Experts call for stricter rules for gasbussar

Just before lunchtime on Sunday collided with a SL-bus with an obstacle when it was on the way down in the klara tunnel. The clash led to a massive explosion – just next to the government quarter. The bus then adopted fire and became in a short time is completely burned out. At the time there was only the driver on board and he managed to get out on their own. He was injured at the time, but the injuries were not life-threatening.

the Government convened on Monday to a säkerhetsmöte with the reason of the explosion. Among others, the Swedish transport agency, Swedish civil contingencies Agency, MSB, Swedish Municipalities and county councils, SKL, to participate in the meeting which is being held on Friday.

– It is important that we get a quick assessment from the responsible authorities, not least from the municipalities who are responsible for the purchase of very many gasbussar. I want to make sure that we do the right safety, says minister for infrastructure, Tomas Eneroth.

has occurred in or in connection to the klara tunnel in the past. On two occasions it has been just gasbussar that have been affected. According to the two experts that DN has spoken with have been lucky that none of the events have led to major damage.

The other sessions have been more dangerous. Then the buses drove into the tunnel, which did not happen this time. The bit is bortbyggd now. But it's a little alarming that you don't have to come to terms with it yet, " said Erik Egardt, fire protection engineer at Swedish civil contingencies Agency, MSB.

occasions kilades buses stuck in the tunnel and gas tanks on the roof began to leak – but exploded never. Had they done so, had it been able to lead to great havoc.

According to Erik Egardt, there are two scenarios when the damaged gas tanks can be dangerous. In the first case, it happens that happened on Sunday: a sharp collision get a tank to explode. And if the event occurs inside a tunnel, the effect becomes even worse.

" It's like being in the barrel of a gun. And there is rarely only one tank, but several. So then, you can get more explosions. You can get away from accidents in these tunnels so much of a success, " he says.

first comes a blast wave that can throw away objects, and smash the window. A secondary effect is that the tank itself is torn apart by the explosion itself can cause damage when it with great force thrown out.

next comes the effect from the gas, which is in the container is compressed to a pressure of about 200 bar. Since the gas in the mode expands and mixes with the surrounding air reaches the shortly thereafter a location where the gas mixture is, in turn, can lead to a new explosion.

"Then it's enough with a spark, a hot surface, or contact with electricity in order to ignite and become a huge fireball," said Erik Egardt.

a number of gas tanks on the roof, and each tank is equipped with a safety relief valve – a so-called safety fuse – bailing out during a fire to avoid an explosion. The valves are designed so that they solve out first at 110 degrees celsius and shall, therefore, at a normal fire give plenty of time to evacuate the bus. But the valves can also pose a danger in itself, " says Tommy Carnebo, a fireman and an expert on vehicle fires.

– It turns out that a svetslåga from these valves. From a regular gas-powered car becomes six feet long. From heavy-duty vehicles can the flame be 20 metres.

Tommy Carnebo also tells us that there are no rules for inspection of these valves – which means that sometimes you can not guarantee their function.

that burns, the risks are greater for the explosion bigger when they are gas-powered. Therefore, Tommy Carnebo that there is also a need for emergency services to be able to quickly determine if a gas-fired vehicles or not.

– A regular car will not explode. But can these vehicles do. We need to get to a regulatory framework to check what it is for vehicles. We work in a completely different way with a gas-driven car than with others.

it is, according to both Tommy Carnebo and Erik Egardt important to consider the direction in which the pressure relief valves are addressed. In an extreme event may the flame represent a mortal danger.

– To get into the flame in a building, it is not a dream scenario, " said Erik Egardt.

At present, there are no rules regarding how such valves should be targeted, according to both Tommy Carnebo and Erik Egardt. Both mean that the rules that apply to a gas-driven car will need to be reviewed so that serious accidents can be avoided in the future.

" We have been spared so far. But you can not drop the sandwich with the jam up every time, " says Erik Egardt.

the new bus terminal to be built in Katarinaberget also kravställt to the valves on the gas tanks should be pointing upwards, " says Aleksander Krajisnik, presskommunikatör on SL. But when it comes to major rule changes in this area so he refers to the parliamentary and EUROPEAN level.

– This is a dialogue that takes place today at the EU-level, and such initiatives should be initiated there. As regards legislation, it must come from the government and parliament, " says Aleksander Krajisnik.

(M), trafikregionråd in the Region of Stockholm, says that he looks serious on the Sunday's accident and says that an investigation has been initiated.

"I was already yesterday in continuous contact with traffic management to comply with the urgent events but also to assure me that such an investigation is something that is added," says Kristoffer Tamsons.

He says that it is about ”safe issues relating to safety, procedures and training in the large” and some other similar issues.

– Environmentally friendly vehicles of this type – heavy vehicles – is here to stay, and it applies irrespective of buses, trucks, garbage trucks or all Finlandsfärjor. Can be wise to periodically take a comprehensive grip on these issues, " says Kristoffer Tamsons.

" I know that it is safer to go SL-bus than to walk the streets of Stockholm. I went myself biogas buses both in the morning and at lunchtime today and know that these accidents and incidents are extremely rare in the stockholm traffic.