Potential fire risks of high rise construction illustrated by Dubai Torch Tower fire
The fire that swept through the 79-storey Torch Tower in Dubai's Marina area in February, which resulted in the evacuation of hundreds of people, wasn't the first fire of its type in the city. There was a similar fire at the nearby 34-storey Tamweel Tower fire in November 2012; and the fact that neither of these building's external cladding system were code compliant was clearly a factor in both cases.
According to fire experts Clive Raybould and Phil Barry, similar fires are occurring with increasing frequency around the world in high rise buildings.
They warn that building managers, wherever they are based, need to check building compliance and ensure they've suitable risk management procedures in place.
Phil Barry draws on his own experiences of working in the Middle East to warn of the inherent dangers of high rise buildings there and elsewhere, but firstly; International Workplace Fire Safety expert, Clive Raybould, looks at the lessons learnt from the Torch Tower fire and suggests some of the difficult questions those responsible for fire safety in high rise buildings need to ask.
"The Torch Tower was built and opened in May 2011. New building standards were put in place in Dubai in 2011, with additional laws in 2013. Unfortunately, the Torch was built prior to these new laws being in place.
It would appear that the fire started on the 51st floor and it is believed that the fire, which spread up 15 floors, did so vertically up the external wall cladding, but that it also may have penetrated into some of the ventilation systems. Fire spread also occurred as burning panels and embers fell onto materials below.
This fire actually seems to be very similar to the one in the Tamweel Tower block in Jumeirah Lakes in Dubai in November 2012. In both cases the fire has spread up vertically and penetrated inside the building. The Tamweel Tower block is still not in full occupancy with repair costs estimated at £14m.
This type of incident brings questions about the type of materials used for the cladding, its flammability and the test methods used for such products. The quality of fire stopping should also be questioned. The only good news with this fire is that it is understood that no one died and there were no major injuries, although I believe that there are however about 100 flats into which families cannot go back into now.
The fire was fanned by the intense winds that are created around this type of structure, so that it spread quickly. Firefighting must have been very difficult, as you would have to try and gain access from adjacent parts of the building to fire fight off balconies.
Questions will now be asked about this type of building around the world, especially any which were built to previous (or lower) standards where the fire resistance of external cladding was not considered, (as it should be today).
There are some difficult questions that now need answering for building owners, including:
- Can the existing cladding be replaced with modern fire retardant products? (This would be very expensive to do).
- Should surveys be done to ensure a buildings fire stopping and fire-compartmentation breaks are in place?
- What are the existing fire active systems in place in the building and in a worst case scenario will these protect the residents, although major building loss could occur?
- Should additional fire active systems such as sprinklers be retro installed if not already in place? (This again is extremely expensive).
- Should the facilities in this type of building be reviewed in light of some of difficulties faced by fire fighters trying to extinguish this type of fire?
- Should additional controls (legal if necessary) be brought into play in such high rise buildings, to try and prevent fire starting in the first place?
- Should we continue to keep building upwards, reaching for the sky as we are and if so do we just accept the risk and take our chances?
I think that time should be taken to at the least review these buildings and assess if the control measures that should be in place are there. The idealist in me says that we should look to upgrade the existing building stock to modern standards to prevent such fires happening again, but I think that would be a little unrealistic. I suspect the power of 'money' that builds such buildings in the first place will win through and old buildings will just run the risk!
Of course events like these should make Governments around the world look at the resources available to fire services, as cuts continue to be made. It is hoped that we don't have buildings where this type of fire could happen in the UK, as any building done to Building Regs standards should be safe.
However, all the major cities in the UK are ever building upwards, so while in theory fires like this should not happen in the UK, would the Fire Services in London, Birmingham and Manchester (to name but a few), be able to cope with such an incident?"
High rise hazards
Former Fire Officer and now Fire Safety Consultant, Phil Barry, has considerable experience of working in Europe and the Middle East and warns of the inherent problems with some high rise buildings – not only in Dubai but around the world.
"I have worked in Europe and the Middle East, and during the two months I worked in Qatar in 2012 there was a serious fire at the Villagio shopping centre in Doha.
As a result I became involved with stakeholders in Qatar and Dubai and was requested to deliver fire safety training and survey various buildings including high rise buildings.
It was as a result of this work that I became aware of serious problems with some high rise buildings - particularly in Dubai - but also on further research I found many examples of similar problems worldwide.
International standards for fire safety
The main international standards related to building control, will vary according to where the building is being constructed, but there is usually a regulatory building control process that ensures that buildings are constructed to achieve appropriate safety standards for persons in and around buildings.
The most commonly used standards are American NFPA codes and British Standards. There is rarely a legal requirement to adopt any particular code provided the functional requirements of the regulations are achieved.
The UAE Code of practise was revised in 2013. That code, together with NFPA Standards, British Standards, European codes and codes and standards used all around the world make similar recommendations for restricting external fire spread in all buildings and particularly in high rise buildings.
Whilst the various codes in use around the world have slight variations, they all broadly make the same recommendations.
Provisions are made to restrict the combustibility of external walls of buildings that are near to a relevant boundary and, irrespective of boundary distance, the external walls of high buildings.
The purpose is two-fold, to reduce the surface’s susceptibility to ignition from an external source and to reduce the danger from fire spread up the external face.
For example, the British Standard requires all buildings with a storey height of 18m or over to have a minimum rating of index (I) not more than 20 (national class) up to a height of 18m and Class 0 i.e. totally non-combustible above 18m.
The risk of external fire spread may also be reduced by adequate space separation and by the protection of openings.
