Control of asbestos dust produced by automotive brake lining machinery
Various types of radial grinding machines are used to manufacture automotive brake shoes containing asbestos material. Most brake re-lining workshops will have one or more of these machines. The Victorian standard of acceptable exposure for asbestos dust is 2 fibres per millilitre of air.
The two radial grinders were fitted with extraction equipment. The system was approved by the local OHS Authority and complied with legal requirements.
The close-fitting hoods ensured an effective capture of grinding dust and waste. The grinding machines will not operate if the extraction unit is not working. A cross-over switch shuts off the second machine when one machine is in operation thereby ensuring sufficient suction where it is needed. The filter medium is cleaned regularly on a prescribed schedule to prevent any dust breakout. A 5-minute delay on the extractor’s motor ensures that it continues in operation well after the radial grinders have been shut down. The extractor is fitted with an automatic shaker to assist with the transport of asbestos waste into the plastic bag which lines the inside of the bottom drum.
Hierarchy of Controls:
- A well-developed hood and local exhaust ventilation system has effectively controlled potential exposure of workers.
Measurements in the workplace have shown asbestos fibre concentrations to be barely detectable.