I notice many new houses are using the flexible plastic coated stainless gas piping for ALL interior piping, yet the instructions for my gas fireplace say to only use black iron pipe. When we installed gas fireplaces we used 100% black pipe as the newer stainless was not yet popular. So, if any here are installers or in the trade, it would be nice to know the common methods today to hook up gas to a DV fireplace. Is there a certain distance away from the unit where the stainless has to be terminated and then to black? Or can this stainless stuff actually go under the unit all the way to the shutoff located near the gas valve under the firebox? Any hints welcome.