8/2/2019 acgih wgbt

1/5

PergamonPII: S0003-4878(00)00003-X

Ann. occup. Hyg., Vol. 44, No. 6, pp. 449^53, 2000C 2000 British Occupational Hygiene SocietyPublished by Elsevier Science Ltd. All rights reservedPrinted in Great Britain.0003-4878/00/$20.00

Heat Exposure Study in the Workplace in a GlassManufacturing Unit in IndiaA. SRIVASTAVAf*, R. KUMARf, E. JOSEPHf and A. KUMARJf Mum bai Zonal Laboratory, N ational Environm ental Engineering Research Institute (NEE RI),89-5, Dr. Annie Besant Road, Worli, Mumbai 400 018, India; %Green Earth Consultants, NationalEnvironm ental Engineering Research Institute (NEE RI), 89-5 , Dr. A.B. Road, Worli, Mumbai400 018, India

The heat exposure for working condit ions in coastal areas of tropical and subtropical countrieslike India is a crucial factor in improved qualitative and quantitative production. The hotcl imate augments the heat exposure c lose to sources l ike furnaces. In the present work heatexposure to workers in glass manufacturing units in a coastal area of India has been assessed.The Wet Bulb Globe Temperature (WBGT), the Corrected Effect ive Temperature (CET) andMean Radiant Temperature (M RT ) were measured. The WB G T values much exceededACGIH TLVs. A revision of these standards to suit tropical and subtropical condit ions isrequired. The recommend ed durations of work and rest have been est imated. 200 0 B rit ishOccupational Hygiene Society. Publ ished by Elsevier Science Ltd. Al l r ights reserved.

Keywords: heat stress; wet bulb globe temperature (WBGT) index; corrected effective temperature (CET);glass factory; tropical country

INTRODUCTIONHeat has been on record as a hazard to man sincebiblical times. Heat stress is still the most neglectedoccupational hazard in tropical and subtropicalcountries. Intense hot environments are prevalent inthe iron, steel, glass and ceramic units, rubber,foundries, coke ovens, mines, and many otherindustries.In India climatic heat exposure leads to high inci-dence of death and morbidity. However, limited in-formation is available to estimate the combinedeffect of climatic as well as industrial heat exposure,known to cause physiological and psychologicalchanges. The effects vary widely in different seasons.Consideration of the factors contributing to thetotal heat stress and knowledge of how people need

to respond to different work conditions and climatewill greatly help.The maximum temperatures in the State ofGujarat in India range from about 32 to 42C.Heat stress naturally occurring due to the hot cli-mate is augmented for the workers involved inwork close to furnaces. Glass manufacturing is onesuch work environment, where some workers areexposed continuously to high temperatures duringthe 8 hour shift. Convective of radiant heat gainsby the human body can lead to heat disorders(Leithend and Lind, 1964; Minard, 1966). A case ofheat exposure to the workers in different areas ofglass manufacturing units with production ca-pacities of 15 tonnes per day (TPD), 18 TPD, 75TPD, 130 TPD and 230 TPD is presented.

Received 13 Octo ber 1999; in final form 21 Decem ber1999.*Author to whom correspondence should be addressed.Tel.: +-91-22 497-3521; Fax: +-91-22 493-6635; E-mail:neeri(rt giasbm01.vsnl.net.in

DESCRIPTION OF THE PROCESSGlass bottle manufacturing consists of batchpreparation from raw materials, melting, forming,annealing, quality inspection and packaging. The

449

byguestonOctober21,20

10

annhyg.oxfordjou

rnals.org

Downloadedfrom

http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/

8/2/2019 acgih wgbt

2/5

8/2/2019 acgih wgbt

3/5

Heat exposure in glass manufacturing 451Temperature (CET), Mean Radiant Temperature(MRT), and Wet Bulb Globe Temperature(WBGT). The American Conference ofGovernmental Industrial Hygienists (ACGIH, 1999)relates WBGT and workload to arrive at aThreshold Limit Value (TLV) for continuous workand work with varying duration of rest periods.In the present study CET, MRT and WBGThave been estimated at different locations in theglass bottle manufacturing unit. The workload ofworkers in these locations has been assessed as pre-scribed by ACGIH. Based on WBGT and work-load, rest periods for workers in these areas havebeen assessed.

ESTIMATION OF WORKLOADThe total heat load is estimated by taking intoaccount the heat produced by the body as well asthe environment. The workload at the differentareas in the unit has been established by rankingworkers" jobs using the metabolic rate tables avail-able in the literature, and summarized by ACGIH(1999).Workload category is determined by averagingmetabolic rates for the tasks and then rankingthem. Light work is categorized as up to 200 kcalh~', moderate work in the range 200-350 kcal h" 1and heavy work in the range 350-500 kcal h" 1. Inthe glass bottle manufacturing unit under study theworkers near the furnace and bottle making areaare involved in walking around with moderate lift-ing and pushing. According to ACGIH classifi-cation, this type of work falls in the moderatecategory.

