Grepi Plast
Pavels Innovation
+47 476 60 111 Monday - Friday 09:00 - 17:00 Sandakerveien 138, Oslo 0484
+47 476 60 111 Monday - Friday 09:00 - 17:00 Hydrovegen 19, 3933 Porsgrunn
+47 476 60 111 Monday - Friday 09:00 - 17:00 Hydrovegen 19, 3933 Porsgrunn

Corrosion in the pipes within the insulation

On offshore installations and onshore refineries and other petrochemical plants where there are large amounts of pipe streets, there is a challenge that corrosion may occur in the pipes on the underside of the insulation. This is mainly due to water penetration during insulation, and in the specialist terminology it is called CUI (corrosion-under-insulation) or WUI (water-under-insulation) This is not visible by regular visual inspection and therefore requires that one must dismantle external metal covers and the ventilation itself in the areas one suspects corrosion. Problems related to this cost the industry large millions of dollars each year.

CustomerBenarx Solutions
BackgroundBenarx designs, manufactures and supplies high-tech insulation products and advanced underwater insulation for the global oil and gas industry.


Benarx describes the problem as follows:

"Corrosion Under Insulation (CUI) is a major risk factor in Oil&Gas producing facilities. The integrity of pipelines and process equipment carrying hydrocarbons under pressure is essential and a potential leak or breakage can have catastrophic results."

There are various methods for detecting CUI problems, among other things. using X-rays and ultrasound, but this is complicated and cost a lot of moneys. There is therefore a big need for simpler and at the same time reliable methods. The solution became a plastic material with unique properties.


The services we assisted with: Product development and plastic production.


Benarx Solution therefore started the development of a detector based on a material expanding in water and thus purely mechanical triggering an indicator. This one wanted injection molded in suitable plastic material, but which had to meet some important requirements in order to be applied to oil installations, among other things. antistatic properties to prevent spark formation.


Grepi Plast was already inside the CUI problem through a collaboration with Fjellanger Dog Training Academy AS, which employs specially trained dogs to detect corrosion, also a very innovative and exciting method. For this purpose, Grepi Plast produces specially developed ampoules used both for sampling and in the test stations.


Benarx Solution therefore contacted Grepi Plast which contributed to the product development. In this process, the product was production-adapted and the correct material was selected. The product was constructed and seven design tools were built for the various plastic components included.


In cooperation with materials suppliers in Finland and the UK, Grepi brought out the right materials for the components of the drainage plug that have conductive properties, and for the expanding component.


After undergoing long pilot tests at construction, the Benarx WUI Drain Plug is now in full production at Grepi Plast.


The plastic material they used in the development of the moisture sensor can expand up to 900% when moisture is supplied. The moisture sensor is currently used in explosive environments where electrical equipment is not used. This saves the industry a large amount of millions each year.

Related customer case

Hidden corrosion for gas companies

/ Offshore /
How to detect corrosion during insulation? It costs gas companies more than 100 million to detect corrosion, and they have therefore needed to develop a new solution for this.

New energy saving requirements

There has been a greater focus on saving energy consumption in the world, and with the new regulatory requirement in Europe related to energy savings, there is a need to find new solutions. Grepi Plast AS developed and patented a new special clamp for insulated pipes, which meets the latest regulatory requirements in Europe related to energy saving.

Water damage, the largest type of damage suffered at insurance companies

/ / /
Water damage accounts for the largest type of damage among insurers. In a meeting between Pavels Innovation, Grepi Plast and Armaturjonsson, it was discussed how to prevent the water damage. The innovative solution was Arjonstop.

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