Retrotec USACE - Manual (Page 249)

Appendix D D119
D.7.7 Foundry
D.7.7.1 Running Exhaust Systems When Not Required (Waste)
Figure D186. Air-cleaning equipment and
exhaust fans required by a foundry. Figure D187. Foundry exhaust air system in
mold department.
A foundry has many process exhaust systems that remove hazardous gases,
smoke, and unwanted particulate from workstations. These exhaust systems
operate in conjunction with the furnaces where metals are melted, the ma-
chines making cores and molds, the pouring line where the molten metal is
poured into molds to make castings, the area where molds are broken apart
and the castings separated from mold and core material, and the grinding
equipment where castings are cleaned of scale and other imperfections (Figure
D186). It is common for these exhaust systems to run continuously whenever
the foundry is operating, even though they may not be needed. These exhaust
systems move a lot of air at a high velocity and thus consume high amounts of
electrical energy. Many foundries provide a wide variety of castings, and thus
their operations are sporadic and varied. Their exhaust systems (Figure D187)
should function only when required. If molds are being poured, then that
system should be functioning, but when the casting operation is completed,
that exhaust system can be shut down.
D.7.7.2 Outside Furnace Temperature Exceeding 52 °C (125 °F)
(Waste)
Figure D188. Melt furnace in foundry that
could have hot surfaces.