4.1.1.3 Vents
shall be protected against entry of foreign material and shall
be provided with readily removable filters to exclude particles
of 5 microns or larger.
4.1.1.4 Permanent
lighting fixtures shall not be installed within the product zone.
If interior lighting is required, externally mounted fixtures
shall be used with shatter-proof transparent panels or disks,
flush mounted.
4.1.1.10 Screw
conveyor housings shall be hinged at the top cover and drop bottoms
or removable so that the area around the helical flights can
be cleaned from the outside. Sufficient clearance shall be provided
between the bottom of the screw housing and the floor to permit
sufficient exposure of the screw for cleaning or the screw must
be removable for cleaning. The screw housing shall be dust-tight
and readily accessible for cleaning.
4.1.1.11 Continuous
welding on both sides of the spiral flight shall be used for
fastening the spiral to the shaft unless the spiral flight is
designed to provide at least 1 inch (25mm) clearance between
the shaft and the spiral.
4.1.1.12 Screw
housings in bin bottoms shall be open along their entire length
and expose at least one-half of the circumference of the screw.
Fixed supports or plates in such openings shall have a width
not greater than two-thirds the pitch of the screw.