This document refers to gas filters and combined filters for use as replaceable components in unassisted respiratory protective devices (RPD) with the exception of escape devices.Filters for use against CO are excluded from this document.Laboratory tests are included for the assessment of compliance with the requirements.Some filters complying with this document can also be suitable for use with assisted respiratory protective devices and/or escape devices. If so they need to be tested and marked in accordance with the appropriate European Standard.