UL-33:2015 pdf free download – STANDARD FOR SAFETY Heat Responsive Links for Fire- Protection Service.
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 (1100) less than its rated operating temperature to 50°F (10°C). At least five sample bulbs are lobe 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 10.1.
10.4 The heat responsive links are to be placed in an upright position under a load equal to the manufacturer’s minimum design load, but not less than 1 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.
10.6 An agitator is to be used as an aid in obtaining uniformity in temperature of the liquid in the bath.
10.7 A calibrated temperature-measuring device is to be used to determine temperature of the liquid in bath tests. The sensing element of the temperature measuring device is to be held level with the heat responsive link by a support member.
10.8 The temperature of the bath liquid is to be raised until the liquid is within 20°F (11°C) of the temperature rating of the device for a device having a temperature rating of 300°F (149°C) or less, and within 30°F (17°C) for a device having a temperature rating of 325°F (163°C) and higher. The temperature rise then is to be controlled at a rate not exceeding 1°F (0.5°C) per minute until operation or until a temperature 20°F (11°C) above the rated temperature is reached. The temperature of the liquid and the time of operation, as each heat responsive link operates, are to be recorded.