CNordane -- Skin.......... -- Chlorinated camuhene -- Skin............................... Chlorinated diphenyl oxide............................ Chlorine.................. .... . Chlorine dioxide.............. __ 1 01 C Chlorine tnfluoride.......... 01 C Chloroaceuldehyde......... 1 a-Chioroacetophenone (phenacykhloride)___ 0.05 Chlorobenzene (monochlorobenzene).. 75 o-Chiorobenzytidene malononitnle (OCBM) -- Skin......................... 005 CdPlUll fta A(X>fTO*0^ Fomnmr> td (hiu h) m.v Page 44 *1971 Addition 5 2,200 1.200 S90 240 710 950 950 300 450 300 15 0.1 270 1.5 60 0.2 01 F 1 5 12 5 3.5 mg/M,bl 9.000 60 55 65 E 0.5 0.5 0.3 3 0.3 0.4 3 03 350 04 Journal of Occupational Medicine/Vol. 16. No. 1/January 1974 41 OLI 2331 Substance ppm** mg'M "') Substance ppm*) CHIorobromomelhanc . 2`Chloro-1, Vbuudiene iiv Chloropreru*......... Chlorodiphenyl {42% Chlorine) -- Skin....... Chlorodiphenyl (54% Chlorine) -- Skin ..... 1-Chloro, 2, 3epoxypropane, see Epichlorhydrin.............. 2-Chlorocthanol, see Ethylene chlorohydrin .. Chloroethylene, see Vinyl chloride........................ Chloroform (Trichloro- methane....................... 1 -Chloro-1 -mtropropane... Chloropicrin.................... Chloroprene (2-Chloro-1, 3-butadiene) --- Skin.. Chromic acid and chromates (as CrOi).... Chromium, sol. chromic chromous salts as Cr.. Metal & insd. salts..... Coal tar pitch volatiles (benzene soluble frac tion) anthracene, BaP, phenanthrene, acridine, chrysene, pyrene)........................ Cobalt, metal fume & dust Copper fume.................... Dusis and Mists.......... Corundum (AliO))......... Cotton Oust (raw).......... Oak ............... Cresol (all isomers) -- Skin............................. Crotonaldehyde................. Cumene -- Skin............. Cyanide (as CN) -- Skin Cyanogen......................... Cyclohexane............... ..... Cyclohexanol....... Cyclohexanone................. Cydohexene.................... Cydepentadiene.............. 2. 4-D............................ DOT............................... DDVP, see Dichlorvos.... Decaborane -- Skin........ Demevon* -- Skin......... Diacctone alcohol (4hydroxy - 4 - methyl- 2 pentanone)................... 1, 2-Diaminoethane, see Ethylenediamine______ Diazinon -- Skin............ Diazomethane................ . Diborane.......................... 1. 2-Dibromoetltine (cthvtene dibromide) -- Skin............................. Dibrom*....-.................... 2-N Oibutylaminoethanol -- Skin......................... Dibutyl phosphate........... Dibutylphthalate............... Dichloracetylene........... . 200 _ __ __ -- (50) 20 0.1 25 __ _ A1' A1' -- -- -- -- -- -- 5 2 SO -- 10 300 50 50 300 75 -- -- -- 0.05 0.01 SO -- 02 01 20 2 1 01 1.050 _ 05 -- (240) 100 07 90 01 05 (1.0) 0.2 0.1 (1) 1 E I1) tu 22 6 245 5 -- 1,050 200 200 1,015 200 10 1 -- 03 0.1 240 ,* -- 0.1 04 0.1 14S 3 14 5 5 0.4 C o-Dichlorobenzene ...... p-Dichlorobenzene ..... Duhloroiif'tizidine -- Skin Dichloroditluoromethane . 1, 3'Oichloro-5, 5- dimethyl hydanioin...... *1,1 -Otchloroethano........ 1, 2-0ichloroethane........ i, 2-Dicliloroethvlene..... Dicbloroethyl ether -- Skin.............................. Dichloromethine, see Methylene chloride....... Dichloromonofluoromethane....................... Cl, 1-Dichloto-lnitroethane.................... 1, 2-Oichloropropane. see Propylenedichloride..... Dichlorotelrafluoroethane Dichlorvos (DDVP) -- Skin............................... Dieldnn -- Skin.............. Diethylaminc........ ........... Diethylammo ethanol -- Skin............................... Diethylene triamine -- Skin............................... Diethylelhcr. see Ethyl etlier............................ Difluorodibromom ethane. C Diglycidyl ether (DGE) .... Dihydroxybenzene, see Hydroqumone.............. Diisooutyl ketone............ Diisopropylamtnc -- Skin Diineliuaymethane, see Methylal ....................... Dimethyl acetamide -- Skin............ .................. Dimethylaminc.............. . SO 75 1,000 200 50 200 1,000 10 1,000 0.1 -- 25 10 1 -- 100 0.5 25 5 10 4-Dimethylaminoazo- benzene........................ _, Dimethylaminobenzene, see Xylidene................. -- Dimethylaniline (Ndimethylaniline) -- Skin Dimethylbenzene, see Xylene........................... Dimethyl 1. 2-dibromo 2-dichlotoethyl phosphate, see DiBrom Dimethytformamide -- Skin............................... 10 2. 6-Dimethylheptanone, see Diisoboiyl ketone... 1, 1-Dimethythydrazine -- Skin............................... 0.5 Dimethylphthalate............ -- Dimethylsulfale -- Skin.... (1) Onitrob*nzene (all isomers) -- Skin.......... 0.15 Oinitro-o-ctesol -- Skm... -- Dinitrotoiuene -- Skin. Dioxane (Diethylene dioxide) -- Skin......... (100) Diphenyl.......................... 0.2 Diphenyl amine............. Diphenylmechane dhsocyanate (see Capital lenen rcinr in Appendices tSce 1973 Revised Documentation. Caiaul lenen ictet to Appendices "See Notice at Intended Changes 42 mg/Mlh) Substance ppm*l mg/M3*'* 300 450 A"' 4,950 0,2 320 200 790 30 4,200 60 7,000 0.25 7S 30 4 -- 860 2.8 150 20 -- 35 A1 -- 25 30 1 5 (5) 1 0.2 1.S (3*0) 1 10 Methylene bisphenyl isocsanato (MDI)........ Dipropylene glycol methyl ether -- Skin.............. Diquat............................. Di-sec, octyl phthalate (Di-2-ethylhexyl- phthalale).................... Emery.............................. Endosulfan (Thiodan*) -- Skin ............................. Endrin -- Skin................. Epichlorhydrin -- Skin.... EPN -- Skin.................. 1, 2-Epoxvpropane, see Propyleneoxide............. 2, 3-Epoxy-1-propanol, see Glycidol................. Ethane............................. Ethanethiol,.see Ethylmet- captan.......................... Ethanolamine................... 2-lhoxyethanol -- Skin... 2-Ethoxyethylacetate (Ccllosolve acetate) -- Skin............................... Ethyl acetate.................... Ethyl acrylate -- Skin..... Ethyl alcohol (ethanol).... Eihylamine....................... Ethyl sec-amyl ketone (S- methyl-3-heptanone).... Ethyl benzene.................. Ethyl bromide.................. Ethyl butyl ketone (3- Heptanone)........ ....... rb- rlu.i.rl ^MlWIlSI^.t .......................... Ethyl ether....................... Ethyl formate.................... Ethyl mercaptan............... Ethyl silicate.................... Ethylene........................... Ethylene chlorohydrin -- Skin.............................. Ethylenediamine............... Ethylene dibromide, 1, 2-Otbromoethane Ethylene dtcNoride, 1, 2-Dichlorethane............ Ethylene glycol, paniculate Ethylene glycol, vapor..... C Ethylene glycol dinitrate and/or Nitroglycerin -- Skin................ .............. Ethylene glycol mono* methyl ether acetate (Methyl ccllosolve acetale -- Skin.................. Ethylene imine -- Skin.... Ethylene oxide................. Ethylidine chloride, see 1, 1-Dichloroethane......... N-Ethyltnarpholine -- Skin Fetbam................. Ferrovanadium dust......... Fluoride (as f)................. Fluorine............................ FIuorotnchlofomethane.... C Formaldehyde................... Formic acid..................... 100 100 100 400 25 1.000 10 25 100 200 50 I 400 100 OS 100 F s 10 100 0.2<t) 25 0.5 50 20 -- -- -- 1 1,000 2 5 Capital lenen icier io Appendices. *1973 AddHion foolnotes (a thru h) see Page 44 600 0.5 5 E 01 0.1 19 0.5 370 540 1,400 100 1,900 18 130 435 890 210 2,600 1,200 300 1 850 -- 16 25 10 260 120 1 90 94 10 1 2.5 2 5,600 3 9 TIVi for Chemical Substances in Workroom Air OLI 2332 Substance r furfural -- Skin............... Fuduryl alcohol ........... 5 (5) Gasoline .................... * Germanium (etrahydride Glass, fibrous1,1 ordust... Glycerin mist .................. Glycidol (2, 3-Epoxy-1- propanol) .................... Glycol monoelhyl ether, see 2-Elhoxyethanol..... Graphiie, (Synthetic)....... Guthion,' see Azin- phos methyl................... Gypsum ....................... Hafnium ......................... Helium ........................... Heptachlor -- Skin ........ Heptane (n-heptane)...... Hexachloroethane -- Skin Hexachloronaphthalene -- Skin............................... Hexafluoroacetone.......... Hexane (n-hexane)......... 2-Hexanone .................... Hexone (Methyl isobutyl ketone)........................ sec-Hexyl acetate............. Hydrazine -- Skin........... Hydrogen........................ Hydrogen bromide......... C Hydrogen chloride......... Hydrogen cyanide -- Skin Hydrogen fluoride........... Hydrogen peroxide ......... Hydrogen selenide.......... Hydrogen sulfide............. Hydroquinone.................. Indene.................. .... Indium and compounds. as In............................. C Iodine............................... Iron oxide fume.............. Iron pentacarbonyl.......... Iron salts, soluble, as Fe. Isoamyl acetate................ Isoamyl alcohol............... Isobutyl acetate............... Isobutyl alcohol............... Isophorone...................... Isopropyl acetate............. Isopropyl alcohol............ Isopropylamine................ bopropylether.................. Isopropyl glycidyl ether (ICE)............................ Kaolin............................... Ketene.............................. lead, inorg., fumes and dusts............................. lead arsenate................... limestone ............... ........ Lindane................ ............ lithium hydride............... I P.C. (liquified petroleum gas)............ Magnesite........................ Magnesium oxide, fume .. Malathion -- Skin........... -- 0.2 -- -- SO r 500 i . __ o,1 500 100 too 50 1 f 3 5 10 3 1 0,05 10 -- 10 -- 0.1 -- 0.01 -- 100 100 150 100 (25) 250 400 5 250 50 -- 0.5 1.000 ... -- -- Maleic anhydride............. CManganese and com pounds, as Mn ........ Marble............................ Mercury (Alkyl com* 0.25 mg/M 20 (20) BJ 0.6 E E 150 E E 0.5 0.5 2,000 10 0.2 07 1,800 410 410 300 1.3 10 7 11 2 1.4 0.2 15 2 45 Substance |ppm*' pounds) -- Skin........ Mercury (All forms except alkyl)............................ M^sityf oxide ................ Methane ....................... Methanethiol, see Methyl mercaptan ........... .... Methoxychlor..... . ... 2-Melhoxyethanol -- Skin (Methyl cellosolve) ..... Methyl acetate .............. Methyl acetylene (propyne) .................... Methyl acetylene- propadiene mixture (MAPP) ...................... Methyl acrylate -- Skin.., Methyl acrylonitrile -- Skin ............................. Methylal (dimelhoxymethane).... Methyl alcohol (methanol) .................. Methylamme............... ..... Methyl amyl alcohol, see Methyl isobutyl carbinof Methyl 2-cyanoacrylate.... Methyl isoamyl ketone.... Methyl (n-amyl) ketone (2-Heptanone)............. Methyl bromide -- Skin.. Methyl butyl ketone, see 2-Hexanone.................. Methyl cellosolve -- Skin see 2-Methoxyeihanol... Methyl cellosolve acetate -- Skin, see Ethylene glycol monomethyl 0.001 -- 25 F -- -- 25 200 1,000 1,000 10 1 1,000 200 10 -- 2 100 100 15 0.1 Methyl chloride................ 1 Methyl chloroform.......... (10) Methylcyclohexane.......... 0.08 Methylcyclohexano!......... 1 . o-Methylcyclohexanone 525 -- Skin............ ........ .... 360 Methyleyclopentadienyl 700 manganese tncarbonyl 300 (as Mn) -- Skin.......... (140) Methyl demeton-- Skin.. 950 Methyl ethyl ketone 960 (MEK), see 2-Butanone 12 Methyl formate............. 1,050 Methyl iodide -- Skin..... Methyl isobutyl carbinol 100 350 500 50 50 0.1 -- 100 5 240 -- Skin.......................... 25 E Methyl isobutyl ketone. 0.9 sec Hexone................. - -- Methyl isocyanate -- Skin 0.02 aaiiss 1 as 0.025 Methyl meicapun............ Methyl methacrylate......... Methyl parathion -- Skin Methyl propyl ketone, see 2-Pentanone................. C Methyl silicate.................. 0.5 100 _ -- 5 1.800 C Methyl styrene.............. 100 E C Methylene bisphenyl 10 isocyanate (MDI)......... 0.02 10 1 Methylene chloride(dicHoromethaoe)........ Molybdenum (soluble (500) s compounds)................ (insoluble compounds) -- -- E Monomethyl aniline -- Skin............................... 2 mg/M3b* Substance .1*) mg/M311* 0.01 C Monomethyl hydrazine -- Skin ........................... 02 0 05 Morpholine -- Skin .. ., 20 1_00 Naphtha (coal tar).......... 100 Naphthalene................... 10 f-Naphlhylamine ............ -- 0 35 70 400 50 A lb -- Neon ............................ r -- 10 Nickel carbonyl............... 0001 A1' 0.007 Nickel, metal and soluble 80 compounds (as Ni)..... ,___ 1 610 Nicotine -- Skin............. 0 075 0.5 Nitric acid....................... 2 5 1,650 Nitric oxide .................... p-Nitroaniline -- Skin.... Nitrobenzene -- Skin..... 25 1 1 30 6 5 1,800 p-Nttrochlorobenzene -- 35 Skin.............................. 1 4-Nitrodiphenyl................ -- A '* 3 Nitroelhane...................... 100 Nitrogen........................... F 310 -- 3,100 C Nitrogen dioxide.............. 5 9 Nitrogen tnfluoride.......... 10 260 Nitroglycenn -- Skin..... 02 12 Nitromethane................... 100 I-Nitropropane................. 25 _- 2-Ni(ropropanc ............... 25 8 N-Nilrosodimethylamme 29 2 250 90 90 475 (dimethylnitrosoamine) -- Skin......................... 465 Nitfololuene -- Skin....... 60 Nitrotrichloromethane, see 5 A* 30 CNoroptCnn................. Nitrous oxide.................. Octachloronaphthalene -- F -- 210 1,900 2,000 235 Skin................. ,............ Octane............................. 400 Oil mist, paniculate........ __ Oil mist, vatzor. XlRJ Osmium ietroxide........... uuu02 Oxalic acid...................... ___ Oxygen difluoride........... Ozone.............................. Paraquat -- Skin............. 0.05 01 -- 0.1 1,900 S'l 0002 1 0.1 0.2 05 Parathion -- Skin.*.......... ___ 230 Pentaborane.................... 0.005 Pentachlorona piithalene 01 0.01 -- Skin......................... 0.2 Pentachlorophenol -- 0.5 0.5 Skin............................... 0.5 Penuerythntol.................. -- E -- Pentane............................ 500 250 2-Pentanone.................... 200 28 Perchloroethyfene............ 100 Perchloromelhyl mer 1.500 700 670 100 captan .......................... 0.1 0.8 Perthlqryl fluoride........... 3 -- Petroleum Distillates 0.05 1 410 0.2 (naphtha).............. -..... Fhienoi -- Skin................ Phenothiaaine -- Skin..... p-ttsenylene diamine -- *>gi 5 -- -- Skin............................... 30 Phenyl ether (vapor)....... 480 Phenyl ether-Diphenyl mixture (vapor)......... -- 1 1 14 19 5 0.1 7 7 0.2 Phenylethyiene, see Styrene........................ ' -- -- (1.740) Phenyl glycidyl ether (PCE)........................... 5 Phenythydrazine -- Skin.. 10 CPhenylphosphine.............. Phosdnn (Mevinphos)S -- 9 Skin......... ..................... 10 5 005 001 60 22 0 25 0.1 Journal of Occupational Medicine/Vol. 16. No. 1/January 1974 43 OLI 2333 Substance ppm'1 Phosgene (carbonyl chloride)...................... Phosphine .................... Phosphoric acid............. Phosphorus (yellow)...... 01 0.3 -- _ Phosphorus pentachloride Phosphorus pentasulfide.. Phosphorus trichloride. ... Phthalic anhydride........... Picric acid -- Skm.......... Rival' (2-Pivalyl-1. 3- indandione)............. . Plaster of Paris................. Platinum (Soluble Salts) as Pt.................................. Polychltxobiphenyls, see -- -- 0.5 _2 -- -- Chlorodiphenyls........... Polytelra (1 uoroc-thylene decomposition products....................... Propane............................ 8 Propiolactone............... Propargy! alcohol -- Skin n-Propyl acetate............... Propyl alcohol................. n-Propyl nitrate............... Propylene dichloride (1, 2- -- -- F -- 1 200 200 25 Dichloropropane)........ Propylene glycol monomethyl ether....... Propylene imine -- Skin . Propylene oxide............... Propyne, see 75 100 2 100 Methylacetylene........... Pyrethrum........................ -- -- Pyridine............................ Qumone................... ....... RDX -- Skin.................... itnooium, v.etai tume and dusts (as Rh)............... 5 0.1 -- Soluble salts............. Ronnel............................. : Rosin Core Solder, pyrolysis products (as formaldehyde).............. Rotenone (commercial)... Rouge............................... Selenium compounds (as -- -- Se)................................ Selenium hexafluouride.... Silicon.............................. -- 0.05 Silicon carbide................. Silver, metal and soluble compounds.................. Sodium fluoroaceute -- -- (1080) -- Skin............. -- 1 Sodium hydroxide,.-........ -- Starch................... ............ Stibine........................ ... Stoddard solvent.......... Strychnine......................... Styrene (Monomer) ____ 0L1 200 -- (Phenyl ethylene)........ Sucrose............................ 100 _ Sulfur dioxide.................. Sulfur hexafluoride.......... Sulfuric acid..................... Sulfur monochfonde....... Sulfur pentafluaride......... Sulfur letrafluoride........... Sulfuryl fluoride............... Systox. see Oemeton*..... S 1,000 1 0.025 0.1 s ___ 2. 4, S T.......................... ____ Tantalum.......................... _ mg/M3b> 04 04 1 0,1 1 1 3 12 01 0,1 E 0.002 -- B1 -- At 2 840 500 110 350 360 5 240 _ 5 15 0.4 4C I.J 0.1 0.001 10 0.1 5 E 0.2 0.4 10 E 0.01 0.05 (2) E 0.5 1,150 0.15 420 E 13 6,000 1 6 025 0.4 20 _ 10 5 Substance ppmJ> TEDP -- Skin.......... ........ __ Teflon* decomposition products ... ........ -- Tellurium ....................... -- Tellurium hexafluoride..... 0 02 TEPP -- Skin................... 0004 CTerphenyls...................... 1 1. i. 1. 2-Tetrachloro-2, 2- difluoroeltane.............. 