Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

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“Step Out From the Old to the New”

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“Invent a New India Using Knowledge”

है”ह”ह

IS 15210 (2002): Workplace Air - Determination of VinylChloride - Charcoal Tube/Gas Chromatographic Method [CHD32: Environmental Protection and Waste Management]

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IS 15210:2002ISO 8762:1988

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IndianStandard

WORKPLACE AIR — DETERMINATION OFVINYL CHLORIDE — CHARCOAL TUBE/GAS

CHROMATOGRAPHIC METHOD

Ics 13.040.30

~

) October 2002

@ BIS 2002

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

Price Group 5

Environment Protection and Waste Management Sectional Committee, CHD 32

NATIONAL FOREWORD

This Indian Standard which is identical with ISO 8762:1988 ‘Workplace air — Determination of vinyl

chloride — Charcoal tube/gas chromatographic method’ issued by the International Organization for

Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendations of

Environment Protection and Waste Management Sectional Committee and approval of the Chemical

Division Council.

The text of ISO Standard has been approved as suitable for publication as Indian Standard without

deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention isparticularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read

as ‘Indian Standard’

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is

to use a point (.) as the decimal marker.

CROSS REFERENCE

In this adopted standard, reference appears to the following International Standards for some of which

Indian Standards also exist. The corresponding Indian Standard which are to be substituted in their

place are listed below along with their degree of equivalence for the editions indicated:

International Standard Corresponding Indian Standard Degree of Equivalence

ISO 5725 : 1986 Precision of test IS 542 (Part 2): 1973 Guide on Not equivalent

methods — Determination of repeat- Not equivalent precision of test

ability and reproducibility for a methods: Part 2 Inter-1aboratory

standard test method by inter- esting (This standard is at

laboratory tests present under revision)

ISO 6349 : 1979 Gas analysis — No IS exists

Preparation of calibration gas mixtures

— Permeation method

For tropical countries like India, the standard temperature and the relative humidity shall be taken as27 ~ 2°C and 65 f 5 percent respectively.

‘1

For the purpose of deciding whether a particular requirement of this standard is complied with, the final

value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance

with ‘IS 2:1960 Rules for rounding Qff numerical values (revisedj’. The number of significant places

retained in the rounded off value should be the same as that of the specified value in this standard.

IS 15210:2002

ISO 8762:1988

1 Scope

Indian Standard

WORKPLACE AIR — DETERMINATION OFVINYL CHLORIDE — CHARCOAL TUBE/GAS

CHROMATOGRAPHIC METHOD

‘Y\

This International Standard specifies a charcoal ,tube/gaschromatographic method for the determination of the vinylchloride monomer concentration in workplace air.

The method is vaiid for vinyl chloride concentrations in therange from 250 w#m3 ( = 100 i.11/m3) to 25 mg/m3( = 10 ml/m3) when Wmpling 30 Iitres of air[ll.

NOTE – The upper limit of the useful renga is set by the adsorptivecapacity of the charcost tube used.. This capacity ia measursd as abreqk-through volume of a~r, which volume should not be exctidadduring sampling. The lower iimit is setby, a number of parameters, in-cluding the noise level of the detector, blank concentration due tocontamination of the charcoal and carbon diaulfide by vinyl chloride,poor resorption efficiency at very low sample Ioadin&, and in-terference of the solvant peak in the gas chromatogrephic analysis.

Ths procedure is compatible with low flow-rate personalsampling equipment and can be used for personal and fixedlocation sampling. It cannot be used to measure instantaneousor short-term fluctuations in vinyl chloride concentrations.Alternative on-site procedures, such as gas chromatography orinfra-red spectrometry, ‘Should be uqed to measure rapidlychanging concentrations. Organic components which have thesame or nearly the same retention time as vinyl chloride duringthe gas chrcrmatographic analysis will interfere. Interferencescan be minimized by proper selection of gas chromatographiccolumns and programme conditions.

For certain applications, alternative detectors. such as thephoto-ionization detector may offer greeter selectivity and sen-sitivity to vinyl chloiide.

Water mists, high relative humidity, and other vapours at highconcentrations reduce the adsorptive capacity of the charcoalfor vinyl chloride.

The sampling method gives a time-weighted averaga result.

