Soundproofing furnace in garage studio

[Suntower]

Hello,

It's been a while. Hope y'all are well.

My current bedroom setup is simply not deep enough to -ever- get rid of that 85hz null and I'm sick of it. So I'm moving my studio into a typical two car garage (concrete floor, 16 studs, finished) that I've cleared out. It's dry and can be (fairly) efficiently heated. The main thing is that it's big enough. I'll be starting out by moving temporary absorbers into key points and then later putting in a proper room within a room.

But what I -must- do now is provide some sort of sound-proofing for the gas furnace and standard 40gl. hot water heater. I don't run these all that often as the climate is fairly mild (Seattle) but they will need to run from time to time. Any ideas on if this is doable in such a way as to be:
a) safe
b) serviceable

My first thought was to build a little sound-proof 'room' around the heater and furnace... basically a big version of the units I've built to enclose computers, but again, there's the safety and serviceability issues.

Thoughts?

TIA,

---JC