500 1, 1, 2, 2-Tetrachloro-1, 2- difluoroethane.............. 500 1, 1, 2, 2-Tetrachloro- ethane -- Skin ........... 5 Tetrachloroethylene, see Tetrachloromethane, see Carbon tetrachloride.... Tetrachloronaphthalene -- Skin............................. Tetraethyl lead (as Pb) -- Skin............................... Tetrahydrofuran.............. . Tetramethyl lead (as Pb) --. Skm......... . .......... Tetramethyl succinonitrile -- Skin......................... Tetranitromethane............ Tetryl (2. 4, 6-trim t ropheriy I methyl - nitramme) -- Skin...... Thallium (soluble com pounds) -- Skm (as T1) Thiram*............................ Tin (inorganic com pounds. except SnHs and SnOj as Sn........... Tin (organic compounds) (35 5n) Tin oxide......................... Titanium dioxide............. Toluene (toluol).............. C Toluene-2, 4- diisocyanate o-Toluidine...................... Toxaphene. see Chlorinated camphene.. Tributyl phosphate........... 1, 1, 1-Trichloroethane. sec Methyl chloroform. 1, 1, 2-Trichloroethane -- Skin............................ ... Trichloroethylene............ Thchloromethane, see Chloroform................... Trichloronaphthalene -- Skin............................... 1, I, J-Tcichloropropane.. 1, 1, 2-Trichloro 1, 2, 2tnfluoroefhane.............. Triefhylamine.................... Trilluoromonobromo- methane........................ Trimethyl benzene........... 2, 4. 6-Tnnitrophenol, see Picric acid.................... 2,4. 6 -- Trinitrophenylmefhyinitramine, see Tetryl...................... Trinitrotoluene -- Skin.... Triothocresyl phosphate.... Triphenyl phosphate......... Tungsten & compounds, as W............................. Soluble...................... Insoluble................... _ -- 200 -- OS 1 100 0.02 5 10 100 SO 1,000 25 1,000 25 0.2 0,2 B' 01 02 0.05 9 4,170 4,170 35 _ a* 2 0.100m 590 0.150m Substance ppm4> Turpentine...................... 100 Urantum (natural) soluble _T & insoluble contponds. as U............................. Vanadium (VtOs), as V Dust............................. Fume....................... Vinyl acetate................. Vinyl benzene, see Styrene Vinyl bromide................. Vinyl chloride.................. Vtnylcyanide, see _ _ 10 -- 250 200 Acrylonitrile................ Vinyl toluene.................. Warfarin........................;. Wood dust 100 -- (nonallergenic)............. Xylene (xylol)................. Xylidine -- Skin.............. Yttrium............................. Zinc chloride fume......... Zinc oxide fume............. Zirconium compounds (as 100 5 -- -- Zr>............................... -- 560 02 0,5 0.05 30 1,100 510 480 0.1 5 435 25 1 1 5 5 a) Parts of vapor or gas per million parts of 1.5 contaminated air by volume al 25* C and 760 mm, Hg pressure. 0.1 5 b) Approximate milligrams of substance per cubic meter of air. d) An atmospheric concentration of not more man 002 ppm, or personal protec tion may be necessary to avoid headache. e) r 5 7 pm in diameter. 0.1 t) As sampled by method that does not E collect vapor. E 375 g) According to analytically determined composition, 0.14 h) for control of general room air, biologic 22 monitoring is essential for personnel con trol. 45 535 5 300 7,600 100 6,100 120 1.5 0.1 3 Radioactivity: for permissible con centrations of radioisotopes in air, see U.S. Department of Commerce, National 8ureau of Standards Handbook 69, "Maximum Permissible Body Burdens and Maximum Permissible Con centrations of Radionuclides in Air and in Water for Occupational Exposure," tune S, 1969. Also, see U S. Department of Commerce National Bureau of Stan dards, Handbook 59, "Permissible Dose from External Sources of Ionizing Radiation," September 24,1954, and ad dendum of April 15, 1958. A report, Basic Radiation Protection Criteria, published by the National Committee on Radiation Protection, revises and moder nizes the concept of the NCRP standards of 1954, 1957 and 1958; obtainable as NCRP Rept No. 39, P.O. Box 4867, Washington. D.C 20008. TLVs for Chemical Substances in Workroom Air OLI 2334 MINERAL DUSTS Substance m.p.p.c.f.') SILICA, StO' Crystalline Quartz TLV in mppcf 30Q'> % quartz a- 10 TLV for respirable dust in mg/mJ: 10 mg/m1111______ % Respirable quartz + 2 TLV for "total dust," respirable and nonrespi table TOmg/m1 % quartz a- 3 Cristobalite.........Use one-half the value calculated from the count or mass formulae for quartz Tridymite Use one-half the value calculated from formulae for quartz. Silica, fused Use quartz formulae. Amorphous, includ ing natural diatomaceous earth................. 20 ( 111v quartz) * Asbestos, all forms......... Mica................................. Perlite............................... Portland Cement .......... Soapstone......................... Talc (non-asbestiform).... Talc (fibrous) use asbestos limit.............................. Tremolite (see Asbestos) . Graphite (natural)........... -- 20 30 30 20 20 -- -- 15 1973 Addition * See Notice of Intended Changes for Mineral Ousts. i) Millions of particles per cubic loot of air, based on impmger samples counied by light-field lechnics. |) The percentage of quartz in the formula is the amount deteimined from airborne samples, except in [hose insiances in which other methods have been shown to be applicable k) Both concentration and pereem quartz for the application of this limit are to be determined from Ihe fraction passing a size-selector wnh the following charac teristics. Aerodynamic Oiameier (urn) (unit density sphere) T2 2.5 3.5 5.0 10 % passing selector 90 75 50 25 0 I) containing < 1% quartz, if quartz content 1%, use formulae for quartz. p) see Page 39 *1973 Addition Substance Ppm*1 . ing/M^t O-Chloroiolucne ......... 2-Chloio-b-finchloromelhyl) pyridine (NServe*) ........................ + Cloptdol (Coyden')........ + Copper fume.................. Cotion dust, raw............. + Crufomale (Ruelene')..... Cyclohexylamine.............. + Dicyclopenfadienyliron.... + Diethylphihalaie............... Dimethyl sulfate -- Skin + 3,5-Dimlro-o-toluamide (Zoalene')................... Dioxane -- Skin.............. Disysfon -- Skin ........... C Fthylidene notbornene.... + formamide....................... Furfuryl alcohol ............. Hexachtorocyclo- pemadiene.................... + Iron oxide fume.............. Isophorone...................... Manganese cyclopen- tadienyl mcarbonyl (as Mn) -- Skin................ 4, 4-Methylene bis (2chloroaniline) -- Skin.. 50 -- -- _ -- 10 -- -- -- _ 50 -- 5 20 5 0.01 -- 10 002 250 10 10 02 0 2ml 5 40 10 5 A* 5 180 01 25 30 20 01 5 55 0.1 AJ C Methylene bis (4- Notice of Intended Changes (for 1973) These substances, with their cyclohexytene isocyanate)..... ............. Methylene chloride (Dichloromethane)...... C Methytethyl ketone 0.01 250 0.11 890 corresponding values, comprise those peroxide....................... for which either a limit has been proposed tor tne nrst time, or tor which a change in the "Adopted" listing has Mineral wool fiber.......... Paraffin was ........... Phofate tlhimci*) -- Skin + Picloram (Fordon*)........ been proposed. In both cases, the C Potassium hydroxide....... proposed limits should be considered Silicon tetrahydride trial limits that will remain in (lie listing (Silane)...................... . for a period of at least two years. If, after + CSodium hydroxide........... Subtilisins (Proteolytic en two years no evidence comes to light zymes as 100% pure that questions the appropriateness of the crystalline enzyme)...... values herein, the values will be recon sidered for the "Adopted" fist, tn the in terim, the 1972 Adopted limit will Tricyclohexyttin hydroxide (Plictran*).................... + Vinylidene chloride........ Zinc stearate.................... prevail. Documentation is available for 0.2 1.5 -- 10 % _ Ous -- 10 --2 0.5 0.7 --2 OOOOOfaoi S 10 4 --E each of these substances. Substance ppm'f ng/M> * Coal Oust (bituminous)- 2 mg/mJ (respirable dustpt fraction 5% quartz). W * 5% quartz use respirable mass formula. Nuisance Particulates (see Appendix E) 30 m.p.p.c.f. or 10 mg/m> of total dust <1% quartz Conversion factors mppcf x 35.3 = million panicles per cubic = particles per c.c. Baygon............................. Butyl laciate..................... + CCadmium oxide fume..... Caprolactam -- Dust...... Vapor........................... Carbofuran -- Skin...... + Carbon lefrabromide....... ''Catechol........................... + Cesium hydroxide........... + Chiorodifluoromethane.... Chloroform....................... bis-CNoromefhylethcr...... + Chlorpynfos (Durtban*) -- Skin........................ + o-CNorostyrene................ -- 1 -- -- 5 -- 0.1 1 -- 1000 25 -- SO Caplal kHIrrx frier In Appmdton + 1973 Krviuun ur Addition 0.S 5 0.05 1 25 0.05 1.4 4:5 2 3500 120 Alb a) Parts of vapor or gas per million parts of contaminated air by volume at 25*C and 760 mm. Hg. pressure. b) Approximate milligrams of particulate per cubic meter of air. m) Lint free dust as measured by the vertical-elutriator, cotton-dust sampler described if} the Transactions oi the National Conference on Cotton Dust. I. R. Lynch, pg. 33, May 2. 1970. o) Based on "high volume" sampling. 0.2 285 Capital tellers icfn In AixwndKit + 1973 Revision or Addition Journal of Occupational Medicine/Vol. 16, No. 1/January 1974 45 OLI 2335 Notice of Intended Changes (Cool'd) Mineral Dusts Substance TLV AsbfSk>5, all tormst.......... 5 tibers/cc > 5u in length"! A'* Silica flout........Use respirablep) mass for mula for quartz. Tripoli............... Use respirable mass formula for quartz. For the substances in 1b, no exposure or contact by any route, respiratory, skin or oral, as detected by the most sensitive methods, shall be permitted "No ex posure or contact" means hermitizmg the process or operation by the best practicable engineering methods, and protecting the worker by proper equip ment that will insure virtually no contact or entry of the carcinogen by any route. n) As determined by the membrane filter method at 400-450 X magnification (4 mm objective) phase contrast illumination. p) "Respirable" dust as defined by the British Medical Research Council Criteria (1) and as sampled by a device producing equivalent results (2). (1) Hatch, T. E. and Cross, P., Pulmonary Deposition and Reten tion of Inhaled Aerosols, p. 149, Academic Press, New York. New York. 1964. (2) Interim Cuidc for Respirable Mass Sampling, AIHA Aerosol Technology Committee. AHIA J. 31: 2, 1970, p. 133. Appendix A Carcinogens The Committee lists below those sub stances in industrial use that have pt'nnf it Ctt'CiiiVgivrilC tH 4, Of !H` duced cancer in animals under ap propriate experimental conditions. Present listing of those substances car cinogenic for man lakes two forms, those for which a TLV has been assigned (la), and those for which environmental conditions have not been sufficiently defined to assign a TLV (1b). la Human Carcinogens -- Substances recognized as occupational car cinogens with an assigned TLV; Asbestos, all forms, 5 fibers/cc > Sum in length. bis (Chloromethyl) ether, 1 ppb. Chromates, certain insoluble forms, 100 ug/mJ Coal tar pitch volatiles 200 ug/m3 Nickel carbonyl, Ippb 1b.Human Carcinogens -- Substances known to be potent occupational carcinogens without an assigned TLV: 4-Aminodiphenyl (p-Xenylamine) Benzidine & its salts beta-Naphthylamine 4-Nitrodiphenyl t A mow tuingem TIV for crocxMile may bt rrqmrwj 2. Experimental Carcinogens -- In dustrial substances found to be of high potency in inducing tumors un der experimental conditions m animals: Beryllium Chloromethyl methyl ether 3, 3'-Dichlorobenzidine Dimethyl sulfate Ethylemmine 4, 4'-Methylene bis (2-chloroaniline) N-Nitrosodimethylamine beta-Propiolactone For the above, worker exposure by alt routes should be reduced to a minimum in light of the warning of the potency of these substances to induce tumors in animals. "Reduced to a minimum" means extraordinary care shall be taken both in manufacture and in handling so that worker exposure oy all routes is kept below the limit of sensitivity of the analytic method of determining the ex posure concentration. Appendix B B1 Polytetrailuoroethylene* decom position products. Thermal decom position of the fluorocarbon chain in air leads to the formation of oxidized products containing carbon, fluorine and oxygen. Because these products decompose in part by hydrolysis in alkaline solution, they can be quan titatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending deter mination of the toxicity of the products, but air concentrations should be kept below the limit of sensitivity of the analytic method. 83 Gasoline and/or Petroleum Distillates. The composition of these materials varies greatly and thus a single TLV for all types of these materials is no longer applicable. In general, the aromatic hydrocarbon content will determine what TLV applies. Con sequently the content of benzene. other aromatics and additives should be determined to arrive at the ap propriate TLV (Elkins, et al A I H A | 24 99, 1%3). 'Trad** Naim.'* Albion, lluon, H4I011, Tcilon, Tetran Appendix C B 1 Threshold Limit Values for Mixtures When two or more hazardous sub stances are present, their combined ef fect, rather tlaan that of either in dividually, should be given primary con sideration. In the absence of information to the contrary, the effects of the dif ferent hazards should be considered as additive. That is, if the sum of the following fractions. exceeds unity, then the threshold limit of the mixture should be considered as being exceeded. Ci indicates the ob served atmospheric concentration, and Ti the corresponding threshold limit (See Example lA.a. and 1A.c.). Exceptions to the above rule may be fT-.ridf w!vi !-ez is guiAJ urdbuti to believe that the chief effects of the dif ferent harmful substances are not in fact additive, but independent as when purely local effects on different organs of the body are produced by the various components of the mixture. In such cases the threshold limit ordinarily is ex ceeded only when at least one member of the series ( + or + ~ etc.) v Ti Tz * itself has a value exceeding unit (See Example 1A.c). Antagonistic action or potentiation may occur with some combinations of atmospheric contaminants. Such cases at present must be determined individually. Potentiating or antagonistic agents are not necessarily harmful by themselves. Potentiating effects of exposure to such agents by routes other than that of inhalation is also possible, e g. imbibed alcohol and inhaled narcotic (trichloro ethylene) . Potentiation is charac teristically exhibited at high concentra tions, less probably at low. When a given operation or process characteristically emits a number of 46 TUTs for Chemical Substances in Workroom Air OLI 2336 Karmlul dusts, fumes, vapors or gases, it will frequently be only feasible to at tempt to evaluate the hazard by measurement of a single substance In such cases, the threshold limit used for this substance should be reduced by a suitable factor, the magnitude of which will depend on the number, toxicity and relative quantity of the other con taminants ordinarily present. Examples of processes which are typically associated with two or more harmful atmospheric contaminants are welding, automobile repair, blasting, painting, lacquering, certain foundry operations, diesel exhausts, etc. (Exam ple 2 in 1A.a.). Threshold Limit Values for Mixtures Examples lA.a General case, where air is analyzed for each component: a. Additive effects. (Note: It is essen tial that the atmosphere be analyzed both qualitatively and quantitatively for each com ponent present, in order to evaluate compliance or noncompliance with this calculated TLV.) Example No 2, Air contains 200 ppm of hexane (TLV = 500 ppm) 100 ppm of melhylene chloride (TLV - 500 ppm) and 20 ppm of perchloroethylene (TIV= 100 ppm) Atmospheric concen tration of mixture = 200 + 100 + 20 = 320 ppm of mixture 200 j 100 , 20 _ 200 + 100-1- 100 500 500 100 500 = JQQ. = nfl 500 Threshold Limit is not ex ceeded. The TLV of this mixture = -5^2 = 400ppm 0.8 lA.b. Special case when the source of contaminant is a liquid mixture and the atmospheric composition is assumed to be similar to that of the original material; e.g. on a tirYlO uiciirrhlnH nvrtnc rn basis, all of the liquid (solvent) mixture eventually evaporates. Example No. 1: Air contains 5 ppm of carbon tetrachloride (TLV = 10 ppm) 20 ppm of ethylene dichloride (TLV = 50 ppm) and 10 ppm of ethylene dibromide (TLV = 20 ppm) Atmospheric concen tration of mixture - S + 20 + 10-35 ppm of mixture -L+J0 10 50 20 2S + 20 4- 25 _ 50 Threshold Limit is ex ceeded. Furthermore, the TLV of this mixture may be calculated by reducing the total frac tion to 1.0; i.e. Additive effects (approximate solution) 1. The percent composition (by weight) of the liquid mixture is known, the TLVs of the con stituents must be listed in mg/m1. (Note: In order to evaluate compliance with this TLV, field sampling instruments should be calibrated, in the laboratory, for response to this specific quantitative and qualitative air-vapor mixture, and also to fractional con centrations of this mixture; e.g., 1/2 the TLV; 1/10 the TLV; 2 X the TLV; 10 X the TLV; etc.) TLV of mixture TLV of mixture - 35 _ 25 ppm 1.4 f. fv TLV. TLVs fn " tTv. Example No, 1: Liquid solvenl contains (by weight) 50% hep tane (TLV = 2000 mg/m>) 30% methylene chloride (TLV = 1740 mg/m}) 20% perchlorethylene (TLV = 670 mg/m3) TLV of mixture = 0 5 ( 0-3 , 02 _ 2000 1740 670 _1 = I .00025 + .00017 + .0003 .00072 1390 mg/m3 Of this mixture; 50% or 695 mg/m3 is heptane, 30% or 417 mg/m3 is melhylene chloride and 20% or 278 mg/m3 is perchloroethylene These values can he converted to ppm as follows; heptane -- 2000 mg/m3 = 500 ppm 1 mg/m3 = 0.25 ppm 695 mg/m3 = 174 ppm methylene chloride -- 1740 mg/m3 = 500 ppm 1 mg/m3 = 0,287 ppm 417 mg/m1 = 119 ppm perchloroethylene -- 670 mg/m1 = 100 ppm 1 mg/m1 = 0.15 ppm 278 mg/m1 = 42 ppm The TLV of this mixture = 174 + 119 + 42 = 335 ppm. lA.c. Independent effects. Air contains 0.15 mg/m1 of lead (TLV, 0.15) and 0.7 mg/m1 of sulfuric acid (TLV, 1). 