This standard BS EN ISO 10510:2011 Tapping screw and washer assemblies with plain washers is classified in these ICS categories:
21.060.10 Bolts, screws, studs
This International Standard specifies the requirements for tapping screws and plain washer assemblies with thread sizes from ST2,2 to ST9,5 inclusive, flat seating heads and mechanical properties as specified in ISO 2702.
The plain washers are captive, i.e. prevented from disassembly and free to rotate.