An explosion registered on Tuesday afternoon in a building in Poblenou forced the evacuation of several residents and caused a subsequent fire. The exact origin of the incident is under investigation by the Mossos d'Esquadra.
The main unknown revolves around butane cylinders. Jordi Sans, president of the Security Commission of the College of Industrial Engineers of Catalonia, maintains that butane cylinders do not explode under normal conditions and places the most probable hypothesis in a gas leak accumulated inside the dwelling.
Jordi Sans places accumulated leakage as the most probable hypothesis
Sans explains that a deflagration can occur if butane gas concentrates in a closed space within the explosivity range. In that scenario, the accumulation can cause damage and injuries, even if the cylinder does not explode.
"What could have happened is that there was a butane gas leak and that, if it accumulates, it can cause a deflagration and cause damage and injuries, but butane cylinders, except in exceptional cases, do not explode" - Jordi Sans, president of the Security Commission of the College of Industrial Engineers of Catalonia
The expert points to two possibilities for that leak inside the Poblenou dwelling. It could be due to a failure in the connection pipe or human error in leaving the gas open.
Even so, Sans emphasizes that butane installations have the same level of safety as natural gas or an electrical installation when used correctly. He also underlines that the danger does not depend so much on the volume released as on its concentration in a closed space.
Black smoke points to a fire after the explosion
The column of black smoke seen after the explosion fits, in Sans's opinion, with a fire after the deflagration. The expert considers it usual that, after a combustion of that type, a fire originates.
"From the black smoke that has been seen, it seems there has been a subsequent fire" - Jordi Sans, president of the Security Commission of the College of Industrial Engineers of Catalonia
The investigation must now clarify what triggered the accident and whether the leak occurred in the connection, in the manipulation of the supply, or for another reason. That determination corresponds to the Mossos d'Esquadra.
Sans also recalls that butane gas can be detected by its smell, which allows action to be taken before it reaches a dangerous concentration. It also recommends storing the cylinders in ventilated places and at appropriate temperatures, as well as paying attention to noise and other signs of leakage.
If someone detects a leak, the first measure is clear. Jordi Sans summarizes the immediate guideline with a specific instruction: first you have to ventilate the area and not light any flames.