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Retrotec Energy Innovations, Ltd.
DM-2A Mark II 2008-02-22
• Flow Pressure The pressure difference between inside the fan (in the flow stream)
and ambient air, outside the fan.
• Room Pressure The pressure difference between inside the building/room under
test and the ambient outside air.
• Pascal (Pa) Often abbreviated to Pa, this represents a very small metric unit of
pressure. There are 249 Pascals in 1 water column. A water column is the pressure
required to push water up 1 inch in a tube. One Pascal = 0.000145 pounds per square
inch.
Abbreviations
• /h Per hour
• cfm Cubic feet per minute
• cm
2
Square centimeters
• fpm Feet per minute
• fps Feet per second
• ft
2
Square feet
• in wc Inches of water column
• in
2
Square inches
• km/h Kilometers per hour
• l/s Liters per second
• m/s Meters per second
• m
2
Square meters
• m
3
/h Cubic meters per hour
• m
3
/s Cubic meters per second
• mph Miles per hour
• Pa Pascals
• PSF Pounds per square foot
• Sig Fig Significant figures
• l/s/m
2
Liters per second per square meter
• NLA Normalized leakage area
DM-2A Mark II Dual-Channel Pressure Gauge User Manual
B: Glossary
