Government ban on combustible materials in high-rise residential buildings
The Government has amended the Building Regulations to prohibit the use of combustible materials in the external walls of buildings in England over 18 metres that contain at least one dwelling.
This ban is the result of a review of fire safety, following the Grenfell tower tragedy.
Here Ancon answers a number of questions about the new regulation.
Does the Building Regulations Amendment apply to my project?
This new regulation applies to any building containing at least one dwelling, with a storey at least 18 metres above ground level. It includes institutions, which means it covers some residential schools, care homes and hospitals, sheltered accommodation, student residences or other institutional accommodation blocks over 18 metres. It excludes hostels, hotels or boarding houses (unless they are being converted into residential accommodation).
The Building (Amendment) Regulations 2018, came into force on 21st December 2018 and will apply to all projects, as described above, that started on site after 21st February 2019.
Where building work started before 21st February 2019, in line with plans deposited with a local authority before 21st December 2018, the previous Building Regulations will apply.
What are the new requirements for external walls?
The Building (Amendment) Regulations 2018 states that building work shall be carried out so that materials which become part of an external wall are of European Classification “A2-s1, d0” or “A1”.
These classifications are taken from BS EN 13501-1:2007+A1:2009, Fire classification of construction products and building elements - Classification using test data from reaction to fire tests.
The most significant change is that other fire test methods and national classifications (typically specified in the BS 476 series of documents) are no longer recognised when selecting materials for residential buildings over 18 metres; BS EN 13501 is the only route to compliance.
Guidance on what is meant by classes “A1” and “A2-s1, d0” to BS EN 13501 is given in the table below.
|Will not contribute in any stage of the fire, including the fully developed fire, or present a smoke hazard|
A2(Compliance with The Building (Amendment) Regulations 2018 depends on further “s” and “d” characteristics)
Will not significantly contribute to the fire load and fire growth in a fully developed fire, and further defined through “s” and “d” characteristics
The characteristics “s” for smoke and “d” for droplets are defined as:
s1 Weak or no smoke
s2 Medium smoke
s3 High smoke
d0 No flaming droplets/particles
d1 Slow dripping recordedd2 High dripping recorded
The highest classification of A2
Will not significantly contribute to the fire load and fire growth in a fully developed fire and further characterised as providing:
Weak or no smoke (s1)No flaming droplets/particles (d0)
Do I need test data for all building materials?
BS EN 13501 references a list of materials that can be considered as class A1 without fire testing, on account of their low level of combustibility.
Steel and stainless steel are on this list of class A1 materials. Therefore no reaction-to fire testing of these materials, or products made from them, is required to comply with The Building (Amendment) Regulations 2018.
This covers most Ancon products including masonry support systems, windposts, head restraints, masonry reinforcement, channels, bolts and tension bar systems.
Are any products excluded from the combustible materials ban?
The Building (Amendment) Regulations 2018 includes a list of construction components that are exempt from the combustible materials ban, for example, ‘fixings’ and ‘thermal break materials’.
This covers a number of products from Ancon which fall into the miscellaneous fixings category and those specified to improve the thermal performance of a building e.g. Ancon Teplo low thermal conductivity wall ties – manufactured from an advanced composite that virtually eliminates thermal bridging in masonry cavity walls. Teplo wall ties should be specified/installed with confidence on high-rise residential construction not just because they are exempt from this regulation but also because they have been fire-tested. Teplo wall tie types BF, BFR and L, for instance, offer a two-hour fire resistance. Based upon an evaluation of all test data, the BBA concludes the effectiveness of installed Teplo ties in fire is equivalent to that of typical steel ties. Contact Ancon for more information.
The full list of exceptions given in the document is as follows:
(a) cavity trays when used between two leaves of masonry;
(b) any part of a roof (other than any part of a roof which falls within paragraph (iv) of regulation 2(6)) if that part is connected to an external wall;
(c) door frames and doors;
(d) electrical installations;
(e) insulation and waterproofing materials used below ground level;
(f) intumescent and fire stopping materials where the inclusion of the materials is necessary to meet the requirements of Part B of Schedule 1;
(h) seals, gaskets, fixings, sealants and backer rods;
(i) thermal break materials where necessary to prevent thermal bridging in order to meet the requirements of Part L of Schedule 1; or
(j) window frames and glass.
What is meant by external wall?
Sometimes referred to as the ban on combustible cladding, it is important to understand that this new regulation applies to the full external wall and not just the cladding element; only the internal decoration or finish is excluded. The scope also includes external attachments such as balconies and solar panels/shading.
Does the combustible materials ban affect refurbishment projects?
This ban applies whenever building work is within the scope of Building Regulations i.e. new construction and refurbishment. It will apply when a building not currently within the scope of the ban undergoes a change of use that means it falls within scope, at which point the external walls should be brought in line with the new requirements.
Does the combustible materials ban mean passive fire protection is not required?
This regulation focusses on ‘reaction to fire’ and not ‘resistance to fire’. It is designed to reduce the health and safety risk of vertical fire spread in the external walls of tall buildings where people are living/sleeping, and the risk of ignition from flames coming from adjacent buildings. It does not deal with the fire resistance of external walls. An external wall may need fire resistance to meet the requirements of other regulations e.g. general provisions, space separation etc. Typically, passive fire protection is needed to compartmentalise fires preventing spread and protect structural steelwork, like Ancon masonry support angles, head restraints etc, from the effects of a fire.
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