Overview
SIST EN 29865:1999 is a European Standard that specifies a precise method for determining the water repellency of textile fabrics. This method employs the Bundesmann rain-shower test, which simulates exposure of fabrics to artificial rain under controlled laboratory conditions. The standard is harmonized with ISO 9865:1991 and is published by the European Committee for Standardization (CEN).
The document details the entire testing process-from preparing fabric specimens and conditioning atmospheres to apparatus calibration, execution of the rain shower test, and evaluation of results. It is designed to assess the effectiveness of water-repellent finishes on textiles and provides a consistent, reliable approach for quality control and product development within the textile industry.
Key Topics
- Test principle: Fabrics are exposed to a uniform artificial rain shower using the Bundesmann apparatus to evaluate the fabric’s water repellency through direct observation and absorbency measurements.
- Specimen preparation: Circular fabric samples (140 mm diameter) are cut avoiding material edges and conditioned in specific atmospheres, typically at 65% relative humidity and either 20°C or 27°C.
- Rain shower apparatus: Includes calibrated drop-forming devices producing water drops of about 4 mm diameter, ensuring a flow rate of 100 ± 5 ml/min over an 80 cm² test surface.
- Specimen mounting: Samples are clamped on special cups, designed to collect water penetrating the fabric, with a wiper mechanism simulating natural water run-off.
- Centrifugation step: After exposure, specimens undergo centrifugation for 15 seconds to remove excess water; weights are measured pre- and post-test to quantify water absorption.
- Visual assessment: Water repellency grades from 1 to 5 are assigned by comparing wet samples with reference photographs-ranging from fully wetted to fast runoff with minimal water adherence.
- Data reporting: Test reports must document testing equipment, water properties (temperature, pH, hardness), durations of rain exposure and centrifugation, quantitative absorption data, and qualitative water repellency grades.
Applications
The EN 29865 Bundesmann rain-shower test is essential for:
- Quality control: Manufacturers use this test to verify the durability and effectiveness of water-repellent finishes on textiles such as outdoor clothing, upholstery, technical fabrics, and protective gear.
- Research & development: Enables precise evaluation of new hydrophobic treatments or coatings under reproducible simulated rain conditions.
- Compliance testing: Supports regulatory and certification processes by providing standardized data on fabric water repellency performance.
- Material selection: Assists designers and specifiers in choosing appropriate textiles for products expected to withstand exposure to wet conditions.
- Performance benchmarking: Facilitates comparison of competing textile products and finishing technologies on an objective basis.
Related Standards
- ISO 139:1973 – Specified standard atmospheres for textile conditioning and testing, referenced within EN 29865 to ensure consistent environmental test parameters.
- ISO 9865:1991 – The equivalent international standard that details the Bundesmann rain-shower test method for water repellency in textiles.
- Other textile performance standards relevant to water resistance, e.g., ISO 811 (water resistance: hydrostatic pressure test) or EN 343 (protective clothing against rain).
By adhering to SIST EN 29865:1999, textile professionals can objectively evaluate and certify the water-repellent properties of fabrics, ensuring product reliability and consumer confidence in wet-weather performance. The standard's rigorous methodology and detailed reporting requirements promote consistent testing worldwide and foster innovation in water-repellent textile treatments.
