This British Standard specifies performance requirements and test methods for a thief resistant mechanically operated single-point lock assembly (including locking plates, fixing screws, fitting instructions, cylinders and protective furniture where appropriate) that:
a) incorporates a lock conforming to BS EN 12209 field of door application grades K, L, M, N, R, S or T, i.e. a lock that can be locked from both sides with a key thereby only allowing key egress; and
b) is used in doors, window doors and entrance doors in buildings.
This standard does not cover thief resistant lock assemblies that provide
keyless egress, i.e. lock assemblies that can always be unlocked from the inside without the need for a key, or lock assemblies that provide a secure (no egress) mode in addition to keyless egress.
NOTE 1 Thief resistant lock assemblies that provide keyless egress or assemblies that provide a secure (no egress) mode in addition to keyless egress are specified in separate standards, BS 8621 and BS 10621 (respectively), because they are sufficiently different in terms of what they offer for means of escape (from fire) and security.
NOTE 2 It is possible that lock assemblies conforming to this standard are not suitable for use on doors constructed from certain types of material, e.g. plastic or aluminium. The marking on the packaging of the lock assembly will provide this information in accordance wit.h 9.2.
BS 3621:2007+A1:2009 history
2017BS 3621:2017 Lock assemblies operated by key from both the inside and outside of the door