Author Archives: denmark

Security in a Corona-virus crisis

security

For most of us, the Corona-virus crisis meant keeping distance and working from home. But, what impact has the crisis had on areas such as terrorism and cybercrime? See the Danish trends here. 

Cybercrime
The Corona-virus crisis has facilitated the ‘work’ of cybercriminals, who have been exploiting the current situation to create various scams.

– There have been numerous cyberattacks, particularly at the beginning of the crisis. Perpetrators analysed the context and adapted their language and wording to match the tone of the authorities. They tried to get people to log on to fake sites using e-mails that looked like they came from the authorities and were important and correct, says Anja Kivac, Project Manager at the security department of the Danish Institute of Fire and Security Technology (DBI).

Clever use of the right language combined with our hunger for news about the Corona-virus resulted in more people than usual clicking on false links. But working from home is also part of the explanation.

– Things are done in a particular way in the workplace, and at the dining table at home, you don’t feel as if you’re at work, so you drop your guard. When you’re in an unfamiliar situation, you’re more likely to make mistakes, e.g. click on links that you wouldn’t normally click on. At the same time, many people have had their children at home, which can also be distracting, says Anja Kivac.

The same applies to mobile phones where fraudulent text messages have become rampant. Lots of people have ordered more parcels than usual and have, therefore, been more susceptible to text messages about parcel collection. When the person clicks on the link, it turns out to be malicious.

– As many people have not been on the company’s network, but their own, it is primarily private individuals who have been affected, and not companies as a whole. In general, however, the authorities have been quick to detect and warn the public about threats from e-mails and text messages, says Anja Kivac.

Burglaries
It has not just been in the digital world that the Corona-virus has had an effect. Burglars also accepted the advice to stay at home, albeit probably less willingly than everyone else. In Denmark, burglary rates have fallen by a quarter compared to the same period last year. As someone known to the police said during questioning:

– It’s hard to find a house where there isn’t someone at home.

Terrorist threat
On 20 March, the Danish Security and Intelligence Service, PET, issued a new assessment of the threat from terror against Denmark, and this remains at a serious level.

– During a crisis like the Corona-virus, terrorists who may be planning attacks against our country are still out there. But society’s focus changes during a crisis. The intention of terrorism is to attract attention and hit symbolic target or populations. Many public places have been closed and gatherings have been limited, so one would imagine that they are saving their energy and will hold off carrying out terrorist attacks until the crisis has passed, says Jesper Florin, head of the security department at DBI.

However, there has been a slight increase in terrorist-related propaganda online, as many people have been at home and searched for information and knowledge. Various terrorist organisations have tried to exploit this by increasing the flow of information in their online forums.

Container puts out inextinguishable fires in electric cars

 

container-fire2

The lithium-ion batteries in electric and hybrid cars present a challenge to the emergency services if the cars are involved in a traffic accident or burst into flames.  Now, the emergency services in Denmark have developed their own solution.

Cars can burst into flames a long time after they have been damaged. They can be exceptionally difficult to extinguish. They can flare up again and again. They emit combustible and harmful gases.  Water is contaminated and damaging to the environment due to chemicals. Yes, the batteries in electric and hybrid cars present numerous challenges when you look at it from the point of view of the emergency services. This is the conclusion of a new report from the Swedish organisation RISE, which has taken a closer look at lithium-ion batteries in vehicles.

The numerous factors specific to electric and hybrid cars present the emergency services with a number of challenges, which the emergency services in Copenhagen are now tackling. They have designed a container specifically for handling damaged electric and hybrid cars.

– We are seeing more and more electric and hybrid cars in the municipalities we cover. And, it would appear that there will be many more in the future. That is why we must be able to deal with the chemical fires they can cause, says Michael Kim Andersen, Deputy Director of Emergency Services in Copenhagen.

A well-equipped container
The individual cells in a lithium-ion batter can be damaged in the event of a traffic accident or if there is a fire in the car. This can result in the development of heat in the cell, which then spreads from cell to cell – also known as thermal runaway.  A chemical fire in a lithium-ion battery can develop very quickly with shooting flames and harmful flammable gases. Heat can develop several hours after an accident has occurred, and if one cell has thermal runaway, the heat from that cell can cause the neighbouring cell to develop heat too. This way, a single cell can start a chain reaction which can cause the battery to burst into flames a long time after an accident has taken place. The effects of heat from, for example, a fire, can result in the same effect in a cell.

