46 C.F.R. § 58.60-5
Industrial systems: Locations
An industrial system under this subpart must not be in a space that is—
(a) Concealed; or
(b) Inaccessible to industrial personnel.
An industrial system under this subpart must not be in a space that is—
(a) Concealed; or
(b) Inaccessible to industrial personnel.