Chimney effect Grenfells unusual design led blaze to spread say investigators
“The greater the gap, the more it acts like a chimney. It is one line of the investigation.” Grenfell Tower Block FireCredit:Eyevine Grenfell Tower was fitted with combustible cladding and flammable insulation. The insulation was fitted between the original concrete pillars and the external aluminium cladding with a plastic flammable core used for rain protection.The source said: “The investigation is not just looking at the materials but the design of Grenfell Tower. The triangular shape created by the cladding has created a void and the flames have shot up the side. Grenfell Tower was built in 1974 and the concrete pillars that ran up its side are unusual. That may give some crumb of comfort to residents in other tower blocks that have also been clad.If the unusual design was central to the speed of the inferno, residents in other tower blocks may feel more reassured. Fire investigators believe the unusual design of Grenfell Tower created a chimney effect that led to the fire engulfing the building in minutes.A well-placed source has told The Telegraph that cladding placed over ‘triangular’ shaped concrete columns may have created a void which sucked up the flames. A total of ten columns run up the sides of the building with a further column at each corner. Investigators now believe that when those columns were fitted with cladding, they could have created an air gap that acted as a chimney.Videos of the blaze clearly show the flames spreading upwards far faster than they spread sideways. Investigators are looking at whether fire breaks were built in to the newly clad columns. Given the speed the fire spread up the side of the building that appears unlikely. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.