To blow in a furnace is to ignite it and bring it up to operating temperature after construction or relining. Crews dry out the refractory brickwork with low heat, pack the hearth with wood and coke, ignite it, and gradually increase the hot air blast and ore burden until the furnace reaches steady-state smelting.
Heard on the job
We're scheduled to blow in the new furnace on Tuesday, so get the cast house prepped.
Insider tip
A blast furnace is blown in once and typically runs continuously for ten to fifteen years before being blown out for repairs.