Fire outbreaks on modern tall towers
Over the last decade and more, major developments across the GCC and other Arab States have become home to some of the most spectacular and iconic high rise towers in the world. However, despite their breathtaking height and imposing profiles that dominate the skylines, a series of recent serious fires involving tall towers, fortunately to date without fatalities, has cast a growing dark shadow over their safety. A number of fire engineering experts have increasingly suggested that there could be a fire disaster waiting to happen.
The root cause of this professional concern for the fire safety of all who either reside or work in tall towers lies is the use of flammability and poor reaction to fire building materials for external and internal construction of modern towers.
With a construction boom in the Gulf States peaking about a decade ago, e.g. the low cost of imported flammable Aluminium Composite Panels (ACP’s) and insulation materials led them to be widely installed on and in many new towers. These panels are formed of two thin gauge aluminium sheets sandwiching a flammable insulating material, either foam or some other plastic-based compound. And exactly the same foam material is being used internally as insulation in other building applications such as HVAC.
The Address Downtown Tower Fire
It was particularly The Address Downtown Hotel fire on New Years Eve 2015 which grabbed the world’s attention when fire broke out whilst nearby tens of thousands of residents and visitors were awaiting the start of Dubai’s Annual New Year firework display.
Over the next few hours via a multitude of media and social network emails and text messages, this outbreak more than any other instantly focussed global attention on the flaming images of the hotel tower, and the widespread fire safety problems of Gulf tall towers. It is worth recalling the events of that dramatic night.
At around 2130 hrs on New Year’s Eve 2015, a fire broke out at 15th floor level and spread to one of the many external flammable facade panels of the 63 storey Address Downtown Hotel. The 991 ft high tall tower was completed in 2008 at a cost of GBP£156 million, and is close to the Burj Kalifa Tower, the world’s tallest building. The hotel has 196 rooms and 626 apartments. The fire spread very rapidly to engulf most facade panels on one of the hotel’s external faces as firefighting units of Dubai Civil Defence quickly arrived to get to work, both firefighting and leading the evacuation of over 1,200 residents.
Dubai Police later confirmed that the fire at the Address Downtown Hotel tower originated with a fault in a power supply to a floodlight. According to investigators, an electrical short circuit in a spotlight between the 14th and 15th floors which was used to illuminate the hotel exterior was the origin of the fire that spread into the easily inflammable facade panels.
Thankfully, owing to the prompt action of Dubai Civil Defence firefighters, no deaths were attributed to the Address Downtown fire, although 15 persons were injured and one man suffered a heart attack during the evacuation process.
Existing International Fire Codes and Tests
One of the problems for fire engineers and fire safety consultants in their quest for the elimination of combustible insulation in buildings, especially facades and HVAC applications is that some existing international fire codes such as BS 476 part 6 and 7 or ASTM E84 do not always provide sufficient protection in event of a real fire.
In the first instance, all kind of building materials should have a limited flame spread but as well a limited release of toxic smoke which is the cause of 75 % of death in case of a fire. Looking at the recent tower fires and their reluctant damage, it is very apparent that flammable material in the ACP’s are a real source of major fire risk to all tower residents and visitors, and are not fulfilling real stringent fire codes such as EN 13501 which clearly outlines flame, smoke and droplet behaviour of the materials.
Fire tests and their methods such as BS 476 Part 7 and ASTM E84 are readily used to establish a material’s surface spread of flame performance. However, these may not be readily applicable to building materials as these tests are frequently not challenging enough in terms of performance against flame and heat.
When applied to the BS 476 and ASTM E84 tests, once ignited, the polyethylene or any other plastic based material in an ACP burns fiercely although the test flames do not always penetrate the facade panel outer skin.
However, during almost all of the recent Gulf tall tower fires involving the flammable panels, flames easily penetrated the aluminium outer edges of each panel, igniting the entire assembly and rapidly setting fire to those adjacent, thus contributing to a very rapid spread of surface flame, both up and down the tower’s faces.
In almost all significant passive fire protection elements of any modern structure the design of compartments and partition walls throughout the building contains non-combustible materials such as glass wool and stone wool to prevent any fire outbreak and to avoid resultant smoke from spreading. This is as well important in the installation of HVAC systems and other utility services which penetrate through partition walls. The insulation material for all these systems needs to be of a rated non-combustible nature and is critical in securing the full integrity of the compartmentation.
It is fair to state that ASTM E84 test used to assess surface burning characteristics of the building materials, including insulation material, is not always a reliable test, as it can yield flame-spread indexes of 25 or less for materials that may perform poorly in a real fire scenario.
Another widely used related test for building facades systems is NFPA 285. This 30 minute test simulates a fire in a multi-story building that bursts out of a window, and tests whether the fire is able to penetrate into the room above, break through the window head and enter the space between the cladding and the substrate, or spread over a larger external area both vertically and horizontally.
Certification and Inspection of Materials
All fire related products submitted for approval by Civil Defence in the UAE must carry Certification by an approved body. However, given that there is an established system of building material fire tests, how do we know that building materials on test will be applied on site in the same way as they were at the test laboratory?
This is where Certification and Inspection comes in, and should be accredited to the relevant acknowledged standard accepted in the Middle East. This implies a process that confirms a manufacturer has a recognised quality management system and goes on to select random premises as a feature of the Certification and Inspection process.
Smoke – the Real Toxic Killer
Every experienced firefighter will tell you that in any fire situation, whether in a small domestic apartment, a large shopping mall, or a tall tower, it is the smoke that is always the lethal element – the real toxic killer, not the angry flames.
