Safe use manual
5. Dust Control Measures for the Chrysotile Product Manufacturing Sectors
Page 12
5.4 Housekeeping
Housekeeping is unquestionably the most important of all dust control methods. Simply cleaning-up all possible emission sources as quickly as possible is the most effective dust suppression technique. Such practices as vacuuming and wet floor cleaning not only prevent high dust levels, they also improve already clean, efficiently controlled asbestos-using environments. By introducing these simple housekeeping techniques, a factory can reduce dust levels by half or even three-quarters. Good housekeeping and work practices require workers' time. Because they are labour intensive rather than capital intensive, they can be used in plants working at any level of technology.
In many situations, particularly those dealing with maintenance, repair and equipment failures, it is not possible to ensure low dust levels at all times in the plant environment. As a result, respirators and special clothing may occasionally be required. This is dicussed in greater detail in Section 6.
5.5 Factory cutting and finishing
In some cases, chrysotile-containing friction materials or cement products can be cut before curing. However, in some plants, hardened products are trimmed to size, small pieces are cut from larger ones using circular saws, friction materials can be shaped and bevelled by grinding and if necessary, fitted with holes for fastening to brake shoes.
These operations can be very dusty. Where possible, these operations should be automated. Whether manual or automated, they must take place in a separate location with special equipment. If high density products are cut by saws, properly designed hoods and exhaust ventilation should be provided. Alternatively, water can be used for dust suppression by directing a stream of water or fog directly onto the saw blade or cutting or drilling tool. Obviously, provisions for collecting and discarding the contaminated water must be available. Cutting and finishing procedures must be carefully monitored, and personal High Efficiency Particulate Air (HEPA) respirators and protective clothing (disposable or washable overalls) must be worn if the dust levels rise above the permissible exposure limit.
The clean-up of dust and debris which can collect around the equipment should be carried out on a frequent basis using wet sweeping, HEPA vacuum cleaners. Clean-up crews must wear approved HEPA respirators when performing vacuuming operations.
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