STEEL FABRICATORS this week urged building owners to check galvanised structural steel sections in their structures for serious cracks.
They warned that some galvanising processes could cause sections to develop cracks up to 500mm long.
This could have 'extremely serious consequences for the performance of the structure'.
The warning came from the British Constructional Steelwork Association (BCSA) and the Galvanisers Association (GA).
They said a phenomenon called liquid metal assisted cracking (LMAC) can occur in galvanising tanks when steel is in contact with molten zinc at a temperature of 450° C.
Cases of LMAC are rare and the phenomenon is hard to reproduce in the laboratory.
But after reports of at least one case in the UK BCSA and GA have produced joint guidance on how to minimise the risks of LMAC in structures.
The two bodies sought to play down the risks of LMAC developing but urged designers and fabricators to heed advice in their document.
'Galvanising structural steelwork - an approach to the management of liquid metal assisted cracking'.
The guide concludes: 'By owing the guidance in this document and by committing a modest amount (of time and money) to detail at each stage of the construction process the chances of LMAC occurring can be substantially reduced.' The problem is often associated with higher grades of steel, so engineers should specify the lowest grade of steel that will do the job, ' GA technical manager Bill Smith said.
INFOPLUS To access a copy of the advice go to www. nceplus.co. uk