To separate conceptually control tests from calibration
To obtain an admission that there are no "assessors" in the province of Ontario
To obtain an admission that the historical maintenance records show a deterioration of performance - deterioration of linearity in this particular instrument
The strategy of using control tests as indication of reliability depends upon completeness of records and transparency
To obtain an admission that at the bottom of the valley in the infrared spectrum at approximately 9.4 microns, your detection limit will certainly be degraded and precision will also suffer in most instances, if you are no longer taking the reading at the absorbant’s maximum.
To obtain an admission as to what may happen if the detector becomes dirty.