In June, RISCAuthority held its annual members seminar in Manchester, which attracted more than 120 delegates from the insurance sector and a diverse programme. Mark Sennett reports
THE RADISSON Blu Edwardian once again played host to the Manchester leg of the RISCAuthority Seminar annual double header. The second leg is due to be held as part of the Fire Sector Summit in London on 17 October, where some of the sessions will be repeated for RISCAuthority members who couldn’t make the trip up north.
Probyn Miers associate director Martin Edwards delivered the first session, speaking on the topic of building envelope fires in Dubai skyscrapers. He explained that external fire spread on skyscrapers may lead to re-entry into buildings via window openings within the fire envelope. Flames will typically extend up to two metres above window openings regardless of the type of cladding, and if this cladding helps the fire spread, it makes firefighting that much more difficult.
If flames become confined in cavities behind the external cladding system, they will become elongated as they seek oxygen and extend five to ten times the original flame length, meaning the fire can spread rapidly and unseen through the cavity barriers. The common insulation cores for composite panels in the UK, in order of decreasing probability of fire propagation are polystyrene, polyurethane, polyisocyanurate, phenolic and mineral fibre.
Sun Valley Poultry
During the 1990s, there were at least 30 fires in the UK involving composite panels, most notably in 1993 at Sun Valley Poultry, where two firefighters died during the blaze when ceiling panels collapsed on them after the fire had developed unseen in the roof void. The fire was also one of the most expensive in the UK at the time with a total loss of more than £70 million. The fire entered the roof void and developed above the ceiling, weakening the panels and their hangers and eventually causing the collapse.
Mr Edwards pointed to safety concerns for firefighters in buildings where sandwich panels are present. These include hidden fire spread within panels, large quantities of thick black smoke, rapid fire spread leading to flashover, delamination of steel facing, hidden fire spread behind the system and the ultimate collapse of the building frame.
The discussion then moved onto Building Regulations in the UK and how Approved Document B (ADB) to the Building Regulations recommends that any building 20m or higher must use insulation material in the external walls that is of limited combustibility. It also recommends that gaps behind rainscreen cladding be closed by cavity barriers at every floor level and on line of compartment walls of buildings greater than 20m.
Full scale fire tests have been developed by BRE to cover BS 8414-1: 2002 and BS 8414-2: 2002, which simulate a fully developed fire for non-loadbearing external cladding systems applied to the face of the building and venting through a window. They compare the performance of insulation with limited combustibility to polyurethane panels. The insulation with limited combustibility survives the test well, whereas the other panels are badly damaged. The tests were carried out both with and without fire barriers, and the results showed the effectiveness of having barriers in place, as they helped to prevent fire spread. Mr Edwards explained the huge risks that insurers face by insuring buildings that consist of composite panels, as any fire will probably result in a total loss.
UAE skyscraper fires
He then discussed recent major fires in the UAE and explained that currently in that region there is no legal requirement to install cavity barriers to seal concealed voids; nor is there a specific requirement to close cavities around doors and windows, unlike in the UK.
For external cladding systems, the UAE Fire Code is actually more demanding than the recommendations in ADB. But UK experience suggests that the incidents of external envelope cladding fires in UAE in buildings constructed from 2013 onwards ought to be hugely reduced or eliminated, provided that the Fire Code is followed during design and construction. However, the continued mass production of composite core panels suggests that combustible panels are still being widely used in the Gulf.
The remaining problem in the UAE is the legacy of buildings constructed with combustible cladding materials erected before the Fire Code was introduced, and at present there is no equivalent legislation to the UK’s Regulatory Reform (Fire Safety) Order 2005. This means there is no obligation to carry out regular risk assessments, although this is expected to change very soon.
Mr Edwards concluded by saying it seems inevitable that there will be further major fires in buildings comprising aluminium faced polyurethane core composite panels. It seems equally inevitable that insurers will soon begin charging higher premiums for buildings with combustible aluminium composite panels and, if another major fire happens, this may lead to insurers refusing to insure any building using these materials.
Hatton Garden raid
Former Fleet Street journalist and true-crime author Wensley Clarkson delivered a session on the inside story of the Hatton Garden heist. His latest book, Sexy Beasts: The Real Inside Story of the Hatton Garden Mob, was published in March and explores how the raid was conducted and financed.
Mr Clarkson began his presentation by stressing that people who stored jewellery in banks or secure facilities never thought it was possible that their possessions could be stolen until the Hatton Garden raid.
He explained that the criminals involved in the raid were old fashion robbers; older men who committed the crime as much for prestige as for the rewards. They believed they were able to break into any facility and planned this particular raid in the pub!
Getting into the facility was way too easy, as one member of the gang entered through the front door with keys and then let the others through via a side entrance. CCTV footage shows the gang dressed as gas repair men, but Mr Clarkson stressed the pictures from the cameras were not great quality and the cameras were poorly positioned. There was only one camera in the entrance and there were no hidden cameras anywhere in the facility, which made it easier for the gang to disguise themselves with masks and hard hats.
