8
SECTION 5
Helpful Information in Using
Rotating Vane Anemometers
When used in airstreams of similar size to or
smaller than the RVA+ head, blockage effects
may occur. Velocity readings should be
considered a relative measurement in this case.
This effect is somewhat variable depending on
the size of the airway and the distance from the
duct walls. If the area is larger than 2.15 ft
2
(0.2 m
2
) the effect should be minimal.
Note
: The RVA+ can display an averaged
result of multiple readings in both
velocity and volumetric modes.
Flow Rate in Larger Areas
When checking air velocity or volume flow rate
over large areas, multiple spot readings should
be taken. When taking multiple readings, it
should be noted that large variations may be
observed between individual readings. In
general, the more readings taken, the more
accurate the averaged result will be.