Calibration of survey instruments

1. The registrant shall ensure that the survey instruments used to show compliance with this chapter have been calibrated before first use, at intervals not to exceed twelve months, and following repair; 2. To satisfy the requirements of subsection 1, the registrant shall: a. Calibrate all required scale readings up to ten millisieverts (1,000 mrem) per hour with an appropriate radiation source that is traceable to the national institute of standards and technology (NIST); and b. Calibrate at least two points on each scale to be calibrated. These points should be at approximately one-third and two-thirds of full scale; 3. To satisfy the requirements of subsection 2, the registrant shall: a. Consider a point as calibrated if the indicated dose rate differs from the calculated dose rate by not more than ten percent; and b. Consider a point as calibrated if the indicated dose rate differs from the calculated dose rate by not more than twenty percent if a correction factor or graph is conspicuously attached to the instrument; 4. The registrant shall retain a record of each calibration required in subsection 1 for three years. The record shall include: a. A description of the calibration procedure; and b. A description of the source used and the certified dose rates from the source, and the rates indicated by the instrument being calibrated, the correction factors deduced from the calibration data, the signature of the individual who performed the calibration, and the date of calibration; and 5. The registrant may obtain the services of individuals registered by the department, or licensed by the United States nuclear regulatory commission, an agreement state, or a licensing state to perform calibrations of survey instruments. Records of calibrations that contain information required by subsection 4 shall be maintained by the registrant.