Multilayer pipe systems with extremely low permeation rates

For offshore injection and hydraulic piping, Evonik offers special VESTAMID^® multilayer piping systems distinguished by extremely low permeation rates, even higher chemical resistance, and, if required, significantly enhanced resistance to external pressure. This allows for the first time the realization of selective, customer-specific requirements for offshore supply lines, known as umbilicals. Umbilicals often consist of a bundle of line systems that contain or convey various media, depending on their purpose. This places particularly high requirements on the material: it must be able to withstand a wide range of media and reliably prevent any cross contamination from neighboring lines carrying different media.

By means of a selective combination of VESTAMID^® with several barrier layer materials based on EVOH (ethylene vinyl alcohol copolymer) and a fluoropolymer, Evonik has succeeded in, for example, drastically reducing permeation rates over a very wide spectrum of media, both liquid and gaseous. The permeation of methane, for instance, lies below the detection limit for the test method used. An internal fluoropolymer layer serves additionally for excellent chemical resistance. The system can therefore be reliably used for a wide range of process media such as methanol, corrosion inhibitors, and demulsifiers. If a high barrier effect against gases is not required, the EVOH-based barrier layer can be dispensed with to give a two-layer piping system.