ISRP 2002 abstract
| Presenter/author | Title | Abstract |
|
Aitken,
R.J.* *) Institute of Occupational Medicine, Edinburgh, UK **) Health and Safety Laboratory, Sheffield, UK ^) Health and Safety Executive, Bootle, UK |
Capacity of Activated Carbon Filters: Theory and Experiment |
Respirators fitted with a filter cartridge
containing activated carbon are widely used to protect against hazardous
vapours present in the workplace. The health and safety of the wearer
depends on a good knowledge of the service life of the carbon filter
fitted to the respirator under the particular conditions of use.
Presently this is poorly understood.
Class A1 respirator filters were loaded with various solvent vapours in the laboratory using apparatus for generating standard atmospheres. The airflow rate and humidity were altered to give a range of test conditions for each solvent used with the challenge concentration set at a nominal 200 ppm for all vapours . Vapour concentrations were measured upstream and downstream of the filter so that the time for vapour breakthrough and the total mass of absorbed vapour could be measured. In general the variability in filter performance was higher than expected. The times for the vapour concentration downstream of a filter to reach 10% of that upstream of a filter was between 10 and 37 hr for Manufacturer A A1P2 filters and 22 to 30 hr for Manufacturer B A1P3 filters. The times taken for the downstream vapour concentration to reach the exposure limits was between 18 and 38 hr. Problems with instantaneous breakthrough were also identified. |