2 Normative references

The following standards contain provisions which, throughreference in thki text, constitute provisions of thka InternationalStandard. At the time of publication, the editions indicatedwere valid. All standards are subject to revision, and parties toagreements based on this International Standard are encour-aged to investigate the possibility of applying the most recenteditions of the standards listed below. Members of IEC and ISOmaintain registers of currently valid International Standards.

I-SO 5725:1986, Precision of test methods – Determination ofrepeatability and reproducibility for e stendard test method byintar-laboratory tests.

ISO 6349:7979, Gas analysis – Preparation of calibration gasmixtures — Permeation method.

3 Principle

A known volume of air sample is passed through a glass ormetal tube packed ~ith activated charcoal. The vinyl chloride isadsorbed onto the charcoal. The collected vinyl chloride isdesorbed using carbon disulfide and analysed with a gaschromatography equipped with a flame ionization detector.

4 Reagents

During the analysis, use only reagents of recognized analyticalgrade and orIly distilled water or water of ~uivalent quality.

4.1 Vinyl chloride liquid in a small gas cylinder.

WARNING – Vinyl chloride is recognized as a humancarcinogen. Avoid any exposure by inhalation or skincontact. Personal protection (e.g. en effective respirator)shall ba available in all cases where exposure to vinylclilorida ie possible.

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1

IS 15210:2002ISO 8762: 1988 /

Vinyl chloride vapour is highly flammable. Usage shall berestricted to a well-ventilated fume cupboard. An effec-tive fire extinguisher shall be permanently available.

4.2 Carbon disulfide (CSJ, chromatographic quality,previously checked for compounds coincident with the vinyl

chloride peak. The CSZ shall not contain impurities that co-elu~ with vinyl chloride giving a responsegreater than 0,08 ngof vifiyl chloride at an injection volume of 1 IJI. This require-ment shall be checked for each batch of CS2.

WARNING – Carbon disulfide vapour is toxic. Avoid anyexposure by inhalation or skin contact. Carbon disulfideis highly flammable. Usage shall be restricted to a well-ventilated fume cupboard. An effective fire extinguishershall be permanently available.

Small waste quantities of carbon disulfide shall bedisposed of only in accordance with local regulations andaccepted practices.

4.3 Activated coconut shell charcoal, particle size 0,35 mmto 0,85 mm. Before packing the tubes, the charcoal shall beheated in an inert atmosphere, e.g. high-purity nitrogen, at ap-

proximately 800 “C for 1 h. To prevent recontamination of the

charcoal, it shall be kept in a clean atmosphere during cooling

to room temperature, storage and loading into the tubes.

4.4.2 Vinyl chloride standard solution containing 52 mg ofC2H3CI per Iitra.

Add approximately 5 ml of the carbon disulfide (4.2) to a 10 mlone-mark volumetric flask. Pipette 2 ml of the standard solu-tion (4.4. 1) into this flask, dilute to the mark with the carbondisulfide and mix well.

1 ml of this standard solution contains 52 ~g of C2H3CI.

4.4.3 Vinyl chloride standard solution containing 5,2 mg ofCZH3CI per Iitre.

Add approximately 5 ml of the carbon disulfide (4:2) to a 10 mlone-mark volumetric flask. Pipette 1 ml of the standard sohJ-tion (4.4.2) into this flask, dilute to the mark with the carbondisulfide and mix well.

1 ml of this standard solution contains 5,2 pg of C2H3CI.

4.4.4 Vhryl chloride standard solution containing 0,52 mg ofCZH3CI per Iitre.

Add approximately 5 ml of the carbon disulfide (4.2) to a 10 mlone-mark volumetric flask. Pipette 1 ml of the standard sokJ-tion (4.4.3) into this flask, dilute to the mark w“th the carbondisulfide and mix well.

1 ml of this standard solution contains 0,52 ~g of C2H3CI.

NOTE – Suitable tubes containing pretreated coconut charcoal arecommercially available (see 5.1 ).

4.4.5 Vinyl chloride standard solution contairiihg 0,052 mgof C2H3CI per Iitre.

4.4 Vinyl chloride standard solutions for the preparation ofthe calibration graph.

4.4.1 Vinyl chlorida standard solution, containing 280 mg ofC2H3CI per Iitre.

Pipette 10,0 ml of the carbon disulfide (4.2) into a vial (5.10),cap the vial and cool in dry ice. Obtain pure vinyl chloridevapour at atmospheric pressure by partially filling a previouslyevacuated gas bag (5. 11) with pure gas from the small gascylinder (4.1 ).

