On blast
On blast means those periods of cupola operation when combustion air is introduced to the cupola furnace and the furnace is capable of producing molten metal. On blast conditions are characterized by both blast air introduction and molten metal production.
Source
40 CFR § 63.7765
Scoping language
Terms used in this subpart are defined in the Clean Air Act (CAA), in 63.2, and in this section.