Metacor Q & As

What’s a corrosion allowance?

The sectional thickness designated expendable to corrosion. It does not necessarily follow that the element will be unfit for purpose when the corrosion allowance is exhausted.

Piping wall thickness specification usually includes a ‘corrosion allowance’. However, it is not specified that this is for internal or external corrosion. The temptation is to ignore quantifying values for internal and external corrosion allowance, but this risks not meeting performance targets for both. The important thing is to recognise that corrosion will occur, and set limits to measure against.