Kewaunee Air Alert 600, Installation And Operating Manual, Page: 36 / 48

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6.4 Calibration Notes
1. When using a standard Fume Hood with Vertical Sliding sash, open the sash to the normal max
safe working height for the Low Air sample.
2. For the Higher Air sample close the sash to approx. 50% of the opening used for the Lower Air
sample. If the Higher air sample value is too close to the Lower Air sample the alarm will detect
this and ask you to repeat with a higher value. To do this, close the sash a little more and repeat
the sample. Avoid closing the sash below 4 inches.
3. The face velocity readings on the open sash may vary at different points on the measuring grid
by up to 20 FPM. This is quite acceptable in terms of the fume hood performance, so long as
no individual point is below the designated Low Air alarm point. The figure entered for the
calibration point should be taken as the average value of all the measuring grid readings.
4. Take time when measuring the face velocities for the calibration procedure to allow for the
velocities across the open sash to stabilize. If the velocities are changing or are turbulent during
the sampling period the alarm will detect this and ask you to repeat the sample.
5. When using a Fume Hood with Horizontal Sliding sashes, open the sashes to the normal max
safe working opening for the Low Air sample.
6. For the Higher Air sample close the sash to approx. 50% of the opening used for the Lower Air
sample. If the Higher air sample value is too close to the Lower Air sample the alarm will detect
this and ask you to repeat with a higher value. To do this, close the sash a little more and repeat
the sample.