Thermo Scientific MIRAN 205B Series, Instruction Manual, Page: 195 / 214

MIRAN SapphIRE Field Performance Verification Kit
E-5
5.
Mark the gas tank in large letters "MT" to denote that it has been used to
perform a gas check.
6. Dispose of the tank properly. The tank should never be refilled.
Assessing the Results
Provided there are no significant deviations from the pressure or temperature at which the
original calibrations were performed, the displayed readings should fall within the
following ranges of values:
Calibration
Gas
Expected
Result
Allowed Calibration
Tolerance
Allowed Sample
Tolerance
Overall
Tolerance
Nitrous Oxide 25.0 ppm ±2.5 ppm ±0.5 ppm ±3.0 ppm
Sulfur
Hexafluoride
1.0 ppm ±0.2 ppm ±0.02 ppm ±0.22 ppm
Call the factory if the actual readings recorded during this test are outside these limits.
There are several reasons why this may occur:
1. Readings a few percent outside the overall tolerance should not be cause for
alarm as these can often be accounted for by pressure or temperature deviation
from the original calibration point. Of course, if atmospheric pressure is quite
different, (usually lower) then this should be factored into the review.
2. Readings substantially lower may indicate an alteration in the internal optical
alignment of the gas cell. Again, consult the factory for assistance.
3. Discordant readings are generally not caused by deterioration in the absolute
signal levels within the instrument, such as may be caused by dirty optical
components. Normally, this only affects the reading noise and not the actual
instrument span.
Once the analysis is completed, secure the sampling accessory in a safe place and
properly dispose of the gas cylinder. Do not dispose of the cylinder in a fire or
incinerator. Tanks are not to be refilled. There may be some slight positive pressure
remaining in the tank. If so, discharge the remaining contents until there is no further
audible evidence of gas flow out of the tank, remembering always to have the tank nozzle
pointed away from the face and body as it is released to atmospheric conditions.