Exposures in manufacture and use

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Appendix C
Exposures in manufacture and use
1. Historical data
1.1. The following exposure data have been published by the International
Programme on Chemical Safety (IPCS).1 They are consistent with workplace
monitoring carried out in manufacturing and user industries during the past ten years.
The available data on levels of airborne insulation wool in the manufacturing industries
include both mass concentrations of particulate matter, and respirable fibre levels.2
1.2. The average concentrations measured by phase contrast optical microscope
(PCOM) during the menufacture of glass wool insulation were of the order of 0.03 f/ml;
and concentrations in mineral wool (rock and slag) plants in the United States ranged
up to one order of magnitude higher. Corresponding concentrations in European rock-
wool plants were of the order of 0.1 f/ml.
1.3. Total inspirable dust concentrations were typically of the order of 1 mg/m³,
irrespective of the fibre type manufactured. Overall averages were 4-5 mg/m³ for one
rock wool and one glass wool plant where manufacturing was reported to be heavy or
very heavy. The situation in 13 European plants was similar.
1.4. Available data on airborne fibre concentrations associated with the
installation of insulation wool products have demonstrated that concentrations vary
considerably, depending on the method of application and the extent of confinement
within the workplace. Concentrations during installation were comparable to, or lower
than, those found in manufacturing (paragraph 1.2), with the important exceptions of
blowing or spraying conducted in poorly ventilated spaces such as attics, and during the
use of products without resin binders.
1.5. Concentrations measured during the installation of unbonded glass wool and
rock wool insulation in attics have been as high as 1.8 and 8.2 f/ml, respectively. Mean
concentrations during the installation of bonded rock-wool blankets in confined spaces
on board ships have been reported as less than 0.7 f/ml. It should be noted that the time
weighted average (TWA) exposure of insulation workers was probably considerably
less than these mean concentrations during application, as insulators often worked with
insulation wool products from less than 10 to 100 per cent of their time. It is likely that
TWA exposures may have exceeded 1.0 f/ml only for workers insulating attics or
1 WHO: Man-made mineral fibres, op. cit.
2 Further examples of historical data have been provided in Note ND 1907.150.93 from the National
Research and Safety Institute (INRS, France), which gives dust exposure levels measured between 1978
and 1991 for various types of insulation glass wools and rock wools, when used. From these, the
following personal exposure levels were measured:
- handling and blowing of mineral wool in bulk: 2.33-3.71 f/cm³ (five samples);
- laying and cutting of insulation wool: 0.08-1.49 f/cm³, and 1.45-4.92 mg/ m³ for respirable dusts (44
samples);
- for wet spraying: 0.16-0.43 f/cm³, and 1.14-3.66 mg/m³ for respirable dusts (eight samples); and
- insulation of industrial materials: 0.58-1.88 f/cm³ (six samples).

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