建筑设备和工业装置用隔热产品.预制管道隔热层水蒸气传输特性的测定

[中文适用范围]： 本文件规定了在规定的测试条件下测定预制管道绝热材料试样稳态水蒸气透过性能的设备和程序。 适用于保温制品。 它旨在用于均质材料（参见下面的注释）以及具有整体表皮或某些不同材料的粘合面的产品。 注：如果材料的密度在整个过程中大致相同，即如果测量的密度值接近其平均密度，则材料被认为在质量分布方面是均匀的。 [外文原描述]： This document specifies the equipment and procedure for determining the water vapour transmission properties in the steady state under specified test conditions for test specimens of preformed pipe insulation. It is applicable to thermal insulating products. It is intended to be used for homogeneous materials (see NOTE below) and for products which can have integral skins or adhered facings of some different material. NOTE A material is considered to be homogeneous in terms of mass distribution if its density is approximately the same throughout, i.e. if the measured density values are close to its mean density.