Approved Document B: The Fire Safety Amendments Taking Effect From 30 September 2026

Most of the fire safety changes we've covered this year — BS 8214:2026, the Building Safety Regulator's move out of the HSE — have been about standards and oversight rather than the underlying Building Regulations themselves. That changes on 30 September 2026, when updated Approved Document B (ADB) guidance comes into effect, with direct implications for how residential blocks are designed, refurbished and fire-risk-assessed.

What it is

Approved Document B sets out how to comply with Part B (Fire Safety) of the Building Regulations. The updated guidance, published following the ongoing review the Building Safety Regulator committed to in line with the Grenfell Tower Inquiry Phase 2 report, tightens requirements around staircase provision, evacuation routes, evacuation lifts and fire door specification in taller residential buildings.

What's changing

The headline change: blocks of flats with a storey 18 metres or more in height must now provide more than one common staircase, rather than relying on a single stair as the primary means of escape. Alongside this, the updated guidance revises expectations around:

• Evacuation routes — clearer requirements for route widths and travel distances in taller buildings.
• Evacuation lifts — updated specification guidance where lifts form part of the evacuation strategy.
• Fire doors — guidance that dovetails with the BS 8214:2026 code of practice we covered last month, reinforcing the shift toward evidence-based, whole-door-set verification.

Does this apply to you?

This is squarely about residential buildings — if you don't own, manage or advise on blocks of flats, this one isn't for you. If you do, the 18m threshold is the number to check first: it's the same height trigger used elsewhere in building safety regulation (including the Building Safety Act's "higher-risk building" definition), so if you're already tracking that threshold for other purposes, this sits alongside it rather than introducing a new one to learn.

New-build and major refurbishment schemes are the most directly affected, since staircase and evacuation route provision is largely a design-stage decision. But existing buildings aren't out of scope either: your fire risk assessment and evacuation strategy should be reviewed against the updated guidance, even where physical alterations aren't immediately required.

What to do before 30 September

1. Check whether any of your buildings meet the 18m threshold — if you're already tracking this for Building Safety Act purposes, cross-reference the same list.
2. Review current staircase and evacuation route provision against the updated guidance, particularly for buildings with a single common staircase.
3. Flag any live design or refurbishment projects to your architect or fire engineer so the updated guidance is factored in before it's too late to change course cheaply.
4. Fold the review into your existing fire risk assessment and Golden Thread documentation, rather than treating it as a standalone exercise.
5. Check your fire door specifications against BS 8214:2026 at the same time — the two updates are closely linked.

If you'd like help working out whether any of your buildings fall within the 18m threshold, or want a second opinion on how the updated guidance affects a live project, get in touch for a free 30-minute consultation.

This article is general guidance, not legal advice. For a definitive view on how the updated Approved Document B applies to a specific building or project, consult the official guidance or a suitably qualified fire engineer.