0.15 0.7 0.7 0.15 1 Threshold limit is not exceeded. IB.a. General Exact Solution for Mixtures of N Components With Additive Ef fects and Different Vapor Pressures Journal of Occupational Medicine/Vol. 16, No. 1/January 1974 47 OLX 2337 c, (1) Ti + ...+ (2) Cl + O + . . . + Cn = T, 18 b Solution to be applied when 'here is a reservoir of the solvent mixture whose composition does not change appreciably by evapora tion. 1C. TLV for Mixtures of Mineral Ousts. For mixtures of biologically active mineral dusts the general formula for mixtures may be used. (2.1) fi4lt SnhjMvt nl Sfvtoi/c Mixture By the Law of Partial Pressures, (3) Ci = api, and by Raoult's Law, (4) pt = Fipi. Combine (3) and (4).to obtain (5) Ci = aFipi". Combining (1), (2,1) and (5), we obtain Solvent Mot Dr'mtls TLV wt, P* * 25*C Mol Irjction in hilf-ind- HiV solution volume Tnehioroetfnlene (i) 1)1 4 1 44i g/m no 73mm Hg O.S27 (6) flEll + f*E2l + .. TT T ,Eig+ Ti Ti .. . + Tn and solving for T, (61) T - Fipi* -t- Fip; + . . . + Fnf>i fH21* + I I ll Tn chtnro form (j) 1 J) 42 1 33* ml JS0 t2$mm Mg 047) F,p. = (0.527) (73) - 38.2 Fipi* = (0.473) (125) - 59.2 TLV 38.2 + 59.2 _ (97 4) (350) 38 2 59.2 133 8 a- 59.2 IS" * 350 For a mixture containing 80% talc and 20% quartz, the TLV for 100% of the mixture is given by: TLV------------------------- -- 8.4 mppcf 08 . 0.2 20 15 Essentially the same result will be obtained if the limit of the more (most) toxic component is used provided the effects are additive. In the above example the limit for 20% quartz is 10 mppcf. For another mixture of 25% quartz, 25% amorphous silica and 50% talc: TLV ------------------------------ = 7.3 mppcf 0 25 0.25 0.5 IT + 20 + 15" The limit for 2S% quartz ap proximates 8 mnnef. oH - n Fipt* (6.2) T2* " j s Fipi Ti T-- Threshold Limit Value in ppm. C-- Vapor concentration in ppm. p-- Vapor pressure of component in solution. p-- Vapor pressure of pure com* ponent F-- Mol fraction of component in solution. a-- A constant of proportionality. Subscripts 1, 2, ... n relate the above quantities of components 1, 2, ... n, respectively. Subscript i refers to an arbitrary component from 1 to n. Absence of subscript relates the quantity to the mixture. (97.4) (350) _ 193.0 TLV * 177 ppm (Note difference in TLV when account is taken of vapor pressure and mol fraction in com parison with the above sample where such ac count is not taken.) 2,`A mixture of one part of (1) parathion (TLV, 0.1) and two parts of (2) EPN (UV, 0.5). C. , Ct.C, 0.1 0.5 " Cn. Cm 30 Ci - 20 Cl 20 30 0.1 + 0.5 " T. 70 30 0.5 " TnT 15 m8'm* Appendix D Permissible Excursions for TimeWeighted Average (TWA) Limits The Excursion TLV Factor in the Table automatically defines the magnitude of the permissible excursion above the limit for those substances not given a "C" designation; i.e., the TWA limits. Exam ples in the Table show that nitroben zene, the TLV for which is 1 ppm, should never be allowed, to exceed 3 ppm. Similarly, carbon tetrachloride, TLV 10 ppm, should never be allowed to ex ceed 20 ptyn. By contrast, those sub stances with a "C" designation are not subject to the excursion factor and must be kept at or below the TLV ceiling. These limiting excursions are to be considered to provide a "rule-of-thumb" guidance for listed substances generally, and may not provide the most ap propriate excursion for a particular sub stance e.g.. the permissible excursion for CO is 400 ppm for IS minutes. For appropriate excursions for 142 substances consult Pa. Rules & Regs., Chap. 4, Art 432, and "Acceptable Con centrations," ANSI. 48 TLVs for Chemical Substances in Workroom Air OLI 2338 Substance <4C' Excursion TLV Factor Max. Cone, Permitted for short time ppm PPm Nitro benzene Carbon tetra chloride O-Dichlorobenzene Acetone Boron tri fluoride Butylamine 1 10 50 1000 Cl C5 3 2 15 1.25 _ -- 3 20 75 1250 1 5 Excursion Factors Tor all substances not bearing C notation Excursion TLV *0-1 (ppm or mg/m5), Factor =3 TLV*1-lO " " -2 TIV* 10-100 " " = 1.5 UV * 100-1000 " " =125 The number of times the excursion above the TLV is permmed is governed by con formity with the Time-Weighted Average TLV. Basis for Assigning Limiting "C" Values By definition in the Preface, a listed value bearing a "C" designation refers to a "ceiling" value that should not be exceeded; all values should fluc tuate below the listed value This, in ef fect, makes the "C" designation a maximal allowable concentration (MAC). In general, the bases for assigning or not assigning a "C" value rest on whether excursions of con centration above a proposed limit for periods up to 75 minutes may result in a) intolerable irritation, b) chronic, or irreversible tissue change, or c) narcosis of sufficient degree to increase accident proneness, impair self-rescue or materially reduce work efficiency. Appendix E Some Nuisance Particulates*5 TLV, 30 mppcf or 10 mg/mJ Alundum (AbOt) Kaolin Calcium carbonate Limestone Cellulose (paper fiber) Magnesite Portland Cement Corundum (AI2O3) Emery Glass, fibrous'1 or dust Glycerin Mist Graphite (synthetic) Gypsum Vegetable oil mists (except castor, cashew nut, or similar irritant oils) Marble Penlaerythritol Plaster of Pans Rouge Silicon Carbide Starch Sucrose Tin Oxide Titanium Dioxide q) When toxic impurities are not present, e g. quartz < 1% r) < 5-7 urn in diameter Appendix F Some Simple Asphyxiants -- "Inert" Gases and Vapors'5 Acetylene Argon Butane Ethane Ethylene Helium TLV. I.OOOppm Hydrogen Methane Neon Nitrogen Nitrous Oxide'5 Propane s) As defined on pg. 6 l) Nontoxic at or below TLV. TLVs Threshold Limit Values for Physical Agents Adopted by ACGIH for 1973 Journal of Occupational Medicine/Vol- 16, No. 1/January 1974 Preface Physical Agents These threshold limit values refer to levels of physical agents and represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after day without adverse effect. Because of wide variations in individual susceptibility, ex posure of an occasional individual, at, or even below, the threshold limit may not prevent annoyance, aggravation of a pre existing condition, or physiological damage. These threshold limits are based on the best available information from in dustrial experience, from experimental human and animal studies, and when possible, from a combination of the three. These limits are intended for use in the practice of industrial hygiene and should be interpreted and apolied only bv a per son trained in this disapline. They are not intended for use, or for modification 49 OLI 2339 for use, (1) in the evaluation or control of the levels of physical agents in the community, (2) as proof or disproof of an existing physical disability, or (3) for adoption by countries whose working .conditions differ from those in the United States of America, These values are reviewed annually by the Gommittee on Threshold Limits for Physical Agents for revisions or ad ditions, as further information becomes available. Since measurement of deep body lemperature is impractical for monitoring the workers' heat load, the measurement of environmental factors is required which most nearly correlate with deep body temperature and other physiological responses to heat. At the present time Wet Bulb-Globe Temperature Index (W8GT) is the simplest and most suitable technique to measure the en vironmental factors. WBGT values are calculated by the following equations: Notice of Intent -- At the beginning of each year, proposed actions of the Com mittee for the forthcoming year are issued in the form of a "Notice of In tent." This notice provides not only an opportunity for comment, but solicits suggestions of physical agents to be add ed to the list. The suggestions should be accompanied by substantiating evi dence. As Legislative Code-- The Conference recognizes that the Threshold Limit' Values may be adopted in legislative codes and regulations. If so used, the in tent of the concepts contained in the Preface should be maintained and pr,-v; inusdu nKr i< tlie list current. Reprint Permission -- This publication may be reprinted provided that written permission is obtained from the Secretary-Treasurer of the Conference and that this Preface be published in its entirety along with the Threshold Limit Values. Notice of Intent to Establish Threshold Limit Values Heat Stress 1. Outdoors with solar load: WBGT =0.7WB + 0.2GT + 0.1DB 2. Indoors or Outdoors with no solar load: WBGT = 0 