Underwriters Laboratories (UL®) is a leading independent organisation specialising in testing and certifying product safety. Every year, the company examines over 19,000 types of products, components, materials and systems.
What does the UL® mark indicate?
When the UL® mark appears on a product, it means that UL has carried out tests on representative samples of the product and has determined that it complies with applicable regulations or other requirements relating to potential fire hazards, electric shock and mechanical hazards.
The UL® mark on a product certifies the manufacturer’s ongoing compliance with applicable regulations. Every year, UL® awards its safety mark to over 20,000 million products worldwide.
Underwriters Laboratories is the only independent certification body authorised to issue the UL® mark.
UL94 standard
One of the most widely recognised testing standards is UL94, a flammability standard for plastics used in a variety of equipment and applications. Manufacturers are increasingly opting for adhesives with UL94 classification.
Flame-retardant adhesives can help extinguish flames and slow the spread of a fire.
Adhesives meeting this UL® standard can be used to encapsulate electronic products, and to coat and assemble composite panels and fittings in aircraft and other modes of transport.
UL94 tests
The UL94 standard specifies a combustion test for materials and may consist of a horizontal combustion test (UL94 HB) or a vertical combustion test (UL94 V). In both tests, an open flame is applied to the sample for a specified period of time.
The tests determine how the material behaves in terms of extinguishing or propagating the flame. The material is classified into categories HB, V0, V1 or V2, taking into account the thickness of the sample.
A material classified as 5VA or 5VB is subjected to a flame ignition source approximately 5 times more intense than that used in the V-0, V-1, V-2 and HB tests.
A material complying with the UL94 V0 classification is considered to be more flame-retardant than one with the UL94 V2 classification.
UL94 Classifications
- HB: slow burning in a horizontal specimen. Burning rate <76 mm/min for thicknesses <3 mm, or the burning stops before reaching 100 mm.
- V-2: the (vertical) burning stops after 30 seconds and any drips may be incandescent.
- V-1: the (vertical) burning stops after 30 seconds and dripping is permitted, but the drips must not burn.
- V-0: the (vertical) burning stops after 10 seconds and dripping is permitted, but the drips must not burn.
- 5VB: (vertical plate specimen) combustion ceases after 60 seconds; no dripping; the plate specimen may have a hole
- 5VA: (vertical plate specimen) combustion ceases after 60 seconds. No dripping occurs and the plate specimen must not have any holes.
Why are UL® classifications and standards important?
UL® certifications and standards indicate that the product is safe and has been tested and assessed for specific properties and risks. Once a manufacturer has passed all the tests required by a particular standard, they receive the UL® mark.
A product bearing the UL® mark gives customers confidence and assurance regarding the product’s safety. An independent testing laboratory carries out periodic checks to ensure that the product complies with the applicable directives and UL® standards.
Some examples of UL94-certified products
MD Poland is able to offer you a wide range of products that have been tested and comply with UL94 V-0 or UL94 V-1 standards, suitable for industrial applications where fire resistance is essential.
UL®-certified Dow products
- Dowsil™ 3165: a one-component silicone, suitable for bonding components such as capacitors to printed circuit boards (PCBs). UL94 V-0 certified.
- Dowsil™ 3140: a single-component, self-levelling silicone sealant for bonding and sealing / Self-levelling / RTV (room-temperature vulcanising). UL94 V-1 approved.
- Dowsil™ 7091: a single-component silicone sealant for general-purpose use. Listed under UL94-HB.
- Dowsil™ SE 9184: a single-component silicone sealant used for fixing components to printed circuit boards or modules, or to power supply module boards; thermally conductive and UL94 V-1 certified.
- Sylgard™ 170: a two-component silicone designed for electrical and electronic applications; cures at room temperature and when heated (HTV and RTV); UL94 V-0 certified and compliant with the MIL-Fluid standard; approved in accordance with EN 45545-2, level HL3 in categories R22 to R26.
UL®-compliant solutions for industrial applications
When selecting a product that complies with UL® standards, you must take into account the application, the materials involved and the required classification.
The experts at MD Poland can help you identify the solution best suited to your project’s specific requirements. For further information on available products and their certifications, please contact the MD Poland team.
