UL certification as an integral part of the column names in order to ensure the UL, UL approved products continue to meet the standards and requirements, UL developed a "test track" system. "Track Test" is sent by the distribution of UL's field representatives around the world to the local factory site to track the products on the UL test. Its purpose is to plant through the production process, inspection process and product control and tracking of UL standard test conditions for verification, to ensure that the manufacturer's production process, inspection process and the products always meet the UL requirements.

● basis for tracking test
In order to ensure that UL's "tracking test" implementation of the system, UL and the manufacturers have been signed between a "track inspection agreement", according to "track inspection agreement" provides on-site representative will periodically without prior notice to inspect factories , factory representatives shall not be unreasonably refused to field inspection.
Site representative to the factory, mainly based on "Tracking Test Conditions" for testing. "Tracking Test Rules" by UL engineering, inspection of the samples in the test preparation, this document includes a comprehensive description of the product, but also including photos] Manual. It also provides manufacturing facility during production often have to do various tests, some test requirements for 100% of the product, such as the pressure test. Some tests can be carried out sampling at the same time, also provides on-site inspection at the factory site representative must be spot checks of pilot projects. Field trials on behalf of the basis of such detailed information and test results provided to determine eligibility.

● Tracking the classification test
UL Class tracking test is divided into R and L classes. L type of service is mainly used for and safety-related products, such as fire extinguishers, smoke detectors, fire doors and a large number of output products, such as electrical equipment, wires and circuit breakers. Categories of products belonging to L, the production plant must be ordered directly to the UL label on the product. R type of service is mainly used in electrical equipment such as electric fans, televisions, hair dryers, ovens and other lines commonly used to produce the corresponding products