The PEX pipes used for heating need to meet the following specific requirements:
Static hydraulic performance: According to the standard "Cross-linked Polyethylene Pipe Systems for Cold and Hot Water" (GB/T18992), the long-term static hydraulic resistance of PEX pipes must be above the standard curve.
Cross-linking degree: The cross-linking degree represents the proportion of cross-linking in the material, which is expressed by the gel content. The cross-linking degree requirements of different cross-linked pipes are different, the cross-linking degree of PEX-b should be greater than 65%, the cross-linking degree of PEX-a should be greater than 70%, and the cross-linking degree of PEX-c should be greater than 60%.
Resistance to thermal-oxygen aging performance: Under the conditions of 2.5MPa of hoop stress (note that it is not the test pressure) and 110 ℃, with water inside the pipe and air outside, it passes the 8,760-hour (1-year) test.
