19 August 2019
You have to understand risk to be able to manage it. Here, Tony Ryan explores how making good choices can help reduce the impact of fire.
WHEN YOU are considering the impact of building elements in the context of fire safety, it is absolutely crucial to understand the nature of risk – where risk lies, what are the most likely scenarios, what will be the greatest contributor to a fire event etc.? Most importantly of all, you must consider how the design and specification of a building will help to preserve life and protect property in the event of a fire.
Following recent high-rise building fires, there has been intense discussion around these topics, coupled with a degree of uncertainty about the direction the government and industry might take next. We now have a clearer pathway in terms of regulatory requirements; however, the situation unearthed some issues endemic within the construction industry that are slowly but surely being addressed, at least with regard to a specific group of high-risk buildings. Before looking at the many different factors that need to be considered, it may be useful to establish exactly what the current requirements are for those high-risk buildings.
On 29 November 2018, an amendment was enacted to Regulation 71 of the Building Regulations 20102 – Materials and Workmanship in England, restricting what materials can be used in a specific range of buildings with a storey over 18 metres above ground level. The restrictions apply only to buildings which contain one or more dwellings, an institution, or a room for residential purposes (not including rooms in hotels, hostels or offices). The types of accommodation this covers currently includes student accommodation, care homes, sheltered housing, hospitals and dormitories in boarding schools. There are also discussions for this to potentially be extended to school buildings in the future. For these buildings, only materials achieving a European Class A1 or A2-s1, d0 in accordance with BS EN 13501-1:2007+A1:20093, may be used in the external walls.
There is a long list of exemptions to this rule, including door frames and doors, membranes, thermal break materials, seals, gaskets, fixings, sealants and backer rods, window frames and glass.
The changes came into force on 21 December 2018 and apply only to buildings and building work that fall within scope in England after that date. Other types of buildings with a storey 18 metres above ground level, such as office blocks and hotels, can still use an alternative route to compliance, by meeting the requirements of BR 135 using the BS 8414 large scale system test. Full guidance on how to meet the regulatory requirements is set out in the recently revised Approved Documents B, volumes 1 (dwellinghouses) and 2 (buildings other than dwellinghouses)4.
The Scottish Government has also recently introduced changes to the Building Standards5, which are set out in Section 2 of the Technical Handbooks (THB2) for domestic buildings6and non-domestic buildings7. However, they have taken a slightly different approach to England. The threshold at which stricter requirements are triggered is where a building has a storey over 11 metres rather than 18 and, rather than a blanket ban on materials which do not achieve the required Euroclass rating, Scotland has maintained the BS 8414 test in accordance with BR 135 as an additional route to compliance as well as materials that are A1 or A2-s1,d0. Mention is also made in the updated THB2 of the soon to be published extended application standard, BS 9414, which will allow strictly limited changes to a BS 8414 tested system where the changes will provide a known higher level of performance.
At the time of writing, Wales and Northern Ireland have not announced any changes to their regulations.
The nature of risk
Places where people sleep or may be otherwise unable to evacuate quickly and easily require a level of forethought to ensure that occupants have the best possible chance of survival in the event of a fire. This is what these changes to the regulations aim to support. However, there are other types of risk that businesses in particular also need to consider, relating to asset protection and business continuity planning if a fire breaks out in a low rise commercial or industrial building. One way to have confidence in the performance of the external wall construction in this situation is to look for products and systems that have successfully undergone large scale insurer tests, such as those from the Loss Prevention Certification Board (LPCB) or FM Approvals.
The relevant tests for external cladding are LPS 1181-1 from the LPCB, and FM 4880 and FM 4881 from FM Approvals. The use of certificated products demonstrates due diligence and is encouraged by insurers, potentially reducing risk and premiums. Global insurance company FM Global, states in the Insights & Impacts section of its website that “FM Approved sandwich panels, for example, have a superior fire rating and prevent the spread of fire within the panel itself and, as such, can be compared to non-combustible panels for protection purposes.”8
More to the point, tested and certified products have been proven in real fire case studies to perform as indicated by these tests, and have enabled businesses to get back up and running, sometimes within hours of a fire on their premises.
Case studies– putting the tests to the test
Audi Dealership, Belgium
The fire occurred in the external compound of a large Audi dealership in Belgium in October 2014 following a deliberate act of arson. The building is of steel frame construction clad with FM/ LPCB certified PIR cored sandwich panels and provides single storey showroom and workshop accommodation and an internal mezzanine floor for additional vehicles and back of house accommodation. The insulated panel cladding was subjected to an intense fire load for at least 10 minutes.
The panels exposed to these conditions sustained damage in terms of delamination of the exposed steel skin of the panels away from the PIR core, removal of the paint coating and pyrolysis of the PIR core material to a depth of approximately 40mm. There was no evidence of fire propagation within the panels, and the inside of the workshop in an area adjacent to the external fire attack showed no evidence of fire penetration, allowing trading to continue as normal the next day.
Furniture Retail Warehouse, Slovakia
A large fire took place outside a furniture store in Presov, Slovakia – a large concrete framed, flat roofed retail building clad with Kingspan insurer certified PIR core insulated panels. The fire, located within close proximity to an external wall, involved the combustible contents of a cooking grill and 5 propane gas cylinders. At the height of the blaze the flames were over 10m high and impinged directly onto the surface of the panels, subjecting the external facade of the furniture store to an intense fire plume for a duration of approximately 10 minutes. The intensity of this fire plume was such that it melted the aluminium composite panel used for the store’s mascot sign within this short fire exposure period.
The insurer certified PIR core material of the external wall panels charred to a depth of about 10mm in the area directly impacted by the fire plume and the external skin of the panels delaminated from the core in these areas. Despite the intensity of the fire plume, there was no propagation of the fire within the panel or fire spread into the interior of the building, and the store was able to re-open within three and a half hours.
What each of these case studies shows is that, even in the event of a fire, making good choices when it comes to building elements can make all the difference between an inconvenience and a potential crisis for your business. Firstly, there is peace of mind in knowing that proven performance will help to support life safety, allowing timely evacuation of people from their places of work. Secondly, there is the difference between essentially limited, largely cosmetic damage and the potential total loss of your building and its contents. Knowing that the external wall construction has been certified by independent third parties using large scale system tests developed by the insurance industry, provides an assurance of reduced risk.
Tony Ryan is technical director at Kingspan Insulated Panels. For more information, visitwww.kingspanpanels.co.uk
1 Regulation 7 – Materials and Workmanship -www.planningportal.co.uk/info/200135/approved_documents/84/regulation_7_-_materials_and_workmanship-
2 The Building Regulations 2010 (England) -www.legislation.gov.uk/uksi/2010/2214/contents/made
3 This test has now been superseded by BS EN 13501-1:2018
4 Part B – Fire Safety -www.planningportal.co.uk/info/200135/approved_documents/63/part_b_-_fire_safety
5 The Building (Scotland) Regulations 2004 -www.legislation.gov.uk/ssi/2004/406/contents/made
6 Building Standards technical handbook 2019: domestic buildings -www.gov.scot/publications/building-standards-technical-handbook-2019-domestic-buildings/
7 Building Standards technical handbook 2019: non-domestic buildings - www.gov.scot/publications/building-standards-technical-handbook-2019-non-domestic-buildings/