Specification for Thief Resistant Locks
BS 3621:1998

A straightforward pass or fail standard i.e. a lock either meets the requirements of the standard or it does not – there are no grades.

The principle design and peformance requirements include:

• The minimum projection of the deadbolt shall be 14mm.
  
  
• The bolt shall resist attack by a handsaw for a minimum of 5 minutes.
  
  
• The lock case, forend, bolt and lock fixing shall resist a side load of 13,500N after the bolt has been subject to the previous saw test.
  
  
• The bolt shall resist an end force of 1200N.

Locks not using cylinders to BS EN 1303 shall provide a minimum of 1,000 effective differs achieved by one of the following three methods:

1. At least five moveable detainers or levers without the use of fixed obstructions such as wards, bullets, etc. but to include an anti-picking device.
   
   
2. Pin tumbler mechanisms having at least 6 pins and including anti-picking devices.
   
   
3. Disc tumbler mechanisms having at least six sliding or rotating tumblers and include a device to resist picking or manipulation by means of other than the use of the correct key. All vulnerable parts of the lock shall be protected against drilling from the outside of the door.

Cylinders covered by BS EN 1303 shall meet the minimum requirements defined by classification: 16-0-14