Why can the wrong louver type pull rain into a high-velocity intake?

Field answer

Some louvers shed normal rain but cannot separate water at high intake velocity or severe wind exposure. If the face velocity is too high for the louver type, water can carry through into filters, plenums, and equipment.

Check face velocity, louver model, drainable blade design, filter/plenum water marks, and the submittal performance rating. The likely recovery is a correctly rated storm/wind-driven-rain louver, added moisture separation, or revised intake design by the engineer/detailer.

What to check first

• Look for water past the louver blades, in filters, or in the plenum.
• Check the louver model/submittal against face velocity and rain performance.
• Confirm whether the blade style is drainable/storm-rated.
• Make sure weeps and sill pan are open.
• Escalate selection mismatch before repeated water damage occurs.

Why it matters

Wrong louver selection can soak filters, damage equipment, and flood the intake plenum.

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Final direction belongs to the foreman, approved drawings/specs, manufacturer instructions, pressure/material schedule, employer policy, and AHJ/code requirements.