BS 8468-3.2:2020 pdf download – Respiratory protective devices for use against chemical, biological, radiological and nuclear (CBRN) agents Part 3.2: Air-purifying devices incorporating a hood for escape — Specification 5.1 General The complete device for use against CBRN agents shall be an air-purifying escape device incorporating a hood conforming to BS EN 403:2004, except for the requirements in BS EN 403:2004,6.10 and 6.11 for both types and except for the requirements in BS EN 403:2004,6.14,6.19 and6.21 for Type 1. The complete device for use against CBRN agents shall also meet the requirements specified in 5.2 to5.6 of this British Standard. In addition, Type 1 devices shall pass the single-burner, moving specimen test, method 3 inaccordance with BS EN 13274-4:2001. In all tests, all test samples shall meet the requirements.5.2Preconditioning Samples shall be preconditioned in accordance with BS EN 403:2004,7.4 prior to visual inspection,testing for inward leakage and chemical agent permeation and penetration. 5.3Visual inspection Visual inspection shall be in accordance with BS 8468-8:2020,Clause 6. A minimum of two samplesshall be inspected. 5.4Inward leakage The maximum inward leakage in the breathing zone shall be 0.1% when tested as a complete systemin accordance with BS EN 403:2004,7.6.1, with 10 test subjects, except that the choice of test agentshall be determined in accordance with BSEN 13274-1,8.1, according to the requirements for combined filtering devices. The maximum inward leakage in the ocular zone shall be 0.67% when tested as a complete systemin accordance with BS EN 403:2004,7.6.1, with 10 test subjects, except that the choice of test agentshall be determined in accordance with BS EN 13274-1,8.1, according to the requirements for combined filtering devices. 5.5 Filters – Gas/vapour element 5.5.1 Test agents – Challenge concentrations and breakthrough concentrations Filters for air-purifying devices incorporating a hood shall be classified according to the breakthroughtimes achieved in the laboratory tests as given in Table 1. NOTE 1The device classification, once established through testing, may be termed the Designated Duration (t) ofthe device. This terminology is used in 5.7,chemical agent permeation and penetration testing. Three filters shall be tested for each test representative agent (TRA) and against each test condition, as given in 5.5.2.1 after the complete device has been preconditioned in accordance withBSEN403:2004,7.4.The gas/vapour test challenges and breakthrough concentrations shown inTable 2 shall be used to establish the filter breakthrough time and thus classification. NOTE 2 The TRAs have been chosen to represent families of potential CBRN threat agents....
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