1. Definitions. - For the purpose of this Schedule ---
(a) “mg/m3” means milligrams of a substance per cubic meter of air;
(b) “mppcm” means million particles of a substance per cubic meter of air;
(c) “ppm” means parts of vapour or gas per million parts of air by volume at 250C and 760 mm of mercury pressure;
(d) ‘times weighted average concentration” means the average concentration of a substance in the air at any work location in a factory computed from evaluation of adequate number of air samples taken at the location, spread over the entire shift on any day, after giving weightage to the duration for which each such sample is collected and the concentration prevailing at the time of taking the sample.
C1T1 + C2T2 + ……..CnTn
Time
weighted aver. =
T1 + T2 + …..Tn
Where C1 represents the concentration of the substance for duration T1 (in hours);
C2 represents the concentration of the substance for duration T2 (in hours); and
Cn represents the concentration of the substance for duration Tn (in hours).
(e) “work location” means a location in a factory in which a worker works or may be required to work at any time during any shift on any day.
2. Limits of concentrations of substances at work locations - (1) The time weighted average concentration of any substance listed in Table 1 or 2 of the Schedule, at any work location in a factory during any shift on any day, shall not exceed the limit of the permissible time weighted average concentration specified in respect of that substance:
Provided that in the case of a substance mentioned in Table 1 in respect of which a limit in terms of short term maximum concentration is indicated, the concentration of such a substance may exceed the permissible limit of the time weighted average concentration for the substance for short periods not exceeding fifteen minutes at a time, subject to the condition that ---
(a) such periods during which the concentration exceeds the prescribed time weighted average concentration are restricted to not more than 4 per shift;
(b) the time interval between any two such periods of higher exposure shall not be less than 60 minutes; and
(c) at no time the concentration of the substance in the air shall exceed the limit of short term maximum concentration.
(2) In the case of any substance given in Table 3, the concentration or the substance at any work location in a factory at any time during any day shall not exceed the limit of exposure for that substance specified in the table.
(3) In cases where the work “skin” has been indicated against certain substances mentioned in Table 1 and 3, appropriate measures shall be taken to prevent absorption through cutaneous routes particularly skin, mucous membranes, and eyes as the limits specified in these Tables are for conditions where the exposure in only through respiratory tract.
(4) (a) In case, the air at any work location contains a mixture of such substances mentioned in Table 1, 2 or 3, which have similar toxic properties, the time weighted concentration of each of these substances during the shift should be such, that when these time weighted concentration divided by the respective permissible time weighted average concentration specified in the above mentioned tables, and the fractions obtained are added together, the total shall not exceed unity;
C1 + C2 + Cn
------ ------ .... --------
L1 L2 Ln
When
C1, C2 ................. Cn are the time weighted
concentration of toxic substances 1, 2, ……and n respectively, determined after
measurement at work location, and L1, L2 ……………Ln are the
permissible time weighted average concentration of the toxic substances
1, 2………………and n respectively;
(b) In case the air at any work location contain a mixture of substances, mentioned in Table 1, 2 or 3, and these do not have similar toxic properties, then the time weighted concentration of each of these substances shall not exceed the permissible time weighted average concentration specified in the above mentioned tables, for that particular substances;
(c) The requirement in clause (a) and (b) shall be in addition to the requirements provided in paragraphs 2(1) and 2(2).
3. Sampling and evaluation procedures - (1) Notwithstanding provisions contained in any other paragraphs, the sampling and evaluation procedures to be adopted for checking compliance with the provisions contained in the Schedule, shall be as per standard procedures in vogue from time to time.
(2) Notwithstanding the provisions contained in paragraph 5, the following conditions regarding the sampling and evaluation procedures relevant to checking compliance with the provisions in this Schedule are specified:
(a) For determination of the number of particles per cubic meter in item 1(a)(i) (1) in Table 2, samples are to be collected by standard or midget impringer and the count made by light-field techniques.
(b) The percentage of quartz in formula (3) given in item 1(a) (i) of Table 2 is to be determined from airborne samples.
(c) For determination of number of fibres as specified in item 2(a) of Table 2, the membrane filter method at 430 x magnification (4 mm objective with phase contrast illumination) shall be used.
(d) Both for determination of concentration and percentage of quartz for use of the formula given in item 1(a)(I)(2) of Table 2, the fraction passing through a x size selector with the following characteristics should only be considered.
Aerodynamic diameter (unit density sphere) |
Percentage allowed by size-selector |
2.0 |
90 |
2.5 |
75 |
3.5 |
50 |
5.0 |
25 |
10.0 |
0 |
4. Power to require assessment of concentration of substances. - (1) An Inspector may, be an order in writing, direct the occupier or manager of a factory to get before any specified date, the assessment of time weighted average concentration at any work location of any of the substances mentioned in Tables 1, 2 or 3 carried out.
(2) The results of such assessment as well as the method followed for air sampling and analysis for such assessment shall be sent to the Inspector within 3 days from the date of completion of such assessment and also a record of the same kept readily available for inspection by an Inspector.
