When using polyurethane foam to seal gaps in pipes, care must be taken to avoid corrosion of the pipes

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In production facilities, some pipes need to pass through the floor. To prevent sewage from flowing down through the openings, a water barrier should be placed around them, but this cannot completely stop sewage and debris from falling in. The operator then sealed the annular gap between the pipeline and the water baffle with foam insulation material. During subsequent maintenance, it was found that the surface of the carbon steel pipes in the areas sealed with foam material had suffered severe corrosion, while the corrosion level in the rest of the pipes was normal. Foam insulation materials create closed areas on the pipe surface, trapping water vapor and thereby exacerbating corrosion conditions, leading to increased corrosion of carbon steel pipes. In the case of stainless steel pipes, if the foam material contains chlorides, it may lead to chloride concentration, thereby causing stress corrosion cracking and damaging the pipe.