The standard system of UL certification
 

The UL certification standards, which involve almost all types of products, are the basis for product identification. UL published more than 500 standards, 70% of which were accepted by the National Institute of standards (ANSI) as U. S. National standards.
 
1, the structure of UL certification standard
Generally speaking, the structure of UL certification standards can be roughly divided into:
(1)     the range of products covered by the standard;
(2)     Product structure requirements;
(3)     Requirements for raw materials used in the product;
(4)     Requirements for components used in the product;
(5)     UL laboratory’s requirements and test methods for sample test instruments;
(6)     Requirements and test methods for the test equipment of manufacturer's plant;
(7)     Product labeling and instruction requirements.
 
2, Revision of UL certification standards
The UL standard is a constantly improving document. The requirements of the revision for the UL certification standards are presented by industry professionals, users, UL engineers, or other interested persons.
 
The industry change process:
When there are some content of the UL certification standard needs to be modified, the requirements of the product will change accordingly, so UL has made a formal industrial modification procedure for this purpose.
 
The effective date is announced when each change in the UL certification standards is published. On the effective date, the products belonging to the UL tracking inspection service must be changed accordingly according to the new requirements, so there is plenty of time between the date of the revision and the effective date of the publication, so that the factory can change its product and submit the UL test again.
 
After the formal adoption of the change request, you can implementation of the industrial amendment process. The program includes: send formal notification to applicant, start date of change, and the UL engineer will assist the applicant in checking the parts that need to be changed in accordance with the same method of identifying the product, and modify the UL factory in the effective date before tracking inspection documents.
 
After the new UL certification standard comes into effect, the UL inspection represents that will visit the manufacturer and according to the revision requirements to review the relevant changes.