Document rB4aERZ5NrYDVJvX9gp19Zoqa
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38 K. L. Ktooht tod D. E. Hkxoh
Vacuum brush The vacuum brush shown in Fig. 2 consisted of a circular nylon bristle brush
mounted on an angled handle and fitted via the handle to the same vacuum cleaner. In use, the brush was used to remove dust from drums and assemblies under vacuum.
EXPERIMENTAL PROCEDURE
In order to determine which of these two methods was the better, the performance of each was compared with the traditional blow-off method, in two separate experi ments shown in Table 1.
Tabu. 1. Efftcr or cuamno ksthoos on dust concsmiuatioks
Hour Activity
Personal sampler Static lampler Peak sample
particks/cnp
fibres/cm* particles/cm* fibres/cm* particlca/cm* fibres/cm*
Personal sampler Static sampler Peak sample
particlea/cm*
fibres/cm* particles/cm*
fibres/cm* particles/cm* fibres/cm*
-
1 Background
2 Blow-off
3 Background
66 Funnel Brush cleaning cleaning
IK 422 107 413
0-96 3-33 093 3-3
161 72 162 210
043 0-32 0-41 0-73
41730
739
87 1*04
123 633 0-16 084 129 133 0-10 0-16
41730 87
140 0-09 110 0-20
138 0-22 122 0-18 310 0-37
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During the first hour of the day air samples were collected to determine background concentrations; during this period the near side front road wheel was removed. In the second hour samples were collected during dust removal from the near side brake assembly by blow-off. Further background samples were taken during the fifth hour while the off side front road wheel was removed, and during the sixth hour dust determinations were made while either the funnel or the brush cleaning methods were used.'
The personal samples were collected from the breathing rones of mechanics en gaged in the work and static samples were collected concurrently to simulate exposure of mechanics working in an adjacent repair bay. Short duration samples were also collected by means of a Drfiger pump from the operator's breathing zone at the peak period of dust generation.
All the samples were subsequently analysed for fibres in accordance with the technique laid down in the Hygiene Standardfor Chrysolite Asbestos published by the British Occupational Hygiene Society (1968). Particle counts were limited to particles greater than 1 ft dla.
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