– Batteries are difficult to extinguish, and they can burst into flames again several hours later – in some cases, right up to a week later.  We can’t close roads and motorways for several hours, so if it isn’t possible for us to extinguish the fire in the battery, we may have to remove the car. That’s why we have developed a container for that very purpose, says Michael Kim Andersen.

The container is constructed in such a way that you lift or tow an electric car into it, place the container on the bed of a tow truck and remove the car.  The container has nozzles in the floor and on the walls which can be used to both extinguish any flames and cool the battery – which more often than not, is located under the car – to hamper the development of heat. The water for the nozzles flows round a circuit, which reduces water consumption significantly and makes it easier to collect the water later and send it for cleansing if it has been contaminated by chemicals from the battery. In addtion, there are installations with inert gas in the container.

– A fire in an electric car battery is a chemical fire and does not require oxygen. Therefore, inert gas has no effect on the battery but is intended for the other parts of the car. Indeed, the development of heat from the battery can potentially cause the cabin to burst into flames. And since it’s a confined space – at least until the windows burst – the water can’t get in there. Therefore, inert gas is required to smother the flames, explains Michael Kim Andersen.

Extended period of isolation required
With the container, the procedure in the event of an accident with an electric or hybrid car will be more or less the same as an accident involving conventional cars. It is cleared up quickly and the traffic can keep flowing. However, an electric car can’t be taken to a car breaker or a workshop where it is placed indoors next to other cars, which a fire could potentially spread to. Instead, it can now be left in the container until the risk of it flaring up has subsided.

– We are in dialogue with other authorities to determine where we can put the container when it contains a damaged electric or hybrid car. It must be kept in an isolated and closed area where it can remain undisturbed for a time, says Michael Kim Andersen.

Requires extra vigilance
The container is the only one of its kind in the Nordic region, and the interest in it is high from neighbouring emergency services, who can requisition it on an equal footing with other cars and from abroad. However, it doesn’t meet the challenges presented by electric and hybrid cars on its own. Poisonous gases from the batteries mean that special procedures are required when the fire brigade arrive at fires in electric cars.

– If there is a fire in an electric or hybrid car, we are acutely aware that the smoke may contain hydrogen fluoride, which is extremely harmful. Even small doses can result in water in the lungs. Therefore, we also take the precaution of using fresh air breathing apparatus from a greater distance than we would in a normal car fire, says Michael Kim Andersen.

Batteries in buildings and multi-storey car parks

electrical-car

The number of batteries is increasing, and so is the size of the batteries. At the same time, batteries are used in places that increase risks.

To meet today’s challenges, the fire department in Denmark has developed a container that can extinguish fires in electric cars involved in accidents. However, the container does not meet all the challenges generally presented by electric cars and lithium-ion batteries when they are indoors. When electric cars are parked side-by-side for charging in multi-storey or underground car parks, or when powerwalls or battery banks containing lithium-ion batteries are installed in buildings.

– In a fire in a multi-storey car park containing many cars, or in a battery bank or powerwall in a space in a building, there could potentially be so much hydrogen fluoride in the air that we can’t stay there for more than a few minutes at a time. It hampers effective fire fighting efforts. Also, the batteries expand all the time and accumulate more energy in a small space, and this can present a challenge to the structures of modern-day buildings as they are not build to withstand such a great fire load as the large lithium-ion batteries contain today, says Michael Kim Andersen from the emergency services in Copenhagen.

Therefore, he hopes that the legislators will introduce requirements to ensure that structures can withstand the fire load and prevent fires spreading and, at the same time, ensure that the emergency services have a sound opportunity to operate safely in the event of a fire.

– For example, this could be requirements for more space between electric cars in multi-storey and underground car parks near the exit so that the emergency services can tow electric and hybrid cars out quickly and easily. In the case of powerwalls and battery banks, it may be worth considering requirements for the placement of cars, active extinguishing equipment and adequate passive fire protection, so that a battery fires do not spread to the rest of the building and the poisonous gases can be dealt with safely, concludes Michael Kim Andersen.

Grenfell Tower fire update

grenfell

Flammable facade cladding, incorrect fire ventilation, no sprinkler system, dubious evacuation strategy and fire doors which only held for 11 minutes. There were problems all round when Grenfell Tower caught fire in summer 2017 and 297 people were trapped inside. The latest information about the fire has been revealed at a recent conference hosted by DBI – The Danish Institute of Fire and Security Technology.

