Correction: December 2013 CT

Correction to Engineering Insights article from June 2012 issue of Composites Technology.

An alert reader recently spotted a factual error in “Making continuous composite pipes,” an online sidebar (visit to the Engineering Insights feature titled “Designing for high pressure: Large-diameter underground pipe,” featured in the June 2012 issue of CT. Author Sara Black began the story thus:

“The continuous filament winding process was developed in the 1970s by Danish inventor Frede Hilmar Drostholm, and it was commercialized first by Toledo, Ohio-based Owens Corning’s engineered pipe systems business, in partnership with several entities, including Amiantit (Dammam, Saudi Arabia) and Vera Fabrikker (later Flowtite Pipe and Tank AS, Sandefjord, Norway).”

As it turns out, Frede Hilmar Drostholm was the inventor of the advancing mandrel machine but not the continuous filament winding process for fiberglass pipes and tanks. It was invented by Agnar Gilbu of Sandefjord, Norway, who used the machine devised by Drostholm in his process.

He took his production method to Vera Fabrikker (at that time a subsidiary of Sandefjord-based global paint supplier Jotun) as a possible use for their resin. Production started in 1965, but, initially, the process was used only to make tanks. In 1968, Vera Fabrikker supplied the first pipes to customers. Veroc Technology AS was established in 1977 as a joint venture between Vera Fabrikker and Owens Corning (Toledo, Ohio). The U.S. patents were granted at this time, which gave rise to the mistaken impression that Drostholm was the inventor of the process.

According to our source, Amiantit was not a partner, but rather a customer, of Veroc for many years. When Owens Corning went through bankruptcy in 2001 due to asbestos-related litigation, Amiantit reportedly acquired the former Veroc, which had by then acquired a new name: Flowtite Pipe and Tank AS.

For more historical details, visit