PAS3621, BS3621, and BS8621: Which Lock Standard Applies to Your Door?

PAS3621 vs BS3621 vs BS8621: What Every Homeowner and Landlord Needs to Know

If you have ever read a home insurance policy or looked into upgrading your locks, you may have encountered one of these standards. They apply to different lock functions and products; whether any particular standard matters to you depends on the actual door, the certified product, written policy terms and any property-specific safety or licensing requirement.

I am Albert, a local locksmith in Coventry. I can identify installed hardware and its visible certification, but an insurer, council or fire-risk assessor must confirm how its own wording applies to a particular property.

Let me break all three down in plain English.

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BS3621: A Standard Some Policies Name

BS3621 is a British Standard for thief-resistant lock assemblies. Some home insurance policies name it for relevant doors; others use different wording. Check the current policy schedule, endorsements and full wording rather than assuming a universal requirement.

What BS3621 Certification Means

Certification applies to an exact lock assembly and dated edition of the standard. Check the product marking and current BSI certification record rather than inferring compliance from a lever count, key shape, brand or marketing phrase. A claim such as "equivalent to BS3621" is not evidence that the exact product carries that certification.

When BS3621 Applies

If your home has a traditional wooden door, inspect the installed lock and compare its certification with the exact wording for that door. Ask the insurer to confirm any ambiguity in writing.

I fit BS3621 mortice deadlocks from £79 including the lock and labour. You can see full pricing on our prices page.

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PAS3621: A Separate Specification to Check Carefully

PAS stands for Publicly Available Specification. Do not treat a similar number as automatic equivalence with BS3621: check the exact standard and dated edition marked on the product and the wording that applies to your property.

Why This Matters

Door construction varies. Traditional timber doors may use lever mortice deadlocks, while many composite and some timber doors use a mortice lock body with a euro cylinder.

The specification can cover different lock constructions, including:

The Policy-Wording Question

If a policy names BS3621, do not assume that a product carrying a different certification will be accepted as equivalent. Policy and claims decisions depend on the written terms and circumstances. Practical next steps are:

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BS8621: Keyless Egress and Property-Specific Safety Decisions

BS8621 is fundamentally different from the other two. It is not primarily about keeping burglars out — it is about letting people get out safely.

What BS8621 Requires

A BS8621 lock allows keyless egress from the inside. In plain English: you can open the door from inside without needing a key.

Requiring a key to release a final exit can impede escape. A suitable keyless-egress arrangement may address that issue, but the correct hardware depends on the door, fire-risk assessment and any licensing conditions.

When Keyless Egress May Be Relevant

The Security Trade-Off

There is an honest trade-off here. A thumbturn on the inside means that if a burglar can reach through a letterbox or broken glass panel near the door, they could potentially turn the thumbturn and open the door from inside.

Good BS8621 locks mitigate this with:

For a Coventry HMO, start with the council's HMO amenities and facilities guide, the licence and the property fire-risk assessment. For hardware that has then been specified, see the lock upgrade service or call 024 7522 4730.

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How to Tell Which Standard Your Lock Meets

Here is a quick guide to checking the visible evidence:

For Mortice Deadlocks (BS3621 / PAS3621)

For BS8621

Look for the BSI Kitemark with BS8621 on the faceplate. The lock will have a thumbturn or push-to-exit mechanism on the inside face. If your lock requires a key to open from both sides, it is not BS8621.

Not Sure?

Call 024 7522 4730 if you want to arrange a visual lock assessment. Before booking, confirm the address, scope, price basis and output required. I can record the lock type, visible markings and available product documentation, then compare those details with wording you provide. Certification may require catalogue or manufacturer confirmation, and only the insurer, council or responsible fire-safety professional can decide compliance for its purpose. Check the listed areas we cover.

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Which Standard Do You Actually Need?

Use the written policy, licence, fire-risk assessment and current product evidence as the decision record:

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If you manage multiple Coventry properties, call with the addresses, door details, authority and required timing. I will define what can be quoted remotely, what needs inspection and the price basis for the agreed scope.

For more on the insurance side of lock standards, read our detailed guide on whether your insurance will pay out with non-compliant locks. And if you want to understand your obligations as a landlord around lock changes between tenants, I have covered that in our guide to changing locks between tenancies.