What is a BS3621 certified lock and why does my insurance company want me to have one?

There are thousands of standards in place relating to all aspects of modern life. These standards are defined and agreed by independent bodies so that products can be manufactured or processes implemented to a minimum set of requirements. Once a standard is defined it is then possible for independent testing to ensure the minimum requirements are being met before the product is certified as compliant.

With regards to domestic locks, this ensures that a specific level of security is being implemented by the property owner and enables the insurance company to understand the risk to the property. It also enables input from the Police and government to help combat property related crime.

The BS 3621 Standard is entitled “Thief Resistant Lock Assembly. Key Egress”. Originally drafted in the 1960’s, the current revision at time of writing this article is BS 3621 2007 + A2:2012. The standard relates to mortice lever locks fitted in wooden doors on domestic property.
The criteria for a lock to meet for the BS3621:2007 standard are as follows:

  • It must not be possible to access any fixing screws on the lock, cylinder or keep when the door is closed and locked.
  •  When dead locked, the bolt must project at least 20mm from the faceplate.
  • When locking, you must not be able to remove the key before the bolt is fully deadlocked.
  • The lock must have a minimum of 5 movable levers. If there are less than 9 movable levers then the levers must utilise false gates or anti pick notches.
  • The lock body must be protected from drilling on both sides, typically by the addition of metal hard plate.
  • The lock design must support a minimum of 1000 different key combinations. Any given key pattern cannot be re-used until 999 different locks have been made produced.
  • Locks which are key operated from both sides must offer the same level of security from each side.
  • Once the lock has been dead locked, you must not be able to operate the bolt via a handle or knobset.

A typical BS3621 mortice deadlock with the case opened is shown below:

Insurance rated lock

BS3621 Dead Lock

The faceplate of the lock will display the BS Kitemark and standard achieved.

Insurance lock face plate kite mark

Kite mark on BS3621 lock faceplate

In addition a BS3621 lock may often have the following features:

 

  • A bolt thrower or curtain which helps to reduce the risk from lock picking.
  • A box keep, to prevent the access to the both through the door frame.
  • Anti-saw bars or rollers within the bolt

The parts of a typical BS3621 Deadlock are shown here:

BS3621 Insurance lock parts

Parts of typical BS3621 mortice dead lock

So if your insurance policy specifies a BS3621 compliant lock is fitted to your door, check the face plate and then if you would like to discuss it further, please call Blackwater Locks and we’ll be happy to help.