How to choose a security cylinder

The European standard EN 1303 grades cylinders on several criteria: durability, corrosion resistance, key security and attack resistance.

For a front door, focus on the last two digits of the classification code: key security (number of key differs) and attack resistance (drilling, picking, snapping). Higher is better.

On top of the standard, some cylinders are tested by independent bodies: VdS (Germany) and A2P (France, rated one, two or three stars).

Many insurers recognise these marks. If your policy requires a lock grade, check which one before you buy.

• Anti-snap / anti-pull: stops the cylinder being extracted with a tool. Essential if the cylinder protrudes at all.
• Anti-drill: hardened inserts protect the plug.
• Anti-pick: security pins, complex key profile.
• Emergency function: the door opens even if a key is left in on the inside.
• Key card: copies can only be cut on presentation of the card.

1. Open the door — Find the fixing screw on the edge of the door, level with the lock.
2. Measure the outside — From the screw (the centre of the cylinder) to the outer end of the cylinder.
3. Measure the inside — From the screw to the inner end. The two sizes often differ, for example 30 × 40 mm.
4. Check the protrusion — On the outside, the cylinder should not stick out more than a few millimetres beyond the handle plate.

Flat in a residence

An EN 1303 cylinder with good attack resistance and a key card. If the front door is a security door, the cylinder must match the door's level.

Detached house

A high-security, anti-snap cylinder with a protective plate. Don't forget secondary doors (garage, cellar), which are often overlooked.

Shop

A high-security cylinder, possibly on a master-key system if several people hold keys, so access can be withdrawn without changing everything.

• After moving in: you don't know who still has a key.
• After keys are lost or stolen.
• After an attempted break-in, even if the door held.
• When the key sticks, turns badly or bends.