ISO 21004:2006规定了基于热塑性塑料的多层管道的一般要求和性能要求，该多层管道拟用于建筑物外供水、埋地水管和服务以及地面供水。 ISO 21004:2006给出了由基于热塑性塑料或塑料的多层管道组成的管道系统的设计指南，其中至少60%的壁厚为聚合物材料，与水接触的内层由聚合物材料制成。 用于应力承载层的聚合物层选自聚丁烯（PB）、聚乙烯（PE）、交联聚乙烯（PE-X）、聚丙烯（PP）、氯化聚氯乙烯（PVC-C）和未增塑聚氯乙烯（PVC-U）。 ISO 21004:2006适用于在冷水压力（高达约20°C）下输送饮用水的管道系统。它也适用于一般用途的输水管道系统（不超过40°C）。

ISO 21004:2006 specifies the general requirements and the performance requirements for multilayer pipes based on thermoplastics intended to be used for water supply outside buildings, for buried water mains and services and for water supplies above ground. ISO 21004:2006 gives guidance for the design of piping systems consisting of multilayer pipes based on thermoplastics or, for which at least 60 % of the wall thickness is polymeric material, and the inner layer in contact with water is made of polymeric material. The polymeric layers used for the stress-bearing layers are selected from polybutylene (PB), polyethylene (PE), crosslinked polyethylene (PE-X), polypropylene (PP), chlorinated poly(vinyl chloride) (PVC-C) and unplasticized poly(vinyl chloride) (PVC-U). ISO 21004:2006 is applicable to piping systems used for the conveyance under pressure of cold water (up to approximately 20 °C) for drinking. It is also applicable to piping systems for the conveyance of water (up to and including 40 °C) for general purposes.