7WB + 0.3GT where: WBGT * Wet Bulb-Globe Temperature Index WB = Natural Wet-Bulb Tempera ture DB* Dry-Bulb Temperature GT = Globe Thermometer Temper ature The determination of WBGT requires the use of a bilick uiobe thermometer a natural (static) wet-bulb thermometer, and a dry-bulb thermometer. Higher heat exposures than shown in Table 1 are permissible if the workers have been undergoing medical sur veillance and it has been established that they are more tolerant to work in heat than the average worker. Workers should not be permitted to continue their work when their deep body temperature ex ceeds 38.0*0. These Threshold Limit Values refer to heat stress conditions under which it is believed that nearly all workers may be repeatedly exposed without adverse health effects. The TlVs shown in Table 1 are based on the assumption that nearly all acclimatized, fully dothed workers with adequate water and salt in take should be able to function ef fectively under the given working con ditions without exceeding a deep body temperature of 38*C (WHO technical report series No. 412, 1969 Health Fac tors Involved in Working Under Con ditions of Heat Stress). Table 1 hnwmbli butotoa* Thuhgld l*** Vitim {Vitim ait gifi hi *C WfGT) Wo* Wqnfc Modmw Mfivy CummiM wttfc 30.0 2*7 290 7S\ Wo* -- 19% MW. taefi tw 304 200 ni m Wert * 50% MW. Urti hour 314 294 279 25*. \V*vk -- 75t ftm. Cacti twt ni 311 0 Appendix G Heat Stress I. Measurement ol the Environment The instruments required are a dry- bulb, a natural wet-bulb, a globe ther mometer, and a stand. The measurement of the environmental factors shall be per formed as follows: A. The range of the dry and the natural wet bulb thermometer shall be -50C to 50'C with an accuracy of O.SC. The dry bulb thermometer must be shielded from the sun and the other radiant surfaces of the environment without restricting the airflow around the bulb. The wick of the natural wet-bulb thermometer shall be kept wet with distilled water for at least 1/2 hour before the temperature reading is made It is not enough to immerse the other end of the wick into a reservoir of distilled water and wait until the whole wick becomes wet by capillarity. The wick shall be wetted by direct application of water from a syringe 1/2 hour before each reading. The wick shall extend over the bulb of the thermometer, covering the stem shout one additional bulb length. I he wick should always be clean and new wicks should be washed before using. B. One glebe thermometer, consisting of a 15 cm. (6-inch) diameter hollow cop per sphere, painted on the outside with a matte black finish or equivalent shall be used. The bulb or sensor of a ther mometer (range -5*C to 100C with an accuracy of 0.5*C) must be fixed in the center of the sphere. The globe ther mometer shall be exposed at least 25 minutes before it is read. C. One stand shall be used to suspend the three thermometers so that they do not restrict free air flow around the bulbs, and the wet-bulb and globe ther mometer are not shaded. D. It is permissible to use any other type of temperature sensor that gives identical reading to a mercury thermometer under the same conditions. E. The thermometers must be so placed that the readings are representative of the condition where the men work or rest, respectively. The methodology outlined above is 50 TLVs lor Chemical Substances in Workroom Air OLI 2340 more fully explained in the following publications. 1 "Prevention of Heat Casualties in Marine Corps Recruits, 1955-1960, with Comparative Incidence Rales and Climatic Heat Stresses in other Training Categories," by Captain David Minard, MC, USN, Research Report No. 4, Contract No MR005.01-0001.01, Naval Medical Research Institute, Belhesda, Maryland, 21 February 1961 2. "Heat Casualties in the Navy and Marine Corps, 1959-1962, with Ap pendices on the Field Use of the Wet Bulb-Globe Temperature Index," by Captain David Minard, MC, USN, and R. I. O'Brien, HMC, USN. Research'Report No. 7, Contract No MR005.01-0001.01, Naval Medical Research Institute, Bethesda, Maryland, 12 March 1964. 3. Minard, D,: Prevention of Heat Casualties in Marine Corps Recruits. Military' Medicine 126(4): 261-272, 1961. II. Work Load Categoric The heat produced by the body and the environmental heat together deter mine the total heat load. Therefore, if work is to be ttetformeri under not en vironmental conditions, the workload category of each job shall be eslablished and the heat exposure limit pertinent to the work load evaluated against the ap plicable standard in order to protect the worker from exposure beyond the per missible limit. A. The work load category may be established by ranking each job into light, medium, and heavy categories on the basis of type of operation, where the work load is ranked into one of said three categories, i.e. (1) light work: e g., sitting or standing to control machines, performing light hand or arm work. (2) moderate work: e.g., walking about with moderate lifting and pushing, (3) heavy work; e g., pick and shovel work, the permissible heat exposure limit for that work load shall be determined from Table 1. B. The ranking of the job may be per formed either by measunng the worker's metabolic rate while performing hts |ob or. by estimating his metabolic 'ate by the use of the scheme shown in Table 2. Tables available in the literature listed below and in other publications as well may also be utilized 1. Per-Olaf Astrand and Kaare Rodahl: "Textbook of Work Physiology" Mc Graw-Hill Book Company, New York, San Francisco, 1970. 2. Ergonomics Guide to Assessment of Metabolic and Cardiac Costs of Physical Work. Amer. Ind. Hyg. Assoc. |. 32' 560, 1971. 3. Energy Requirements for Physical Work. Purdue Farm Cardiac Project. Agricultural Experiment Station. Research Progress Report No. 30, 1961. 4. |. V. G. A. Durnin and R. Passmore: "Energy, Work and Leisure." Heinemann Educational Books, Ltd., London, 1967. Table 2 Aiiciimwl o( Work lo*d Average value* oi metabolic flic during aciivitre* IA Mjuy laahnx) aitu Hiuven<4*m Si.'firt# Standing Walking Walking up hill K<ai imm Oi 06 10-10 add OS Am (\ardl rite 6 IvtK O* Work Average Kcal imm Range Kcal mn Hind work V* 04 hoavy 09 0 2*1 Z Work with one arm SfM * 10 hNvy 10 07-23 Work with bok ifim lM Iwvy vs is 10-3 5 Work wah body *># moderate heavy very heavy IS VO 70 90 2 5-ISO Light hand Work; writing, hand knitting Heavy hand work:'typewriting Heavy work with one arm; hammering in nails (shoemaker, upholsterer) Light work with two arriis; filing metal, planing wood, raking of a garden Moderate work with ihe body cleaning a floor, beating a carpel Heavy work wiih the body railroad track laying, digging, barking trees Sample Calculation: Using a heavy hand tool on an assembly line A Walking along 2.0 Kcal./min, B. Intermediate value be tween heavy work with two arms and light work with the body 3 0 Kcal /min 5.0 Kcal./min C. Add for basal meta bolism 1 0 Kcal /min Total 6.0 Kcal /min Adapted from Lehmann, G.E., A Muller and H. Spilzer: Der Kalorienbedarf bei gewerblicher Arbeit. Arbeitsphs ioI. 14: 166, 1950. III. Work-Rest Regimen The permissible exposure limits specified in Table I and Diagram A are based on the assumption that the WBGT value of the resting place is the same or very close to that of the wn:k olace. If the resting place is air condmoned and its climate is kept at or below 24C (75*F.) WBGT, the allowable resting time may be reduced by 25%. The per missible exposure* limits for continuous work are applicable where there is a work-rest regimen of a 5-day work week and an 8-hour work day with a short morning and afternoon break (ap proximately 15 minutes) and a longer lunch break (approximately 30 minutes). Higher exposure limits are permitted if additional resting time is allowed. Alt breaks, including unscheduled pauses and administrative or operational waiting periods during work may be counted as rest time when additional rest allowance must be given because of high environmental temperatures. It is a common experience that when the work on a job is self-paced, the workers will spontaneously limit their hourly work load to 30-50% of their maximum physical performance capacity. They do this either by setting an appropriate work speed or by in terspersing unscheduled breaks. Thus the daily average of ihe workers' metabolic rate seldom exceeds 330 kcal/hr. However, within an 8-hour work shift Journal of Occupational Medicine/Vo!. 16. No. 1/linuary 1974 OLI 2341 51 there may be periods where the workers' hourly average metabolic rate will be higher. /V. Water and Salt Supplementation During the hot season or when the worker is exposed to artificially generated heat, drinking water shall be made available to the workers in such a way that they are stimulated to frequent ly drink small amounts, i.e., one cup every 