Fire Collar Obstruction

[Belinda]

Hello there!

Could anyone tell me what is the unobstructed distance between a fire collar and another element? Planning to install a PIV unit, running a PVC pipe straight from the rear inlet to a fire-rated wall. I need to install a fire collar behind the unit, but I was wondering what's the separation I have to leave between the PIV and the collar so that the collar won't be affected in performance? Or can the PIV unit be located just after the fire collar? I would like to avoid separating the unit from the wall as much as possible.

I have asked different manufactures but no one has been able to tell me.

I hope this makes sense.

Thanks in advance.