1945 - 1946
Pierre Heymes, a young test engineer, filed two major patents on fibre production processes. The second, in particular, described the combination of centrifugal force and the action of a hot air jet to stretch the glass. It was the first version of the famous Saint-Gobain fiberising principle.

1950
After disappointing tests with the excessively complicated LET (Laboratoire Etudes Thermiques) machine, it was decided to “turn it upside down” Heymes had in fact already voiced this idea a few years beforehand. The first TEL (LET reversed) machine with fibre disk on the bottom therefore appeared at Billancourt before starting trials at Rantigny.

1957
Finally, after seven years of development, the TEL – in actual fact Supertel as researchers called it – started its industrial career at Rantigny, where it replaced the Owens process. Gabriel Aufaure, the factory manager, took on the risk. It was a gamble that came off, as the TEL, much better than any other process, was to soon conquer the world.

1960
Construction started on the Rantigny Industrial Research Centre, better known under the acronym CRIR. A genuine development research centre, it combined three fundamental laboratories (chemistry, physics and applications) with pilot lines on an industrial scale. Research finally found its rightful place.

1967
Through CSG, a joint-venture created between Saint-Gobain and CertainTeed to sell glasswool to the USA, TEL started to compete with Owens Corning on its own territory!

1973 - 1979
The Yom Kippur war (1973) followed by the Iranian revolution (1979) sparked off the two oil crises heralding the end of the post-war glory days. Energy became expensive and insulation was riding high. Despite a difficult economic context, Isover experienced a prosperous decade.
