Document 4J5akZe7XoepL3MvyJzJmOmYj

36 G. L. Lee The fixed sampler in the area of the highest concentration gave a dust concentra tion of 21 mg 'm5 and the personal sampler, 2-7 mg/ms. An improvement in controlling the release of dust had been obtained but was not considered completely satisfactory and an alternative approach was sought. CONDITIONS OBTAINED USING A MODIFIED TECHNIQUE After some preliminary experiments, the following general technique was devised. Firstly, the loose deposits of dusts inside the brake drum and on readily accessible surfaces of brake shoes and the brake assembly were removed, using the smallest brush supplied with the cleaner--the equipment being used as a vacuum cleaner. A much narrower, tubular brush, made from available materials was then used to remove deposits from less accessible surfaces. Finally, a rag, soaked in water and wrung fairly dry, was used to remove adherent deposits. No visible emissions of dust were observed but a few particles were detected by the objective methods, as shown in Table 3. Table 3. Results of Konimeter samples during modified technique Sample Number of-brake dust particles/5 cm* Brushing with standard brush Brushing with tubular brush Rag wiping 16-25 20-25 1-5 No fibres were detected and the mass concentrations involved were too low to determine. CONCLUSIONS The objective measurements made seem to confirm that vacuum cleaning provides a useful contribution towards obtaining satisfactory dust control when brake assem blies are cleaned. The design of the particular cleaner chosen prevents the discharge of particles back into the environment and the collection in a paper bag enables suitable disposal methods to be adopted. This work was completed in the early part of 1968 and subsequently the method described was recommended for use until such time as the results of studies being carried out elsewhere in the Motor Industry were known and detailed requirements subsequently formulated. Acknowledgements--The assistance of Mr D. Smith of the Industrial Hygiene Department and Mr Young, Works Engineers, is gratefully acknowledged. REFERENCES Addingley, C. G. (1966), Ann. occup. Hyg. 9, 73. Higgins, R. I. and Dewell, P. in Instruction Leaflet 3107/AI, C. F. Casella. Ann. Oeei < THE M( asserab a dust < being c generat mum li Enc is to al in itself the pat total cl The method that it \ was nee The Vacuun The for an i periphe the fun and coi dust-lac the clea This Clutch h