Fill a syringe (5.8) with 1,0 ml of the vinyl chloride vapour fromthe gas bag and close the valve of the syringe. Insert the tip ofthe needle through the septum cap into the carbon disulfide.Open the valve and withdraw the plunger slightly to allow thacarbon disulfide to enter the syringe. The action of the vinylchloride dissolving in the carbon disulfide creates a vacuum andthe syringe becomes filled with the solvent. Return the solutionto the vial. Flush the syringe twice with the solution and returnthe f Iushings to the vial.

Add approximately 5 ml of the carbon disulfide (4.2) to a 10 mlone-mark volumetric flask. Pipette 1 ml of the standard solu-tion (4.4.4) into this flask, dilute to the mark with tha carbondisulfide and mix well.

1 ml of this standard solution contains 0,052 ~g of C2H3CI.

4.5 Vinyl chloride control solutions for checking the cali-bration graph.

4.5.1 Vinyl chlo~de control solution, containing 130 mg ofCZH3CI per Iitre.

Prepare this solution as described in 4.4.1, but inject 0,5 ml in-stead of 1,0 ml of the vinyl chloride vapour.

.

1 ml of this control solution contains 130 ~g of C2H3CI.

4.5.2 Vinyl chloride control solution, containing 52 mg ofC2H3CI per Iitre.

1 ml of this standard solution contains 260 ~g of C2H3CI.

Use the solution prepared as described in B.3. 1.4.

NOTE – The vinyl chloride concentrations are given for the case inwhich the vinyl chloride vapour is injected at”2U ‘C and 101,3 kPa. 1 ml of this control solution contains 52 ~g of C2H3CI.

2

IS 15210:2002

ISO 8762:1988

5 Apparatus

Ordina~ laboratory apparatus, and

5.1 Charcoal tuba, intwoxtions, 5mmto7mm internaldiameter, and packed with activated coconut shell charcoal(4.3), the front section containing 750 mg to 600 mg and theback-up section 200 mg to 250 mg. The sections are separatedand their contents held in place with an inert material, e.g.glass wool plugs (preferably siiicated).

Thepressure drop across the charcoal tube shall not exceed3 kPa at the maximum flow rate used for sampling (in this inter-national Standard, 2(X) ml/min). Giass. tubes .4@ be kept inholders. Thedesorption eticiency, D, foreach batch of tubesshall becheckedby one of themethods described in annex B.If the resorption efficiency is lower than 0,75 (75 Yo), the tubesshall not be used.

Clips shall be provided to hold the charcoal tube and connec-ting tubing tothewearer’s lapel area.

WARNING – Do not usa charcoal tubes with any tubingupstraam of the charcoal as this may intarfere withsampling and/or analysis. -

NOTES

1 Instead of a commercial two-section tube, two single-section tubeain series may be used with at Iasat 7KI “mg of charcoal in the first tube.This arrangement haa the advantage that it is not neceeaary to storetubes at sub-ambient air temperatures after sampling.

2 Tubaa meeting these raquiramanta are commercially available, butthey may aLsobe made by the user.

5.2 Polyethylene end caps, for capping charcoal tubaa.The caps shall fit the tubaa tightly to prevent leakage.

5.3 Pump, with adjustable flow rate, capable of being wornby a personwhile carrying out his normal work, and capable ofoperating continuously for 8 h at the flow rate used (between50 ml/min and200 ml/min, sea clause 6). The volume of airsampled by the pump over the recommended sampling periodshall be within 10 % of the calculated volume. The flow rateshall be constant within 5 % over the period of sampling.

Calibrate the pum’p with a repraae~tative charcoal tube (5.1) inline using the soap bubble flowmeter (5.5).

The pump shall comply with local safety regulations.

5.4 Plasticsor rubber tubing, of length about 80 cm and ofappropriate diameter to ensure a leak-proof fit to both pumpand sample tube or tuba ‘holder, ~ used.

