Your article (NCE last week) about the fire at Torre Windsor in Madrid quotes fire engineering specialists saying that aluminium framed curtain walling 'could disintegrate completely in 30 minutes'.
There is a misconception among structural and fire engineers that all aluminium framed curtain walling is part of a one-type family and behaves exactly the same.
This could not be further from reality. Just as different types of structural frame and floor types behave in different ways, the same is true of curtain walling. Making sweeping assumptions about how curtain walling behaves can only lead to errors being built into designs.
For decades facades have been seen as a 'non-structural' element of the building and their design has been left to the architect to muddle through with the cladding subcontractor. Facade design is pushed back in the design process and isolated from the 'structural and fire engineering design process' until a cladding subcontractor is appointed - which could be years after the design is concluded.
Generalisations about how curtain walling may respond in fire therefore have to be taken with a good pinch of salt.
Often it is no more than guess work or is based on inaccurate computer simulation.
Stephen Tanno (M), stephen. tanno@schneiderfacades. co. uk