UL 94, the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing, is a plastics flammability standard released by Underwriters Laboratories of the United States. [1]

What is UL 94? Which materials show flame retardance? What factors influence flammability? Why it is important to examine how plastic burn? What are the main types of flame ratings to classify plastics? What is vertical burning test for classifying materials? What is horizontal burning test for classifying materials?

Flammability UL 94 HB - Horizontal Burning The horizontal burning test is used to determine the HB flammability rating of a material. The flammability rating is calculated for a test specimen as a function of the burning rate and taking account of the material thickness.

2019年7月15日 · Two UL 94 ratings that code officials commonly run across are HB and V (V-0, V-1, or V-2). These ratings are established using small-scale tests in which approximately 5 by ½ inch samples are subject to a ¾ inch, 50W tirrel burner flame ignition source.

2019年3月1日 · UL 94 is a plastics flammability standard released by the Underwriters Laboratories (USA). The standard classifies plastics according to how they burn in various orientations and part thicknesses from the lowest flame-retardant to most flame-retardant in six different classifications.

UL 94 H-B Horizontal Burn; Slow horizontal burn test (H-B) are considered "self-extinguishing". The lowest (least flame retardant) UL94 rating.

2021年6月9日 · UL 94 flammability testing ranks plastics according to their ability to ward off ignition, remain consistent in high temperatures, and produce flammable plastic drippings. Since actual fire conditions are unpredictable, UL 94 flammability does not reflect how a material will react while on fire.

HB testing is generally considered the easiest flammability test to pass and is the lowest and least flame-retardant UL 94 rating. A UL 94 HB rating would typically be acceptable for portable, attended, intermittent-duty, household-use appliance enclosures (e.g. hair dryers).

2023年12月21日 · UL 94 testing methods assign flammability ratings based on how plastic materials burn in horizontal and vertical orientations, with HB indicating horizontal burning rate and V ratings indicating vertical self-extinguishing properties and resistance to …

Three specimens of each thickness are tested after conditioning for 48 hours at 23 degrees C and 50% RH. Each specimen is mounted with its long axis horizontal and its short axis at a 45 degree angle. Each specimen is marked with two lines, 25 mm …