5. Exemption. - If in respect of any factory or a part thereof the Chief Inspector is satisfied that by virtue of the pattern of working time of the workers at different work locations or on account of other circumstances, no worker is exposed in the air at the work locations, to a substance or substances specified in Table 1, 2 or 3 to such an extent as likely to be injurious to his health, he (the Chief Inspector) may be an order in writing, which he may at his discretion revoke at any time, exempt such factory or a part of the factory from the requirements of paragraph 2, subject to such conditions, if any as he may specify therein.
TABLE I
Substance |
Permissible Limits of exposure |
|||
Time-weighted average concentration |
Short term maximum concentration |
|||
|
ppm |
mg/m3 |
ppm |
mg/m3 |
Acetic acid |
10 |
25 |
15 |
37 |
Acrolein |
0.1 |
0.25 |
0.3 |
0.8 |
Aldrin-Skin |
... |
0.25 |
... |
0.75 |
Ammonia |
25 |
18 |
35 |
27 |
Aniline-Skin |
2 |
10 |
5 |
20 |
Anisidine (O-p-isomers) skin |
0.1 |
0.5 |
... |
... |
Arsenic & Compounds (As) |
... |
0.2 |
... |
... |
Benzene |
10 |
30 |
... |
... |
Bromine |
0.1 |
0.7 |
0.3 |
2 |
2 Butanone (Methylethyl) (Ketone-MEK) |
200 |
590 |
300 |
885 |
N-Butyl acetate |
150 |
710 |
200 |
950 |
Sec/tert, Butyl acetate |
200 |
950 |
250 |
1190 |
Cadmium-dust and salts (as Cd) |
... |
0.05 |
... |
0.2 |
Calcium |
... |
2 |
... |
... |
Carbaryl (Sevin) |
... |
5 |
... |
10 |
Carbofaran (Furadan) |
... |
0.1 |
... |
... |
Carbon disulfide-skin |
2 |
60 |
30 |
90 |
Carbon monoxide |
50 |
55 |
400 |
440 |
Carbon tetrachloride-skin |
10 |
65 |
20 |
130 |
Carbonyl Chloride (Phosgane) |
0.1 |
0.4 |
... |
... |
Chlordane-skin |
... |
9.5 |
... |
2 |
Chlorobenzone (mono Chlorobenzene) |
75 |
350 |
... |
... |
Chlorine |
1 |
3 |
3 |
9 |
Bis-Chloromethyl ether |
0.001 |
... |
... |
... |
Chromic acid and chromates (as Cr) |
... |
0.05 |
... |
... |
Chromium. Sel. Chromic, Chromous salts (as Cr) |
... |
0.5 |
... |
... |
Copper fume |
... |
0.2 |
... |
... |
Cotton dust, raw |
... |
0.2 |
... |
0.6 |
Cresol, all isomers-skin |
5 |
22 |
... |
... |
Cyanides (as CN) skin |
... |
5 |
... |
... |
Cyanogen |
10 |
20 |
... |
... |
DDT (Dichlorodiphenyl-trichloro-ethane) |
... |
1 |
... |
3 |
Demton-skin |
0.01 |
0.1 |
0.03 |
0.3 |
Diazinon-skin |
... |
0.1 |
... |
0.3 |
Dibutyl Phthalate |
... |
5 |
... |
10 |
Nichlorves (DDV)-skin |
0.1 |
1 |
0.3 |
3 |
Dieldrin-skin |
... |
0.25 |
... |
0.75 |
Dinitrobenzene (all isomers)-skin |
0.15 |
1 |
0.5 |
3 |
Dinitrotoluene-skin |
... |
1.5 |
... |
5 |
Diphenyl |
0.2 |
1.5 |
0.6 |
4 |
Endosulfan (Thiodan)-skin |
... |
0.1 |
... |
0.3 |
Endrin-skin |
... |
0.1 |
... |
0.3 |
Ethyl acetate |
400 |
1,000 |
... |
... |
Ethyl alcohol |
1,000 |
1,900 |
... |
... |
Ethyl amine |
60 |
18 |
... |
... |
Fluorides (as F) |
... |
2.5 |
... |
... |
Flourine |
1 |
2 |
2 |
4 |
Hydrogen Cyanide-skin |
10 |
11 |
15 |
16 |
Hydrogen sulfide |
10 |
15 |
15 |
27 |
Iron oxide fume (Fe2 O3 as Fe) |
... |
5 |
... |
10 |
Isoamyl acetate |
100 |
525 |
125 |
655 |
Isoamyl alcohol |
100 |
360 |
125 |
450 |
Isobutyl alcohol |
50 |
150 |
75 |
225 |
Lead, inorg, fumes and dusts (as Pb) |
... |
0.15 |
... |
0.45 |
Libdane-skin |
... |
0.5 |
... |
1.5 |
Malathion-skin |
... |
10 |
... |
... |
Manganese fume (as Mn) |
... |
1 |
... |
1 |
Mercury (as Hg) |
... |
0.05 |
... |
0.15 |
Mercury alkyl compounds skin |
0.001 |
0.01 |
0.003 |
0.03 |
Methyl alcohol (methanol) skin |
200 |
260 |
250 |
310 |
Methyl cellosplve-skin (2 methoxy ethanol) |