ESTIMATION OF HEAT STRESS PARAMETERSAt a location indoors or outdoors with no solar

load. WBGT is defined asWBGT = 0.7WB + 0.3GTwhere, WB is the wet bulb temperature and GT isthe globe thermometer temperature, and at lo-cations outdoors with solar radiation load

WBGT = 0.7WB + 0.2GT + 0.1DBwhere DB is the dry bulb temperature.Mean radiant temperature, MRT, has been esti-mated from globe thermometer temperature anddry bulb temperature as

(MRT + 273)4= (GT + 273 )4+ 2.5 x 10 8v a 6(GT-DB )

where all temperatures are in C and v, the air vel-ocity, is in ms"1. Corrected effective temperature

(CET) has been estimated from psychromaticcharts, using a katathermometer.

RESULTS AND D ISCUSSIONTable 1 summarizes the WBGT, CET and MRTcalculated from the observed temperatures. Theglobe thermometer temperature observed at all thelocations except the compressor room, is higherthan the dry air temperature, indicating that all thesurfaces which surround the globe are warmer thanthe air, thereby radiating heat to the atmosphere.It is observed that WBGT peaked to 40C againstthe ACGIH TLVs of 26.7C in front of an IS ma-chine. At all the points in the manufacturing sectionWBGT exceeds the TLV limits. The WBGT obser-vation calls for a rapid action to control problemsof heat stress in the manufacturing section of glassmanufacturing units. However, according to a noteto TLV for heat stress, higher heat exposure thanthose stated in the TLV are permissible if theworkers are under medical surveillance and it isestablished that they are more tolerant to work inheat than the average worker. But under no circum-stances should a worker be permitted to continuework when their deep body temperature exceeds38C.The ACGIH recommendations for work and restregime with respect to WBGT could not directly beextrapolated as the WBGTs are quite high, Indiabeing a tropical country. However, the observedvalues of WBGT can be said to require 25% workand 75% rest and 50% work and 50% rest eachhour for workers working near IS machines and infront of furnaces, respectively. At other places, 75%work and 25% rest each hour is desirable.According to ACGIH recommendations, this is notpractical and stresses the need for development ofTLVs for tropical countries. It is observed that

people in general are more tolerant to heat ex-posures as compared to people in colder regions.The TLVs for tropical countries should be based onlocal climatic conditions. Moreover, in developingand under-developed countries poverty invariablyforces the labour class to work in unhygienic con-ditions.

CONCLUSIONSThe heat exposure represents a major factor

which may have negative impact on worker effi-ciency and consequently the production of the unit.It may be concluded that to avoid heat stress pro-blems in glass manufacturing units the recommen-dations of ACGIH should be taken as indicative ofstress areas and workers should be under constantmedical supervision. This would enhance the effi-ciency of the workers resulting in reduced reject

byguestonOctober21,20

10

annhyg.oxfordjou

rnals.org

Downloadedfrom

http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/

8/2/2019 acgih wgbt

4/5

Te1Hsepamenagamaunu(afgeaenC

Dybb

Webb

Goemaue

WB

MR

C

Pemnwky

WBTVcn

wk(C

1TDISmn

FnCg

1TDISmn

FnCg

7TDISmn

FnCg

1TD

ISmn

FnCg

2TD

ISmn

FnCg

3 4 4 4 4 4 4 4 4 3 4 4 374 43

2 3 3 3 3 3 3 3 3 3 3 3 2 2533

4 4 4 335 4 4 4 4 4 4 4 4 5

258

3 4 3 3 3 3 3 3 3 3 3 3 3 3 3

4 5 4 4 5 5 5 5 5 7 5 5 6 7 7

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

Moae

MoaeLg Mo

ae

MoaeLg Mo

ae

MoaeLg Mo

ae

MoaeLg Mo

ae

MoaeLg

27273 2

7273 2

7273 2

7273 2

7273

Oyd

30

2

42.2

30

48

31

Lg

30

'Moae23kh;Lg11kh

byguestonOctober21,20

10

annhyg.oxfordjou

rnals.org

Downloadedfrom

http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/

8/2/2019 acgih wgbt

5/5

Heat exposure in glass manufacturing 453quantity, improved production and hence increasedprofits.In view of the high ambient temperatures preva-lent in tropical and subtropical countries, it is feltthat ACGIH standards would not suit local con-ditions leading to higher WBGT indices for thesame type of work performed in cooler climates. Arevision of these standards to suit tropical and sub-tropical conditions would be in order.

REFERENCESACGIH (1999) Threshold Limit V alves (TLV) andBiological Exposure Indices 1999. American Conferenceof Governmental Industrial Hygienists, Cincinnati, OH.Leithend, C. S. and Lind, A. R. (1964) Heat Stress and

Heat Discharges. Davis Co, Philadelphia, PA.Minard, D. (1966) Evaluation of Heat Stress UnderWorking Conditions. In Proceeding of the VIConference of the Industrial Co uncil for Tropical Health.Harvard School of Public Health, Boston, MA.

byguestonOctober21,20

10

annhyg.oxfordjou

rnals.org

Downloadedfrom

http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/http://annhyg.oxfordjournals.org/