The additional class notation COMF includes requirements for noise levels, whole-body vibration levels and the design and performance of the HVAC system. The class notation covers crew and passenger areas on all vessel types. Typical areas included are cabins- and indoor- and outdoor public and recreational spaces for crew and passengers, crew working areas like wheelhouse, radio rooms, offices, control rooms, hospital and machinery areas.

Compliance with the rules shall be verified through documentation and measurements of defined environmental parameters. Possible influence of mechanical vibration on machinery, structure or other systems is considered in other relevant Society rules. The least strict noise level and sound insulation requirements (crn = 3) for crew areas correspond to the requirements in IMO Res. MSC.337(91) Code on noise levels on board ships. The least strict vibration level requirements (crn = 3) satisfy the requirements in ISO 20283-5.

The COMF class notation provide standards at the time of delivery and during the ship's life. If substantial changes to the machinery installation or interior arrangements are made, re-evaluation of the COMF notation is required.