
MRK-D-0034 V2.0
Aeroqual AQM 65 User Guide
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5.2 Guidelines for purchasing calibration gas cylinders and gas
regulators
The AQM 65 is calibrated using certified calibration gas cylinders from a reputable gas supplier.
Calibration gas is purchased at high concentrations, in a balance of air or nitrogen and then diluted to
a lower concentration using a gas dilution calibrator such as the Aeroqual AirCal 1000 or Aeroqual
AirCal 8000 gas dilution systems. Other gas dilution systems can also be used.
Span calibration gas must be delivered to the AQM 65 in a balance of Air.
Gas cylinders can purchased in a balance of Air or Nitrogen (N2). Calibration gas will be
diluted with air (at least 50 x) using a gas dilution calibrator so the final span gas mixture will
always be in a balance of air.
Aeroqual does not recommend calibrating from a cylinder of mixed gases. Only single gases
should be used to calibrate the AQM 65.
Calibration directly from a gas cylinder without dilution is not recommended.
Ozone is calibrated using an ozone calibrator (Ozone cannot be purchased in a cylinder).
CO2 is calibrated by direct injection of zero air from a cylinder and then CO2 from a cylinder
(via a tee) to the AQM 65 inlet, See Appendix 4 for details on CO2 calibration.
5.2.1 Purchasing calibration gas: recommended cylinder concentrations and
sizes.
Calibration gas should be purchased from a reputable calibration gas supplier, there are several such
suppliers worldwide. Aeroqual recommends Calgaz, (
) for portability. A list of Calgaz
part numbers for calibration gas cylinders which Aeroqual recommends is given in Table 5-1.
The Calgaz cylinders have a C10 (5/8
– 18 UNF) thread (C10 fitting) which easily fits the Aeroqual
two stage pressure gas regulator (Aeroqual part number
AIC GASREG01
), also shown in Figure 5-2
Note that two different cylinder types are specified; the 8AL cylinder is an aluminium cylinder which
holds 58 litres of gas, the physical size of this cylinder is shown in Figure 5-1. The 6D cylinder is a
steel cylinder which holds 103 litres of gas, it is the same physical size as the 8AL cylinder.
A single gas module calibration will use 1 to 2 litres per calibration if using the Aeroqual calibration
systems. This means that approximately 40 calibrations can be achieved with the 8AL cylinder and 70
calibration can be achieved with the 6D cylinder.