Industry Tests & Specifications

1 drop, 3 drop, FED STD 191, Method 5516. A water column is raised to determine the height at which drops of water permeate the fabric. The higher the water column, the more pressure is applied. It is measured at 1 drop & 3 drops. The higher the number, the more water resistant the fabric is.
This is equivalent to water "resting" on a fabric and the results equates to how resistant the fabric will be to letting the water permeate.

Spray Rating, AATCC-22-1974. Specific amount of water is poured over a fabric at a 45 degree angle.
A visual inspection is made and a comparison is then made to a chart, which equates to a number rating. 100 is the best. The higher the number the more the fabric will repel water. This test equates to the fabrics water repellent performance in the rain.