With high rise buildings being a feature of many cities across the world, they are often designed to look attractive and to blend with existing construction in the area. External cladding is often applied for cosmetic reasons, for insulation and sometimes to transform the look of old buildings.
The rules are clear in the building codes, but many designers in my opinion do not understand the importance of restricting the combustibility of the external surfaces.
It is rare to find a building that has passed through the building control procedure without the required internal structural fire safety requirements, but it is becoming increasingly apparent that many buildings have been constructed using combustible external finishes and this is placing many people at unnecessary risk.
Cladding systems are available that meet the requirements of the building codes but all too often they are not being used. A discarded cigarette is thought to have ignited rubbish piled up outside de the Tamweel Tower, in Dubai in 2012.
The fire gutted half of the tower block and began in a pile of combustible material in an outdoor passageway at the base of the building. It had been left there by contractors working on a shop inside the building.
Once lit, the fire quickly spread up the highly flammable building cladding, which contained aluminium and fibreglass, to the roof. Flaming sections of cladding fell down on the balconies and cars below. The fire also spread inside the building, mainly through the balconies.
Similar fires are occurring with increasing frequency around the world in high rise buildings.
In London in 2009, six people were killed in Lakanal House, a relatively low rise 15 storey residential building. The started in a dwelling on the seventh floor and quickly spread internally and externally to the ninth floor.
More unusually, the fire also spread downwards to the fifth floor. A contributory factor to the external fire spread has been confirmed as the replacement of external panels that were previously non-combustible with plastic based panels.
These panels contributed to the rapid fire spread by melting and causing burning droplets to fall and enter the open windows of the units of accommodation on the floors below.
The reason why there have not been more serious consequences in similar fires that have occurred in recent years is the effective provision of fire separation by compartmentation within the buildings.
It is important to understand that although the various codes of practice require the external walls to be fire resisting in load bearing capacity, there is rarely a requirement for the walls themselves to restrict fire penetration through them i.e. the load bearing capacity is often provided by columns and beams thereby enabling the incorporation of unprotected areas within the walls such as windows.
The use of glazing for windows is entirely desirable, it would be impractical and cost prohibitive to have fixed shut fire resisting glazing on all the exterior walls.
The percentage of the wall area that may be unprotected depends on the height, use and proximity of neighbouring buildings.
It is therefore essential that the external wall construction does not permit fire spread across its surface as there will always be the potential for an external fire to enter the building through open or non-fire resisting glazing.
The cause of the Torch fire is still under investigation but having seen video footage of the fire and its development, I am in no doubt that the building cladding system was not code compliant.
UAE Regulations and beyond
The new Regulations introduced in the UAE in 2013 require the use of fire resistant Aluminium Composite Panels with a mineral core rated as per international fire regulations, in the place of an inflammable core. They disallow the use of Silicon or fillers in the Cladding Assembly joints, and specify an open joint ventilated sub-structure backed with fire resistant and high density insulation.
The regulations also direct that the complete system is supplied from a single manufacturer source. The entire system should be verified and approved at all the stages of construction including design, pre and post installation, and by the manufacturer/ fire consultant. This should help ensure the whole process is tightly regulated and accountable.
The new Regulations will adequately cover new building work provided they are robustly enforced. It is essential that architects and building designers specify appropriate external wall linings and that manufacturers can clearly demonstrate that their products have been tested to an appropriate standard and will perform to that required standard in a fire situation.
However, it is believed that about 70% of existing high-rise buildings in Dubai use cladding with a highly flammable thermo-plastic core. There are also potentially many thousands of existing buildings around the world that will have been built incorrectly, either because the regulatory building control process has not been correctly followed or because the building was constructed prior to the existing controls and recommendations being introduced.
The solution to these existing buildings is problematic. While most high rise buildings have internal sprinklers and fire mains, very few have a means of controlling a fire if it starts on or if it spreads to the outside.
Fire safety of high rise buildings
Building owners and managers need to identify whether or not their buildings are code compliant. If they are not, or cannot be confirmed to be, appropriate mitigating measures will need to be introduced to reduce the risk to building occupants and persons in the vicinity so far as is reasonable practicable.
Such measures could include the replacement or treatment of existing panels or the provision of active fire safety measures such as external sprinklers.
Extensive testing and modelling would need to be carried out before safety systems such as external sprinklers were installed to ensure they would be effective in the particular circumstances.
There are potentially a number of different approaches and it would be a case of looking at each one individually.
A suitable and sufficient Fire Risk Assessment must be carried out by a suitably competent person to determine what needs to be done and what would work on each particular design.
The risk may also be reduced by controlling sources of ignition and fuel in the proximity of these buildings. Effective security, arson control, refuse management and control over smoking all may need to be considered.
The fire in Torch started on an upper floor, so it is not just the ground floor that must be considered when looking to reduce sources of ignition and fuel. Modern buildings contain numerous electrical systems and devices, so ignition sources can never be totally eliminated and measures to reduce the risk of fire spread must therefore always be introduced.
Consideration may also need to be given to evacuation planning. Alarm systems and means of escape provisions such as stair capacity in many of these buildings, particularly residential buildings are designed around a 'defend in place' strategy.
This means only the occupants of the unit of accommodation involved in the fire usually evacuate. The buildings are designed to restrict fire spread beyond the unit of origin and therefore simultaneous evacuation of all floors is not usually necessary or desirable. The stairs are therefore of limited width and the alarm system is not designed to raise warning for all building occupants.
If serious design flaws are identified with the evacuation strategy - general fire precautions may need to be modified accordingly."