This European Standard is applicable to centre threads for respiratory protective devices. This standard does not apply to diving equipment and to positive pressure demand breathing apparatus.
DS/EN 148-2:1999 history
1999DS/EN 148-2:1999 Respiratory protective devices - Threads for facepieces - Part 2: Centre thread connection
1992DS/EN 148-2/AC 1:1992 Respiratory protective devices. Threads for facepieces. Centre thread connection