Seismic Bracing for Ceiling-Mount Furnace

[SarBear]

Hi everyone, I've got an interesting project here that I'd like to see if anyone has any insight on.

The owner of an auto shop hung a 450 lb. furnace from a steel roof beam. The city found out and is now requiring seismic bracing for the furnace, so the owner called us to take a look. See the drawing below. The furnace came with (4) pre-made holes for mounting. I've run the numbers on the steel beam and it is adequate to carry the weight of the furnace. I've looked at a lot of different bracing products, but they all seem suited for piping, ductwork, etc. I'm not sure what to do here. My initial thought is to have a cable brace attach to each of the 4 bolts and run diagonally away from the unit and attach to the z-purlins. Does anyone have any experience and/or insight they could share?

 

[Harbringer]

What a mess the threaded rods are going at an angle through the beam? How far away is the next wide flange? I'd probably make them re-hang this, something similar to the duct trapeze, image below, with a small channel or even a double strut for vertical support to the next beam.

Cable sway bracing would be okay or unistrut, though attaching to zee purlins is not something I would normally recommend. How much is the lateral load (Fp)?

 

[SarBear]

Thanks for your thoughts!

What a mess the threaded rods are going at an angle through the beam?

They have some angled brackets at the unit and the steel beam, so the rods themselves don't go through at an angle.

How far away is the next wide flange?

They are spaced at 16'-0".

though attaching to zee purlins is not something I would normally recommend

Yeah, that was my thought as well. With the trapeze, the rods would miss the wide flange and have to attach to the z-purlins.

 

[Harbringer]

Yeah, that was my thought as well. With the trapeze, the rods would miss the wide flange and have to attach to the z-purlins.

I'd probably make them re-hang this, something similar to the duct trapeze, image below, with a small channel or even a double strut for vertical support to the next beam.