Weight arrestance test

Weight, arrestance Tests carried out with synthetic dusts to determine the weight of dust collected on a filter during testing. 

The toxic effects manifested in humans from inhaling trichloroethylene vapors are headache, dizziness, drowsiness, fatigue, and visual disturbances. A 2-hour exposure to a 1000-ppm concentration affected the visual perception. Higher concentrations can produce narcotic effects. Heavy exposures may cause death due to respiratory failure or cardiac arrest. A 4-hour exposure to 8000 ppm was lethal to rats. Chronic exposure caused increase in kidney and liver weights in test animals. 

BS 6540 (Pt 1) 1985 Methods of test for atmospheric dust spot and efficiency, and synthetic dust weight arrestance HSE Guidance Notes, HMSO, London MS 13 Asbestos (1988)... 

These classifications are considered to be a proven method for designing air filtration media according to average synthetic dust weight arrestance and average dust spot efficiency, although it should be slated that the whole test situation is complicated by not only the diverse test procedure but the diversity of particulate materials specified for them. 

Arrestance, average The weighted percentage ratio of the total amount of standardized test dust retained by a filter to the total amount of dust fed into the filter in order to achieve a specified final pressure drop. 

VI.ll. The basis for determining the NDTT is the highest temperature at which brittle fracture does not run in the parent material from a brittle weld bead in the standard drop weight test [V1.2]. This can be thought of as the bottom of the transition temperature curve either for propagation/crack arrest or for dynamic initiation from small initial cracks. 

The concentrations are adjusted so that cardiac arrest occurs between twenty and forty minutes from the commencement of the injection and so that the mean duration of the injection time for standard and unknown do not differ by more than 10 per cent. The amount of digitalis to produce this effect is taken as the lethal dose which may be recorded in terms of units per kg body-weight for the standard and mg per kg for the sample being tested. 

The diluted extracts are injected via the alar vein from a burette calibrated to 0-05 ml, infusing 1 ml per kg body weight within a few seconds at five-minute intervals until the pigeon dies of cardiac arrest. If the number of doses required to produce this is less than 13 or exceeds 19 or if the larger average in one test exceeds the lower by more than 4 doses the data are regarded as preliminary. Not less than 6 pigeons are used for standard and not less than 6 for the assay preparation. 

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