Development of the fire

It appears that the fire fighters used the stairs to reach the 21st Floor. Nothing has been said of their efforts to connect to the dry riser system or its effectiveness in relaying water to the 21st Floor (about 75m above ground). By the time the firemen intervened, fire fighters were not able to control the fire from the inside. By 01:00 they had retreated and adopted a defensive mode; wetting down the facades of adjacent buildings to avoid fire spread.

By about 01:15 the fire had spread to most of the floors above the 21st Floor, resulting in a 10-storey blaze. Soon afterwards the first chunks of facade started falling off, taking the perimeter bay of the RC slab with it in places. The spread of fire downwards was gradual at first, probably due to burning embers dropping through services penetrations, through slab edge openings and through other openings in the concrete slabs caused by core wall expansion.

The fire led to the collapse of virtually all the slab edge bay above 17th Floor as well as one internal bay on the north side. The transition floor resisted the impact of the partial collapses. Below this level there was substantial structural damage and deformation, but no significant collapse.