Corrosion under insulation layer
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What are the standards for insulation materials used to prevent corrosion beneath the insulation layer, and what should be the maximum allowable level of chloride ions?
Corrosion has already occurred beneath the insulation layer; polymer temperature-activated materials can be used to remove the traditional insulation layer and carry out on-site anti-corrosion treatment, after which an insulation coating can be applied to permanently prevent corrosion beneath the insulation layer. Similarly, with new equipment and a direct insulation coating, corrosion beneath the insulation layer can be avoided.
Painting is also typically used for corrosion protection beneath the insulation layer; corrosion prevention relies mainly on painting. The only insulation material that has requirements regarding chloride ions is stainless steel; other materials have no such requirements. The chloride content in the insulating materials used for austenitic stainless steel pipes and their products is generally required to meet the requirements of (GB/T17393) \"Specifications for Insulating Materials Used to Cover Austenitic Stainless Steel\".
I read online that corrosion beneath the insulation layer needs to be considered from three main aspects； 1. Insulation structure to prevent rainwater from entering the insulation layer. 2. Selection of insulation material. 3. Choice of appropriate coating system. Moreover, a standard called NACE RP 0198 (Corrosion Control under Insulation and Fire Protection Materials – Systematic Approach) was found; it explains in detail the structures and coating systems, but it is rather vague regarding the selection of insulation materials. I would like to know how experts make their decisions when purchasing such insulation materials
When designing, hydrophobic insulation materials are chosen. The selection of materials is generally based on factors such as the design temperature of the insulated pipeline and its thermal conductivity. Insulation materials specified in GB 50264-2013, the Design Code for Insulation of Industrial Equipment and Pipelines, and SH/T 3010-2013, the Design Code for Insulation of Petrochemical Equipment and Pipelines, are all options available, with many different materials listed in these standards
You’re too kind. I’m not an expert by any means; let’s keep communicating more
I’ve learned it :) Thank you, experts! !
Corrosion beneath the insulation layer is primarily related to the materials used; the moisture content of these materials must be within acceptable limits, and the chloride content in them must also meet the required standards for pipes. Secondly, the rust removal level of the insulated pipes must be satisfactory, and their anti-corrosion properties must also be adequate. Once again, the insulation structure must be proper; otherwise, after water enters, a layer of corrosive film will form between the insulation material and the pipes.