High Performance Damp Proof Course BBA Certificated. Radbar Hydrocarbon Damp Proof Course is a high quality tri-polymer that prevents the ingress of hydrocarbon, methane, carbon dioxide and radon gases. The DPC has been developed to offer superior chemical resistance while remaining supple for ease of installation. Radbar DPC is suitable for sites that have been contaminated by methane and other hydrocarbons, such as petrol stations or landfill sites. Radbar Hydrocarbon DPC is compliant to both BS EN 14909:2012 and BS 8485:2015. It can be joined with tapes or by welding.