Non-contact insulation is an insulation technique in which the insulation is prevented from making contact with the material surface. Non-contact insulation is a practical solution in preventing corrosion under insulation (CUI).
By creating a cavity between the pipe and thermal insulation (generally mineral wool), it prevents water from accumulating within insulating materials and also enables water or moisture to drain freely.
Corrosion under insulation is a severe form of localized external corrosion that occurs in carbon and low-alloy steel equipment that has been insulated. CUI is common in refineries and process plants that typically operate equipment at high temperatures.
Non-contact insulation is also known as contact-free insulation.
Non-contact insulation prevents the direct contact between the insulating layer and the object surface. Consequently, the accumulated humidity and corrosive materials within the insulating material cannot result in damage of the anticorrosive coating or the surface of the object, respectively. Corrosion processes, therefore, cannot begin.
It is a relatively recent insulation design which has proven successful in preventing corrosion between the interfaces of insulation and object. The insulation contacts a mesh screen that is raised above the equipment surface; hence any ingress of water into the insulation does not contact the equipment to cause corrosion damage. The air gap enables the equipment surface to stay relatively dry and also allows insertion of a boroscope inspection tool to check the external condition of the equipment, without removing the insulation and weatherproofing.
Previous techniques often did not ensure a lasting gap of air, were very work-intensive or even damaged the anticorrosive coating of the object, which leads to corrosion under insulation.
The newly developed corrosion-prevention-insulation (CPI) system is the optimal constructive solution for the realization of non-contact insulations. CPI, with its precisely intertuned system of gap construction and insulation, ideally fulfills the technical requirements for insulation and corrosion-protection for the avoidance of CUI.