GB/T 21332-2025 Active National standards

GB/T 21332-2025 Rigid cellular plastics—Determination of water vapour transmission properties

Publish Date: 2025-12-31 Implement Date: 2026-07-01 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: GB/T 21332-2025

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Synthetic resins and plastics

ICS Name: Foam material

Publish Date: 2025-12-31

Implement Date: 2026-07-01

Pages: 20 pages

Scope

This document describes the methods for measuring the water vapor permeability, water vapor transmission rate, water vapor transmission coefficient, and water vapor diffusion resistance index of rigid foam plastics.
This document is applicable to rigid foam plastics with a thickness of more than 10 mm. These can be self-skinned foam materials or foam materials adhered to different surface materials.
This document specifies three different temperature and humidity conditions:
a) 38°C, with a relative humidity gradient of 0% to 88% on both sides of the sample;
b) 23°C, with a relative humidity gradient of 0% to 85% on both sides of the sample;
c) 23°C, with a relative humidity gradient of 0% to 50% on both sides of the sample.
The results obtained by this method are used for product design, production control, and product specifications.
This method is applicable to materials with a water vapor permeability ranging from 3 μg/m2·s to 1,400 μg/m2·s.