What is the most effective design to protect window systems from water penetration?

The most effective design to protect window systems from water penetration is the pressure-equalized design. This design approach works by allowing air to move behind the wall system, equalizing the pressure on both sides of the window or wall. By balancing pressure, it reduces the driving force of water intrusion during rain events or high winds.

In a pressure-equalized system, any water that may infiltrate through joints or penetrations is effectively managed, allowing it to drain away rather than accumulate and cause damage. This method is particularly advantageous in climates that experience heavy rainfall or high wind conditions, as it provides a robust barrier against potential leaks.

The other design types, while they may offer some level of water resistance, do not provide the same level of effectiveness in mitigating water penetration. For instance, slope design directs water away by grading surfaces, but it doesn't address pressure differentials that can facilitate leaks. Continuous bead design focuses on sealant application but may still fail under high-pressure scenarios. Closed design can help reduce openings for water entry but might not be as effective in managing pressure differences as the pressure-equalized design.