NAFA Guide to Air Filtration questions and
answers with solutions
Quantity of air is expressed in cubic feet per minute (CFM) and is represented by the letter? -
ANSWER Q
The Velocity of air is expressed in feet per minute and is represented by the letter? - ANSWER V
The area of a filter is expressed in square feet and is represented by the letter? - ANSWER A
Formula for Airflow through a filter is - ANSWER Q=VA
Static Pressure (SP) - ANSWER in a duct exerts itself in all directions at once. "bursting pressure"
SP is independent of the velocity of the air and can be either negative or positive.
Velocity Pressure (VP) - ANSWER is only measured in the direction of flow and is always positive.
PItot Tube - ANSWER Both Static and Velocity Pressure can be measured with an instrument
called?
Formula for Total Pressure (TP) - ANSWER Velocity Pressure plus Static Pressure combine to give
you total Pressure (TP) in a system. TP=SP+VP
Because filters add resistance to flow into the system, increasing filter pressure drop - ANSWER
decreases air flow velocity.
Mechanical air filters - ANSWER remove dust by capturing it on the filter media, the material
that comprises the filter element.
answers with solutions
Quantity of air is expressed in cubic feet per minute (CFM) and is represented by the letter? -
ANSWER Q
The Velocity of air is expressed in feet per minute and is represented by the letter? - ANSWER V
The area of a filter is expressed in square feet and is represented by the letter? - ANSWER A
Formula for Airflow through a filter is - ANSWER Q=VA
Static Pressure (SP) - ANSWER in a duct exerts itself in all directions at once. "bursting pressure"
SP is independent of the velocity of the air and can be either negative or positive.
Velocity Pressure (VP) - ANSWER is only measured in the direction of flow and is always positive.
PItot Tube - ANSWER Both Static and Velocity Pressure can be measured with an instrument
called?
Formula for Total Pressure (TP) - ANSWER Velocity Pressure plus Static Pressure combine to give
you total Pressure (TP) in a system. TP=SP+VP
Because filters add resistance to flow into the system, increasing filter pressure drop - ANSWER
decreases air flow velocity.
Mechanical air filters - ANSWER remove dust by capturing it on the filter media, the material
that comprises the filter element.
