46 CFR § 32.56-25
Category A machinery spaces: Windows and port lights—T/ALL
April 15, 2021
(a) Except as provided in paragraph (b) of this section and subpart 111.105, of this chapter, boundaries of category A machinery spaces and boundaries of cargo pumprooms must not be pierced for windows or portlights.
(b) Skylights that can be closed from outside the spaces they serve may be fitted in boundaries of category A machinery spaces.
[CGD 74-127, 41 FR 3844, Jan. 26, 1976, as amended by CGD 74-125A, 47 FR 15230, Apr. 8, 1982]