GENEVA — September 30, 2013 — SGS provides a technical update on common water vapor permeability
testing methods and procedures for rainwear and other functional fabrics or textiles.
Many outdoor jackets or rainwear may be labeled with functional claims such as waterproof
breathable. The shell fabrics may be treated with finishes, coating or lamination to achieve the
waterproof breathable function. However, if an improper treatment is applied, it may reduce the
breathability and therefore inhibit the evaporation of sweat from skin, which may cause discomfort.
There are various methods used to assess the water vapor permeability of textiles. The tables below
summarize the common methods and their differences.
Comparison of Testing Methods for Water Vapor Permeability
ASTM E96
– Cup methods
– Upright cup for water permeable fabric
– Inverted cup for water impermeable fabric
JIS L 1099
– Cup methods
– Upright cup for water permeable fabric
– Inverted cup for water impermeable fabric (for single membrane method)
– Inverted cup for water permeable or water impermeable fabric (for double membrane method)
ISO 15496
– Cup method
– Inverted cup for water permeable or water impermeable fabric (double membrane method)
BS 7209
– Cup method
– Only upright orientation
– Cup is moving on a turntable
ISO 11092 / ASTM F1868
– Sweating hot plate method
– Simulate sweating skin
– Commonly applied to water impermeable fabric
Various Water Vapor Permeability Testing Methods and Procedures
Water Vapor Transmission ASTM E96, JIS L 1099,ISO 15496, Water Vapor Permeability (WVP), BS
7209 and differences between BS 7209 and other cup methods as well as differences between cup
methods and sweating hot plate methods are summarized within the latest Safeguards bulletin.
Posted October 1, 2013
Source: SGS