5.5 Soap bubble flowmeter, for calibration of the pump(5.31, capacity 50 ml to 1(X) ml.

5.6 Syringa, capacity 10 pl, graduated to 0,1 I.11.

5.7 Syringe, capacity 50 PI, graduated to 1 I.11.

5.8 Syringa, capacity 1 ml, graduated to 0,05 ml, gas-tight.

5.9 Syringe, capacity 20 ml, graduated to 0,5 ml, gas-tight.

5.10 VieIs, fitted with septum caps, or glass-stoppered,nominal capacity 10 ml.

5.11 Gas bags, capacity 1 Iitre or 5 Iitres, for preparingcalibration mixtures. Bags made of inert material, e.g. polyesterlaminated with aluminium foil, are suitable. Because of thesignificant volubility of vinyl chloride in polytetrafiuorethene(PTFE), bags made of PTFE are unsuitable.

NOTES

1 Standard concentrations of vinyl chloride in air may be purchased.

Standard concentrations may also be prepared in the laboratory, e.g.dynamically with permeation tubes (see ISO 6349).

2 For an alternative method for generating standard atmospheres,sea bibliographic rafarence [11 (annex C).

5.12 Gas chromatography, with flame ionization detector,capable of detecting 0,25 ng of vinyl chloride with a signal-to-noise ratio of at least 5 to 1.

5.13 Gaa chromatography column capable of separatingvinyl chloride from other components.

The column suitability shall be verified by testing with two ormore columns of .diaaimilar packing to ensurt? {he absence of in-terferences. Examples of gas chromatography columns thathave bean found suitable are presented in table 1. This list isnot exhaustive. Capillary columns may also be suitable,

6 Sampling

Attach the pump (5.3) to a charcoal sampling tube (5.1) withthe rubbar or plastics tubing (5.4), placing the back-up sectionnearest, to the pump.

When a relative humidity above 80. % or high concentrations ofother interferences are suspected, use a second charcoalsampling tube connected in series and identical to the firsttube.

When using a second charcoal sampling tube in series, ensurethat the calibration of the pump has bean previously carried outwith two tubes in series.

Attach the charcoal sampling tube in a vertical position to thelapel of the operator for personal sampling. Then attach thepump to the operator as appropriate to minimize inconve-nience. For fixed Iocation sampling choose a suitable samplingsite.

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3

Is 15210:2002ISO 8762:1988

Table 1 – Characteristics of gas chromatography columns capable of separating vinyl chloride from other components

Column 1 2 3 4 5 6 7

Length m 3 6 1,8 1,8 1,8 2 1,5

Internaldiamater mm 2,2 2,2 2,2 2,2 2,2 2,2 2,2

StationaryDC 200 SE30 ‘

picricphaae Carbowax 1500 acid Porapak S

ChromosorbPorapak Cl

ChromosorbChromoaorb 102 Porapak T

supportVVII+P WI AWIDMCS

Carbopek A Carbopak C so:m

Particle sizepm 135 to 777 135 to 177 135 to 177 — 60 to 100 MJto 100

Stationaryphaseon support 10 10 — 0,4 0,19 —

%0

Columntamparature 75 60 135 145“c

ambient 50 110

Bibliographicraferanca [31 [41 [51 [61 [71 [81 [91

Turn the pump on and adjust the flow rate to provide a sam-

pling rate of 100 ml/min to 200 ml/min for a 4 h sampling

period or 50 ml/min to 100 ml/min for an 8 h sampling period.

Note and record the time, temperature, flow rate and

barometric pressure when the pump was turned on:

NOTES

1 The adsorption efficiency does not significantly change at flowrates lower than 2C41ml/min.

2 The sampling efficiency will be 100 % provided that the samplingcapacity of the charcoal is not exceeded. If this capacity is exceeded,break-through of the vapour from the front section to the back-up sac-tion (or second charcoal tube, if used) will occur. The. break-throughvolume is defined and may be determined aa specified in annex A. Thebreak-through volume varies with ambient air temperature, relativehumidity, concentration of vinyl chloride and of other contaminants,and with the sampling flow rate. Increases in any of these paramatarecause a reduction of the break-through volume. A typical breal(-through volume for coconut shell charcoal at a concentration of vinylchloride of 2,6 mg /m3 and low ralative humidity (less than 50 %) isabout 100 I/g, e.g. about 75 Iitres for the f rent section.

3 A sample volume of about 30 Iitres is sufficient for determiningvinyl chloride concentrations in the range of 2Ell ~g/m3 to 25 mg/m3withcwt break-through.