As a general figure, 75% of fire deaths, not just in the Middle East, but globally, are caused by the inhalation of toxic smoke. Even in low levels of obscuration, smoke blinds the path to an escape route, quickly disorientates a person trapped in a burning building, and within a minute induces uncontrollable coughing, collapse, and oxygen starvation with the rapid onset of fatal unconsciousness.
Manufacturers of flammable foam based insulation including ACP’s, are known to add fire retardant chemicals to their products which, when burning, add an even greater toxicity to the smoke being emitted. These type insulations are widely used in various applications, including HVAC ducting systems.
The particular smoke emitting from, for example, burning plastics such as polyethylene and a range of PVC products also has an increased toxicity and threat to life. The vast majority of today’s fires are likely to involve plastics, and apart from soot, the smoke will produce poisonous gases that will include carbon monoxide, hydrogen chloride, hydrogen oxide, sulphur dioxide, ammonia and chlorine amongst others, depending on the plastic that is burning.
Recent Gulf tall tower fire outbreaks, initially on the external faces of the structure, have led to upper glazing fractures with the developing fire and smoke then spreading internally into apartments and offices, with great risk to life and limb.
It is very fortunate that there has been no direct loss of life in any of these Gulf outbreaks, but most fire safety experts think the clock is certainly ticking in this respect, and that is a view that I have to agree with.
Other Serious Outcomes of Fire Involving Using Flammable/Combustible Insulation Material in Buildings
Even when wearing modern personal protective equipment (PPE), firefighting teams rigged in breathing apparatus will face the additional danger of burning droplets falling from ceilings when penetrating into a burning building to search for missing persons.
Sprinkler systems if not properly installed may not have enough water pressure on higher floors to control a fire outbreak until fire crews arrive.
Insulation manufacturers rely of product test reports and certifications such as ASTM E 84 (Surface Burning Characteristics), which does not fully explain the fire behaviour in terms of combustibility, smoke development and melt/drop behaviour. This potentially raises the risk of fire in the areas of insulation that is installed.
The Drive towards Greater Fire Safety
So what can be practically done about the large stock of existing high rise towers and other buildings that may or may not have combustible HDPE (Low-density polyethylene) core cladding and foam based insulations for HVAC ducting, facade panels and other indoor equipment, which both day and night continue to pose significant fire risks to all those who resort to these buildings?
- Firstly we have to see what requirements come forward from the various Gulf Civil Defence regulating authorities and the anticipated amendments to the existing fire safety codes currently in the pipeline. This will hopefully include precisely what retro-fitting might be feasible to offset the risk from non fire-rated insulation materials. However, the ultimate outlawing of flammable/combustible insulations must be the final solution in order to prevent a major fire disaster occurring. European standard EN 13501 comprehensive test which covers the flame, smoke and droplets produced during a fire may well assist to re-inforce future updated fire safety codes. Also, the BS standards for fire testing method has currently reviewed and BSI has been adopted the EN standards, which later would be called BS EN standards in UK. It has been proven that BS EN standards are more effective in differentiating between non-combustible and combustible products in buildings.
- Secondly, fire engineers, architects and consultants must collectively campaign for a fresh culture that raises the awareness of the ready solutions to this modern danger to life and property, and ensure that all new building design scope utilises non-combustible insulations in HVAC and all other applications.
Insurance Concerns of Tall Tower Fires
Another outcome of the string of recent tall tower fires is the growing concern associated with the flammable insulation materials being used in facade panels and HVAC that are already affecting the willingness of insurance companies to insure high-rise and other buildings, not just in the Gulf States, but worldwide.
Insurance industry trends report that underwriters are becoming increasingly wary of inappropriate use of non-fire rated materials, and are either demanding higher premiums for buildings installed with certain products, precluding certain materials or systems from coverage, or altogether refusing to insure buildings.
Recalling the Tragic German Multi-Fatal Fire Involving Combustible Insulation: Düsseldorf Airport – 11 April 1996
This was the worst fire in the history of Düsseldorf, and the highest fire loss of life in the Federal Republic of Germany since the end of World War II.
17 passengers and civilians died, 72 persons suffered serious injuries, and several hundred people suffered minor injuries when fire broke out in the Airport terminal building.
The subsequent inquiry determined that the fire began when a welder working on expansion plates in a roadway above the lower level of the terminal building, ignited the polystyrene insulation used in the void above the ceiling on the first level.
The smoke and flames spread very rapidly throughout the first level, then extended to the second level through unprotected open stairwells and escalator openings. The fire did significant damage in the vicinity of the stairwells, and heavy smoke damage throughout to approximately two-thirds of the second and third levels. Smoke also spread to the fourth level through unprotected escalator openings.
The Federal Republic of Germany subsequently banned the use of combustible insulation material in all construction projects.
The Ready Availability of Non-Combustible Materials
Fire Safety solutions as above can be readily achieved as non-combustible insulation materials are available for all types of applications in modern buildings.
Non-flammable insulation materials are available on the market from long established and reputable Gulf companies, who are leading manufacturers of glass wool and stone wool. Their range of products including building and mechanical insulation applications bring a complete assurance of performance through meeting the stringent Euroclass non-combustible classifications A1 and A2.
In Closing – A Fire Chief’s Perspective
I know only too well from my many years of front-line firefighting and rescue experience in central London and elsewhere, that the physical challenges for firefighting crews who are involved in tackling an outbreak of fire in a high rise tower or other complex building are immense.
Consequently, I make no apology in stating that fire as man’s oldest friend also has a habit of regularly reminding us that in an uncontrolled form, it is one of man’s most deadly enemies.
This is exactly why the science and application of modern fire safety, and passive and active fire protection measures, allied with certified products and non combustible materials, has never been more important in safeguarding life and property in communities, commerce and industry, not just in the Middle East region, but around the world.
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