Breakthrough Time of Organic Vapours in Activated Carbon Filters as a Function of the Air Flow Pattern

Abstract

Gasmask canisters are usually tested for their adsorption capacity towards specific toxic gases in standardized experiments. These experiments establish how long a canister, under defined conditions, is capable to reduce a given challenge concentration to a predefined value. The air flow through the filter is held at a constant value (mostly 0.5 l/s) during the test. The choice of maintaining the flow at a constant level is not selfevident, as the actual flow through a canister is pulsating: during inhalation air comes through, during exhalation there is a standstill. Evidence proves that the air flow pattern may influence breakthrough times considerably. The present study is aimed at obtaining an insight into this influence on the basis of an existing physical model that enables to simulate breakthrough curves of organic vapours in activated carbon filters.