UL 482 Standard For Portable Sun/Heat Lamps

24.2 Unless the timer contacts have been found to be acceptable for the purpose, they shall be subjected to 50 cycles conditioning. The conditioning load is to consist of an inductive load having a power factor of 70 percent to 80 percent adjusted to 150 percent of the operating current of the lamp. The endurance load is to consist of a tungsten lamp load equal to the operating current of the lamp. The rate of operating is to be such that a minimum of 55 seconds is provided for cooling of the lamp load between cycles. A synthetic tungsten lamp load having equivalent characteristics or a synthetic load that represent the actual current characteristic of the particular lamp load, including inrush, may be used in place of the tungsten lamp load.

25.1 A sun/heat lamp overturned in any position on a softwood surface covered with a double layer of cloth shall not cause the cloth or wood to glow or flame.

25.2 After having been pushed over, the lamp is to be operated under the most severe conditions that will result when it comes to rest without further guiding or propping.

25.3 A sun/heat lamp with its rays directed against a vertical softwood surface covered with a double layer of cloth at any distance from the lamp shall not cause the cloth or wood to glow or flame. The vertical wood surface shall abut a horizontal surface supporting the lamp.

25.4 The distance between the lamp and the vertical wood surface is to be such that maximum heating will occur on the latter.

25.5 A sun/heat lamp, loosely covered with a double layer of cloth, shall not cause the cloth to glow or flame.

25.6 The lamp is to be operated until constant temperatures are attained before covering it with a cloth.

25.7 Wherever cloth is mentioned in the abnormal tests, the cloth is to be bleached cheesecloth, running 14—15 yd(2)/lb (approximately 26—28 m(2)/kg) and having what is known in the trade as a "count of 32 by 28," that is, for any square inch 32 threads in one direction and 28 threads in the other direction (for any square centimeter, 13 threads in one direction and 11 in the other direction).

25.8 If abnormal conditions in addition to those described in paragraphs 25.1, 25.3 and 25.5 are likely to be obtained in actual service, a sun/heat lamp shall not involve a risk of fire when operated under such abnormal conditions.

25.9 To determine if a risk of fire actually exists, a separate burnout or abnormal heating test is to be conducted with the lamp operating continuously until the ultimate result has been determined. During the test, the lamp is to be supported on white tissue paper on a softwood surface. Among the abnormal conditions to be considered is operation of the lamp with rays directed downward toward the supporting surface to the greatest degree possible.