At the end of the sampling period, note and record the flow

rate, turn the pump off, and nota and racord the tima,

temperature and barometric pressure.

Disconnect the sampling tube and seal both ends with thepolyethylene end caps (5.2). Place identifying labels on eachtube.

NOTE 4 – If a second charcoal tube is used, this should be storadseparately.

If the samples are not to be analyaed within 8 h, store them in asaaled. metal or glass container placed either in dry ice or in afreezer maintained at – 20 ‘C or lower.

NOTES

5 Storage for up to 10 daya under theaa conditions has no influenceon the results of analysis[l 11

6 Storage at – ~ “C is recommended in order to retard migrationand to prevent loss of the sample.

Select one charcoal tube from the same batch of tubes used forsampling and subject it to the same procedure as the sampletubes except that no air shall ba drawn through it. Label this asthe blank.

7 Procedure

7.1 Calibration

Ana!yae each vinyl chlorida standard solution (4.4) in triplicateby gas chromatography.

Introduca in a raproducibla way a known aliquot in the range of1 @to 5 Vi of the standard solution into the gas chromatography

(5. 12). The volume of the aliquot shall be the same for eachsample standard solution.

In the casa of overloading toe chromatographic system, smallersample volumes shall be used. The lower limit of detection willthen be increased accordingly.

Prepare a calibration graph by plotting the areas of tha vinylchloride peaks, corrected for the blank value (carbon disulfide),against tha mass concentrations of the vinyl chloride standardsolutions, in micrograms per millilitre.

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‘,-,

IS 15210:2002

ISO 8762:1988 j$

Check the calibration graph by analysing the control solutions(4.5). If the difference is more than 5 %, carry out a newcalibration.

7.2 Determination

Pipette exactly 5,0 ml of the carbon disulfide (4.2) into a 10 mlvial (5.10) and cap the vial immediately. Cool in dry ice forabout2 min.

Score the charcoal tube containing the sample in the front(Iarger) section of charcoal and break open the tube. Removethe glass wool and discard it. Open the vial and transfer thecharcoal from the frent section to this vial and close the vial.Repeat the same procedure for the back-up sectbn, using a dif-ferent vial. Allow the contents to desorb for 30 mint with occa-

sional swirling.

Inject the same volume of the sample as used for preparing thecalibration graph into the gas chromatography.

Determine the area of the vinyl chloride peak. Read from thecalibration graph the corresponding mass concentration, inmicrograms per millilitre, of vinyl chloride in the injected sam-ple.

If the back-up section contains more than 10 ‘A of the vinyl

chloride contained in the front section, discard the sample as

unreliable.

Analyse the blank tube in the same manner. Analyse a freshly

prepared standard solution (4.4) with each batch of samples.

8

8.1

Expression of results

Calculation

The mass concentration of vinyl chloride in the air sampleQ(VC), in milligrams per cubic metre, is given by the equation

(@l + @2 – @3)~dL?(vc) =

D. v

where

@l is the mass concentration of vinyl chloride, inmicrograms per millilitre, in,the solution prepared from thefront section of the charcoal tube;

Q2 is the mass concentration of vinyl chloride, inmicrograms per millilitre, in the solution prepared from theback-up section of the charcoal tube (Q2 <0,1 @l);

p3 is the mass concentration of vinyl chloride, inmicrograms per millilitre, in the solution prepared from bothsections of the blank;

Vd.. -isthe volume of carbon disulfide, in millilitres, used fordasorption (5 ml);

D is the resorption efficiency as read from the D-curve,taking (Q1 + &12– @3)~d as the mass of vinyl chloride

d~

found (6.2.6); 4

V is the volume, in Iitres, of the air sample.

NOTES

1 If the vinyl chloride concentration has to be expressed at referenceconditions (283 K and 101,3 kPa), use the following equation:

101,3 (f + 273)e(vc)corr= Q(vc) x

px 293

where

L?(VC) is the concentration of vinyl chloride, in milligrams percubIc metre, as calculated above;

t is the temperature, in dagrees Calsius, during sampling;

p is the atmospheric pressure, in kilopascals, during sampling;

101,3 is the standard atmospheric pressure, in kilopascal~

273 is the standard temperature, in kelvins;

293 is the temperature in kelvins corresponding to 20 ‘C.