15-20 minutes (about 150 ml or 1/4 pint). The water shall be kept reasonably cool (10o-l5oC or 50.0-60.0F) and shall be placed close to the workplace so that the worker can reach it without aban doning the work area. The workers should be encouraged to salt their food abundantly during the hot season and particularly during hot spells. If the workers are unacclimatized, salted drinking water shall be made available in a concentration of 0.1% (1g NaCI to 1.0 liter or 1 level tablespoon of salt to 15 quarts of water). The added salt shall be completely dissolved before the water is distributed, and the water shall be kept reasonably cool. V. Other Considerations A Clothing The permissible heat ex posure TLVs are valid for light summer clothing as customarily worn by workers when working under hot environmental conditions. If special clothing is required for performing a particular job and this clothing is heavier or it impedes sweat evaporation or has higher insulation value, the worker's heat tolerance is reduced, and the permissible heat ex posure limits indicated in Table 1 and Figure 1 are not applicable. For each job category where special clothing is required, the permissible heat exposure limit shall be established by an expert 6. Acclimatization and Fitness: The recommended heat stress TIVs are valid for acclimated workers who are physically fit. Ionizing Radiation See U.S. Department of Commerce National Bureau of Standards, Handbook 59, "Permissible Dose from External Sources of Ionizing Radiation," Sep tember 24, 1954, and addendum of April 15, 1958. A report, Basic Radiation y o 0 * 400 mo BKi;TcoUdol//hhtr iooo net Rate 4 wo* Fij 1-- Ftrmissiblt Htit Eipasnn Threshold Limit Vilue Protection Cnteria, published by the National Committee on Radiation Protection, revises and modernizes the concept of the NCRP standards of 1954, 1957 and 1958; obtainable as NCRP Rept. No. 39, P.O. Box 4867, Washington, DC. 20008, Lasers The threshold limit values are for ex posure to laser radiation under con ditions to which nearly all workers may be exposed without adverse effects. Thp aluin siioulu be used as guides in me control of exposures and should not be regarded as fine lines between safe and dangerous levels. They are based on the best available information from ex perimental studies. Limiting Apertures The TLVs expressed as radiant ex posure or irradiance in this section may be averaged over an aperture of 1 mm except for TLVs for the eye in the spec tral range of 400-1400 nm, which should be averaged over a 7 mm limiting aper ture (pupil). No modification of the TLVs is permitted for pupil sizes less than 7 mm. The TLVs for "extended sources" ap ply to sources which subtend an angle greater than r (Table 5) which varies with exposure time. This angle is not the beam divergence of the source. Correction Factor A (CFA) for Eye Ex posure All TLVs in Tables 3 and 4 are to be used as given for wavelengths 400 nm to 700 nm. At all wavelengths greater than 1.06 pm and less than 1.4 pm the TLVs are to be increased by a factor of 5. TIV at wavelengths between 700 nm and 1,06 pm are to be increased by a uni formly extrapolated factor as shown tn Figure 2. Repetitively Pulsed Lasers Since there are few experimental data for multiple pulses, caution must be used in the evaluation' of such ex posures. The protection standards for irradiance or radiant exposure in multiple pulse trains have the following limitations: (1) The exposure from any single pulse in the train is limited to the protec tion standard for a single comparable pulse. (2) The average irradiance for a group of pulses is limited to the protection standard as given tn Tables 3, 4, or 6 of a single pulse of the same duration as the entire pulse group. (3) When the Instantaneous Pulse Repetition Frequency (PRF) of any pulses within a train exceeds one, the protection standard applicable to each pulse is reduced as shown in Figure 6 for pulse durations less than 10 5 second. For pulses of greater duration, the following formula should be followed: Standard (S;fepU,Se) = \ m tram / where: Standard (pulse nr) n N - number of pulses in train T m duration of a single pulse in the train Standard (nr) protection standard of one pulse having a duration equal to nr seconds flf Z. -- Rtf centra-- tadm W laser mntmifOu 52 TLVs for Chemical Substances in Workroom Air OLI 2342 I0'5 10*4 10'3 10'2 I0'1 1.0 EXPOSURE DURATION (S) Fi( la. -- TIV for intrabaam (direct) vinini of UMf bum (409-700 Mb) Noise* These threshold limit values refer to sound pressure levels that represent con ditions under which it is believed that nearly all workers may be repeatedly ex posed without adverse eftect on their ability to hear and understand normal speech. The medical profession (1,2) has defined hearing impairment as an average hearing threshold level in excess of 25 decibels (ANSI $3.6 - 1969) at 500, 1000, and 2000 Hz, and the limits which are given have been established to prevent a hearing loss in excess of this 10 value. These values should be used as guides in the control of noise exposure and, due to individual susceptibility, should not be regarded as fine lines be tween safe and dangerous levels. Continuous or Intermittent The sound level shall be determined by a sound level meter, meeting the standards of the American National Stan dards Institute and operating on the Aweighting network with slow meter response. Duration of exposure shall not exceed that shown in Table 7. 1. Cuid1?? for of Moafim Impairment. Transactions of the American Academy of Ophthalmolo gy and Otolaryngology, (March-April, 1%1). Rl )b. -- Tl for iotrobum (direct) mwh( of CW taw boom (400-700 *m) Microwaves These Threshold limit Values refer to microwave energy in the frequency range of 100 MHz to 100 GHz and represent conditions under which it is believed that nearly all workers may be repeatedly exposed without adverse ef fect. These values should be used as guides in the control of exposure of microwaves and should not be regarded as a fine line between safe and dangerous levels. Recommended Values The Threshold limit Value for oc cupational microwave energy exposure where power densities are known and exposure lime controlled is as follows: 1. For average power density levels up to but not exceeding 10 milliwatts per square centimeter, total exposure time shall be limited to the 8-hour workday ' (continuous exposure). 2. For average power density levels from 10 milliwatts per square centimeter up to but not exceeding 25 milliwatts per square centimeter, total exposure time shall be limited to no more than 10 minutes for any 60 minute period during an 8-hour workday (in termittent exposure). 3. For average power density levels in excess of 25 milliwatts per square centimeter, exposure is not per missible. NOTE: For repetitively pulsed sources the average power density may be calculated by multiplying the peak power density by the duty cycle The duty cycle is equal to the pulse duration in seconds times the pulse repetition rate in hertz. 2. Guides to the Evaluation of the Per manent Impairment; Ear, Nose, Throat and Related Structures, (ournal of the American Medical Association 197:489 (August 1961). These values apply to total time of ex posure per working day regardless of whether this is one continuous exposure or a number of short-term exposures but does not apply to impact or impulsive type of noises. When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each. If the sum of the following fractions, * S* Malic* Ol MflM Ounftv Pin* 57 Journal of Occupational Medicine/Vol. 16, No. 1/Januiry 1974 53 OLX 2343 Special Scgion UVC uve UVA light Tible 3 Threshold lnut \jltn' for Ofpri Ocutar Ekprxtum '"nm > la'*'! ftr.im Wawc length Exposure lime (i) Seconds 200 nm io 280 nm 200 nm io 302 nm 303 nm 304 nm 305 nm 306 nm 307 nm 308 nm 309 nm 310 nm 3llnm 312 nm 313 nm 314 nm 3lS nm 31S nm to 400 nm 400 nm to 700 nm 10 * IQ 1 X 10* * 10 to 10* 101 in 3 x 10* 10 ** to 1 6 i 10 14 10 -4 m 10 * TLV 3 m| cm 3 4 6 10 16 25 " 40 63 *' too 160 ,, 250 ,, 400 630 10 1 cm -* 10 1 e cm * i 1 0 mW * cm * 4 S i 10 *' cm " * 5 i___iI i 10 to 10* 10* to 3 i 10* Infared A 700 nm to 1 06 pm 1 06 pm to 1 40 urn 700 nm to 1 06 pm 1 06 pm to 1 4 pm 10 * to 10* IQ ^ m 10* to 3 X 10* Infrjrcd H C l 4 pm to 101 pm 10 "4 to 10*' 10 **' to 10 * J" * " NOTE, To ikJ m the ddermtnooon of TIV't tor exposure duwont requiring cjkuUuom of factional power* f 10 ml 4 cm * * 10 *W t cm-* flight TLV *| X |CFA) o*w nvi x s 10 -* |Cf*| sv cm -i J X 10 W 4 cm* 10 -* f cm* '"'`t/TT-* cm-> > i ** # m * 3. 