Heat Pump Room = Mechanical Room?

Hi Samantha, In strict terms, yes an enclosed room dedicated for mechanical equipment would be considered a mechanical equipment room and the associated STC criteria would apply. That said, in practice there are some cases where the equipment in question is relatively small (low-tonnage) and/or quiet and may not need STC-60 partitions in order to meet the ASHRAE background noise criteria in adjacent spaces. We would recommend an acoustic analysis of unit sound pressure levels assuming a lesser demising construction to demonstrate that ASHRAE criteria is still met. In our experience this credit is not intending to require teams to design STC-60 chase wall partitions around what amounts to be heat pump closets.

Hi Iris, Apologies I used the wrong name, must have been confused from a previous post/thread. As to your question... Technically, exposed rooftop equipment is not a mechanical room and would not have criteria. That said, just because there is no LEED criteria does not mean there won't be a problem. This should certainly be analyzed and could very well be an issue if not accounted for. The transmission loss of the floor/ceiling assembly should be used along with the radiated sound power levels from the equipment in question to determine if upgrades are needed to the floor/ceiling assembly.