2 The volume fraction qXVC) of vinyl chloride in the air sample, inmillilitres per cubic metre (ppm), is given by the equation:

WC)=Q(vc)corr~w82,5

= Q(vc)corrx 0,384

where

Q(VC)corr is the vinyl chloride concentration, in, milligrams percubic metre, at reference conditions (8.1, note 1);

24,0 is the molar volume of an ideal gas, in Iitres per mole, at

20 ‘C and 101,3 kPa;

82,5 is the relative molar mass, in grams per mole, of vinylchloride.

8.2 Precision

Pre~minary investigations by a collaborative study[l ] in therange of 0,2 mg/m3 to 18 mg/m3 indicated a repaatabllity ofabout 22 % (a coefficient of variation of about 8 %) and areproducibility of about 45 % calculated as described inIso 5725.

9 Test report

The test report shall include at least the following information:

a)

b)

c)

d]

e)

f)

g)

a complete identification of the sample;

a reference to this International Standard;

the place and period of sampling;

the atmospheric pressure and temperature;

the test result;

any unusual features noted during the determination;

any operation not included in this International Stan-dard or in the International Standards to which reference ismade, or regarded as optional.

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5

IS 15210:2002ISO 8762:1988

Annex A(nOrmative)

Determination of break-through volume

A.1 Definition

For the purposes of this International Standard, the following

definition applies.

break-through volume for the charcoel tube: The volume

of a standard mixture of vinyl chloride in air that can be passed

through the front section of the charcoal tube before the con-

centration of the eluting vinyl chloride reaches 5 % of the ap-

plied test concentration.

The break-through volume is dependent among other things onthe concentration of the vinyl chloride and the relative humidityof the ambient air.

A.2 Reagents

LJseeither A.2. 1 oravailable.

A.2.2 depending on the equipment

A.2.I Static standard concentration of vinyl

chloride in air

Prepare static standard concentrations of vinyl chloride in air bypressure dilution in stainless steel cylinders or by atmosphericpressure dilution in gas bags.

NOTE – These standards are commercially available.

A.2.2 Dynamic standard concentration of vinylchloride in air

Prepare dynamic standard concentrations of vinyl chloride in airby dilution of a metered flow of pure vinyl chloride (4.1) with ametered flow of air[l] or dynamically with permeation tubes

(see ISO 6349). Other methods might be suitable.

A.3 Apparatus

Ordinary laboratory apparatus, and

A.3.1 Charcoaltube, single-section, containing 750 mg to600 mg of the charcoal (4.3) (see 5.1 ).

If commercially available two-section tubes are used, the char-coal from the back-up section shall be removed before use.

A.3.2 Flowmeter,range 50 ml/min to 200 ml/min.

A.3.3 Flameionizationdetector.

A.4 Determination

A.4.1 Assemble a sampling train consisting of a dynamicstandard atmosphere generator (see A.2.2) (e.g. pressurizedcylinder) which produces a gas .of approximately 10 mg/m3vinyl chloride, a charcoal tube (A.3. 1) with 750 mg to ~ mgof charcoal, the flowmeter (A.3.2) and the detector (A.3.3).

Pass the gas through the sampling train at a known constantrate between 50 ml/min and 200 ml/min. Note the time thaflow was initiated. When the vinyl chloride begins to emerge,the detector will show a response. Continue the measurementuntil a plateau corresponding to a concentration of vinylchloride of 10 mg/m3 is observed or otherwise until theresponse is determined to be caused principally or totally byvinyl chloride. Determine the time at which 5 % of the plateauvalue has been reached.

A.4.2 Usually the dead volume of the sampling train is low. incomparison with the break-through volume. If this is not thecase, determine the dead volume by repeating the determina-tion with an empty tube in the sampling train and correct theresult accordingly.

A.4.3 Determine the effect of moisture on the break-throughvolume by humidifying the gas stream to approximately 80 %relative humidity at 20 ‘C and repeating the test in A.4. 1.

Humidify the gas stream by diluting in a ratio of 1 :4 by volumea prima~ gas stream of vinyl chloride, at a concentration of50 mg/m3, with a stream of moist air at UIO % relative humid-ity. The moist air is preparad by passing clean air through aseries of water bubblers or tubes. Do not pass the vinyl chloridegas stream through water.

NOTE – The relative humidity specified (S0 %) is a practical value; itdoes not imply that the method is invalid at higher reletive humiditiesprovided that due attention is given to the restriction on break-throughvolume at high humidity in clause 6.

