A recurrent theme at Interflam was follow-up from the Grenfell Tower fire catastrophe. (14 June 2017). Despite previous occurrences of fires in high-rise building exterior cladding, it seems this disaster was necessary for regulators to take action. Several speakers at Interflam underlined the problems of lack of confidence in the construction industry (lack of chain of responsibility, inadequate controls and monitoring, lack of competence), as indicated by the Dame Judith Hackitt report on the Grenfell catastrophe, see pinfa Newsletter n°92.
The conference opened with plenary presentations by Sir Ken Knight and Colin Todd, respectively advisors to the UK and to the Scotland Governments on building fire safety following the Grenfell Tower fire.
Colin Todd indicated that the Scotland Government has taken significant actions since Grenfell, but also taking into account other major fires such as the Glasgow Art School fires in 2014 and again in 2018
- changes to building regulations concerning cavities
- only Euroclass specifications now accepted for fire safety of building materials
- Euroclass A1/A2 materials only for cladding for all buildings >11m height (considered to be the height reachable with a water jet, reduced from 18m) and on nearly all hospitals and buildings used for public assembly (except very small)
- from 2021, all households must have installed smoke and heat and carbon monoxide alarms
- evacuation alarm systems (for use only by the fire and rescue service) in all new high rise blocks of flats
- a minimum of two staircases in high rise blocks of flats (over 18m in height)
Sir Ken Knight presented the actions taken since Grenfell in the UK:
- 434 high-rise buildings with ACM cladding similar to that used on Grenfell have been identified and programming of cladding replacement is underway, with approximately:
- 100 buildings – cladding today replaced
- 100 – work has started
- 250 – work is planned
- 80 – no plan yet in place
- Combustible cladding has been banned on all new buildings >18m high (not retroactive), see pinfa Newsletter n°95
- Other widespread problems in buildings have been identified, indicating generalised failures to respect fire safety requirements, but also failure to respect other specifications, in the construction industry:
- absence of cavity barriers
- non-conform fire doors
- structural problems with large panels
The UK government is working to address the conclusions of the Hackitt report into Grenfell (see pinfa Newsletter n°92), with two priorities: improving residents’ voice, so that fire safety concerns expressed by residents are heard and taken into account; and addressing failures of the construction industry chain of responsibility and overseeing (implementation of a “Clerk of Works”).
In discussion with participants, it was suggested that the US uses flammable cladding, but has considerably fewer major fire incidents, and to date no significant fatalities. One reason for this may be the quality of the US Building Codes which control cladding, including testing of both materials and installation. Another reason may be that the litigation culture in the US may incite architects, project managers and the construction industry to implement better systems of responsibility and overseeing than in Europe, because of fear of law suits from victims or insurance companies in case of fire.
Margaret McNamee (Lund University) underlined the need to marry fire safety with sustainable construction objectives (in particular energy efficiency – insulation). She proposed to engage dialogue with ‘Green’ and energy efficiency certification and labelling bodies, such as LEED to foster the inclusion of fire safety considerations into the overall building evaluation, but noted that past efforts have been met with a low level of interest from the organisations responsible for developing the green building labelling systems. Debbie Smith noted that the BREEAM system does give points for fire safety although only in a simplistic manner and that more work on this matter is needed.
Marcello Hirschler, FSTB (GBH International and Fire Safety & Technology Bulletin), https://www.gbhint.com/fire-safety-and-technology-bulletin/ outlined developments in building façade fire safety requirements in the USA. The IBC (International Building Code), which is used throughout the US, specifies in chapter 14 fire testing for both complete façade assemblies and for the separate components of the assemblies. The key fire test for the assemblies is NFPA 285, the scope of which has been expanded (in 2019): assemblies must be tested to NFPA 285 even if the only combustible is a water resistive barrier (unless it has excellent fire performance). The NFPA 285 fire test involves a 30-minute full wall test, with a window in the wall, applicable to all “combustible” claddings for all buildings >40 feet (12m). The 2021 edition of the IBC eliminates exceptions that had allowed, in previous editions, light-transmitting plastics to be incorporated into sprinklered buildings of any height. It also eliminates the use of MCM (metal composite materials) in sprinklered buildings up to any height without testing to NFPA 285. Some other improvements have been added also but the key requirements for fire testing of systems called ETICs (external thermal insulation composite systems) in Europe and EIFS (exterior insulation and finish systems) in the US, have been retained and they are well regulated. The new code also removes certain exceptions for HPLs (high pressure laminates). NFPA 285 is implicitly “always applicable” to all assemblies in new construction. The IBC also contains detailed fire tests for all individual components of cladding assemblies, with emphasis on insulation materials. Furthermore, the new edition of the IEBC (International Existing Building Code) will require fire testing to NFPA 285 for existing buildings when new claddings are being added or major renovations are being made. Mr. Hirschler underlines the importance of both updating building codes and standards frequently, and of ensuring effective implementation. His paper presents in detail the different fire tests used for façade installations worldwide.
Susan Lamont (photo), Arup, USA, and Birgitte Messerschmidt, NFPA (US National Fire Protection Association) presented NFPA’s EFFECT® Tool, developed by Arup with Jensen Hughes as peer reviewers. This enables a simple, online risk assessment of office, residential or hotel buildings of over 18m height, based on questions on aspects such as façade component materials and installation, cavities, wear and tear, proximity to other buildings, egress routes and evacuation strategies, fire protection systems. A first tier based on simple questions enables identification of buildings potentially with façade fire risk and enables an owner or AHJ (Authority Having Jurisdiction) of a portfolio of buildings to prioritise which buildings need further investigation. A second tier with more detailed questions, provides a more in-depth assessment of the risk. The tool is available to the public at www.nfpaeffect.com with some 450 users today. Feedback is that the information required to respond to tier 2 is often difficult to obtain, but expert analysis in the tool construction shows that meaningful risk assessment is not possible without such detail, for example specifications of the façade materials and structure / installation.
Anja Hofmann, BAM Germany and Alex Webb, CSIRO Australia, summarised building regulations relevant to facades in the UK (see above), Germany and Australia. The German fire services have identified 125 fires concerning ETIC (external thermal insulation cladding) in German buildings 2001 – 2018, with most occurring in recent years. These fires led to 11 fatalities and 140 injuries. Full scale testing carried out by German Building Ministry concluded that fires starting outside the building (e.g. in waste containers or cars next to the building) pose higher risks for façade materials than fires inside the building. The presenters conclude that German regulations for claddings are complex to understand, with specific additional requirements for buildings >18m high, but that roles and responsibilities are relatively clear, with requirements for relevant training of personnel, independent verification for certain building types, and a strong accent on enforcement. Façade fires both worldwide and in Australia (e.g. Neo2000, 4th February 2019) are driving tighter fire safety requirements in Australia, including amendments to the National Construction Code (NCC) including the new testing method AS 5113-2016 (including flame spread, flaming falling debris …), clarification of provisions applicable to external claddings, sprinkler requirements for balconies. Australian States have brought in additional requirements, and are carrying our audits to identify buildings at risk. Modelling and testing of façade materials was further discussed by Gaurav Agarwal, FM Global, USA, Pergiocomo Cancalliere, Italy Fire Rescue Service and Virginie Drean, Efectis, France.
In discussion, participants indicated that facade fire risks are essentially not linked to smoke toxicity, but to the size and the spread of the fire, and that smoke risks are mainly related to the quantity of material burning, not to its nature.
It was also indicated that more information needs to be developed on flame retardant plastic containing façade insulation systems: different solutions available and their different characteristics, performance in large scale installations in complex façade systems, new materials and developments.