Did Grenfell cladding meet standards, and were the standards right?

SIR – I heard on the BBC news that the cladding specified for the outside of Grenfell Tower was changed to a cheaper variety for the recent refurbishment. The implication was that, being cheaper, the cladding’s fire-retardant performance was necessarily inferior, and that cutting costs in this way contributed in part to the tragic loss of life.

Let us have some clear thinking on this matter. The critical issues are: did the cladding as installed meet the required performance standards? And are these standards appropriate for such high-rise tower blocks? Anthony Metcalfe

Ashtead, Surrey

SIR – We are amazed that aluminium has been used as part of the cladding for tall buildings.

Let’s look at the chemistry. Aluminium is naturally coated with an impervious film of aluminium oxide. Thus, in the solid state, aluminium is not in contact with the air. So, we can use aluminium saucepans on top of a gas ring to boil vegetables; you might even get away with it if there were no water in the saucepan, as the gas flame would probably not melt it.

However, if it is in close contact with a combustible material and subject to fire, it will start to melt if the temperature exceeds 660C (1,220F).

Then the aluminium will come into contact with oxygen in the air – and burn, releasing great heat.

B C Williams

Dr T E Rogers

Dr B Wallis

Marlborough, Wiltshire

SIR – The dangers of aluminium were catastrophically demonstrated in the Falklands conflict when British ships were hit by Exocet missiles.

Do these lessons never filter down from military to civilian projects? John Heather

Portland, Dorset

SIR – Many have pointed to building regulations being complicated, badly presented and ambiguous. Such ambiguity is present in The Building Regulations 2010 – Fire Safety. On external wall construction, it says: “The external envelope of a building should not provide a medium for fire spread if it is likely to be a risk to health or safety. The use of combustible materials in the cladding system and extensive cavities may present such a risk in tall buildings.”

For something so critical as safety from spread of fire by combustible materials, you would expect much clearer and well-defined standards. Paul Wenman

Abingdon, Oxfordshire

SIR – The Grenfell Tower inquiry will no doubt cost too much, and take too long. Professional journalists, skilled at digging out the truth, could do a better, cheaper, and quicker job.

Can it not passed to a committee formed by leading quality newspapers with different political leanings, such as The Telegraph and The Guardian? Harry Leeming

Heysham, Lancashire