Friction|equal ________ method is a method of sizing air distribution systems by designing for a consistent amount of pressure loss per unit length of duct (usually 100 feet).
Fan|____ brake power is the actual total power needed to drive a fan to deliver the required volume of air through a duct system. 
Homogeneous|a mixture of material that is uniform in its composition throughout.
R-value|a unit of measure for the thermal resistance of a given insulating material.
Regain|static _______ method is a method of sizing ducts such that the regain in static pressure due to a decreasing velocity between two points fully or partially makes up for the frictional resistance between the two points. 
Thermal conductivity|the heat flow per hour (Btuh) through one square foot of one-inch thick homogeneous material for every 1-degree F of temperature difference between the two surfaces.
U-factor|the unit of measure for thermal conductivity.
Reduction|velocity _________ method is a method of sizing ducts such that the desired velocities occur in specific duct lengths.