We have a GC on site that is insisting on sheet rocking the underside of the wood floor joists for fire rating before we install our hangers. They are securing the sheet rock to furring channels which makes it very difficult to find the wood floor joists. Is it possible to hang our cpvc piping (1 1/4" and smaller) to the furring channels. I have attached a data sheet of the furring channels and am waiting to find out the channel thickness. Where would I look on the datasheet to find out if it can support five times the weight of the water plus 250 lbs?