A question, if
Inspector “A” does a passive radon test, he sets his test kit 18 inches away from a wall and 30 inches off the floor. 48 inches away is an active A/C return vent. Inspector “A” has a high radon reading. Inspector “B” is asked to do a follow up test (time is limited) Inspector"B" sets up a CRM in the same position, distance from the wall and height off the floor and 48 inches from the active A/C return vent
I am inspector “B” , is this comment true?
“As with a typical follow-up measurement I placed a CRM in the same location as I was advised the initial screening was taken from, for a comparison this may work, however the actual measurements I believe to be in error due to the proximity of the measuring devices and the return air vent for the HVAC system. I believe that[FONT=‘Helvetica’,‘sans-serif’] Charcoal Liquid Scintillation, a passive radon measurement device such as the one I am led to believe was used for the original screening placed in close proximity (48 inches) to an active vent may yield a higher Radon Measurement than is actually present. These same conditions may cause a CRM or active Radon Measurement device to yield a higher Radon Measurement as well, however it being an active test device I believe it to be influenced less by the above stated conditions. I suggest a properly done retest to obtain accurate measurements.”[/FONT]
or, would these conditions effect a CRM differently than I am thinking?