Neutral pressure plane

Insulation · The Basics · printed page 234 (PDF page 235)

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Neutral Pressure Plane Pressure Plane – Neutral Insulation – the Basics

Text in the illustration

outside
pressure
higher pressure
exfiltrating air
neutral pressure plane
lower pressure
infiltrating air
note:
assumes calm conditions (no wind)

Generated explanation

A schematic house section illustrates indoor air pressures relative to outside pressure under calm, no-wind conditions. A dashed horizontal line marks the neutral pressure plane, where the indoor and outdoor pressures are equal. Above this plane, higher indoor pressure drives air outward through the upper walls and roof, shown by red exfiltration arrows. Below the plane, lower indoor pressure draws outside air inward through the lower walls, shown by gray infiltration arrows. Pressure gauges indicate the relative pressures outside, above, at, and below the neutral plane.

Components

roof exterior walls intermediate floor lower floor building envelope