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Corrosion Protection

Margel VPI 595CUI®

Corrosion Inhibitor for Corrosion Under Insulation (CUI) Protection

Protech Global Ltd has formulated a unique corrosion inhibitor for the protection of steel pipe surfaces from corrosion under insulation(CUI). Designed to be installed directly onto the surface of pipes fitted with insulation materials, Margel VPI 595CUI® corrosion inhibitor is a mid to long term fit and forget cost effective solution to the problems of corrosion under insulation(CUI) in industry the world over. Margel VPI 595CUI® is formulated for use in temperatures from -55 ºC to +150ºC, with this upper temperature limit currently bearing witness to stringent scientific test.

Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI), in liquid or patch form, works by emitting a controlled amount of corrosion inhibiting vapour that when applied to steel surfaces, disperses and is adsorbed by its substrate, blocking the path of chlorides, water and oxygen. Margel VPI 595CUI® corrosion under insulation(CUI) is manufactured with organic compounds and forms a monomolecular layer onto the surface of steel, this eliminates any further corrosion, working equally well on both newly manufactured or already corroded steel products.

Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI) migrates up to 2mtrs from its placement location, which is dependent on environmental condition, and will start working from the moment it is applied, typically eliminating further corrosion activity as soon as14 days from application. ProTech Global have a portfolio of projects where Margel® is still working 25 years from application. Margel® variants have to date been applied to more than 2000 projects worldwide.

Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI) is unaffected by damp/humid environments and works best in hermetically sealed environment to prolong the effectiveness. This can be achieved by sealing with a suitable enclosure system such as ProTech Global’s Proclad150™️ or Proclad350 PLUS™️.

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Characteristics / Advantages

Please find below the key characteristics of our Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI) product. For more information and enquiries please get in touch.

  • Long term protection durability
  • Resistant to freeze/thaw cycle
  • Unaffected by water ingress
  • Resistant to arctic conditions up to -55 ºC
  • Performance unaffected by damp/humid conditions
  • Can be easily applied to steel with zero preparation
  • Renewable solution
  • Compatible with a wide range of other products
  • Flame retardant chemical included in the capsule formula
  • Meets environmental guidelines - extending the serviceable life of infrastructure and lowers maintenance costs


Compatible with other systems such as fire and flame retardants, paints and sealants.

Product Data

  • Supplied in boxes of 25 patches or in 5l or 25 containers in liquid form
  • Manufactured and supplied from the UK, shipping worldwide
  • Appearance: small patches of liquid form
  • Storage: store below 20 ºC
  • Application conditions: preferable to apply below 25 ºC
  • Shelf life: 24 months

Product Uses

Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI) is widely used for the following applications.

  • Storage of drill piping, box girders and pipes for civil engineering use
  • Protection of external surfaces for oil and gas pipelines - preventing CUI
  • Interior surfaces of ship hulls
  • Suspension bridge cable conduits / bridge structural steel components
  • Protection from corrosion for structural steel in construction industry

Margel VPI 595CUI® Information


Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI) should be applied within the vicinity of the steel to be protected. Product should be applied as per the indicated consumption rate(above) directly to the steel surface. Once applied Margel VPI 595CUI® for corrosion under insulation(CUI) it is preferable to have low air movement where the product is placed to avoid loss of vapour pressure and to ensure continued concentration of the vapours to migrate and coat the steel surfaces. If water ingress is anticipated at time of application, then care should be taken to apply Margel VPI 595CUI® for corrosion under insulation(CUI) on the upper side of the intended surface to avoid sitting in pooling water. Water will not affect the properties of the corrosion inhibitor but may impact the migration of vapour and if significant reduce the effective life of the Margel Margel VPI 595CUI® for corrosion under insulation(CUI) product.

Surface Preparation

Margel VPI 595CUI® corrosion inhibitor for corrosion under insulation(CUI) requires no preparation of the steel surface to be protected. It works equally well on both newly manufactured steel as well as corroded steel surfaces.

Coverage Rate

ProTech Global recommends a coverage rate for Margel VPI 595CUI® for corrosion under insulation(CUI) of 2 patches per m² or 15ml measure of liquid per m² (minimum)

Protech Global Ltd will provide advice on a per project basis to determine long term effective protection.

Alternative Products

Margel VPI 600CUF® gel corrosion inhibitor is formulated for use on pipelines with operating temperatures up to 150ºC. This product is designed for steel products without insulation.

Test Results/Performance Data

Extensive testing of Margel VPI 595CUI® for corrosion under insulation(CUI) is currently in progress and trials are possible on a limited basis by application to ProTech Global.

Data Sheets & Downloads

Looking for a data sheet or an installation guide for our Margel VPI 595CUI® product range, then the following downloads might come in handy.

Technical Data Sheet Margel VPI 595CUI® UK182 Kb Download .pdf

CUI margel Corrosion Inhibitor

ProTech Global

Specialist Insulation Jacketing Solutions

Over the years, we’ve been able to build a reputation as one of the best independent company's in our industry, supplying premium weatherproof jacketing & insulation cladding systems, aluminium foil jointing adhesive tapes, and anti-corrosion control products across multiple markets. Those interested to work with us in any field relating to our work are encouraged to contact us by way of telephone or e-mail by using the contact form to obtain more information.


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