21 Changi South Street 1 Singapore 486777 Phone: +65 65420833 Fax: +65 65426920
E-mail: ductless@escoglobal.com Website:
www.escoglobal.com/ductless
APPENDIX
APPENDIX A
FILTER SATURATION TEST
SECTION A: INTRODUCTION
Electronic detectors for monitoring filter saturation (efficiency) have not been shown to be sufficiently
reliable for the range of gases used in school/lab and over a reasonable time scale; therefore chemical
tests are needed.
As there are strict limits to the concentrations of hazardous gases in air which can be breathed, it is
necessary to test the efficiency of the filter regularly. Further, it is prudent to conduct an initial test to
ensure that the filter is seated properly and that its contents have not been displaced in transit. It is
advisable to test for this every time the filter is replaced.
There are 3 methods according to the COSHH regulation to test for filter saturation by chemical (acid
gases). There are namely:-
• Propan-2-ol challenge test (BS 7989:2001 Standard)
• Method using a canister (cease to be practicable)
• Method using the burning sulphur (BS 7989:2001 Standard)
• Test for saturation by organic gases (limited usage)
For our purpose, Esco will be using the propan-2-ol challenge and burning sulphur test method.
SECTION B: PROPAN-2-OL CHALLENGE TEST
The filter, when challenged continuously at 800 ppm +/- 50 ppm of propan-2-ol, shall maintain the
concentration of propan-2-ol in the exhaust stream at below 40 ppm throughout the period of evaporation
of 1 liter of propan-2-ol and below 400 ppm throughout the period of evaporation of 2 liter of propan-2-ol.
The rate of release of propan-2-ol vapor is calculated by evaporating a weighted quantity of propan-2-ol
for a measured time. The filter challenge concentration and filter efficiency are then calculated as shown.
B.1 APPARATUS
1. Gas detection kit
2. Propan-2-ol
3. Anti-bumping granules
4. Balance, weighting to 0.1 gram or less
5. Stop clock
6. 250 ml conical flask, with a stopper.
7. Hotplate
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