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What is a BS3621 British Standard Lock?

November 2nd, 2015

BS3621 is a British Standard for locks fitted to doors, designed so we can easily know that a lock is of a good, theft-resistant standard. It's important for homeowners to know about this as having BS3621 locks fitted to your doors may be a requirement for your home insurance, or it could give you access to bigger savings on your insurance policy.

This standard is most often specified for final exit doors on a property (front and back doors) as these are the most prone to break-in attempts. It's generally agreed that internal doors do not require the level of security offered by BS3621, although in some circumstances you may consider it necessary. If you don't need that level of security then cheaper locks with lower levels of security, such as 2 lever and 3 lever models, are available.

There are various features required to make a lock comply with BS3621. Firstly, the lock needs to be of a 5 lever design. This can be confusing for some as 5 lever locks are available that don't conform to BS3612. These will still offer a good level of security but won't necessarily offer additional security features which are present on approved locks.

Most of the features of the British Standard focus around attack resistance. To meet the standard the lock must be able to withstand drill attacks for at least 5 minutes, bolt attacks for at least 5 minutes and also the lock has to have an anti-picking mechanism in place. The main bolt of the lock must be at least 20mm in length and the keep, where the bolt sits in the door frame, must be of a good quality design.

If you're not sure if your lock is BS3621 compliant then it's easy to check. Simply look for the “kite mark” somewhere on the lock. Most often this is engraved on to the face plate, close to where the bolt protrudes from the door when locked. If you don't think your lock is of a theft-resistant standard and want to upgrade then you can browse our range of deadlocks. If you aren't sure what to buy then just get in touch for advice on what you need to fit to keep your home safe