2015-08-08

Test procedure for UL94 Classed HB testing?

According to requirements of UL94 standard, shall follow test procedure as below to complete UL94 classed HB testing:

1.Three specimen are to be tested. Each specimen is to be marked with 2 lines perpendicular to the longitudinal axis of the bar, 25±1mm and 100±1mm from the end that is to be ignited
2.Clamp the specimen at the end farthest from the 25mm mark,with its longitudinal axis horizontal and its transverse axis inclined at 45±2 degrees. The wire gauze is to be clamped horizontally beneath the specimen, with distance of 10±1mm between the lowest edge of the specimen and the gauze with the free end of the specimen even with the edge of the gauze.
3.To product the nominal 50W test flame, the methane gas supply to the burner shall be adjusted to product a gas flow rate 105±ml/min with a back pressure less than 10mm water.
4.The burner is to be placed remote from the specimen and ignited. Adjust the burner to product a blue flame 20±1mm high. The flame is to be obtained by adjusting the gas supply and the air ports of the burner until approximate 20±1mm yellow-tipped blue flame is produced. Increase the air supply until yellow tip disappears. Measure the height of the flame again and adjust it if necessary.
5.Apply the flame to the free end at the lowest edge of the specimen. The central axis of the burner tube is to be in the same vertical plane as the longitudinal bottom edge of the specimen and inclined towards the end of the specimen at an angle of 45±2 degrees to the horizontal.
6.Position the burner so that the flame impinges on the free end of the specimen to a depth of 6±1mm. Apply the test flame for 30±1 seconds without changing its position. Remote the burner after 30±1 seconds,or as soon as the combustion front of the specimen reaches the 25mm mark (if less than 30 seconds), Start the timing device when the combustion from reaches the 25mm mark.
7.Calculate the linear burning rate, V in millimeters per minute, using the equation V=60 L/t ,in which . V is the linear burning rate in mm/minute , L is the damaged length ,in millimeter, t is time, in seconds

The Horizontal Vertical Flame Test Equipment  manufactured by ZHILITONG Electromechanical Co., Ltd can perform UL94 classed HB Testing.

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