Industrial Hygiene
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• • Chemical Hazards Physical hazards Biological Hazards Ergonomics Hazards
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– – : – Inhalation-* Absorption-* Ingestion-* Accidental Injection-*
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Inhalation
Particulate Matters Gases and Vapors
Dusts Fumes Mists Fibers
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• 250.1 • Non – Respirable10 • 51Respirable 10 •
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Fumes • 1 • • •
Mists . •
Fibers •
ASBESTOS
Asbestos
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PPM • Mg/M³ • F/cc •
ACGIH 408TLV-TWA • 415TLV-STEL • TLV-C •
OSHA 408PEL - TWA 415PEL – STEL PEL – C
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8 8X8 • • CaTa + CbTb………………….+ CnTn = -------------------------------------------PEL-TWA • • 8
ppm 1008 ppm 150 ppm 75 ppm 50 4
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• 150 X 2 + 75 X 2 + 50 X 4 • PEL – TWA = -----------------------------------
8 =
81.25 .PPM 150 (PPM 100)
Mixture of Contaminants • In case of a mixture of air contaminants an employer shall compute the equivalent exposure as follows: • Em = (C1 ÷ L1 + C2 ÷ L2) + …….+ (Cn ÷ Ln) • Em : is the equivalent exposure for the mixture. • C: is the concentration of a particular contaminant. • L: is the exposure limit (PEL) for that substance specified in subpart Z of 29 CFR 1910 • The value of Em shall not exceed unity (1).
Example Substance
A B C
Actual 8 – Hour TWA PEL concentration of 8(PPM) hour exposure PPM 500 PPM 45 PPM 40 PPM
1000 PPM 200 PPM 200 PPM
EM = (500 ÷ 1000) + (45 ÷ 200) + (40 ÷ 200) = 0.500 + 0.225 + 0.200 = 0.925 Since Em is less than unity (1) the exposure combination is within acceptable levels.
Physical Hazards 1 2 3 4 5 6
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• • • • • • Use PPE •