AQ EXPERT Instruction & Operations Manual
Version 1.13
Page 33 of 63
B. SPAN CALIBRATION
E Instruments recommends performing a span calibration of the instrument once every
6 months for maximum accuracy, or at a minimum of once per year. The parameters
that require a span calibration are: carbon monoxide, carbon dioxide, nitric oxide,
nitrogen dioxide, sulfur dioxide, hydrogen sulfide, oxygen, formaldehyde, and VOCs.
You can carry out all span calibrations in sequence.
Span calibration using your own gas
If you wish to use your own span gas to perform span calibrations, you must take
certain precautions and follow the instructions below carefully in order to calibrate the
sensors properly.
Notice that you will need a number of certified gas cylinders. Make sure that you use a
bypass flow meter as shown below in the CALIBRATION APPARATUS section, in order
to supply an adequate flow of span gas without developing excessive or insufficient
pressure on the sensors.
NOTE: You must always span calibrate the instrument when a sensor is replaced.
