Euro Cylinders: Profile Cylinders, Snap Resistance, and UK Standards

How a Profile Cylinder Works

A euro cylinder has a key plug on one or both sides and a cam in the middle. LIST defines a cam as "a lock or cylinder component which transfers the rotational motion of a key or cylinder plug to the bolt works of a lock." Turning the key turns the cam, and the cam moves the bolt or latch inside the lock case.

LIST's dictionary has several terms that apply specifically to profile cylinders:

• Clutch. "The part of a profile cylinder which transfers rotational motion from the inside or outside element to a common cam or actuator."
• Frictioned plug. "A type of clutch system permitting both sides of a double profile cylinder to operate the lock regardless of whether the opposite plug is turned."
• Anti-slip positioned. The orientation of the cam "which requires rotation before it may be removed from the lock case."
• Thumb turn cylinder. "A cylinder with a turn knob rather than a keyway and tumbler mechanism." On a profile cylinder, this usually means a key on one side and a turn on the other.

Per LIST, profile cylinders are typically fitted to mortise locks of non-U.S. manufacture. See mortise locks and multipoint locks.

European Standard: EN 1303

Across Europe, cylinders are tested to EN 1303. The current edition is EN 1303:2026, Building hardware. Cylinders and master key systems (MKS) for locks. BSI's summary says it "specifies performance and other requirements for the strength, security, durability, performance and corrosion resistance of cylinders and their original keys."

The standard grades cylinders in several categories, including durability, fire, corrosion, "six grades of key related security based on design requirements and five grades on performance tests." It also covers attack resistance. Results are expressed as a classification code with one digit per category. See EN 1303 for the full breakdown.

The Snapping Problem

A profile cylinder runs through the door in one piece, inside and outside halves joined at the cam. Cylinder snapping is a brute-force attack on that cylinder. This page names it only as a risk category and describes no method.

LIST's dictionary includes a related defensive term: an anti-wrench reinforcement spring is "a lock cylinder spring designed to protect the inner and outer halves of a profile cylinder from being forcibly separated as a means of brute force entry."

In the UK, the problem became prominent around 2009 and 2010. Locksmith Journal reports that "in 2009/10, a worrying criminal trend began to show its face in certain parts of the country and cylinder snapping began to become a serious issue." Before then, the journal notes, a standard cylinder in a certified door set relied on the door's handles or escutcheons for protection against snapping.

The industry responded in two ways. Manufacturers designed cylinders to resist the attack, and test bodies wrote specifications that test either the cylinder alone or the cylinder together with its handle.

UK Standards: TS 007, Sold Secure SS 312, and PAS 24

TS 007 and the star ratings

The door and hardware trade body DHF says TS 007 was developed by Secured by Design (the police crime prevention initiative) with DHF and the Glass & Glazing Federation. Sold Secure's catalogue notes that BSI has adopted TS 007 for its Kitemark.

DHF lists two ways to meet the TS 007 level of protection on an entrance door:

• A TS 007 Kitemarked 3-star cylinder on its own, or
• A TS 007 Kitemarked 1-star cylinder combined with a TS 007 2-star Kitemarked armoured handle or lock surround.

Warringtonfire also tests to TS007:2014+A1:2015. Its scheme covers "Euro profile cylinders, oval cylinders and threaded cylinders" along with escutcheons, cylinder guards, and security handles.

Sold Secure SS 312

Sold Secure was established in 1992 by Northumbria and Essex Police and is administered by the Master Locksmiths Association. It grades products Bronze, Silver, Gold, and Diamond. Locksmith Journal says the snapping trend "led Sold Secure to develop a brand new test specification called SS 312 Specification for Cylinders for Locks." Sold Secure describes SS 312 as using "classification from BS EN 1303 and BS 3621" with additional tools at Diamond level.

DHF states that cylinders meeting "Sold Secure Diamond (SS312)… will also achieve this level of protection and are Secured by Design (police) approved."

PAS 24 and Approved Document Q

In England, Approved Document Q covers "the standards for doors and windows to resist physical attack by a burglar." Requirement Q1 applies to new dwellings. Locksmith Journal calls PAS 24 "the easiest way to meet the requirement of Approved Document Q."

PAS 24:2022 accepts several cylinder routes. These include TS 007 products and two Sold Secure options:

• a cylinder meeting SS 312:2019 with a Diamond rating, or
• an SS 312:2019 Gold cylinder plus a handle or escutcheon meeting SS 301:2015 at a minimum Bronze rating.

As with all Sold Secure products, "approval is only valid when a product is fitted correctly."

Master Keying and Key Control

Euro cylinders can be part of master key systems. EN 1303 includes grades for MKS cylinders, and it points to CEN/TS 17814 for protecting master-key-system data. Restricted or patented keyways limit who can get key blanks. See restricted keyways and key control.

North American Context

North American locks traditionally use different cylinder formats. LIST defines a mortise cylinder as "a threaded cylinder typically used in mortise locks of American manufacture." It defines a rim cylinder as one "typically used with surface applied locks and attached with a back plate and machine screws." Bored locks use cylinders built into the knob or lever. See rim and mortise cylinders and cylindrical locks. North American high-security cylinders are evaluated to ANSI/BHMA A156.30 (High Security Cylinders) and UL 437, not EN 1303.

Related Topics

• EN 1303
• Mortise locks
• Multipoint locks
• Rim and mortise cylinders
• Pin tumbler locks
• High-security locks
• Master keying
• Restricted keyways
• Key control
• UL 437
• Dimple locks

Sources