A.5 Expression of results.

Calculate the break-through volume by multiplying the flowrate, expressed in Iitres per minute, by the elapsed time, inminutes, from zero until the moment at which 5 % of theplateau value corresponding.to 10 mg/m3 has bean reached.

NOTE - Break-through volumes for activated coconut charcoal aretypically in excess of 30 Wee aemple volume per gram of charcoal.

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6I

IS 15210:2002ISO 8762:1988

Annex B(normative)

Determination of the resorption efficiency

B.1 Definition

For the purposes of this International Standard, the followingdefinition applies.

dksorption efficiency for the charcoal tube: The massrecovered from the tuba divided by the mesa applied.

Thedaaorption efficiency of vinyl chloride from charcoal canvary with the type and batch of charcoal, with the.concentra-

tion of adsorbed vapour and with the laboratory. Thus it isnecesaaryto determine foraach bath of charcoal the resorp-tion efficiency over the expected vinyl chloride concentrationrange. Two methods are provided for the determination ofdasorption efficiency. The method using calibration gases (B.2)is the more stringent method.

B.2

B.2.1

Determination using calibration gases

Reagents

B.2.1.1 Static standard concentrations of vinyl chloridein air (see A.2.1 ).

B.2.1,.2 Dynamic standard concentrations of vinylchloride in air (see A.2.2)i

B.2.2 Apparatua

B.2.2.1 Pump (see 5.3).

B.2.2.2 Calibrated flowmeter.

B.2.3 Procedure

Determine the resorption efficiency at five load Ietrels in therange of 0,5 ~g to 650 ~g vinyl chloride. Preferably use threecharcoal tubes for each load level.

Sample known concentrations of vinyl chloride in-air (see A.2. 1and A.2.2), measuring the total sample volume with theflowmeter (B .2.2.2). The sample may be passed through thecharcoal tube and the flowmeter from a pressurized source, or

tdraw through the tube by a calibrated pump (B.2.2.1 ). Themaxim m pressure drop across the charcoal section specifiedin 5.1 shall be observed. The flow rate shall be in the range of50 ml/min to 200 ml/min. The total volume shall be a factor2 less thafithe break-through volume (sea annex A).

The sampling efficiency is assumed to be 1C41%.

At the end of the sampling period, disconnect the charcoalsampling tube, seal the tube with polyethylene end caps (5.2)and label.

Record and note the volume.

B.2.4 Blank test

Select one charcoal tube from the same batch of tubes used forsampling and subject it to the same procedure as the sampletubes except that no air shall be drawn through it. Label this asthe blank.

6.2.5 Determination

Analyse the loaded tubes and the blank as specified in 7.2.

B.2.6 Expression of results

The resorption efficiency D k given by the equation

D=(@4+@j–@6)~d

m

where

Q4 is the mass concentration, of vinyl chlofide inmicrograms per millilitre, in the solution prepared from thefront section of the charcoal tube;

@5 is the mass concentration, of vinyl chlofide inmicrograms per millilitre, in the solution prepared from theback-up section .of the charcoal tube;

@6 is the mass. iconcentration, of vinyl chloride inmicrograms par millilitre, in the solution prepared from bothsections of the blank (6.2.4);

Vd is the voiume of carbon disulfide, in millilitres, used fordasorption (5 ml);

m is the mass of vinyl chloride, in micrograms, loaded onthe charcoal tube (B.2.3).

Prepare a graph (D-curve) by plotting the dasorption efficien-cies at the five load levels against the corresponding masses ofvinyl chloride (&74+ Q5 – ,4@vd .

6.3 Determination using vinyl chloridesolutions

NOTE – This method dms not take account of smbiant conditionsprevailing during sampling.

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7

pj-

IS 15210:2002ISO 8762:1988

B.3.1 Reagents

6.3.1.1 Vinyl chloride standard solution containing13000 mg of CZH3CIper Iitre.

Pipette 4,0 ml of carbon disulfide (4.2) into a vial (5.10), cap thevial and cool in dry ice. Obtain pure vinyl chloride vapour asspecified in 4.4.1.

Fill a 20 ml gas-tight syringe (5.9) with pure vinyl chloridevapour from the gas bag and dissolve the vapour in the carbondisulfide as specified in 4.4.1.

