scope:

This standard specifies requirements for welding filters which automatically switch their luminous transmittance to a lower value when a welding arc is ignited (referred to as welding filters with switchable scale numbers). The requirements of this standard apply if such a filter is to be used for continuous viewing of the welding process and if it is to be used only during the period when the arc is being ignited. This standard also specifies requirements for welding filters with zones of differing luminous transmittance (referred to as welding filters with dual scale number). These filters are used in welders eye protectors (as specified in standard in preparation) or are fixed to equipment.