Photo: Christian Bjørøen Hvatum, Drammen Municipality. A combination of heat, drought, wind […]
Photo: Christian Bjørøen Hvatum, Drammen Municipality.
A combination of heat, drought, wind and dense wooden housing on a slope was probably the reason why a recent fire in the small southern Norwegian town of Krokstadelva was able to spread so quickly. A similar fire could also occur in Denmark, but it would be unlikely to reach the same scale, according to DBI fire safety consultant Marcello Francati.
When a fire develops catastrophically, it is usually due to a combination of several unfortunate circumstances. That was probably also the case with the fire in Krokstadelva, which broke out in the afternoon of 17th July and, in record time, destroyed more than 100 of the town’s old wooden houses. Fortunately, no one was injured or killed, but 400 people had to be evacuated in what has been described as the largest fire in Norway in recent times.
“Wooden houses on a forested slope, combined with wind, high temperatures and extremely dry vegetation, are all factors that together can have fatal consequences if a fire breaks out. It is not rocket science that things can go seriously wrong under such conditions, because the fire spreads with the wind up the slope and only loses strength when it reaches the top,” says Marcello Francati, fire safety consultant at DBI and a former firefighter.
It is not yet known what caused the fire, but according to Norwegian media, it behaved almost explosively. Several of the affected houses had gas cylinders stored for their barbecues, and it is therefore assumed that these may also have contributed to the development of the fire.
Difficult firefighting operation
“The firefighting operation will certainly not have been easy in the hilly terrain, where fire engines may have struggled to gain access, and heavy equipment and large-diameter fire hoses will have been needed to fight the fire effectively,” says Marcello Francati.
For the same reason, helicopters were also deployed to fight the flames from the air, while excavators attempted to remove concrete and burnt timber to create access to the fire. During the first 24 hours, more than 800,000 litres of water were used in the firefighting operation. The water was taken from the nearby lake Svarttjern, located in an area surrounded by forest above the burning neighbourhood.
“We do not know whether the water supply was also a challenge. But in general, it can take time to get an adequate water supply to the hose lines, just as it can take time simply to gain access to sufficient quantities of water. And time is exactly what you do not have in a situation like this,” says Marcello Francati, who also points to the emergency services’ use of firebreaks in the firefighting operation:
“Wind can cause a fire to spread faster and farther than you might expect. That is why emergency services often establish so-called firebreaks, which need to be placed in the right locations so that they can get ahead of the fire and prevent it from spreading further. Unfortunately, this can mean having to abandon some rows of houses and concentrate on buildings that can still be saved. It is a difficult manoeuvre that rarely earns you much praise as a firefighter.”
Over the course of the next few days, however, the more than 60 firefighters finally succeeded in bringing the fire under control. But the fire risk remains due to heat in the ground, embers beneath the burnt buildings and the hot weather. The emergency services therefore remain in the area.
Dense development
Under Norwegian building regulations, the general rule is that there must be at least 8 metres between detached buildings in order to limit the risk of fire spread. However, the distance can be smaller if buildings are constructed with special fire safety measures, or if they are terraced houses or attached dwellings – as was the case in parts of the Norwegian neighbourhood that was destroyed.
“Many older buildings in Norway are located closer together than would probably be the case if they were built today. They were constructed in accordance with the building regulations that applied at the time and are therefore still legal, even though they may not meet today’s requirements,” says Marcello Francati, while also pointing out that fire safety in Norway’s existing building stock has been strengthened in recent years:
“More fire safety systems have been installed in older buildings, including churches, and some private homes now also have hose reels. But Norway continues to build with timber. Therefore, it is difficult to identify which of the factors that contributed to the severe fire spread could realistically be removed from the equation in order to prevent a similar fire,” he says.
Differences between Norway and Denmark
In 2009, Norway launched an ambitious national prevention strategy with the clear aim of reducing the number of fires and bringing the number of fire-related deaths down to zero.
“In Denmark, a national prevention strategy was not presented until 2017, after several stakeholders in the industry, including DBI, had prepared a joint proposal. The aim was to strengthen the culture of prevention and reduce the number of serious accidents, including fires. Unlike the Norwegian strategy, however, the Danish strategy did not contain the same specific and measurable targets,” explains Marcello Francati, who, nevertheless, believes that Denmark is unlikely to experience a fire on the same scale as the one that unfolded in the southern Norwegian town:
“We do not have the same tradition of building with timber as they do in Norway. And in Danish holiday-home areas, where there are many wooden houses, the houses are generally not located right next to one another as they were in the Norwegian fire. At the same time, our landscape is much flatter, meaning that a fire cannot move uphill and accelerate in the same way.”
“My assessment is therefore that we can certainly experience a serious fire with extensive spread if several unfortunate factors occur at the same time. But I find it difficult to imagine a fire in Denmark developing into a scenario in which 100 houses are lost,” concludes Marcello Francati.
The fire in Krokstadelva
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