Fire safety: Approved Document B
Robust and regulated fire safety is essential in the built environment. In December 2022, the industry’s Approved Document B was updated to support specific requirements and regulations to the Building Regulations 2010.
Approved Document B “addresses fire safety precautions which must be adhered to, to ensure the safety of occupants, firefighters and those close to the building in the event of a fire”.
Here we will examine Approved Document B more closely, and its implications when specifying frameless glass balustrading on a build.
What is 2022 Approved Document B?
Approved documents are approved by the Secretary of State and give practical guidance on meeting the construction requirements of the Building Regulations 2010. Approved Document B was originally published in 2006 and brought into effect in 2007.
Amendments to Approved Document B were introduced in 2019, 2020, and most recently in December 2022. The 2022 amendments to Approved Document B extended the ban on combustible materials used on external surfaces of residential buildings over 11m high, and boundary walls of buildings that are 11m high and below. External surfaces include frameless glass balustrading.
What fire safety standards are covered in approved Document B?
Approved Document B covers all fire safety standards including:
- means of escape
- the capability of internally isolating a blaze to stop a fire spreading
- external fire spread
- access to the building and facilities for firefighters
- fire detection and warning systems in place within a building
- the internal spread of a fire due to the structure of a building or materials used in its lining, along with associated safety measures.
Main changes to Approved Document B in the 2022 amendments
To be compliant, all materials on the external face of residential buildings over 11m high must achieve a fire classification of A1 or A2, s1-d0 in full accordance with BS EN13501.
A complete ban on combustible materials in and on the external walls of buildings
Metal composite cladding is now completely banned on buildings of any height, not just tall buildings. Options for the wall construction of buildings between 11m and 18m were limited further.
Balconies should only contain materials achieving class A1 or A2-s1, d0 specification, or meet other specific criteria relating to the soffit and boundary line of a single compartment.
Secure information boxes for residential buildings with a storey at 11m or higher
A new recommendation was stipulated for secure information boxes to be made available to firefighters in the event of a fire in blocks of flats with storeys over 11m.
The boxes should include the contact details of relevant people and floorplans that identify the location of key fire-fighting equipment.
Evacuation alert systems
The 2022 Approved Document B made a new recommendation for evacuation alert systems in blocks of flats with storeys over 18m, including an additional alarm system that can be operated by firefighters to trigger evacuation alerts for specific areas of the building.
Clarifications and corrections
The 2022 Approved Document B provided revised diagrams, text clarifications and corrections to make the document easier to understand.
What does Approved Document B mean for frameless glass balustrades?
The performance of all materials used in frameless glass balustrades must meet the specifications of class A1 or A2-s1 d0 ratings:
• An A1 rating confirms the product is non-combustible. An A2 rating confirms limited combustibility and very limited contribution to fire.
• S1 confirms low smoke emission rate and speed.
• D0 confirms no generation of droplets.
Issues such as glass containment and UV stability must also be addressed:
Glass containment measures must ensure that when a single ply breaks, the fragments of glass stay adhered to the interlayer, maintaining rigidity and still acting as fall protection, thereby providing the same performance as regular laminated glass.
UV stability is another important consideration when specifying glass in frameless balustrades and must be validated by testing products for outdoor usage, ensuring suitability for use on external balconies. Only suitably tested and warrantied products should be used.
Frameless glass balustrade system materials such as toughened glass and nano composite gel meet the required classifications.
Contact Onlevel for more information
For advice on the compliance of frameless glass balustrades to the new regulations, contact Onlevel here