Two and a half years after the catastrophic fire at Grenfell Tower in London, which claimed 72 lives, work on the final report is still ongoing. In the meantime, new information is constantly coming to light and contributing to an overall picture of how things could go so wrong. The latest information has been presented at a conference at DBI.

At the conference, it was once again established that the fire started in a fridge-freezer in a 4th floor flat. The fire services arrived after 6 minutes, quickly extinguished the fire and were on their way back when they noticed flames on the exterior of the building. Shortly afterwards, a resident on the 21st floor of the block reported signs of fire. A few minutes later, a resident on the 14th floor reported smoke inside their flat, and immediately afterwards the fire reached the roof of the 23 storey high residential block. It can thus be concluded that the fire leapt 19 storeys in just 30 minutes.

Flammable materials
What had happened was that the fire had reached the facade via the kitchen window at the point where the fire originated and had travelled to the other side of the building and into a bedroom there. That the fire could spread so quickly was due to the fact that the kitchen window reveals were made of uPVC, which became soft and bent from the heat from the fire. This created an opening into the external wall and allowed flames and hot gases to enter the cavity between the building’s insulation and the facade panels, which were a sandwich construction with aluminium on the outside and a polyethylene core.

A chimney effect in the cavity caused the temperature to rise very rapidly. Fire stops mounted in the facade did not work, so the fire was able to move upwards. As the window sashes and frames were of flammable plastic materials, they melted and caught light, after which the fire was able to penetrate into more flats.

– No-one had imagined that a fire would enter the building from the outside. It was thought it would be the other way round, said John Briggs of Britain’s National Fire Protection Association (FPA), who has participated in the work on one of the Grenfell reports.

A string of problems
But this was not the end of the chain of unfortunate events. The ventilation system in the stairwell also failed to work as it should. Moreover, it was only designed for extracting smoke from one floor at a time, as the assumption was that a fire would only come from one flat. Subsequent testing of the fire doors in the building shows that they could only withstand a fire for 11 minutes.

– The evacuation strategy also had a role in the number of fatalities. In accordance with the so-called ‘stay-put’ policy, residents were instructed to stay in their own flats as long as they were not on fire. The flats were designed to prevent fire spread, and it was wished to avoid hundreds of residents heading down a narrow stairway while firefighters were on their way up, Briggs explained.

Only at 2:35 a.m. – one and a half hours after the fire services were called out – did the fire control centre change tactics and began to ask residents to leave the building when they rang the emergency services. At 8:00 a.m. the last surviving resident was evacuated.

Investigations have shown that at least the smoke alarm system worked as it should.

Would a sprinkler system have helped?
One of the subsequent questions has also been whether sprinkler systems would have made a difference. Here the experts behind the reports are somewhat in doubt.

– If a sprinkler system had been able to put out the fire before it reached the facade, this may possibly have been sufficient to control the fire. But, if all four sprinkler heads were triggered, there would only have been water for three minutes. In addition, to activate a sprinkler system, there would have to have been more flames and much higher temperatures than was the case, Briggs noted, observing that:

– As the fire services had already arrived after six minutes, sprinkling would have made no difference.

After the accident, sprinkler systems were installed in all high-rise buildings in England. This took nine months and cost 9 million pounds.

Government denies responsibility
The official report indicates that there is strong evidence that the building’s external wall construction did not meet the requirement for adequately preventing fire spread in relation to the height, use and location of the building. The British Government has thus commissioned a second report to define the regulatory changes needed to prevent similar accidents. However, the government denies any responsibility and refers to incompetence among those involved as the cause of the disaster. According to John Briggs and the FPA, however, the problem is that building legislation is out of date.

– We have not had a proper review of UK building regulations for more than 15 years. Modern building methods mean you can build pretty much what you want, because the building legislation does not compel you to do so in a specified safe way. No-one checks that the components for preventing fire spread are made properly, and the legislation does not touch on how to produce them, Briggs said, stressing that construction players will not change until they are forced to do so.

The final report with recommendations for changes is expected to be completed by the end of 2020.

Fire and explosion in battery compartment in Norwegian hybrid ferry

Brand-på-hybridfærge

In October, the Norwegian hybrid ferry “Ytterøyningen” was hit first by a fire and then an explosion. The cause of the fire is still unknown, but the incident has resulted in increased focus on other hybrid ferries which are in operation.

