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close this bookAsbestos Overview and Handling Recommendations (GTZ, 1996)
close this folderPart VII Annexes
View the documentAnnex 1: Maps on the deposits of Asbestos, Asbestos consumption and commercial trade of raw Asbestos
View the documentAnnex 2: Health and safety data sheet for Asbestos cement in UK
View the documentAnnex 3: Asbestos fiber emissions from particular processes
View the documentAnnex 4: US Federal Regulations for Asbestos
View the documentAnnex 5: Commercial names of Asbestos containing products
View the documentAnnex 6: Advantages and disadvantages of Asbestos abatement methods
View the documentAnnex 7: Asbestos data from the environmental handbook Vol. III: Compendium of environmental standards
View the documentAnnex 8: Questionnaire on country profiles regarding Asbestos

Annex 3: Asbestos fiber emissions from particular processes

DUST CONCENTRATIONS

The figures below arc a guide lo the airborne fibre levels that may be expected close to the operator's breathing zone in a number of different processes. The following points should be borne in mind when using them.

(a) They are based on measurement taken by HSE. Different processes in different locations may result in higher or lower concentrations than those listed in the table;

(b) They are average concentrations for the time during which the process is actually taking place. To check whether a control limit or action level is exceeded a time-weighted average over the appropriate reference period must be calculated;

(c) Selection of a figure from the list is not itself an assessment. The person making the assessment must consider whether it is reasonably practicable to use methods that give a still lower value.

Process

Concentration fibres/ml

Process

Concentration fibres/ml

Asbestos Stripping Operations


Asbestos insulation board and titles (normally amosite and chrysotile)


(a) De-lagging


(a) Sanding and surforming


(i) dry stripping of crocidolite

100-1000



(ii) dry stripping, except crocidolite

greater than 20

(b) Machine cueing without exhaust ventilation


(iii) stripping with water sprays

540

(ii) circular saw greater than

20

(iv) controlled wet stripped


(iii) jig saw

5-20

(thorough soaking of insulation)

1-5

(with exhaust ventilation)

(1-5)

(c) Drilling overhead

5-10



(b) Removal of insulation board and tiles


(d) Drilling vertical columns

2-5

(i) breaking and ripping out

5-20

(e) Hand sawing

5-10

(ii) unscrewing and careful removal with application of local exhaust ventilation less than

2

(f) Scribing and breaking

1-5



(g) Rough handling of insulating board and greater than removal of pieces

15



(h) Careful removal of whole boards

Up to 5



Note: The dust levels are likely to be highest if amosite is present and the material is handled roughly. Bad handling practices may result in much higher concentrations.


Asbestos cement sheets and pipes (normally chrysotile)


Decorative Plasters


(a) Machine cutting without exhaust ventilation


Scraping painted plaster

0. 1-0.2

(i) abrasive disc cutting

15-25

Light hand sanding of unpainted areagreater than 0.3


(ii) circular sew

10-20

Mixinggreater than

0.1

(iii) jig saw

2-10



(b) Machine sawing without exhaust ventilation

below 2



(c) Reciprocating saw

below 1



(d) Hand sawing

below 1



(e) Machine drilling

below 1



(f) Removing of Asbestos-cement sheeting

below 0.5



(g) Stacking of Asbestos-cement sheet after removal

below 0.5



(h) Remote demolition of Asbestos-cement structures

below 1



Caution: subsequent clearance may give rise

greater than 1)



(i) Cleaning of Asbestos cement:





Roofing

Vertical cladding


Dry brushing (wire)

3

5-8


Wet brushing (wire)

1-3

1-2


Water-jetting

0-0.5

1-2


(Note: water jetting may produce debris and slurry which is difficult to control.)