PENTANE has been and is still largely responsible for the fact that rigid and integral skin foams can be manufactured without an impact on the environment. Pentane Process Technology (PPT) was launched by Hennecke already in 1993 and has been playing a leading role since. The processing of pentane as a substitute for CFCs was mainly driven by the refrigerator and freezer industry. Apart from this application, Pentane-blown PU systems are also used in the production of sandwich panels, district heating pipes and steering wheels made of semi-rigid integral skin foam. Because PENTANE can create an explosive atmosphere at certain gas concentrations, PPT technology comprises a catalogue of primary and secondary measures that prevent the emergence of explosive mixes right from the start. One additional safety plus is realised by technical precautions which have been developed in close cooperation with TÜV Süddeutschland (Southern German Technical Inspectorate).