A fire can become life-threatening within a few minutes. The Finnish company Fläkt Woods Oy has developed equipment for residential blocks of flats that saves human lives by keeping toxic combustion gases at bay.

When a fire starts in a block of flats, panic generally breaks out. People rush from a burning flat, leaving the door to the stairway open. This only gives the fire more air, the stairs fill up with smoke and rescuing others living in the building via the stairway becomes almost impossible.

According to the fire brigade, people know how to be afraid of fire, but not of smoke. However, once a flat starts burning, large amounts of hazardous toxic combustion gases may spread to the stairway within a few minutes.

“There is a solution to the problem,” stresses fire expert Raimo Perttunen from the ventilation company Fläkt Woods Oy. A method that the company has developed is based on the idea that smoke control is an important part of fire safety.

Good visibility

When a fire breaks out, Fläkt Woods’s equipment starts automatically with a signal given by smoke detectors in the flat. Within twenty seconds there is overpressure in the stairwell in the building that prevents the smoke from spreading from the burning flat.

A fan installed on the roof of the building operates in two directions. In addition to producing pressurization in the stairway, the equipment revolves in the reverse direction and extracts the smoke.

“The pressurization keeps the stairway smoke-free and safe for escape. When the fire brigade arrives, visibility on the stairway is good and the firefighters are able to extinguish the fire in the flat quickly,” Perttunen says.

The pressurization technique has traditionally been used only with high buildings more than eight floors high. Most residential blocks of flats, however, are lower. Fläkt Woods’s fire safety solution can be applied to buildings with a maximum of eight floors.

Successful testing

Fläkt Woods tested the new equipment together with the VTT Technical Research Centre of Finland in real fire conditions in Helsinki in February. A one-room flat in a building that was going to be demolished was fitted out with typical personal property: a bed, sofa, bookshelf and television.

The flat was set on fire, and then observers followed how the pressurization on the stairway was able to push the smoke coming out of the flat back into it – including when the flat’s front door was open.

The test came up to expectations. Visibility in the burning premises was good thanks to the pressurization, which made it much easier for the firefighters to attack the blaze. The stairway remained almost smoke-free all the way through the extinguishing work.

“The total price of the tested system is some ten thousand euros for a stairway. The investment saves human lives, minimizes physical damage and protects the working conditions of fire fighters,” Perttunen emphasizes.

Targets of fire safety 1. Saving the lives of human-beings 2. Minimizing physical damage 3. Protecting the working conditions of firefighters

>> www.flaktwoods.com

Fläkt Woods Oy tested its fire-safety solution in Helsinki in real fire conditions in February.
(Photo: Fläkt Woods Oy)