Building and Fire Safety Regulations after Grenfell
Article written by our Assistant Surveyor Daniel Finlayson
The Grenfell Tower Block Fire that occurred on 14th June 2017 has shunted the building control profession into the limelight amid unfavourable circumstances. The media out-pouring may have been less than well informed on the matter but it served to highlight a number of inadequacies and partly expose, if only in layman’s terms, aspects of the routes to demonstrating compliance for external cladding systems that are currently accepted. At present, there are four recognised routes to demonstrating compliance with B4 (1) external fire spread, these being; compliance in accordance with section 12 of ADB Vol. 2, meeting the performance criteria in BR 135, a desktop study approach or a holistic fire engineered approach. Each of the approaches is not without its limitations.
The relevant sections in ADB Vol. 2 are relatively basic and open to interpretation if only in part. This has necessitated the provision of supplementary guidance tasked with clarifying the detail within, such as BCA Technical Guidance Note 18. Furthermore, materials of limited combustibility (MOLC) applied together in a wall system may behave differently in a fully developed fire than how they behave in isolation. Given that compliance in accordance with ADB Vol. 2 does not require full-scale fire testing, the efficacy of the individual components, even if designated as a MOLC, remains questionable.
Compliance in accordance with BR 135 is performance based. Entire wall systems must meet the acceptance criteria in BR 135 utilising large scale test-data from BS 8414-1: 2002 or BS 8414-2: 2005 respectively. The BS 8414 series do not provide a pass or fail result as the information from the test is used for additional purposes. One of the major concerns held by Fire Protection Association is the increasing volume of combustible materials within building structures. It appears that compliance with BR 135 is contributing towards this problem. BR 135 does not explicitly prohibit the use of combustible materials in external wall systems and in fact entire wall systems incorporating combustible materials can be deemed to meet the performance criteria of BR 135. If the performance criteria is met, external wall systems incorporating combustible materials can be applied to the façade of a building of any height.
Desktop studies can be utilised to demonstrate compliance with The Building Regulations where the report is submitted by a suitably qualified fire specialist. This report is used to ascertain if, in the specialist’s opinion, the proposed system meets the performance criteria within BR 135. Any conclusions drawn should be supported by data from an accredited body, such as UKAS. Given that this approach is based on previously tested systems, it is only suitable where existing test data is available for the product in question and where it has been tested in multiple arrangements and situations. Desktop studies should not be accepted where supporting test data is not supplied and each report should specifically make reference to the tests already undertaken on the products in question. With such safeguarding’s in place desktop studies may appear to be thoroughly robust. In a recent RIBA journal publication, however, the desktop study approach was described as the most interpretive of the four compliance options suggesting that it can potentially be manipulated to suit a desired outcome. If we know that desktop studies are interpretive, we can also deduce that sector-wide consistency is an issue. Consistently, the Association of Specialist Fire Protections Chief Operations Officer, stated that the ASFP held strong concerns that some desktop studies are lacking the level of rigor they should have. It could be viewed that some of the large key bodies in the construction industry are publicly voicing their criticisms of the current systems as a result of the Grenfell Tower Block Fire, however, the RIBA claim that the call for a review dates back to 2013, when the Secretary of State for Communities and Local Government acted in response to the Coroner’s rule 43 letter following the 2009 fire at Lakanal House.
The final option available is a holistic fire engineered approach (FEA), generally publicised as the most practical option in complex projects. A FEA considers the entire building, accounting for building geometry, use, ignition risks and factors that hinder fire spread and is based around the eight key stages referred to in BS 7974:2001, application of fire safety engineering principles to the design of buildings. This is referenced in ADB Vol. 2 as an appropriate framework from which to base the design of a building on. In addition to BS 7974:2001, fire engineers may also consult BS 9999, the code of practise for fire safety in design, management and use of buildings. This has received some level of criticism due to it being a massive and largely impenetrable document that has been specifically designed for fire engineers. The criticism extends to the level of technical expertise required to decipher the document. There is general agreement that the complexities in BS 9999 serve to ring-fence fire engineering, rather than providing useful information for architects and surveyors.
The information presented here is a mixture of opinion and fact yet with Grenfell firmly in our minds, this has served to outline the recognised routes to compliance for B4 (1) and, to some extent, the issues associated with each. The ultimate question that needs addressing is ‘do the regulations and supporting guidance need to be reviewed?’ This would be inclusive of the currently recognised routes to demonstrating compliance with B4 (1). On September 12th 2017 the Department for Communities and Local Government issued a call for evidence in an attempt to gain opinion on the matter with the submission deadline passing on 13th October 2017. The outcome is not yet known, however, the impact of Grenfell will almost certainly have a profound impact on fire safety regulations, guidance and compliance going forward.Back to news