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UL 33-2020 pdf free download

UL 33-2020 pdf free download.Heat Responsive Links for Fire Protection Service.
8.2.2 The bulb strength is to be measured by applying a steadily increasing load, using a compression testing machine, until the bulb breaks or fractures. This test is to be conducted with the bulb mounted in the seating parts used in the assembly and the load is to be applied at a rate not exceeding 55 pounds- force per second (245 N/s) or at a rate the deflects the bulb 0.02 inch (0.51 mm) per minute, whichever measurement is convenient for the test apparatus being used. Bulb seatings may be reinforced circumferentially in a manner not interfering with the bulb breakage. A minimum of 15 samples of each temperature rating and each bulb type are to be tested. Calculations are to be based on the Normal or Gaussian Distribution except where another distribution can be shown to be more applicable due to manufacturing or design factors, See Appendix A.
9 Glass-Bulb Thermal Shock Test
9.1 A glass bulb type heat responsive element assembly shall withstand the thermal shock of rapid temperature changes having a range from 20°F (11°C) less than its rated operating temperature to 50°F (10°C). At least five sample bulbs are to be conditioned for 5 minutes in a liquid bath at 20°F (11°C) less than the rated operating temperature. The samples then are to be removed and immediately submerged in another liquid bath at 50°F. There shall be no breakage or fracture of the glass bulb.
10 OperatIng Temperature (Bath) Test
10.1 The operating temperature of heat responsive links, when bath tested, shall operate within the range having a maximum temperature not in excess of 10° F (5° C) or 107 percent of the minimum Fahrenheit temperature of the range. whichever is greater. For the purpose of this determination, the marked temperature rating is to be included as one of the ranged values, making a total of 11 values in the range. Table 6.1 defines temperature ratings.
10.2 Link operation for this test includes the intended functioning of the eutectic elements or any rupture of the glass bulb heat responsive element. If partial fracture of the glass bulb in the liquid environment occurs which does not result in link operation, the temperature at which the bulb fracture occurred shall be considered the operating temperature.
10.3 Not less than ten heat responsive links of both coated and uncoated types of each temperature rating are to be subjected to this test, All ten samples shall comply with the requirements of 1QI..
10.4 The heat responsive links are to be placed in an upnght position under a load equal to the manufacturer’s minimum design load, but not less than I pound-force (4 N), and completely immersed in the water or oil bath. The bath vessel is to be provided with a source for heating the liquid at the prescribed rate and with means to agitate the liquid and measure the temperature of the liquid bath.
10.5 Water Is to be used in bath tests of heat responsive links which have operating temperature ratings of 175°F (79°C) or lower. Samples having operating temperature ratings of 176 to 575°F (80 to 302°C) are to be bath-tested in an oil having a flash point exceeding the test temperature.UL 33-2020 pdf free download.

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