Reading your post again, I think you may be talking about plenum rated materials. These are materials that will not be fuel for any fire that may enter the plenum. The danger is a fire will use the sheathed electrical cable or PVC to spread to another floor faster than burning through the drywall and 2x4s.
I don't know thatyou can find such rated materials. I don't think most PVC is rated as such. I wouldn't really worry about it. If you can find some rated cable that is not too expensive, go for it.