4 4hd 6 iNy be Pied 10'* 10** I0*T I0`* I0`5 IO*4 I0*J !0*? I0`* EXPOSURE DURATION IS) 1.0 -- TUffer Uwr tit-Jakuwi radMte (MMiHffks (rutor Mm LI pa) exceeds unity, then, the mixed exposure should be considered to exceed the threshold limit value, Ci indicates the total time of exposure at a specified noise level, and Ti indicates the total time of exposure permitted at that level. Noise exposures of less than 90 dBA do not enter into the above calculations. Impulse or Impact Noise It is recommended that exposure to impulsive or impact noise should not ex ceed 140 decibels peak sound pressure level. 54 TIVs far Chemical Substances in Workroom Mr OLI 2344 EXPOSURE DURATION tS) Fi| 4b. -- TLV for CW liMr tipoturi of tkin and eyes for fir-mfrart4 radiation (wwknftbi ireitcr tine 1.4 jrrn) Ultraviolet Radiation' These threshold limit values refer to Ultraviolet radiation in the spectral region-between 200 and 400 nm and represent conditions under which it is believed that nearly all workers may be repeatedly exposed without adverse ef fect. These values for exposure of the eye or the skin apply to ultraviolet radiation from arcs, gas, and vapor discharges, fluorescent, and incandescent sources, but do not apply to ultraviolet lasers** or solar radiation. These levels should not be used for determining exposure of photosensitive individuals to ultraviolet radiation. These values should be used as guides in the control of exposure to continuous sources where the exposure duration shall not be less than 0.1 sec. These values should be used as guides in the control of exposure to ultraviolet sources and should not be regarded as a fine line between safe and dangerous levels. Recommended Values. The threshold limit value for oc cupational exposure to ultraviolet radiation incident upon skin or eye where irradiance values are known and lima ir follows: 1. For the near ultraviolet spectral region (320 to 400 mm) total irradiance in cident upon the unprotected skin or eye should not exceed 1 mw/cm* for periods greater than 10* seconds (ap proximately 16 minutes) and for ex posure times less than 10* seconds should not exceed one |/cm*. 2. For the actinic ultraviolet spectral region (200-315 nm), radiant exposure incident upon the unprotected skin or eye should not exceed the values given in Table 8 within an 8-hour period. 3. To determine the effective irradiance of a broadband source weighted against the peak of the spectral ef fectiveness curve (270 nm), the following weighting formula should be used: Journal of Occupational MediciM/V6l. 16, No. 1/January 1974 E* - IExSxAx where: * See Notice of heendrd Chances, page S7 See Uter UV. SS OLI 2345 Tihte 4 - Thrho*d L*m Vjlu for Viewing 1 Otfuw Reflection Of > U*nr Bnjm or jn {itendfd Soti'lr lasnr Spectral Wave length Exposure Time,. (t) Second^ TIV uv 200 nm to 400 nm 10 * 1 to 3 X to* Sam* a* Table 3 LigN Infrared A Infrared 1 ( C 400 nm to 700 rtm "" 700 nm to 1 06 uffl " 1 06 pm to 1 4 urn " 1 4 pm to 1 mm 10 *4 to 10 10 to 10* 10* to 3 X 10* 10 to 10 10 to io> 10 to 3 X 10 +4 10 - to 10 10 to 10i to J X io* 10 - to 3 X 10* 10 )JT\ cm"i e tt *' 20 1 * <m -1 * w *1 IKIO'IW 1 curt tr1 CM X 10 *i/T 1 cm*i *r*' CM X 20 1 cm -i *r - CM X 0 2 W e cm - * v - 50 * i/71 cm-' SI 100 1 cm *i e if - * 1.0 W cm -1 * v Same at Table 3 Note To ard m the determination of TlV's for nposore duration* requiring calculation* of fractional power* f^um* 3. 4 and 6 may be u*ed. Table 4 TlmMd Info Value for Skin (gntut from later teem Spectral Region Uv Wave Ian** 200 nm m 400 *m Fipcfoum Time. 01 Second* 10 -> io J X W>* nv Sm m M 1 lt fc foforawd A 400 nm to 1400 nm i *4 lo fr ^ 10 i io 10 2 X 10 * | 4 cm **. 11 <i/t 1 on* 10IO J X H>* 02 W cm - Miamd 4 C 14 pm to i mm 10-4 IO 1 X Same n Table l Note To aid m Pie rtmerminitmn of TIVt lot emtmum dinexi'e mpumng caktdatww of beefooryf powei ipafo J. 4 and 4 may be vfof 56 TIVs for Chtmical Substincts in Workroom Mr OLI 2346 Erff = effective trracliance relative to a monochromatic source at 270 nm E^ = spectral irradiance in W/cmJ/nm Sx = relative spectral effectiveness (unitless) A ^ 11 band width in nanometers 4, Permissible exposure time in seconds for exposure to actinic ultraviolet radiation incident upon the un protected skin or eye may be com puted by dividing 0,0003 |/cm2 by Ee in W/cm2. The exposure time may also be determined using Table 9 which provides exposure times corresponding to effective irradiances in UWlcm2. Table 7 Permissible Noise Exposures Duration per day Hours Sound Level dBAii 8 6 4 3 2 1-1/2 1 3/4 1/2 1/4 90 92 95 97 100 102 105 107 110 115* * No exposure in excess of 115 dBA a) Sound level in decibels as measured on a standard level meter operating on the Aweighting network with slow meter response. Table 8 Relative Spectral Effectiveness by Wave Length Wavelength (nm) . 200 210 220 230 240 250 254 260 270 280 290 300 305 310 315 TLV (ml/cm2) 100 40 25 16 10 7.0 60 46 3,0 3,4 4.7 10 50 200 1000 Relative Spectral Effectiveness SX 0.03 0,075 0,12 019 0.30 0 43 05 0 65 10 0 88 0.64 0,30 0,06 0 015 0,003 All the preceding TLVs for ultraviolet energy apply to sources which subtend an angle less than 80. Sources which subtend a greater angle need to be measured only over an angle of 80s. Notice of Intended Changes 1IItV.M. -* If! Jp fi| 6 -- MuHiplicatitt correction (actor for ropotitively pvlud liun kanni polio dwritMM Itu ttiao 10*4 tocond. ILK for a tintla potto of tho polio train it mottipliod by tbo bo* corrtdion factor. Correction (actor for PRF ireater tban 1000 Hi ia 0.00 These physical agents, with their corresponding values, compnse those for which either a limit has been proposed for the first time, or for which a change in the "Adopted" listing has been proposed. In both cases, the proposed limits should be considered trial limits that will remain in the listing for a period of at least one year. If, after one year no evidence comes to light that questions the appropriateness of the values herein, the values will be recon sidered for the "Adopted" list Noise Hz, and the limits which are given have been established to prevent a hearing loss in excess of this level. The values should be used as guides in the control of noise exposure and, due to individual susceptibility, should not be regarded as fine tines between safe and dangerous levels. fi| 7. -- TkrothoM IMt Viloei lor UtriKOfot ladiation These threshold limit values refer to sound pressure levels and durations of exposure that represent conditions under which' it is believed that nearly all workers may be repeatedly exposed without adverse effect on their ability to hear and understand normal speech. The medical profession has defined hearing impairment as an average hearing threshold level in excess of 25 decibels (ANSI-S3 6-1969) at 500.1000. and 2000 Journal of Occupational Medieine/Vol. 16. No. 1/January 1974 Continuous or Intermittent The sound level shall be determined by a sound level meter, conforming as a minimum to the requirements of the American National Standard Spec ification for Sound Level Meiers, SI .4 (1971) Type S2A, and set to use the A-weighled network with slow meter response. Duration of exposure shall not exceed that shown in Table 10. These values apply to foul duration of 57 OLI 2347 exposure per working day regardless of whether this is one continuous exposure or a number of short-term exposures but does not apply to impact or impulsive type of noise. When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each. If the sum of the following fractions: Ci + 0_ + Tl Tl Cn^ Tn exceeds unity, then, the mixed exposure should be considered to exceed the threshold limit value, Ci indicates the total duration of exposure at a specific noise level, and Ti indicates the total duration of exposure permitted at that level. All on the job noise exposures of 80 dBA or greater shall be used in the above calculations. Impulsive or Impact Noise It is recommended that exposure to impulsive or impact noise should not ex ceed 140 decibels peak sound pressure level. Impulsive or impact noise is con sidered to be those variations in noise levels that involve maxima at intervals of greater than one per second. Where the intervals are less than one second, it should be considered continuous. Comments or questions regarding these limits should be addressed to: Herbert H. tones. Chairman Threshold Limits Committee for Physical Agents Department of Industrial Safety and Hygiene, Central Missouri State University, Warrensburg, Mo. 64093. Tabic 10 Mwr-hnhl Itntil \alu<t Ouratinn per rtav Moun 18 8 4 2 1 1/2 1/4 1/8 A>und level dBAa) ao as 90 95 100 105 HO US* ' No otposur* to continuous O' intermittent m etcAt of US dBA a) Sound kvrt tn daetbeft at measured on 4 sound level nraer. conforming at a mmtmum to the rapuircmentt of the American National Standard Specification for Sound Iftel Mtfwv $1 4 (1971) Type S2A and tA to uv> the Awci^hfnd network with tim* mnter response Ultraviolet Radiation The threshold limit value shall apply also to solar radiation. TLVs for Chemical Substances in Workroom Air OLI 2348