BS EN 12320

BS EN 12320 : 2001
Building hardware – padlocks and padlock fittings

UNION products applicable: high security padlocks (section 3A)


BS EN 12320 classifies padlocks and padlock fittings by using a 7 digit coding system.

Each digit refers to a particular feature of the product measured against the standard's performance requirements.

Digit 1 - Category of use
No requirement

Digit 2 - Durability (no. of test cycles)
No requirement

Digit 3 - Door mass
No requirement

Digit 4 - Fire resistance
No requirement

Digit 5 - Safety in use
No requirement

Digit 6 - Corrosion resistance
Products are classified in accordance with EN1670:1998
- grade 1: internal applications
- grade 3*: external applications
*The standard has been published containing an error. BSI is making arrangements to correct this.

Digit 7 - Security Requirements
There are 6 grades of security, where 6 is the highest and 1 is the lowest

Products are tested to the following criteria

  • Minimum number of effective differs
  • Non-interpassing of keys
  • Resistance to force on cylinder plug or locking mechanism
  • Resistance to torque on cylinder plug or locking mechanism
  • Resistance of shackle or staple to pulling, twisting and cutting
  • Resistance of padlock body, shackle and staple to impact, drilling and sawing


The following marking denotes a padlock or padlock fitting which is suitable for use on internal or external applications and has a security grade 4:

- - - - - 3 4


Box 1 - 5 - No classification

Box 6: Corrosion grade 3

Box 7: Security grade 4

Only the classified requirements of BS EN 12320 are listed in UNION padlock product literature.