To comply with the requirements of some insurance policies, the insurance companies stipulate that security locks are tested to conform to BS 3621. BS 3621 is the standard that, for several years now, has been the yardstick by which thief-resistant locks have been tested in the UK, and insurance companies have come to depend on this standard to provide an indication of the level of security in any given property. If you live (or work) in an older property, you might find that you can reduce your insurance premium by upgrading your current locksets to BS 3621 certified insurance rated locks; consult your insurance provider to see if you're eligible!
What Does BS 3621 Test?
For a lockset to be Kite marked by the British Standards Institute, it has to meet certain minimum performance requirements which are based on the stresses it will encounter in everyday use. The lockset will also under go general vulnerability tests, and then it will be graded according to its performances in these tests. As consumers, it's then possible for us to look at this grading and work out the lock's working tolerances, and decide which the best is for our purposes.
The tests are divided into several categories, and we'll look at each of those now.
Category of Use
The locks are given a category of use, which then determines how strong they should be. There are three grades, which project the stresses the locks will undergo on a daily basis. The stresses are measured on torque; the turning force required to operate (or to break) the lockset. A BS 3621 rated lock must withstand 40Nm, but they're rated to go over 60Nm too.
Durability & Load on Latch
The durability of a lock's latch is graded according to the amount of force it can withstand. This force is measured in kilos of weight applied to the latch, combined with Newton metres of force applied.
Door Mass & Closing Force
This is a test of the effort required to close a lock. In the eyes of BS 3621, the bigger a door is and the easier it is to close, the better. Therefore, a door that weighs 200kg and requires 25N to push closed is less desirable than a door which weighs 100kg and requires 15N to close.
Suitability for Fire Door Use
Simple. Either a lock is suitable for use on a fire door, or it isn't.
Corrosion Resistance & Temperature
For a lock to qualify for BS 3621 certification, it must be able to stand up resist either -20 degree Celsius or 80 degree Celsius for at least 96 continuous hours, and preferably for 240 hours.