Underwriter Laboratories (UL), is a non profit organization dedicated to certify and security testing of products and equipments. UL is one of the must recognized and credited advisors in the world.
Underwriters Laboratories Inc. was established on 1894 by William H. Merrill. On 1903 it’s first standard was published: “Tin Clad Fire Doors”. Following year, UL started to validate extinguishers. UL inspectors run the first direct inspections to origin manufacturing plants of each product and currently they have expand their testing laboratories to over 60 units, serving clients in more than 100 countries.
UL does not approve products but evaluate them to establish requirement compliance and only accepted products has UL stamp. A UL manufacturer has to prove the fulfillment of all security requirements, a lot of which have been developed by UL itself. Manufacturer has to prove that each copy of it’s products complies with the specific requirements as the one tested. UL coordinates periodic “non announced” inspections to manufacturers to verify consistent compliance. UL has developed more than 1,000 security standards, must of them are included in the American National Standards (ANSI). A typical standard includes not only the requirements for electronic security but for mechanical and fire risks. UL develops it’s standards relating them with other installation codes as “NEC”.
UL logo means that a product is approved as long as security requirements for it’s normal operation. It also means that periodical testing of manufacturing facilities certified by UL are confirming it’s security status.