Schedule to Schedule XXVIII

1. Definitions.- For the purpose of this schedule,-

(a) "mg/m3" means milligrams of a substance per cubic meter of air:

(b) "mppcm" means a million particles of a substance per cubic meter of air;

(c) "ppm" means parts of vapour or gas per million parts air by volume at 25°C and

760 mm. of mercury pressure:

(d) "Time 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 that 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.

Time weighted average C T + C T + …..C T

1 1 2 2 n n

Concentration = ------------------------------------

T + T .......T

1 2 n

Where C represents the concentration of the substance for duration T (in hours);

I 1

C represents the concentration of the substance for duration T (in hours): and

2 2

C represents the concentration of the substance for duration T (in hours);

n n

(e) "work location" means a location in a factory at 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 15 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 of 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 the cases where the word "skin" has been indicated against certain substance mentioned

in Tables 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 is only through respiratory track.

(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 C /L + C /L +....... C /L should not exceed unity when C C ...

1 1 2 2 n n 1 2

C are the time weighted concentration of toxic substance 1, 2, ……….. and n

n

respectively, determined after measurement at work location, and L , L .. Ln are

1 2

the permissible time weighted average concentration of the toxic substance 1, 2,

... and n respectively.

(b) In case the air at any work location contains a mixture of substances, mentioned in

Table 1, 2 or 3 and these do not have similar toxic properties, that 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 substance.

(c) The requirement in clauses (a) and (b) shall be in addition to the requirements in

clause 2 (1) and 2 (2).

3. Sampling and evaluation procedures.- (1) Notwithstanding provisions in any other

clauses, the sampling and evaluation procedures to be adopted for checking compliance with

the provision in the schedule shall be as per standard procedure in vogue, from time to time.

(2) Notwithstanding the provisions in clause 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 impinger and the

counts made by light-field technique.

(b) The percentage of quartz in the 3 formulae given in item 1 (a) (i) of Table 2 is to

be determined from air borne samples.

(c) For determination of number of fibres as specified in item 2 (a) of Table 2, the

membrane filter method at 430 magnification (4 mm. objective) phase contrast

illumination should 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 size-

selector with the following characteristics should only be considered:-

Aerodynamic diameter Percentage allowed by

(Unit density Sphere) size-selector

2.0 90

2.5 75

3.5 50

‍599

5.0 25

10.0 0

4. Power to require assessment of concentration of substances.- (1) An Inspector-cum-

Facilitator may, by an order in writing, direct the occupier or manager of a factory to get

before any specified date, the assessment of the time weighted average concentration at any

work location of any of the substances mentioned in Table 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-cum-Facilitator within 3 days from

the date of completion of such assess merit and also a record of the same kept readily

available for inspection by an Inspector-cum-Facilitator.

5. Exemption.- If in respect of any factory or a part of factory, the Chief Inspector-cum-

Facilitator is satisfied that, by virtue of the pattern of working time of the workers at different

work location or an 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

is likely to be injurious to his health, the Chief Inspector-cum-Facilitator may by an order in

writing, exempt the factory or a part of the factory from the requirements in clause 2, subject

to such conditions, if any as he may specify therein.

Permissible limits

Table 1

Substance Permissible limits of exposure

Time weighted average Short term maximum

concentration concentrated

1 2 3

ppm mg/m3 ppm mg/m3

Acetic acid 10 25 15 37

Acrolein 0.1 0.25 0.03 0.8

Aldrin-skin - 0.25 - 0.75

Anisidine (o-poisonous)-skin 0.1 0.5 - -

Ammonia 25 18 35 27

Aniline Skin 2 10 5 20

Arsenic & Compound (as) - 0.2 - -

Benzene 10 30 - -

Bromine 0.1 0.7 0.3 2

2 Butanene Methyl ethyl 200 590 300 885

(Ketone-MEK)

n-Butyl acetate 150 710 200 950

Sec/ter. Butyl acetate 200 950 250 1190

Cadmium-dust and salts (as Cd) - 0.05 - 0.2

Calcium Oxide - 2 - -

Carbaryl (Sovin) - 5 - 10

Carbofuran (Furadan) - 0.1 - -

Carbon disulphide- skin 2 60 30 90

Carbon monoxide 50 55 400 440

Carbon tetrachloride- skin 10 65 20 130

Carbonyl chloride (Phosgene) 0.1 0.4 - -

Chlordane-skin - 0.5 - 2

Chlorobenzene (mono chloro- 75 350 - -

benzene)

Chlorine 1 3 3 9

bis-chloromethyl ether .001 - - -

Chromic acid and chromates (as - 0.05 - -

Cr.)

