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Prevent moisture from entering hot insulation systems

In industrial environments, protecting hot insulation systems is essential for energy efficiency and pipe protection. It is imperative to prevent moisture from entering the insulation system. This can reduce the performance of the insulation system and contribute to corrosion of the underlying pipes, vessels, flanges, valves and more. In addition, the weather barrier coating must be able to “breathe” so that any moisture present in the system can get out. This is where FOSTER® brand breather coatings provide a solution.

The problem of moisture in hot insulation

In hot insulation systems, controlling moisture from entering is paramount. Moisture and water can penetrate the insulation system and cause problems. Besides loss of performance, moisture or water can also contribute to corrosion of the underlying pipes, vessels, flanges, valves and other components. This can lead to costly repairs and maintenance work, and can even compromise safety. In terms of thermal insulation protection, FOSTER® weather barrier coatings provide total protection without seams, overlaps or joints that can cause short- or long-term failures. This is especially important on bends, T-joints, vessels and other complex shapes. FOSTER® weather barrier coatings are fully weatherproof and make the use of additional metal cladding optional.

Components of thermal insulation systems

Hot insulation systems consist of several layers to prevent the penetration of moisture and water and optimally protect pipes :

  • Adhesive: When fibrous insulation or calcium silicate needs to be attached to a hot surface, HT Silicate Adhesive 1000 is used. For lower temperatures, FOS-STIK™ spray adhesive (aerosol adhesive) can provide easy, clean, strong bonding of a wide range of materials.
  • Insulation: On the adhesive, the insulation layer is applied, e.g. PIR, PUR or cellular glass.
  • Reinforcement: To reinforce the insulated pipe sections and hold them in place, Filament tape is used; a longitudinally reinforced tape with glass fibres.
  • Weather barrier – A FOSTER® weather barrier coating is applied in two layers over the outer surface of the insulation. A reinforcement such as Scrimtex or Mast-A-Fab is wrapped in the first layer before the second layer is applied. Different colours are often used to ensure no spots are skipped. 
  • Sealant: In hot insulation systems, metal cladding is generally not needed, as the FOSTER® coating already provides a watertight seal. However, when metal cladding is used as exterior cladding over insulation, the overlaps are sealed using Foster 95-44; a flexible vapour barrier sealant.

Support and advice on hot insulation

This article covers best-practices for most situations. But we have other insulation materials in our range for hot applications, such as two-component PU foam and a variety of insulation jackets. For more specific information and technical support, please contact our team. Based on our technical materials for insulation protection, we can advise on specific details and applications.

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