December Updates to Approved Document B

The government approved several adjustments and enhancements to Approved Document B on June 1, 2022, intending to strengthen existing building standards and safety recommendations while clarifying essential parts. These changes to Approved Document B (ADB) come into effect December 1st 2022.

ADB Critical Updates

Installation of Evacuation Alert Systems:

It is currently suggested that instructions on evacuation alert systems be provided in new buildings that are over 18 metres in height.

Second, per BS 8629, the installation of an evacuation alarm system is also suggested in new blocks of flats over 18 metres high, as stated in Approved Document B (June 2022): ‘In blocks of flats with a top storey over 18m above ground level an evacuation alert system should be provided in accordance with BS 8629’.

This code of practice is strongly recommended for new buildings with flats, although it is also applicable to existing buildings as best practice.

What is the reason for this? Having an evacuation alert system in place allows resources to focus on essential firefighting operations when extensive evacuation is required. Furthermore, a faster evacuation ensured the residents’ safety.

Secure information boxes are now required for new structures exceeding 11 metres.

In new structures over 11 metres, secure information boxes are currently recommended to be installed. A secure information box allows the fire department to access important building information.

New requirements for external balconies and walls have been established for new blocks of flats between 11 and 18 metres.

The goal of this new guidance is to raise the standards for the combustibility of materials used for exterior walls.

As a result, buildings of flats between 11 and 18 metres meet the essential precautionary measures. Furthermore, designers and developers can use more environmentally friendly materials while creating walls.

The external surfaces (i.e. outermost external material) of external walls should comply with the provisions in Table 10.1. The provisions in Table 10.1 apply to each wall individually in relation to its proximity to the relevant boundary.

Table 10.1 Reaction to fire performance of external surface of walls

Building Type Building Height Less than 1000mm from relevant boundary 1000mm or more from relevant boundary
Relevant buildings as classed in regulation 7(4) Class A2-s1, d0
or better
Class A2-s1, d0
or better
 

All ‘residential’ purpose groups

 

More than 11m Class A2-s1, d0
or better
Class A2-s1, d0
or better
11m or less Class B-s3, d2
or better
No provisions
Assembly and recreation More than 18m Class B-s3, d2
or better
From ground to 18m: Class C-s3, d2 or better
From 18m and above:
Class B-s3, d2 or better
18m or less Class B-s3, d2
or better
Up to 10m above ground level: Class C-s3, d2 or better
Up to 10m above a roof or any part of the building to which public has access: Class C-s3, d2 or better
From 10m and above: no minimum performance
Any other building More than 18m Class B-s3, d2
or better
From ground to 18m: Class C-s3, d2 or better
From 18m and above:
Class B-s3, d2 or better
18m or less Class B-s3, d2
or better
No provisions


The new guidance update strikes a balance between the requirement to give mid-rise buildings flexibility while reducing risk. As a result, they no longer interfere with the usage of ecologically favourable substances when they are part of a well-designed system.

What is the significance of BS 8629?

BS 89629 is a code of practice by the British Standards Institution for “the design, installation, commissioning, and maintenance of evacuation alert systems for use by fire and rescue services in buildings containing flats”.

In 2017, BS8629 was created as part of a revision of Scottish building standards.

Following the catastrophic Grenfell Tower fire in June 2017, the suggestions for BS8629 compliance were promptly implemented.

How does an Evacuation Alert System work?

The fire and rescue agency operates evacuation alert systems through a control panel that sends out evacuation notifications for specific regions or floors within the apartment building. An alarm sounder must be installed in each flat in a block per BS 8629, and it must be equipped with both an alarm sounder and a visual alarm device. The benefits of an evacuation alert system include:

  • Notifying occupants of danger as soon as possible

In each flat, Evacuation Alert Systems deliver enhanced audio and visual alarms indicating the need to leave.

  • This will result in shorter evacuation times.

With Evacuation Alert Systems installed in each flat, all inhabitants will be informed of the hazard, regardless of whether they have visual or hearing impairments.

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