UL calibration requirements:  equipment used for UL/C-UL/ULC Mark Follow-Up Services

It is important for both manufacturers and UL to have confidence in the validity and accuracy of inspection, measuring and test results. Use of calibrated Inspection, Measuring and Test Equipment (IMTE) is a key element in the system of controls used by manufacturers to achieve compliance with UL requirements.

All IMTE required as part of the UL Follow-Up Services procedure or used by the UL Representative in the conduct of inspection activities at the factory must be calibrated and included in a calibration system at the manufacturer. To facilitate a common understanding of calibration requirements, UL has developed a calibration requirements document for our customers.

For information related to calibration traceability, please consult your country's national standards body. In the United States, the National Institutes of Standards and Technology Web site provides additional information related to traceability, measurement uncertainty and metrology.