Chromium, Sol. Chromic - 0.5 - -

Chromous Salts (as Cr.)

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 (Dichloro-diphenyl- - 1 - 3

trichloroethane)

Dameton- skin 0.01 0.1 0.03 0.3

Diazion- skin - 0.1 - 0.3

Dibutyl Phthalate - 5 - 10

Dichlorves (DDVP) skin 0.01 1 0.03 3

Dieldrin- skin - 0.25 - 0.75

Dinitro Benzene (all isomers) 0.15 1 0.5 3

skin

Dinitro toluene 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 1000 - -

Ethyl alcohol 1000 1900 - -

Ethyl amine 10 18 - -

Fluorides (as F) - 2.5 - -

Fluorine 1 2 2 4

Hydrogen Cyanide- Skin 10 11 15 16

Hydrogen Sulphide 10 15 15 27

Iron Oxide Fume (Fe O as Fe) - 5 - 10

2 3

Isoamyl acetate 100 525 125 655

Isoamyl alcohol 100 360 125 450

Isobutyl alcohol 50 150 75 225

Lead, inorg, fumes and dusts (as - 0.15 - 0.45

Pb)

Lindane -skin - 0.5 - 1.5

Melathion- skin - 10 - -

‍601

Manganese fume (as Mn) - 1 - 3

Mercury (as Hg) - 0.05 - 0.15

Mercury (alkyl compounds) skin 0.001 0.01 0.003 0.03

(as Hg)

Methyl alcohol (methanel) skin 200 260 250 310

Methyl cellosolve skin (2 25 80 35 120

methoxy ethanol)

Methyl isobutyl Ketone skin 100 410 125 510

Naphthalene 10 50 15 75

Nickel carbonyl (as Ni) 0.05 0.35 - -

Nitiric acid 2 5 4 10

Nitric oxide 25 30 35 45

Nitrobenzene- skin 1 5 2 10

Oil Mist mineral - 5 - 10

Parathion skin - 0.1 - 0.3

Phenel skin 5 19 10 38

Phorate (Thimet) skin - 0.05 - 0.2

Phosgene (carbonyl chloride) 0.1 0.4 - -

Phosphine 0.3 0.4 1 1

Phosphours Pentachloride - 1 - 3

Phosphours Trichloride 0.5 3 - -

Picric acid skin - 0.1 - 0.3

Phosphorus (yellow) - 0.1 - 0.3

Pyridine 5 15 10 30

Silane (silicon tetrahydride) 0.5 0.7 1 1.5

Styrene, monower (Phenyl 100 420 125 525

ethylene)

Sulphure dioxide 5 13 - -

Sulphuric acid - 1 - -

Toluene (toluol)- 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-isomers) skin 100 435 150 655

Table 2

Substance Permissible time weighted average

1 concentration

2

1. Silica

(a) Crystalline

(i) Quartz

(1) In terms of dust count mppcm

(2) In terms of repairable dust

mg/m3

(3) In terms of total dust

mg/m3

(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 items 2

given against quartz.

(b) Amorphous 705 mppcm.

2. Silicate having less than 1% free silica

by weight

(a) Asbestos fibres longer than 5

microne.

(i) Amosite 0.5% fibre/cubic centimeter.

(ii) Chrysolite 2% fibre/cubic centimeter.

(iii) Crocidolite 0.2% fibre/cubic centimeter.

(iv) Other form 2% fibre/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 (nonobosti form) 705 mppcm

(h) Talc (fibrous) Same limits as for asbestos

(I) Tromolite Same limits as for asbestos

3. Coal dust

(1) For airborne dust having less than 2 mg/m3

5% silicon dioxide by weight

(2) For airborne dust having over 5% Same limit as prescribed by formula in

silicon dioxide. item (2) against quartz.

‍603

Table 3

Permissible limit of

Substance exposure

ppm mg/m3

Acetic anhydride 5 20

O- Dichlorbenzene 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