In the early evening on 10 October 2019, fire broke out in the battery compartment on the Norwegian hybrid ferry “Ytterøyningen”, which runs the route Sydnes-Halsnøy south of Bergen. The fire department and the police were alerted, and the fire was declared under control a couple of hours later. 15 people were on board, of which two needed to be checked by a doctor due to suspicion of smoke inhalation.

However, at 7:00 the next morning, the ferry was shaken by an explosion in the battery compartment which was so powerful that the car deck was pushed up. Now, a couple months later, there is still no official accident report from the Norwegian authorities of the incident, so the cause of both the fire and the explosion are still unknown. Still, several experts have come forward with some general assessments.

– The battery pack on Ytterøyningen was just under 2,000 kWh, which according to DBI’s experts in lithium-ion battery-fires suggests that the fire was not in the battery itself. This is because fires in much smaller batteries can take several days to extinguish. Therefore, the fire probably started somewhere else and then spread to parts of the battery compartment, says Carsten Møller, who is a business developer at DBI, the Danish Institute of Fire and Security Technology.

Disconnected BMS
In addition, yet another unanswered question is whether thorough ventilation of the battery compartment was initiated after the fire was extinguished, since a damaged battery can leak explosive gases. Even minor physical damage on the battery can develop, posing problems over time, since chemical reactions in some of the materials can occur.

– However, this is usually not a problem, since the battery management system (BMS) normally alerts in good time, e.g. of gas formation and increases in temperature, says Carsten Møller.

Still, after the fire, it has now emerged that Ytterøyningen’s battery pack was not in use or connected to the management system during the two weeks prior to the incident.

– Large batteries are to be handled in accordance with the so-called SoC rule (State of Charge) if they are not connected to a battery management system, which in practice means that the battery must be discharged to a certain level. Therefore, the question is also how much the battery was discharged during the period when it was not connected to the battery management system, says Carsten Møller.

New recommendations
While a clarification of the cause of fire is being prepared, the Norwegian Maritime Authority recommends that battery packs on ships must always be connected to a battery management system, also even if they are not used for a period of time.

Whether the incident has consequences for some of the other hybrid ferries in operation is difficult to predict as long as the cause of the fire is still unclear. Work is currently being done in Norway on a conversion of the country’s many small ferries to battery power. Thus, 60 ferries are expected to run on battery power by the end of 2021.

Take human behaviour into account, and improve your fire safety

ship

New knowledge about human behaviour can be applied to the design of ships and their fire safety plans. This leads to more safety and minimises the risk of lives and assets being lost.

It is not enough to look to preventive measures and technical solutions if you want to ensure fire safety on ships. If you solely focus on this, you are not taking into account the most frequent cause of fires – human behaviour. Experts from the US Coast Guard believe that this is the cause of almost all fires on ships. If you take behaviour into account, however, you can make more realistic risk assessment and make better plans for the fire strategy – and safety.

– It leads to better fire safety, and we expect this will lead to less casualties in the event of fires and less assets being lost. But it requires a great deal of knowledge within the area, and we haven’t had that before now, says Thomas Hulin, Project Manager at DBI – The Danish Institute of Fire and Security Technology.

Small factors with great consequences
That knowledge has been gained through anthropological studies of human behaviour during incidents at sea. It has provided DBI with insights into a number of factors that are not covered by any guidelines, but which have significant consequences in the event of a fire. For example, a ship’s fire safety strategy is based on every crew member knowing precisely what to do if a fire breaks out. But the training for that might have taken place after the members of the crew had just flown halfway across the world to sign on – in other words, at a time when they were not really ready to be instructed.

Another example is that different cultures and languages found among a multinational crew makes communication difficult during a fire. Or perhaps spaces are being used in a different way that the fire strategy requires – for example, flammable materials might be stored near a potential source of ignition. Each of those examples may have far-reaching consequences for whether a fire will occur and spread.

A holistic approach leads to better safety
The new knowledge makes it possible to add the human factor to the fire strategy and to take it into account when designing ships.

– It makes it possible to have a holistic approach where you don’t just focus on technical solutions and regulations, but also focus on how people act and react. It leads to far more realistic scenarios and can, among other things, be used with the FMEA methodology (Failure Mode and Effects Analysis). The robust experience on the area can be translated into specific designs, and even the early design will allow one to see where the critical points will be, says Thomas Hulin.

Delayed alert cost Notre Dame dearly

notre-dame-cfpa

During the fire at Notre Dame in Paris, alerting the fire department was delayed by approx. 25 minutes. This time-lapse may have meant that the fire went from being a problem to a catastrophe.

