UL is an American safety consulting and certification company headquartered in Northbrook, Illinois. It maintains offices in 46 countries. Established in 1894 as the Underwriters' Electrical Bureau (a bureau of the National Board of Fire Underwriters), it was known throughout the 20th century as Underwriters Laboratories and participated in the safety analysis of many of that century's new technologies, most notably the public adoption of electricity and the drafting of safety standards for electrical devices and components.
UL provides safety-related certification, validation, testing, inspection, auditing, advising and training services to a wide range of clients, including manufacturers, retailers, policymakers, regulators, service companies, and consumers.
UL is one of several companies approved to perform safety testing by the US federal agency Occupational Safety and Health Administration (OSHA). OSHA maintains a list of approved testing laboratories, which are known as Nationally Recognized Testing Laboratories.
Underwriters Laboratories Inc. was founded in 1894 by William Henry Merrill. Early in his career as an electrical engineer in Boston, a 25-year-old Merrill was sent to investigate the World Fair’s Palace of Electricity. Upon seeing a growing potential in his field, Merrill stayed in Chicago to found Underwriters Laboratories.
Merrill soon went to work developing standards, launching tests, designing equipment and uncovering hazards. Aside from his work at UL, Merrill served as the National Fire Protection Association’s secretary-treasurer (1903–1909) and president (1910–1912) and was an active member of the Chicago Board and Union Committee. In 1916, Merrill became UL’s first president.
UL published its first standard, “Tin Clad Fire Doors”, in 1903. The following year, the UL Mark made its debut with the labeling of a fire extinguisher. In 1905, UL established a Label Service for certain product categories that require more frequent inspections. UL inspectors conducted the first factory inspections on labeled products at manufacturers’ facilities—a practice that remains a hallmark of UL’s testing and certification program.
UL has expanded into an organization with 64 Laboratories, testing and certification facilities serving customers in 104 countries. It has also evolved from its roots in electrical and fire safety to address broader safety issues, such as hazardous substances, water quality, food safety, performance testing, safety and compliance education and environmental sustainability.
In 2012, UL transformed from a non-profit company into a for-profit corporation.
UL Standards
Sustainability Standards
UL 106, Standard for Sustainability for Luminaires (under development)
UL 110, Standard for Sustainability for Mobile Phones
Standards for Electrical and Electronic Products
UL 153, Portable Electric Lamps
UL 197, Commercial Electrical Cooking Appliances
UL 796, Printed-Wiring Boards
UL 1026, Electric Household Cooking and Food Serving Appliances
UL 1492, Audio/Video Products and Accessories
UL 1598, Luminaires
UL 1642, Lithium Batteries
UL 1995, Heating and Cooling Equipment
UL 6500, Audio/Video and Musical Instrument Apparatuses for Household, Commercial and Similar General Uses
UL 60065, Audio, Video and Similar Electronic Apparatuses: Safety Requirements
UL 60335-1, Household and Similar Electrical Appliances, Part 1: General Requirements
UL 60335-2-24, Household and Similar Electrical Appliances, Part 2: Particular Requirements for Motor Compressors
UL 60335-2-3, Household and Similar Electrical Appliances, Part 2: Particular Requirements for Electric Irons
UL 60335-2-34, Household and Similar Electrical Appliances, Part 2: Particular Requirements for Motor Compressors
UL 60335-2-8, Household and Similar Electrical Appliances, Part 2: Particular Requirements for Shavers, Hair Clippers and Similar Appliances
UL 60950, Information Technology Equipment
UL 60950-1, Information Technology Equipment - Safety, Part 1: General Requirements
