Historical
BS ISO 16972:2010
Respiratory protective devices. Terms, definitions, graphical symbols and units of measurement (British Standard)
ISO 16972:2010 is applicable to respiratory protective devices. It defines commonly used terms and specifies units of measurement to achieve a uniform interpretation and to prevent ambiguous use. It indicates graphical symbols that may be required to be placed on respiratory protective devices (RPD) or parts of RPD or instruction manuals, in order to instruct the person(s) using the RPD about its operation.
British Standards Institution [bsi]