PDFWAC 296-99-080
How must continuous-flow bulk raw grain dryers be equipped and installed?
(1) You must ensure that all direct-heat grain dryers have automatic controls that:
(a) Shut off the fuel supply in case of power, flame, or ventilation airflow shutoff; and
(b) Stop the grain flow into the dryer if the dryer exhaust gets too hot.
(2) You must ensure that each direct-heat grain dryer installed after March 30, 1988, is:
(a) Located outside the grain elevator; or
(b) When located inside the grain elevator, protected by a fire or explosion suppression system; or
(c) Isolated by a structure with at least a one hour fire-resistance rating.