UL 60950-21, Information Technology Equipment - Safety, Part 21: Remote Power Feeding
UL 60950-22, Information Technology Equipment - Safety, Part 22: Equipment to be Installed Outdoors
UL 60950-23, Information Technology Equipment - Safety, Part 23: Large Data Storage Equipment
Life Safety Standards
UL 217, Single- and Multiple- Station Smoke Alarms
UL 268, Smoke Detectors for Fire Protective Signaling Systems
UL 268A, Smoke Detectors for Duct Application
UL 1626, Residential Sprinklers for Fire Protection Service
UL 1971, Signaling Devices for the Hearing Impaired
Standards for Building Products
UL 10A, Tin-Clad Fire Doors
UL 20, General-Use Snap Switches
UL 486E, Equipment Wiring Terminals for Use with Aluminum and/or Copper Conductors
UL 1256, Fire Test of Roof/Deck Constructions
Standards for Industrial Control Equipment
UL 508, Industrial Control Equipment
UL 508A, Industrial Control Panels
UL 508C, Power Conversion Equipment
Standards for Plastic Materials
UL 94, Tests for Flammability of Plastic Materials for Parts in Devices and Appliances
UL 746A, Polymeric Materials: Short-Term Property Evaluations
UL 746B, Polymeric Materials: Long-Term Property Evaluations
UL 746C, Polymeric Materials: Use in Electrical Equipment Evaluations
UL 746D, Polymeric Materials: Fabricated Parts
UL 746E, Polymeric Materials: Industrial Laminates, Filament Wound Tubing, Vulcanized Fiber and Materials Used in Printed-Wiring Boards
UL 746F, Polymeric Materials: -– Flexible Dielectric Film Materials for Use in Printed-Wiring Boards and Flexible Materials Interconnect Constructions
Standards for Wire and Cable
UL 62, Flexible Cords and Cables
UL 758, Appliance Wiring Material
UL 817, Cord Sets and Power Supply Cords
UL 2556, Wire and Cable Test Methods
Standards for Canada developed by ULC Standards, a member of the UL family of companies
CAN/ULC-S101-07, Standard Methods for Fire Endurance Tests of Building Construction and Materials
CAN/ULC-S102-10, Standard Methods of Test for Surface-Burning Characteristics of Building Materials and Assemblies
CAN/ULC-S102.2-10, Standard Methods of Test for Surface-Burning Characteristics of Flooring, Floor Coverings, and Miscellaneous Materials and Assemblies
CAN/ULC-S104-10, Standard Methods for Fire Tests of Door Assemblies
CAN/ULC-S107-10, Standard Methods for Fire Tests of Roof Coverings
CAN/ULC-S303-M91 (R1999), Standard Methods for Local Burglar Alarm Units and Systems
Photovoltaic
UL 1703, Photovoltaic Flat-Plate Modules
UL 1741, Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy Resources
UL 2703, Rack Mounting Systems and Clamping Devices for Flat-Plate Photovoltaic Modules and Panels
The "Recognized Component Mark" is a type of quality mark issued by Underwriters Laboratories. It is placed on components which are intended to be part of a UL listed product, but which cannot bear the full UL logo themselves. The general public does not ordinarily come across it, as it is borne on components which make up finished products.
Baseefa — a similar organization in the United Kingdom
Canadian Standards Association (CSA) — a similar organization in Canada; also serves as a competitive alternative for U.S. products
Efectis — a similar organization in Europe, fire science expert, testing laboratory and certification body
ETL SEMKO — a competing testing laboratory, part of Intertek; based in London, England, UK
FM Global — a competing certification body, based in Rhode Island, U.S.A.
IAPMO R&T — a competing certification body, based in Ontario, California, U.S.A.
MET Laboratories, Inc. — a competing testing laboratory based in Baltimore, Maryland, U.S.A.
NTA Inc — a competing certification agency based in Nappanee, Indiana, U.S.A.
Sira — a similar organization for the UK/Europe
TÜV — German approvals organizations
KFI — a Korea Fire Institute, a similar organization in Korea
Applied Research Laboratories (ARL) - a competing testing laboratory, based in Florida, U.S.A.
CCOE - Chief Controller of Explosives
ICC-ES - International Code Council Evaluation Services