Most purging applications require a minimum enclosure pressure of 0.10 inches (2.5 mm) of water. One psi is equal to 27.7 inches of water. In some circumstances, a minimum enclosure pressure of 0.50 inches (12.7 mm) of water is required to protect against ignitable DUST. But in all cases, a higher enclosure pressure should be maintained to CREATE a reasonable SAFETY factor. In rare circumstances, enclosure pressures as high as 2.5inches (63.5mm) of water may be required to offset sudden atmospheric pressure fluctuations, such as those created near MISSILE LAUNCHING or off-shore drilling platforms.

Most purging applications require a minimum enclosure pressure of 0.10 inches (2.5 mm) of water. One psi is equal to 27.7 inches of water. In some circumstances, a minimum enclosure pressure of 0.50 inches (12.7 mm) of water is required to protect against ignitable dust. But in all cases, a higher enclosure pressure should be maintained to create a reasonable safety factor. In rare circumstances, enclosure pressures as high as 2.5inches (63.5mm) of water may be required to offset sudden atmospheric pressure fluctuations, such as those created near missile launching or off-shore drilling platforms.