9 CFR § 590.506 - Candling and transfer-room facilities and equipment.
(a) The room shall be so constructed that it can be adequately darkened to assure accuracy in removal of inedible or loss eggs by candling. Equipment shall be arranged so as to facilitate cleaning and the removal of refuse and excess packing material.
(b) The construction of the floor shall allow thorough cleaning. The floors shall be of water-resistant composition and provided with proper drainage.
(c) An approved exhaust system shall be provided for the continuous removal directly to the outside of any steam, vapors, odors, or dust in the room. The room shall be maintained at reasonable working temperatures during operations.
(e) Leaker trays shall be made of a material and of such design that is conducive to easy cleaning and sanitizing.
(h) Shell egg conveyors shall be constructed so that they can be thoroughly cleaned.