Relocated Monitor and a Request to Use the Low Result
A landlord hires a measurement professional to test a three-unit building before renting the basement apartment. Three continuous monitors are deployed for 48 hours, one in each unit. On retrieval, the basement monitor is not where it was placed; the landlord says a cleaner moved it to a kitchen cabinet and unplugged it for about six hours because the cord was in the way. The monitor's log shows a six-hour data gap and a tilt event. The other two monitors read 5.0 and 4.6 pCi/L. The basement monitor's partial data average 1.1 pCi/L. The landlord asks the professional to use the 1.1 result because the basement apartment is the one that must be rented, and offers to sign a statement that the unit was closed and undisturbed. The professional must decide whether the basement result is valid, what to do before reporting, and how to handle the landlord's request.
1. Is the basement monitor's 1.1 pCi/L result valid? What in the record supports your decision?
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No. The monitor was moved from its placement and unplugged for about six hours, and the log shows both a data gap and a tilt event. A result from a device that was relocated to a kitchen cabinet and lost power is not a valid measurement of the basement apartment. The partial data period after the move is not representative, and the missing hours cannot be reconstructed. The landlord's offer to sign a statement that the unit was undisturbed does not cure the problem; the device record contradicts the statement, and the measurement professional cannot rely on a client's assurance to override the instrument log. The other two monitors at 5.0 and 4.6 pCi/L do not substitute for a basement test. The basement unit needs a new test with a properly placed device and documented conditions.
2. What should the professional do before issuing any report?
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Document the condition of the device on retrieval, the placement location, the six-hour gap, the tilt event, and the landlord's explanation. Photograph the device and the original and found locations if possible. Do not edit the data or interpolate the missing period. Notify the landlord in writing that the basement result is invalid and explain why. Schedule a new 48-hour test in the basement apartment under closed-house conditions, with the monitor placed in the lowest livable level away from exterior walls, doors, and appliances. Consider deploying a duplicate in the basement to provide a precision check. Confirm that no one will move or unplug the device, and record the serial number and placement. Only after a valid test should a report be issued for that unit.
3. How should the request to use the low result be handled?
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Refuse the request. The 1.1 pCi/L result cannot be reported as the basement apartment result because the monitor was moved and lost power. Using it would misrepresent an invalid measurement and could lead to renting a unit without knowing its radon level. Explain to the landlord that the statement about the unit being undisturbed is inconsistent with the device log and that your report must reflect the record. Offer the retest and a clear timeline. If the landlord insists on the 1.1 result or asks you to omit the data gap, decline and document the exchange. The professional obligation is to report valid measurements and to protect occupants, not to provide a favorable number for a rental transaction.