Detection of corrosion and protection for directly buried heating pipeline

Presents that the main causes of heating system malfunction are corrosions of pipeline and compensators. Analyses the characteristics of corrosion on directly buried heating pipeline. Because of transported medium with higher temperature and higher occurrence probability of thermogalvanic corrosion in the heating pipeline, the heating pipeline has a higher corrosion rate than other types of municipal pipeline, and water supply pipeline has a higher malfunction rate than water return pipeline. Taking a main heating pipe with ten years of operation located in Harbin as the case, conducts the detection of corrosion conditions. The results show that the soil along the main heating pine has stronger corrosion effect  and weaker interference stray current inside, and that most of the preformed directly buried insulating pipes with polyurethane foamed-plastics and high density polyethylene casing pipes have good anti-corrosion performance although certain degree of corrosion can be observed near the compensators and anchor blocks. The detected results provide evidence for maintenance and further corrosion prevention measures.