Water Barrier
Resistance of a fabric to penetration by water under increasing pressure determines its performance in outdoor apparel and medical protective gear. This hydrostatic head resistance is measured by the height of a water column that the fabric can support before three drops penetrate the textile surface. The test establishes the waterproof rating of a material, which helps garment brands classify its suitability for different weather conditions.
Testing Procedure
Standard laboratories mount the fabric specimen securely in a clamp where water is pumped against one side at a steady rate. This method determines the hydrostatic head resistance of the material under controlled conditions. When the first droplets penetrate the fabric, the pressure is recorded in millimeters of water gauge.
Coating Influence
Polyurethane coatings and laminated membranes provide the highest level of protection against water penetration. These treatments increase the hydrostatic head resistance to levels exceeding ten thousand millimeters, which is required for heavy rainwear. Without these barriers, plain fabrics rely on tight construction or water repellent finishes, which fail at much lower pressures.
Garment Durability
Wear and tear during active use can reduce this barrier performance over time. When the fabric is flexed, micro-cracks develop in the coating, lowering the hydrostatic head resistance.
