First ask what product is being assessed

A lock standard may concern a lock assembly or a cylinder, while a doorset specification covers a broader product. The name alone does not tell you whether the test applies to your entire installed door. Product certification may also belong to a specific model and configuration, not every item from the same brand.

When comparing claims, read the certificate or scheme listing. Check the model number, product type, test scope, certification mark and conditions of use. If the documentation is unclear, ask the manufacturer or a suitably qualified installer to explain what has and has not been assessed.

BS 3621 concerns a lock assembly

BSI's catalogue describes BS 3621 as a standard for lock assemblies operated by key from both the inside and outside of the door. BSI lists the current release as BS 3621:2017+A1:2024. The full text is a paid standard, so this article does not claim to reproduce its detailed requirements.

This scope differs from a cylinder-only rating. The product marking and installation still matter, and a door can have other weak points. If an insurer specifies a standard, ask it which lock type and door it expects rather than relying on a generic online summary.

TS 007 and SS 312 relate to cylinders

TS 007 is a security specification used for relevant cylinder and door-furniture combinations. The Door & Hardware Federation describes two routes: a one-star cylinder with two-star security furniture, or a three-star cylinder. On 22 October 2026, its catalogue listed TS 007-1:2024+A1:2026 for replacement cylinders and hardware, and TS 007-2:2019 for mechatronic cylinders and hardware. Check the relevant part, current catalogue and exact product certificate before relying on an edition or rating.

SS 312 Diamond is another scheme associated with high-security cylinders. Ratings can be useful when they are verified against the exact product, but labels do not establish that a cylinder is the right size, correctly fitted or suitable for every door. A cylinder that projects beyond the protective furniture may still create an avoidable weakness.

PAS 24 assesses doorsets and windows

BSI describes PAS 24:2022+A1:2024 as enhanced security performance requirements for UK doorsets and windows intended for dwellings and comparable-risk buildings. It has a different scope from a standalone lock standard. A certified doorset is a configured product, and substitutions or changes can affect whether the certified specification still applies.

For a flat entrance door, security is only one part of the decision. Fire performance and the building's arrangements matter too. Government guidance says residents should make alterations with the knowledge and agreement of the Responsible Person so changes do not undermine the building's fire risk assessment. Check the official flat fire-door guidance.

A quick checklist

  • Identify whether the claim is about a cylinder, lock assembly, door hardware or complete doorset.
  • Check current edition, exact model and certification listing.
  • Ask your insurer for its written requirement if cover depends on a standard.
  • For a flat entrance door, consult the Responsible Person before changing hardware.

Sources and further reading

These sources support the general guidance above. Standards may change; check the issuing body for current editions and product scope.