Underwriters Laboratories Testing Procedure

Relative long-time experiments are often performed according to the Underwriters Laboratories (UL) testing protocol [29]. The results, the retention of certain properties upon exposure to heat, are expressed in UL temperature index values. The time and material consuming UL testing procedure is usually preceded by short-time mass retention measurements, mainly performed with TGA equipment. 

The most widely accepted test method is that used by Underwriters Laboratories (UL) to determine the temperature index (continuous-use temperature rating) of a plastic material. This test procedure is predicated on a linear time-temperature relationship for the aging of a thermoplastic polymer, i.e., thermal degradation... 

Note flammability is normally tested according to Underwriters Laboratory Procedure UL 94. 

Similar tables indicating the decision tree and test requirements for portable equipment and fixed equipment have been developed by Underwriters Laboratories. In each case, the procedure for determining the suitability of a plastic material used in electrical equipment is basically the same. If the plastic parts used in this application are required to go through a special process such as plating,... 

Flame retardancy tests were performed following the procedure of Underwriter s Laboratory Bulletin 94 entitled Tests for Flammability of Plastic Materials, UL94. According to this procedure, materials may be classified as HB, VO, VI, V2, VA and/or VB on the basis of the test results obtained for five samples. In this study, UL test was done at 0.8 mm thickness for all samples. Heat deflection Temperature (HDT, ISO 75/Be flat, 1.8 Mpa load) and Vicat softening temperature (Vicat, ISO 306, Vicat B, heating rate 120 °C/min load of 50 N) were used to determine thermal properties of compositions. Standard impact bars were used to measure these properties. Duplicate measurements were done and average of two samples were reported. 

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