ISO 21225-2:2018规定了塑料管道系统中的管道和配件的要求和试验方法，这些管道和配件用于通过水平定向钻孔和冲击成型的方式非开挖更换各种地下管网、地下无压排水和污水管网以及地下供水和供气管网。 ISO 21225-2:2018适用于制造的聚乙烯（PE）管道和配件，以及安装的更换系统。 ISO 21225-2:2018拟与适用于PE管道系统施工的标准（如适用）结合使用。 对于制造的管道，它适用于三种不同的PE管道类型: -PE实心壁单层管（公称外径dn），包括任何识别条纹； -按照附录A的规定，管道内外各有一层或两层共挤出层的PE管（总外径，dn），其中所有层具有相同的MRS等级； -聚乙烯管（外径，dn），管外有可剥离、连续的热塑性附加层（“涂层管”），见附录a。 此外，ISO 21225-2:2018适用于: -安装前，通过对接熔合接头连接管道长度，形成连续管柱； -聚乙烯制成的预制和注塑配件。 由其他塑料制成的管道，例如聚丙烯（PP）不在本文件的范围内。 ISO 21225-2:2018不适用于作为非开挖安装过程一部分组装的推装连接离散管道。

ISO 21225-2:2018 specifies requirements and test methods for pipes and fittings which are part of plastics piping systems for the trenchless replacement of various underground pipeline networks, underground non-pressure and pressure drainage and sewerage networks and underground water and gas supply networks, by means of horizontal directional drilling and impact moling. ISO 21225-2:2018 is applicable to polyethylene (PE) pipes and fittings, as manufactured, as well as to the installed replacement system. ISO 21225-2:2018 is intended to be used in conjunction with standards applicable for the construction of PE pipeline systems where available. Regarding manufactured pipes it is applicable to three different PE pipe types: - PE solid wall single layered pipes (nominal outside diameter, dn), including any identification stripes; - PE pipes with co-extruded layers on either or both the outside and inside of the pipe (total outside diameter, dn), as specified in Annex A, where all layers have the same MRS rating; - PE pipes (outside diameter, dn) having a peelable, contiguous, thermoplastics additional layer on the outside of the pipe ("coated pipe"), see Annex A. In addition, ISO 21225-2:2018 is applicable to: - jointing of pipe lengths by means of butt fusion joint to form continuous strings prior to installation; - fabricated and injection-moulded fittings made of PE. Pipes made from other plastics, e.g. polypropylene (PP) are outside the scope of this document. ISO 21225-2:2018 is not applicable to push-fit jointed discrete pipes assembled as part of the trenchless installation process.