Resistance to Water Penetration according to AATCC 42-2017 / ISO 18695

raincoats
Testing lab
Physical lab
Legislation
PPE Regulation (EU) 2016/425
Testing standard

AATCC 42-2017

ISO 18695

Principle

  • The test measures the resistance of a fabric (or fabric assembly) to water penetration when subjected to the impact of a controlled volume of water dropped from a specified height.
  • The falling water simulates rain hitting a fabric surface, causing possible penetration through to the underside.
  • The amount of water that passes through the specimen and is collected on a blotter paper placed beneath is measured.
  • A lower mass of water absorbed by the blotter indicates better water resistance.

Test Method

Apparatus & Materials

  • An impact penetration tester with funnel and spray head at a fixed height.
  • Blotter paper of standard absorbency, weighed prior to testing.
  • A reservoir or graduated cylinder delivering 500 mL of water.
  • A balance accurate to at least 0.01 g.

Procedure

Specimens are conditioned in the standard textile testing atmosphere of 21 ± 1 °C and 65 ± 2% relative humidity. The specimen is mounted in the hoop of the tester with its face side exposed to the water and blotter paper placed directly beneath it. A volume of 500 mL of water is then released from the funnel and allowed to fall through the spray head from a height of 610 mm onto the specimen surface.

Following completion of the water discharge, the blotter paper is removed and weighed. The increase in mass compared to its pre-test weight represents the amount of water that penetrated. Testing is typically carried out on at least three specimens, and the results are averaged to provide a representative value.

Reporting

The test report normally includes the following elements:

  • A reference to AATCC 42-2017 / ISO 18695.
  • Identification of the specimen tested, including fiber content, structure, finishes, or coatings.
  • The number of specimens examined.
  • The mean increase in blotter weight, expressed in grams, together with either the range or standard deviation of results.
  • Any observed differences in wetting, repellency, or leakage during the test.
  • A note of any deviation from the specified procedure.

Example report entry:

  • Method: AATCC 42-2017 / ISO 18695
  • Fabric: 100% polyester, plain weave, durable water repellent finish
  • Number of specimens: 3
  • Blotter weight gain: 0.2 g, 0.3 g, 0.4 g → Mean = 0.3 g
  • Observation: Good resistance to water penetration; no visible leakage
rain jacket

Applications

This test is widely used to evaluate fabrics and fabric assemblies that are intended to provide water resistance under conditions of rainfall or water splash. Typical applications include:

  • Apparel: rainwear, outerwear, performance sportswear, military uniforms.
  • Protective clothing: medical gowns, surgical drapes, and protective coveralls where barrier properties are critical.
  • Outdoor products: tents, awnings, umbrellas, backpacks, and sleeping bags.
  • Upholstery and automotive textiles: seating fabrics, convertible tops, and other components exposed to rain or spray.
  • Quality control in finishing: assessment of water-repellent finishes (e.g., DWR coatings) and verification of consistent performance in production.

The method is especially suited to materials where surface finishes or coatings are expected to repel liquid water, rather than materials designed to be fully waterproof (where hydrostatic pressure tests such as AATCC 127 / ISO 811 may be more appropriate).

Hydrostatic Pressure Test according to AATCC 127 / ISO 811

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