A complex technical fire safety system, no direct connection to the fire department, human error and a delay of approx. 25 minutes seem to be the reasons why the fire which ravaged Notre Dame in Paris in April had such grave consequences. Now that the smoke had dissipated, the task of identifying what happened has commenced, and several interesting things have emerged from the ashes and been reported in the newspapers Le Monde, Le Canard Enchaîné and the New York Times.

As a national treasure, Notre Dame had its own fire alarm system. It was a rather advanced system which had been developed and designed specifically for the church over a period of six years. Among other things, it consisted of an aspiration system which was installed in 2013 with detectors on the ceiling of the church where the fire broke out. And the system was functional. Because when the fire began to develop, presumably as a smouldering fire, it gave off an alarm.

The fire department was alerted after 30 minutes
But unlike automatic fire alarm systems in some other countries, it was not connected directly to the fire department. Instead, the alarm went directly to the church’s own fire-detection unit. And it was not just any alarm. The complex system sent an equally complex alarm: “Attic Nave Sacristy ZDA-110-3-15-1 aspirating framework”. This referred to a zone in the church and a specific detector which had gone off in a system of more than 160 detectors and manual alarms.

The employee who manned the system and received the alarm had been on the job for three days and was on his second consecutive eight-hour shift. He misinterpreted the alarm and sent a guard to the loft of the small sacristy, which is next to the church itself. He also called his manager who did not pick up the phone. It took 25 minutes after the first alarm went off before the manager called back, the error was discovered and the guard was sent to the ceiling of the actual church. He then quickly instructed the church’s own fire-detection unit to call the fire department. By this time, 30 minutes had passed since the first alarm had gone off, and 25 of them had been wasted by searching for a fire in the wrong place. In the meantime, the fire had begun to spread undisturbed in a loft which was constructed from oak beams which were several hundred years old.

A fatal delay
This is a critical time delay in relation to what emergency services can do in the event of a fire.

– In a building of this age, the difference is whether a fire can be extinguished or merely controlled, says Tim Ole Simonsen, who is Director of Operations and Fire Chief of the Greater Copenhagen Fire Department.

He emphasises that he is not familiar with the exact details of the sequence of events of the fire in Notre Dame, but adds:

– A delay of this calibre will typically mean that there is a lot of smoke which makes it difficult to get to the fire, and there may be the danger of the structure collapsing. If you arrive quickly, you can sometimes extinguish the fire at an early stage. If more time passes, putting the fire out can take 12-24 hours. A delay of 25 minutes is fatal in this respect.

Few false alarms from modern systems
When automatic fire alarm systems in France do not automatically alert the fire department, it is because they do not want to respond to false alarms. Therefore, an alarm must be investigated and confirmed before the fire department is alerted.

– When the systems were introduced many years ago, it is likely that it was taken into consideration whether they should be connected directly to the fire department. But modern automatic fire alarm systems can actually be calibrated so that they never give false alarms in practise. The system in Notre Dame was modern, and for this reason, false alarms should not have been expected from it. It may seem strange that the fire department was not alerted immediately. Roof fires develop in seconds, and a delay of 20-30 minutes is a long time in this context, says Tim Ole Simonsen.

High density fireproofing of cannabis

Cannabis Drivhuse

Cannabis is being legalised in an increasing number of countries worldwide. Not least in the USA where, up to now, cannabis for recreational use is legal in 10 states. Also, cannabis is increasingly being legalised for medical use. However, the production of cannabis can entail a number of potential fire hazards that we do not experience in the cultivation of other plants.

The increasing legalisation of cannabis means that, in future, there will be production facilities that cultivate hemp plants on an industrial scale. But, growing cannabis is not the same as growing lettuce or watercress. To grow optimally, the plants require very specific conditions, and these conditions can result in fire technical challenges. Therefore, in the USA, they have drawn up guidelines aimed at facilities for producing and extracting cannabis.

– It’s interesting to take a glance at this because they have had legal production facilities over there for a couple of years now, and they have identified several elements of danger, says Mikael N. Gam, a fire safety consultant with DBI, the Danish Institute of Fire & Security Technogogy.

Heat, CO2 and alcohol
Some of these dangers are related to the plants’ need for light. They require light for up to 18 hours a day, and it must be full-spectrum, which is typically achieved by means of incandescent bulbs, which also emit a great deal of heat.

