UL94
Encyclopedia
UL 94 is a plastics flammability standard
released by Underwriters Laboratories
of the USA.
The standard classifies plastics according to how they burn in various orientations and thicknesses. From lowest (least flame-retardant) to highest (most flame-retardant), the classifications are:
Tests are generally conducted on a 5" x 1/2" (12.7 cm x 1.27 cm) specimen of the minimum approved thickness. For 5VA and 5VB ratings, tests are performed on both bar and plaque specimens, and the flame ignition source is approximately five times as severe as that used for testing the other materials.
There are other classifications that apply to low density foam materials (HF-1, HF-2, HBF) and thin films (VTM-0, VTM-1, VTM-2).
Standardization
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....
released by Underwriters Laboratories
Underwriters Laboratories
Underwriters Laboratories Inc. is an independent product safety certification organization. Established in 1894, the company has its headquarters in Northbrook, Illinois. UL develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing...
of the USA.
The standard classifies plastics according to how they burn in various orientations and thicknesses. From lowest (least flame-retardant) to highest (most flame-retardant), the classifications are:
- HB: slow burning on a horizontal specimen; burning rate < 76 mm/min for thickness < 3 mm.
- V2 burning stops within 30 seconds on a vertical specimen; drips of flaming particles are allowed.
- V1: burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
- V0: burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
- 5VB: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may develop a hole.
- 5VA: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may not develop a hole
Tests are generally conducted on a 5" x 1/2" (12.7 cm x 1.27 cm) specimen of the minimum approved thickness. For 5VA and 5VB ratings, tests are performed on both bar and plaque specimens, and the flame ignition source is approximately five times as severe as that used for testing the other materials.
There are other classifications that apply to low density foam materials (HF-1, HF-2, HBF) and thin films (VTM-0, VTM-1, VTM-2).
External links
- Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing - UL site, general description of UL94 tests
- Fire Testing Technology - UL94 information.
- Laird Technologies (PDFPortable Document FormatPortable Document Format is an open standard for document exchange. This file format, created by Adobe Systems in 1993, is used for representing documents in a manner independent of application software, hardware, and operating systems....
) - UL94 technical notes. - Stockwell Elastomerics, UL Gasket - UL Listed Gasket Materials.
- The Plastics Web - UL94 information.
- UL Website - Flammability test information.