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Fire Regulation Compliance for Roofs

Building Products Index Ltd December 17, 2019 Roofing, waterproofing Leave a Comment

Following the Grenfell Tragedy in June 2017, and the subsequent investigations, the Governments of England and Scotland made significant changes to their respective Regulations related to fire performance. Approved Document B Volumes 1 and 2 in England, and Technical Handbook Annex 2.C and 2.F in Scotland, introduced a new category of ‘relevant buildings’ with the aim of reducing the fire risk in high rise buildings (those over 18m in England and over 11m in Scotland).

Whilst generally clear with regards to the fire performance requirements for external wall construction (external wall systems on buildings over 18m high have to be fire resistant, achieving class than A2-s1, d0 or Class A1 under the European classification system set out in the standard BS EN 13501-1, subject to exemptions) the regulation changes have resulted in some confusion with regards to the fire performance requirements for roofing systems, and the definitions of ‘specified attachments’, insulated balconies, roof terraces and podiums.

With the entire UK Government in Purdah (the period leading up to an election, during which government departments generally refrain from making any new announcements) the Ministry of Housing, Communities and Local Government (MHCLG) are unable to make further clarifications, however what is clear is that:

Roofing systems must achieve Broof(t4) European classification in accordance with BS EN 13501-5.
Roof finishes covered under the Annex of Commission Decision 2000/553/EC are considered to be unrestricted under the national Requirements (Loose laid gravel with a thickness of at least 50 mm or a mass ≥ 80 kg/m2, Sand/cement screed to a thickness of at least 30 mm or Cast stone or mineral slabs of at least 40 mm thickness).
Any decoration or other finish applied to any external (but not internal) surface forming part of the wall must achieve class a minimum A2-s1, d0 classification to BS EN 13501-1.

This latter requirement means that any insulation board used as part of the roofing system where it abuts an external wall must be non-combustible, effectively banning the use of PIR, XPS and EPS insulation boards between the vertical waterproofing and the external wall.

In warm roof applications it is easy to switch the vertical upstand board in this application to mineral wool or cellular glass, but with no suitable product available for inverted roof applications specialist roofing system manufacturer Radmat Building Products had to develop a suitable solution quickly.

ProTherm RockFace A2, a non-combustible upstand insulation board for inverted roof applications, consists of a special mineral wool insulation board factory laminated to a 6mm Cement Particle board. This combination, tested by WarringtonFire to BSEN1350–1, achieved an A2-s1, d0 rating. Radmat Building Products believe that this is currently the only inverted roof upstand insulation board available that meets the requirements for ‘Relevant Buildings’ within Approved Document B, and the Scottish Technical Handbooks (those over 18 m in England and over 11m in Scotland).

For further information on RockFace A2, a copy of the WarringtonFire classification report no. 19808F dated 10 10 2019, or to find out about Radmat’s range of Regulatory compliant roofing systems go to www.radmat.com or call 01858 410372.

Impact of the Fire Regulation Changes on Roofing Systems

Building Products Index Ltd May 30, 2019 Insulation, Waterproof Membranes, waterproofing Leave a Comment

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On 21^stDecember 2018 the Government of England and Wales brought into force revisions to the Building Regulations aimed at preventing a repeat of the Grenfell Tragedy. Unfortunately, the nature of the release of the Amendments, and the requirement for reader to insert information into the existing Building Regulation’s has led to some misinterpretation of the revised regulations (which have now been re-published in full).

What is clear is that the Government of England & Wales now require that materials which become part of an external wall, or specified attachment, are of European Classification A2-s1, d0 or A1, classified in accordance with BS EN 13501-1:2007+A1:2009 entitled “Fire classification of construction products and building elements” on high-rise buildings that contains flats, as well as hospitals, residential care premises and student accommodation above 18 metres. These products are widely referred to as ‘non-combustible’.

What is also clear is that the requirement for ‘non-combustible’ products does not extend to roofing systems as they are covered by a specific statement in regulation 7(3) Paragraph (2) does not apply to:

(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’.
and
(g) membranes

Where the requirement for ‘non-combustible’ materials does apply is in regulation 2(6)(a)(iv) any part of a roof pitched at an angle of more than 70 degrees to the horizontal if that part of the roof adjoins a space within the building to which persons have access, but not access only for the purpose of carrying out repairs or maintenance;. However, there remains a requirement for clarification of this statement, which the roofing sector is currently seeking from MHCLG as flexible roof waterproofing materials are not ‘non-combustible’. They are manufactured to meet the relevant fire test standards contained in Approved Document B section B4 (BS 476-3 and BS EN 13501-5:2005+A1). The does not apply statement in regulation 7(3)(g) membranes would seem to confirm the waterproofing does not need to be ‘non-combustible’ but the other elements of the roofing system such as deck and insulation will need to be.

A second area requiring clarification is regulation 2(6)(b)(i) a balcony attached to an external wall;. Traditional balcony construction projects from the building, as it is were an attachment to the external wall. But modern construction includes for ‘balcony over balcony’ construction and ‘balcony over habitable space’ construction. It is the general belief of the roofing sector that the requirement for ‘non-combustible’ material does impact ‘balcony over balcony’ construction, but that a ‘balcony over habitable space’ construction is not affected as it is actually a flat roof due to the requirement for waterproofing and insulation and is therefore covered under Approved Document B section B4.

The last area requiring clarification is regulation 2(6)(a)(ii) any decoration or other finish applied to any external (but not internal) surface forming part of the wall;. Whilst it is clear that a flat roof is exempt from the non-combustible requirements of the regulations there remains a question about high parapet walls as they form the internal face of the external wall. It is the belief of the author that the ‘non-combustible’ requirements of the regulations do apply to the detailing of the roof at this point and the insulation and substrate should meet European Classification A2-s1, d0 or A1.

A point of note in closing, in Scotland the Technical Handbooks change the height of building impacted by the regulation changes to those above 11 metres.