25 |
80 |
35 |
120 |
Methyl isobutyl ketone-skin |
100 |
410 |
125 |
510 |
Naphthalene |
10 |
50 |
15 |
75 |
Nickel carbonyl (as Ni) |
0.05 |
0.35 |
... |
... |
Nitric acid |
2 |
5 |
4 |
10 |
Nitric oxide |
25 |
30 |
35 |
45 |
Nitrobenzene-skin |
1 |
5 |
2 |
10 |
Oil mist-mineral |
... |
5 |
... |
10 |
Parathion-skin |
... |
0.01 |
... |
0.03 |
Phenel-skin |
5 |
19 |
10 |
38 |
Phorate (Thimet)-skin |
... |
0.5 |
... |
0.2 |
Phosgane (Carbonyl chloride) |
0.1 |
0.4 |
1 |
1 |
Phosphine |
0.3 |
0.4 |
1 |
1 |
Phosphorus (Yellow) |
... |
0.1 |
... |
0.3 |
Phosphorus pentachloride |
... |
1 |
... |
3 |
Phosphorus trichloride |
0.5 |
3 |
... |
... |
Picric acid-skin |
... |
0.1 |
... |
0.3 |
Pyridine |
5 |
15 |
10 |
30 |
Silane (silicon tetrahydride) |
0.5 |
0.7 |
1 |
1.5 |
Styrene, monomer (phenylethylene) |
100 |
420 |
125 |
525 |
Sulfur-dioxide |
5 |
13 |
... |
... |
Sulfuric acid |
... |
1 |
... |
... |
Toludine (totuol) skin |
100 |
375 |
150 |
560 |
O-Toludine |
5 |
22 |
10 |
44 |
Trichloroethylene |
100 |
535 |
150 |
800 |
Vinyl chloride |
5 |
10 |
... |
... |
Welding fumes (NOC) |
... |
5 |
... |
... |
Xylene (o-m-p-isomers) skin |
100 |
435 |
150 |
655 |
TABLE 2
Substance |
Permissible time weighted average concentration |
|||
1. Silica |
||||
(a) |
Crystalline |
|||
|
(i) |
Quartz |
||
|
|
(1) |
In terms of Dust count |
1060 --------------------- mppcm % Quartz + 10 |
|
|
(2) |
In terms of respirable dust |
10 ------------------------- mg m3 % respirable quartz + 2 |
|
|
(3) |
In terms of total dust |
30 ------------------------- mg/m3 % quartz + 3 |
|
|
(ii) |
Cristobalite |
Half the limits given against quartz. |
|
|
(iii) |
Tridymite |
Half the limits given against quartz. |
|
|
(iv) |
Silica fused |
Same limit as for quartz. |
|
|
(v) |
Tripoli |
Same limit as in formula in item 2 given against quartz. |
(b) |
Amorphous |
705 mppcm |
||
|
||||
2. Silicates having less than |
||||
1% free silica by weight --- |
||||
(a) |
Asbestos-fibres longer than 5 microns |
2 fibres per cubic centimeter |
||
(b) |
Mica |
705 mppcm |
||
(c) |
Mineral wool fibre |
10 mg/m3 |
||
(d) |
Porlite |
1060 mppcm |
||
(e) |
Portland cement |
1060 mppcm |
||
(f) |
Soapstone |
705 mppcm |
||
(g) |
Talc (nonabostiform) |
705 mppcm |
||
(h) |
Talc (Fibrous) |
Same limit as for asbestos |
||
(i) |
Ttemolite |
Same limit as for asbestos |
||
|
|
|
||
3. Coal dust |
||||
(1) |
For airborne dust having less than 5% silicone dioxide by weight |
2 mg/m3 |
||
(2) |
For airborne dust having over 5% silicone dioxide. |
Same limit as prescribed by formula in item (2) against quartz. |
Substance |
Permissible limit of exposure |
|
Ppm |
mg/m3 |
|
Acetic anhydride |
5 |
20 |
O-Dichlorobenzene |
50 |
300 |
Formaldehyde |
2 |
3 |
Hydrogen Chloride |
5 |
7 |
Manganese & compounds (as Mn) |
... |
5 |
Nitrogen dioxide |
5 |
9 |
Nitroglycerin-skin |
0.2 |
2 |
Potassium hydroxide |
... |
2 |
Sodium hydroxide |
... |
2 |
2, 4, 6-Trinitrotoluene (TNT) |
... |
0.5 |
19. Exemption – If in respect of any factory, the Chief Inspector of Factories is satisfied that owing to the exceptional circumstances or infrequency of the processes or for any other reason, all or any of the provisions of this Schedule is not necessary for protection of the workers in the factory, the Chief Inspector of Factories may by certificate in writing which he may at his discretion revoke at any time, exempt such factory from all or any of such provisions subject to such conditions, if any as he may specify therein.