Covers test methods, performance requirements and marking requirements for half masks (re-usable) without inhalation valves and with separable filters (designed for a maximum of single shift use) to protect against gases, or gases and particles, or particles only. Does not cover devices designed for the use in circumstances where there is or might be an oxygen deficiency (oxygen less than 17 % by volume) or for escape purposes. Practical and laboratory performance tests are included for the assessment of compliance with the requirements.