1 VI of this standard solution contains 13 pg of C2H3CI.

NOTE – The vinyl chloride concentrations are given for the case inwhich the vinyl chloride vapour is injected at 20 ‘C end 101,3 kPa.

B.3.1.2 Vinyl chloride standard solution, containin9

5 ~ mg of C2H3CI per Iitre.

Introduce 3,0 ml of carbon disulfide (4.2) into a vial (4.10), add

2,0 ml of the standard solution (Bi3.1. 1), immediately cap the

vial and mix well.

1 l.d of this standard solution contains 5,2 ~g of C2H3CI.

B.3.1.3 Vinyl chloride standard solution, containing 520 mg

of C2H3CI per Iitre.

Introduce 9,0 ml of carbon disulfide (4.2) into a vial (4.10), add

1,0’ ml of the standard solution (B.3.1 .2), immediately cap the

vial, and mix well.

1 @ of this standard solution contains 0,52 ~g of C2H3CI,

B.3.1.4 Vinyl chloride standard solution, containing 52 mgOf CZH3CI per litr~.

Introduce 9,0 ml of carbon disulfide (4.2) into a vial (4.10), add1,0 ml of the standard solution (B.3.1 .3), immediately cap thevial, and mix well.

1 @ of this standard solution contains 0,052 ~g of C2H3CI.

B.3.1.5 Vinyl chloridestandardsolution,containing10mg

b

j

of C.2H3CIperIitre..4

Introduce 8,0 ml of carbon disulfide (4.2) into a“vial (4.10), add2,0 ml of the standard solution (B.3. 1.4), immediately cap thevial, and mix well.

1 VI of this standard solution contains 0,010 Ug of C2H3CI.

B.3.2.1 Pump (see5.3).

B.3.2.2 Syringe, CSpacity50VI.

B.3.3 Procedure

Determine the deaorption efficiency at five load levels in therange of 0,5 ~g to 650 Kg vinyl chloride. Preferably use threecharcoal tubes for each load level.

By meena of the syringe (B.3.2.2), slowly inject, 50 @ of thevinyl chloride standard solution (B.3. 1.1 ) into the 9!aea WOOIpreceding the front section of the charcoal sampling tube con-nected to the operating pump (B.3.2. 1). Allow the pump to runcontinuously for approximately 10 min at a rate of about200 ml/min. Then stop the pump, seal the charcoal samplingtube with the polyethylene end caps (5.2) and store it overnightin a refrigerator,. Repeat the procedure with the other vinylchloride standard solutions (B.3. 1.2 to B.3. 1.5). Intermediatevalues can be obtained by injecting dtierent aliquots of thevinyl chloride standard solutions.

B.3.4 Blank test

Carry out a blank teat by the procedure specified in B.3.3 butinjecting 60 @ of pure carbon disulfiie (42).

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,

B.3.5 Determination.b

Analyse the loaded tubes and the blakk as specified in 7.2.

B.3.6 Expression of results

Calculate the daaorption efficiencies and plot a graph asspecifiad in B.2.6.

Annex C(informative)

Bibliography

[11 SPEE, T., RoCmd-robin test for the determination of vinylchloride in air, Reporl No.. F 1856. TNO research institutefor environmental hygiene, Delft, the Netherlands (1962).

[21 SPEE,T. and LANTING,R.W., Evaluation’of an ISO DraftProposal for sampling and analysis of vinyl chlorida inworkplace atmospheres — Generation of teat at-,mospheres in low concentration ‘ranges. StaubReinhaltung Luft 43 (1983), 337-340.

[31 BANKOVICH, P. W. etal., Am. Ind. Hyg. Assoc. J. 37(1976), 690.

[41 HILL, R.H. et al, Anal Chem. 48 (1976), 13&-13BB.

IS 15210:2002ISO 8762: 1988

[51 :;IEBACK, J.E. et al, Environ. Sci. Techn. 9 (1975),

[61 LAO,R.C. et al., Am. Ind. Hyg. Assoc. J. 37 (1976), 1.i

[71 GOING,J. E., .PB-262-966, National Technical InformationSarvica, Springfield, USA (1976).

[81 BURGHARDT,E. etal., Atmowharic Environment13(1979),7, 1057.

[91 KROCKENBURGER,D. et ai., Chrornatographia 12 (1979), 12,787.

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