Faster GLOVEFAST ASEPTIC, Operating And Maintenance Manual

Page: 41 / 65

a D:GROUP Company
0254EN
– Rev. 06 – 09/2019
Page 41 of 65
15 TESTS PERFORMED ACCORDING TO EN 14644-3 STANDARD
15.A MEASUREMENT OF LAMINAR AIRFLOW VELOCITY
The LAF velocity is measured at 250 mm under the HEPA filter taking the reading in at least 8 points:
In our tests the readings are taken in 12 points as above-diagrammed. Each one of the 12 readings lasts at
least 1 minute. The velocity is measured with a hot-wire thermo anemometer with the following features:
Measure-Range
0

2 m/s
Precision (of the device including the probe) +/- 0.05 m/s +/- 5%
Working temperature From
– 20 to + 70°C.
Resolution m/s
The average velocity is obtained by the following formula:
Average velocity = (V
1
+ V
2
+…+V
n
) / n
n = number of readings points
V
1
, V
2
…V
n
= velocities measured in the various points.
The average velocity must be 0,45 m/s
Ensure that no single measurement differs from the average of all the measures by +/- 20 %.