They forced their way through three outer doors into the vault room with relative ease, which should cause alarm to insurers as the doors were clearly not secure enough to prevent or delay the raid. The robbers then targeted the concrete wall next to the vault door, as the door itself was too secure to try and crack open. They began drilling through the wall and created three connecting holes for them to sneak through into the vault. But the pneumatic ram wouldn’t operate, so they left the site and returned the next day after buying a new tool on one of the crew’s personal credit card! What they were unaware of is that they had triggered an alarm the previous evening, but the local police chose to ignore the signal. They deemed it to be a false alarm and the security company sent a guard round to look at the outside of the building – he reported no signs of a disturbance.
Mr Clarkson raised further concerns about insurance risks at the site starting with the security deposit boxes, which were opened the following day with ease using an angle grinder. He also questioned how an insurer can provide adequate cover for the site if the owners of the safety deposit boxes aren’t required to list the contents and value of the items in each box.
There are key lessons to learn from this heist. Alarm systems need to be properly monitored. It can’t possibly be right that a text has been sent from an alarm system to a police station and the police simply choose to class it as a false alarm. There should be CCTV cameras inside vaults, but this may prove tricky as people won’t want to be filmed showing the contents of their box, although this would at least then provide an accurate account of the contents of the boxes so insurance companies can correctly value the contents of the vault.
This type of premises attracts criminals’ interest because of the nature of what’s stored inside them, which includes stolen goods. It attracts criminals, as many of the contents of the Hatton Garden heist were never reported missing, because they were themselves stolen. He believes the ownership of these premises needs to be monitored by the police to help ensure that those responsible for access to the vault are not criminals themselves.
MMI engineering principal consultant Andrew Nelson spoke to delegates about designing buildings for resilience to terrorism. He explained that cladding is critical to resilience since it generally suffers most damage, transfers load to frame (blast) and affects post-event building integrity. Heavy facades, such as concrete walls or reinforced blockwork, are cosmetically unappealing but are typical of blast-resistant structures; whereas light facades, such as highly glazed curtain walls, are more aesthetically pleasing but harder to engineer towards resilience.
Mr Nelson then drew comparisons between blast and seismic loads on structures, explaining that blast loads are very short duration (milliseconds), while earthquake vibrations act over longer durations. Blast loads primarily act – and thus cause structural damage – locally, whereas earthquake excitation causes global response of the whole structure. Mass can help to dissipate the effects of blast loading, but mass can exasperate the effects of earthquake loading.
Typical terrorist attack methods that can affect building integrity include:
- explosive attack – PBIEDs, VBIEDs, RPG, mortar
- incendiary attack – petrol bombs
- impactive attack – hostile vehicles, aircraft
Incendiary attacks introduce fire into the building, which then has the potential to spread, whereas impactive attacks can cause local severe damage that can lead to progressive failure. Cladding systems are particularly vulnerable to the same hazards, which can challenge the structural frames. For blast scenarios, as they are lighter systems directly facing the hazard with large exposed surface areas, they collect
For earthquake loading, loading is imposed on cladding from structural displacements. They rely on fixing systems that are typically much lighter than structural connections. Also, cladding systems present significant challenges to the engineering community and a good deal of testing has been carried out, particularly for blast loading.
Defining acceptance criteria is full of uncertainty, hence the drive for resilience rather than resistance. It’s critical for design to incorporate blast/seismic resilience as early as possible in the design process to ensure cost effective solutions. Glazing is a known blast vulnerability. CPNI guidance says: ‘up to 95% of all injuries from a bomb are caused by flying or falling glass.’
The purpose of the glazing is to maintain a weather envelope, but some traditional ‘blast resistant’ glazing solutions (eg ASF, blast net curtains etc) are insufficient for blast resilience, as these solutions allow the glazing to fail in a blast and hence the weather tightness is lost. This has led to the use of laminated glass within insulated glass units. Fixed point, or planar glazing, is increasingly used for commercial buildings where architects want to reduce the visual impact of any support system. CPNI recommends that the blast design of such window systems should be undertaken by RSES registered blast engineers.
RISCAuthority director Dr Jim Glockling concluded the session by highlighting some of the key deliverables from the past 12 months. He also looked ahead to which emerging areas and insurer concerns will be addressed in the coming months. The London RISCAuthority seminar will take place on 17 October at the Royal College of Surgeons. The event is free to attend for all RISCAuthority members and takes place on day one of the Fire Sector Summit. More information is available at www.riscauthority.co.uk
Members of RISCAuthority can get more information on the London seminar by emailing firstname.lastname@example.org and for more information on the Fire Sector Summit, please visit www.thefpa.co.uk/summit.
Mark Sennett is the managing editor of Fire Risk Management