15
Delayed Results
Test results can be displayed, printed, or downloaded later or at another location,
provided you understand the following differences:
• When power is disconnected, the value of the latest partial interval and the
CUR value are lost from temporary memory.
• When power is on (including battery power) Model 1027 continues to
operate, providing values that are averaged into the result.
•If you take an AVG reading, disconnect power, restore power later and take
a second reading, the second AVG reading may be slightly different from the
first reading. This is because the first AVG reading includes the value for the
partial one hour interval in process. This partial value is stored in temporary
memory and is lost when power is disconnected.
This second AVG value is calculated using only completed intervals stored
in non-volatile memory.
Interpreting Results
The Model 1027 radon monitor is calibrated by setting internal switches to
determine the calibration J-factor, which provides the conversion between counts
per hour and pCi/L for that Model 1027. A separate calibration factor is also
calculated and printed on the calibration report.
The Model 1027 automatically multiplies the hourly measurements by the
J-factor to yield the actual pCi/L to within 5%, and then displays these results on
the printed report.
To improve accuracy, the user can manually multiply the measurement results by
the calibration factor that is listed on the calibration report for the Model 1027.
The measurement results on the printed report are calculated as follows:
• The hourly measurements are the number of counts recorded during that
hour, times the J-factor, rounded to the nearest 0.1 pCi/L.
• The Overall Average is the number of total counts, divided by the number of
hours, times the J-factor, then rounded to the nearest 0.1 pCi/L.
• The EPA Protocol Average is calculated the same as the Overall Average,
excluding the first four hours of measurements.
Note that the average of the displayed hourly measurements and the reported
averages may not be the same. This is due to differences in the rounding. As
described above, the displayed hourly measurements are rounded each hour,
while each average is only rounded once. The reported average is thus a more
accurate measurement than averaging the displayed hourly measurements.
If the EPA Protocol Average is close enough to the 4.0 pCi/L EPA threshold that
rounding is a possible issue, additional radon measurements should help to
determine the actual radon level.
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