NBN EN 405+A1:2009

This European Standard specifies the performance requirements, test methods and marking requirements for valved filtering half masks incorporating either gas or combined filters as respiratory protective devices except for escape purposes. It does not cover gas filtering half masks which do not have valves or are fitted only with exhalation valves. It does not cover devices designed for use in circumstances where there is or might be an oxygen deficiency (oxygen less than a volume fraction of 17 %).
Laboratory and practical performance tests are included for the assessment of compliance with the requirements.