The latest changes to Approved Document B are becoming clearer, writes Andrew Mellor

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The recently published consultation on the proposed changes to Approved Document B (ADB) includes the provision of sprinklers in new care homes, removal of national standards for reaction to fire and fire resistance and the anticipated requirement of two staircases in new tall residential buildings.

There are no options for the second stair trigger height in the consultation document - there is just the one proposed height of 30m. This surely gives near certainty that the trigger height will be 30m. In previous consultations, trigger height options have been proposed to get industry feedback.

This time it is a Hobson’s choice - there is no choice. The consultation does however suggest that other trigger heights were considered by government as the draft impact assessment includes them.

The document further states that all currently planned developments should prepare for this change now

Many in the industry will be relieved that the trigger point is at 30m and not at a lower height of perhaps 18m. It could well have been lower, especially as the recent National Fire Chiefs Council guidance is calling for two stairs to be provided in residential buildings over 18m, or seven storeys, and above.

We understand that the 30m trigger point will align with the emerging changes to BS9991, although this standard will likely recommend second stairs in residential buildings between 18-30m unless other mitigating measures are installed such as pressurisation. The ADB consultation document is silent on any such requirement being incorporated into the Building Regulations guidance.

The consultation document sets out the proposed transition periods. For sprinklers in care homes it is 6 months. For national standards it is 12 months and for second stairs it is ‘a very short transition period’. The document further states that all currently planned developments should prepare for this change now.

Many developers are already reviewing schemes to understand the re-design, programme and viability impacts

If we consider that the last changes to ADB had a 6 month transition phase and those to Approved Document L had a 12 month transition, we must assume that a very short transition phase for second stairs is less than 6 months. It could therefore be 3 months or less.

If we surmise that the amended ADB is published before parliamentary summer recess in mid-July and that the changes come into force in early October this year, then it could mean that the transition period ends before mid-January. This allows a short window to get the foundations started on site for individual buildings over 30m, in order to avoid the new requirement. This is of course intentional as the government will want as many new 30m+ buildings as possible to have second stairs.

Many developers are already reviewing schemes to understand the re-design, programme and viability impacts of the introduction of second stairs in current projects. They are also considering the impacts of not including second stairs in buildings that could start on site prior to the end of any proposed transition phase.

The industry urgently needs clarification

These could include impacts on sales times, sales values and future Safety Cases not signed off by the Building Safety Regulator. There is also the commercial risk posed by a potential future safety incident where the developer has little defence because they knew the second stair change was coming.

The consultation does not provide a full understanding as to whether the second stair will need to be an escape stair, a firefighting stair or an accommodation stair, or perhaps all of these. The industry urgently needs clarification on this matter and will need sight of the new ADB guidance as soon as possible - ideally prior to the introduction of the changes, to enable it to prepare compliant designs for current schemes.

Changes to fire safety legislation are understandable in the post Grenfell environment but constant periodic step changes are more difficult for the industry to respond to. It would better if as many of the planned future changes to ADB can be incorporated into as few new editions of the document as possible. It would of course also reduce the number of recently completed buildings which only partially meet the latest fire safety policy.