WAC 296-806-42524. Use properly designed covers for screw conveyors (augers)

EXEMPTION: This requirement does not apply to screw conveyors where there are drop or hinged bottom sections that cannot remain airtight. You must design covers for screw conveyors that are: (1) Removable in convenient sections. (2) Held in place with stationary clamps. Locate stationary clamps at intervals that will keep all covers dust tight.