– In addition, it also requires the addition of CO2 to the air in order to ensure optimal photosynthesis, which means gas bottles, which in the event of a fire pose a risk in themselves. Furthermore, the equipment poses a risk of leakages and carbon monoxide poisoning in the event of a fire, says Mikael N. Gam.

On top of that, the plants grow quickly, and this can make it difficult to gain an overview and hamper the fire fighters’ visibility in their efforts to extinguish the fire.  At the same time, the plants are moved around the production facilities, depending on their size, which can block access routes and escape routes.

– When it comes to extracting the substances in the plant, this is done in the production facility with the help of flammable substances, for example, methane, alcohol or CO2. In addition, the production facilities are often protected against theft and break-ins, and this protection must be arranged in such a way that allows the fire fighting service to gain access quickly in the event of a fire, adds Mikael N. Gam.

Newer, but not more dangerous
Therefore, the task in hand is to deal with all the potential fire technical challenges. There is no single solution, but it is important to think about the layout thoroughly. Moreover, the fire fighting authorities must be aware of any particular risks when they respond to an emergency.

– There are aspects of cannabis production that can lead to problems when it comes to fighting a fire. It is not, as such, any more dangerous than many other things, but it is a new area and therefore we should perhaps take a look at the American guidelines in the area, concludes Mikael N. Gam.

The world’s tallest and safest timber building

Mjoestaarnet-1

The prestige building, Mjøstårnet in Norway, proves that timber can be used when building to a height. The level of fire safety is high with a number of passive measures and a reinforced sprinkler system, which also covers parts of the facade.

In Norway, the world’s tallest timber building is located. It is called Mjøstårnet and was completed in March 2019. The supporting structure comprises enormous glued timber pellets. The stairway and lift shafts are of CLT (Cross Laminated Timber). The same material was also used for the balconies on the upper storeys. The storeys up to the 11th floor comprise a building system of timber and rock wool. And, of course, the facade is also timber.

– Even though we have extensive experience in building with timber in Norway, Mjøstårnet is an unusual building, says Even Andersen, Senior Fire Engineer in Sweco in Norway and fire consultant for Mjøstårnet.

– It is a prestige project in the field of building with timber. The rules in the area have been the same for many years, but it has only been within the last few years that we have started to build to a height with timber. The environmental and climate aspects are of crucial importance in this development, he says.

Withstands a natural progression of a fire
Another aspect that has to be taken into consideration when building timber tower blocks is fire safety.

– The organisation of fire safety is function-based, and takes as its point of departure the presumption that the building must be able to withstand a natural fire progression, which we have modelled on the basis of Eurocode 1, and which takes account of the timber’s contribution to the fire, says Even Andersen.

The pre-accepted solution stipulates that the supporting structure in taller buildings must be non-combustible and be able to withstand a fire for 90 minutes. In the case of Mjøstårnet,  it was decided that the construction must be able to withstand a natural fire progression which corresponds to a standard fire of less than 90 minutes. Moreover, the building must be able to handle a standard fire for 120 minutes.

– All scenarios and fire progressions have been calculated and are far shorter than 90 minutes. Moreover, the supporting structure has an even greater resistance to fire than we assumed was needed, explains Even Andersen.

The fire safety documentation is controlled by a third party, and even though the emergency services do not have a regulatory authority role in Norway, they have been involved in the dialogue along the way.

A timber frame remains
In connection with the construction, Sweco had fire tests carried out on the glued timber pellets of which the supporting structure was to comprise. The pellets were tested by SP Fire Research and were exposed to the ISO Standard fire curve for 90 minutes. The test showed that the pellets developed a carbonised surface which protected the underlying timber against the fire. And, when the furnaces were turned off, the carbonisation stopped by itself after a while.

– The glued timber pellets are of considerable dimensions, and a relatively small section of them burns away in a fire. Therefore, they are fairly resistant in a fire. Also, they are self-extinguishing if there is nothing around them to feed the fire. Based on the tests, we have calculated that, in a fire that is not tackled but is allowed to develop and burn out, the supporting structure maintains its resistance and leaves behind a timber frame, even if the rest of the building burns away, says Even Andersen.

Its excellent properties mean that the glued timber pellets do not require any further protection or covering, but that they can be visible in the tower’s interior. Any visible timber in escape routes and the stairwell has been fireproofed.

