GB/T 17146-2015 in English

GB/T 17146-2015 is an important standard for testing the hygrothermal performance of building materials. It adopts the ISO 12572:2001 international standard method to measure the water vapor transmission characteristics of materials through dry method (desiccant method) and wet method (saturated solution method). The standard is applicable to various building products such as insulating materials, waterproof materials, and paints.

Instrument configuration

• Test cup: glass/metal material, corrosion-resistant (acid resistance is required when anhydrous calcium chloride is used as the desiccant)
• Thickness tester: accuracy 0.1mm or 0.5% of the thickness value (whichever is more stringent)
• Analytical balance: minimum accuracy 0.001g (can be relaxed to 0.01g when the mass is greater than 200g)

Specimen preparation specifications

1. Exposed area ≥ 0.005m² (diameter/side length ≥ 2 times the thickness)
2. Standard thickness ≤100mm (homogeneous materials can be cut, non-homogeneous materials need to maintain the original structure)
3. State adjustment requirements: (23±5)℃, (50±5)%RH environment to constant weight (24h mass change <5%)

Thin film materials (Appendix C)

Use a mechanical seal test cup, key points to note:

• Air layer resistance correction (when S_d＜0.2m, it needs to be corrected according to Appendix G)
• Thickness measurement is not mandatory, the result is expressed in moisture permeability

Coating materials (Appendix E)

Two preparation methods:

1. Self-supporting film: curing according to JG/T 309-2011
2. Substrate coating method: The substrate’s background moisture permeability resistance must be tested first

Key points for error control

Unit conversion guide

Moisture permeability coefficient unit conversion: 1kg/(m·s·Pa) = 3.6×10⁹mg/(m·h·Pa)