ISO 811:1981 Preview
Textile fabrics -- Determination of resistance to water penetration -- Hydrostatic pressure test
This standard was last reviewed and confirmed in 2007. Therefore this version remains current.
A specimen is subjected to a steadily increasing pressure of water on one face, under standard conditions, until penetration occurs in three places. The water pressure may be applied from below or from above the test specimen. The hydrostatic head supported by a fabric is a measure of the resistance to the passage of water through the fabric.