A multitude of fire sections and cells
The weak points in the structure are the steel plates and the dowels placed at the pellet joints. Therefore, spaces and gaps around the joints are endowed with a material that expands at 150 degrees and protects the joints. Each storey constitutes its own fire section, and every single hotel room and apartment is its own fire cell. Every horizontal division structure is dimensioned to be able to remain standing if the overlying horizontal division structure collapses. The horizontal division structures for the top floors are made of concrete, but not because of the fire risk – the concrete adds extra weight to the building, which prevents it swaying too much and making the residents feel ill.

– The facade has been fireproofed and consists of elements which all have cavity barriers in the event of a fire in the cavity. In addition, there are cavity barriers over all the windows, adds Even Andersen.

The swimming pool is a reservoir
On the active side, the building has full sprinkler coverage with a reinforced sprinkler system which also covers the lowermost storeys of the facade in order to prevent incidents due to pyromania or criminality. The communal water supply is good and ensures an abundant supply of water under normal circumstances.

– If extra water is required, the swimming pool – which is part of the building and lies up and down the tower – functions as a reservoir. That is a rarity in Norway, says Even Andersen.

The building also has an automatic fire alarm system with a direct connection to the local emergency services and riser pipes in all stairwells, which have been dimensioned to enable the emergency services to fight the fire from just one of the tower’s stairwells. The stairwells are equipped with overpressure relief valves, and there is also a control room from which the emergency services can easily survey the building and see exactly where the alarm has gone off and where the sprinklers have been triggered.

– Building to a height with timber does not go without its risks, and you have to know what you are doing. Mjøstårnet is located in rural surroundings and it is completely different from building in, for example, the middle of the city where the risk of the fire spreading is different. So, even if it is possible to build to a height in timber, that doesn’t mean that it is always the right thing to do, concludes Even Andersen.

Wild fires in the USA mobilise the fire brigade’s elite troops

Skovbrande-i-USA

Every year, wild fires cause havoc in the USA. They cause people to flee, cost billions and can continue for weeks. When such a fire needs to be brought under control, the authorities enlist the help of the elite firemen – also known as ‘hotshot crews’.

In the USA they have a season we don’t have in Europe: Fire season. This is the time of year when  cause havoc, particularly in the western part of the USA. In 2015, they had the worst season ever, when more than 40,400 km2 went up in smoke. And in 2018 it was even more disastrous, with the fires in California resulting in many fatalities.

More frequent droughts and increasing temperatures as a result of climate change only make the problem much worse. Therefore, combating wild fires in the USA requires a massive effort. And that massive effort in particular is what the so-called ‘hotshots’ provide. They are the fire brigade’s elite troops who specialise in wild fires and are called on to fight the worst and biggest wild fires all over the USA. In the wilderness they create ‘fire lines’ – i.e. Fire belts in the terrain, the purpose of which is to limit the spread of the fires. This is done by hand – using power saws and axes – or by means of controlled burning, when the direction of the wind is favourable.

The most dangerous tasks
There are around 100 hotshot crews in the USA, each of which comprises 20 firemen. They undergo intensive training in all forms of fire fighting tactics, and the physical requirements are rigorous.  Normally, they are sent out into the wilderness without logistical support in order to create fire lines in shifts lasting up to 48-64 hours for several weeks in a row.

The firemen in every hotshot crew each have their own roles to play. Some of them are trained in first aid, while others are highly specialised lumberjacks who are able to cut down dead or burning trees. Others create fire lines by cutting down vegetation bordering the fire and moving the cut down trees into the fire.

They risk their lives
It is dangerous work, so even if you are one of the best, every now and again it costs human lives. Therefore, all hotshots carry a ‘fire shelter’ which they can use if the fire encircles them. It is designed to withstand flames and radiant heat and contains sufficient breathable air so that the fireman, in an emergency situation, can roll out the fire cover, crawl into it and survive.

However, there are no guarantees. In 1994, nine hotshot member perished in the flames in Oregon when a rapidly moving fire engulfed them. And in 2013, a particularly rapidly moving and violent fire cut a hotshot crew off from their escape route in the wilderness in Arizona. The fire spread more quickly than the crew were able to run and the violent wind created 70 metre high flames and temperatures of approximately 1,100 degrees. The crew were encircled and all of them perished.

If hotshots are the elite troops, smokejumpers are the parachute troops. They jump out of an aeroplane instead of driving or trekking to the fires. The rapid mobilisation means that they can often contain the fire before it grows too big and gets out of control.