BS 6069-4.2:1991

Committees responsible
Foreword
Method
1. Scope
2. Definitions
3. Principle
4. Apparatus
5. Facilities at the sampling site
6. Site work prior to sampling
7. Sampling procedure
8. Analytical procedures
9. Method of calculation
10. Presentation and interpretation of results
Appendices
A. Safety precautions
B. Care of apparatus
C. Incorrect circumstances
D. Typical site data sheet
E. Typical presentation of results
F. Accuracy and precision of method
Table
1. Sampling location distances from obstacles
Figures
1. Sampling train
2. Typical access port with probe support/port sealer
3. Typical sample nozzle and filter holder designs
4. Typical sampling time graph for 4 mm diameter nozzle
5. Position of sampling points
6. Typical velocity/sampling rate/nozzle size setting
    chart

Applicable to flowing gas streams in ducts, chimneys or flues from asbestos industrial processes, in the range 0.05 fibre/ml to 10 fibre/ml.

This Section of BS 6069 describes a method, using a fibre count technique, for the assessment of fibre concentrations in flowing gas streams in ducts, chimneys or flues from asbestos-using industrial processes.

This method is intended to be used to determine fibre concentrations from a wide range of processes where it is known that regulated fibres are present in emissions. No attempt is made to identify asbestos fibre types separately from other fibres.

NOTE 1 If fibre identification is required, then reference should be made to the use of electron microscopy and the Health and Safety Executive.

NOTE 2 This method may be used to check that dust collection equipment used to trap asbestos fibres, or prevent their escaping into the atmosphere, is working properly and effectively.

NOTE 3 This method is suitable for measuring fibre concentrations as described in European Community Council Directive No. 87/217/EEC on the prevention and reduction of environmental pollution by asbestos.

The range of application of the method for concentrations of fibres in ducts is about 0.05 fibres/mL to 10 fibres/mL, although this range may vary slightly according to the sampled volume which, in turn, will depend on duct velocities and the sampling apparatus used. Appendix A gives safety precautions to be considered when carrying out the method described in this British Standard. Information on the accuracy and precision of the method is given in Appendix F. Appendix C gives information on sampling and measurement when the criteria given in this method cannot be met.

NOTE 4 The titles of the publications referred to in this standard are listed on the inside back cover.