46 CFR § 108.213
Heating requirements
April 15, 2021
(a) Each accommodation space must be heated by a heating system that can maintain at least 20 °C. (68 °F.).
(b) Radiators and other heating apparatuses must be constructed, located or shielded so as to avoid risk of—
(1) Fire;
(2) Danger; and
(3) Discomfort
to the occupants of each accommodation space.
(c) Each exposed pipe in an accommodation space, leading to a radiator or other heating apparatus must be insulated.