Refers to UL certification.

UL is the abbreviation of Underwriter Laboratories Inc. UL Safety Testing Institute is the most authoritative in the United States and the largest private institution engaged in safety testing and identification in the world. It is an independent, non-profit, professional organization that conducts experiments on public security. It uses scientific testing methods to study and determine whether various materials, devices, products, equipment, buildings, etc. are harmful to life and property and the degree of harm; it determines, writes, and issues corresponding standards and helps reduce and prevent hazards to life. We will collect information on property damage and conduct fact-finding research at the same time. In short, it is mainly engaged in product safety certification and business safety certification business. Its ultimate goal is to obtain products with a considerable safety level for the market and contribute to ensuring the safety of personal health and property. As far as product safety certification is an effective means of eliminating technical barriers to international trade, UL also plays an active role in promoting the development of international trade.

UL standards are a document that is constantly being improved. Requests for revision of UL standards are made by industry insiders, users, UL engineers or other interested parties. Industry modification procedures: When certain contents of the UL standard need to be modified, the product requirements will change accordingly. To this end, UL has formulated a formal industry modification procedure.

The effective date will be announced when each UL standard change is published. From the effective date, the relevant products belonging to UL's tracking inspection service must be changed accordingly according to the new requirements. Therefore, sufficient time is left between the date of standard revision and the announced effective date to allow factories to change their own product and submit it again for UL testing. Once the change request is formally adopted, the industry revision process is implemented. The procedure includes: sending a formal notice to the applicant, the starting date of the change, and having UL engineers help the applicant check the parts of the product that need to be changed according to the same method used to identify the product, and modify the UL factory tracking inspection document before the effective date. After the new standard takes effect, UL inspection representatives will visit the manufacturer to review the corresponding changes according to the revised requirements.