(A) A licensee shall calibrate the survey instruments used to show compliance with this chapter and Chapter 3701:1-38 of the Administrative Code before first use, annually, and following a repair that affects the calibration. A licensee shall:
(1) Calibrate all scales with readings up to ten millisievert (one thousand millirem) per hour with a radiation source;
(2) Calibrate two separate readings on each scale or decade that will be used to show compliance; and
(3) Conspicuously note on the instrument the date of calibration.
(B) A licensee may not use survey instruments if the difference between the indicated exposure rate and the calculated exposure rate is more than twenty per cent.