What type of design is less effective in preventing water penetration in window systems?

The concave design is less effective in preventing water penetration in window systems primarily due to its shape, which can create pockets where water may accumulate. Unlike other designs, which actively direct water away from the structure, the concave profile might promote water retention, leading to an increased risk of leaks.

In contrast, pressure-equalized designs effectively manage airflow and minimize water intrusion by balancing pressure differences, helping to prevent water from entering through the window assemblies. Vertical drainage designs enhance water management by allowing water to flow freely downward and away from the window, reducing the chances of water accumulation. Flat designs can also offer some level of water management, but they may not be as effective in controlling water flow as more specialized designs. Overall, the unique shape of the concave design contributes to its reduced effectiveness in water penetration prevention in comparison to these other options.