What is AMCA 500-L Wind Driven Rain?

The AMCA 500-L Wind Driven Rain standard is a dynamic water test for louver products and is not to be confused with AMCA 550 High Velocity Wind Driven Rain, which is a requirement of the Hurricane Prone Region. The AMCA 500-L Wind Driven Rain test simulates horizontal driving rain by positioning a wind-generating fan that simulates either a 29 MPH or 50 MPH external wind. Between the wind-generating fan and the louver test specimen, water spray nozzles drive either 3 or 8 in. rain/hr. at the louvers (29 MPH/3 in. rain/hr., 50 MPH/8 in. rain/hr.). A fan attempts to pull water through the louver from a fully enclosed chamber behind the louver. The louver is given a letter grade rating at specific escalating inlet velocities, which defines the percentage of water rejection (A = 99%, B = 95% - 98.9%, C = 80% - 94.9%, D = <80%).