Out of Tolerance - Low Flow

There are two operational conditions for the photometer to consider when looking at low sample flow tolerances. The sample flow being found beneath the operational tolerance range would result in a slight increase in the photometer response (<10%) when operated using the Internal Reference for setting the 100% upstream concentration. This would have the effect of overstating leakage rates and providing a more conservative leakage test result than typical. Using the worst case as an example, a 0.0090% leak would present as 0.0100%.

If the 100% setting was performed by sampling the upstream aerosol the flow out of tolerance condition would have no measurable effect on the leak values measured. Standard instrument accuracy levels would remain unchanged.