N.Y. Comp. Codes R. & Regs. tit. 1, § 2.31 – Doors and windows—Item 3p.

(a) All openings to the outer air are effectively protected by:
1. (1) screening;
2. (2) effective electric screen panels;
3. (3) fans or air curtains which provide sufficient air velocity so as to prevent the entrance of flies;
4. (4) properly constructed flaps where it is impractical to use self-closing doors or air curtains; or
5. (5) any effective combination of paragraph (1), (2), (3) or (4) of this subdivision, or by any other method which prevents the entrance of flies.
(b) All outer doors are tight and self-closing. Screen doors shall open outward.
(c) All openings shall be adequately screened or otherwise configured to protect against the entry of pests.