D.C. Mun. Regs. tit. 25-A, § 1514
1514.1 A cover or lid for equipment shall overlap the opening and be sloped to drain.
1514.2 An opening located within the top of a unit of equipment that is designed for use with a cover or lid shall be flanged upward at least five millimeters (5 mm) (two-tenths of an inch (2/10 in.)).
1514.3 Fixed piping, temperature measuring devices, rotary shafts, and other parts extending into equipment shall be provided with a watertight joint at the point where the item enters the equipment, except as specified in § 1514.4.
1514.4 If a watertight joint is not provided under § 1514.3:
(a) The piping, temperature measuring devices, rotary shafts, and other parts extending through the openings shall be equipped with an apron designed to deflect condensation, drips, and dust from openings into the food; and
(b) The opening shall be flanged as specified in § 1514.2.
SOURCE: Final Rulemaking published at 50 DCR 4394 (June 6, 2003); as amended by Final Rulemaking published at 59 DCR 13690 (November 30, 2012).