Every window and door goes through a journey of rigorous testing before it can display a DP rating. Here's what that process looks like and what those numbers actually mean for your wind load requirements.
From factory floor to approved product - watch a window earn its DP rating.
The manufacturer sends representative product samples to an accredited testing laboratory. These aren't cherry-picked - they're production units that must represent actual products customers will receive.
The window is sealed in a chamber and subjected to uniform air pressure at 1.5 times the target DP rating. A DP-50 window gets hit with 75 PSF. The product must hold without permanent deformation.
Water sprays at 5 gallons per hour per square foot while pressure is applied at 15% of design pressure. For DP-50, that's 7.5 PSF. No water can enter the interior side - zero tolerance.
Pass all tests and the product receives its official DP rating and product approval. The FL number or NOA is issued, documenting exactly which configurations were tested and approved.
What each design pressure level means for your wind load requirements.
Common questions about DP ratings and product wind certifications.
Get instant wind load calculations to know exactly what DP rating your project needs.