Seismic design load - Rooftop Equipments

[cgstrucg]

Hello,

I have a rooftop mechanical equipment for which I have to design dunnage steel. Dunnage steel is going to be supported by HSS posts on long span joists. The equipment is of 2 levels so I have to also design an elevated platform supported on top of the dunnage steel so that the doors of equipment at the second level can be accessed. I have attached a snapshot of my STAAD Model to show the situation.

I am stuck in Seismic Load calculation for this structure. I can calculate the seismic load on equipment from Chapter 13 of AISC 7-05 (non-structural components). But what about the seismic load on the dunnage steel and the rooftop platform on top of that dunnage. I tried following guidelines mentioned in Ch15 for nonbuilding structures and it looks like I have to use Ch12 Section 12.8 as mentioned in Section 15.1.3 of AISC.

Can someone please let me know if my approach is right or if not then what section shall I follow.

Thanks

 

[cgstrucg]

Just want to add a note. My equipment is in Seismic Design Category B. As per Section 13.1.4, it falls under an exception. Does that mean I don't have to check for seismic load at all on the equipment?