Don't Get Caughtout 

BS 3621 Insurance Approved Locks BS 3621


Since its inception, BS 3621 has always required that a door is secure from both sides, meaning that once locked; a key is always needed to open the door, whether from the inside or the outside.

 Typically BS 3621 is a standard that would be applied in a private house or small business as opposed to a public building and is often stipulated as an insurance requirement.  Provided that the key is removed, this type of lock is secure against operation by intruders reaching through a letter-plate, breaking nearby glazing, etc. Best used where emergency escape is not required or other means of escape exist.

A BS 3621 lock will permanently be stamped with the British Standard 3621 Kitemark, and the lock would normally be in the form of a mortise deadlock, or a deadlocking rim-type night latch lock.

A BS 3621 Kitemarked lock will have undergone vigorous testing to ensure it meets the required standard of security and protection; typically it will have the following characteristics:

  • A 20mm protruding lock bolt (BS 3621-2007) was tested to withstand extreme force and attack.

  • Hardened steel roller pins in the lock bolt to protect the lock bolt against cutting attack.

  • Hardened plate surrounds to protect the lock against attack by drilling.

  • Steel box frame receiver tested to resist attack.

  • The lock should have anti-pick features to help prevent lock picking.

  • The minimum of 1000 + key differs.

  • Minimum of 5 levers (for mortise deadlocks)

In addition to BS 3621 two other more recent standards have been developed with virtually identical lock characteristics (as described above), but which are used in public buildings where fire and safety are considered more important than physical security: