UL 753-2013 pdf download

UL 753-2013 pdf download.Alarm Accessories for Automatic Water-Supply Control Valves for Fire Protection Service.
34.3.3 Free field conditions may be simulated by mounting me gong not less than 10 feet (3.05 m) from the ground and with the microphone located 10 feet from the gong and conducting the test outdoors on a clear day with me wind velocity not more than 5 miles per hour (2.23 m/s) and at ambient temperature of 15 to 25°C (59 to 77°F). Alternatively, an anechoic chamber of not less than 1000 cubic feet (28.3 m3), with no dimension less than 7 feet (2.13 m), and with an absorption factor 010.99 or greater between 100 hertz and 10 kilohertz for all surfaces. may be used for this measurement.
35 Pressure Actuated Accessory Test
35.1 Sensitivity
35.1.1 A pressure actuated alarm accessory, such as a pressure operated switch, shall close circuits on a static pressure of 5 psi9 (35 kPa) and open circuits on a reduction in static pressure from 5 to 3 psi9 (35 to 21 kPa).
35.1,2 A pressure operated switch shall operate within ±5 percent of the nominal pressure rating indicated either in the product markings or the manufacturer’s installation instructions. It the pressure switch has a range of settings, or has a different setting br an alarm condition than for the return to normal, th€ switch is to be tested at each setting.
35.1.3 After being tested in the as-received condition, the pressure operated switch is to be subjected to the Endurance Test, Section 38. The switch then is to be tested as specified in 35.1.2 and shall have a sensitivity within ±5 percent of the pressure value originally determined for the switch.
35.1.4 A control with an adjustable set point is to be calibrated at the maximum and minimum set points and at a set point approximately midway between the maximum and minimum.
35.1.5 A pressure operated control is to be connected to a source of aerostatic or hydrostatic pressure, whichever is consistent with its intended use- The source of pressure is to be accurately controlled and measured. Pressures are to be Increased and decreased during the test at a rate of approximately 1 psig (7 kPa) per minute when approaching the set point.
35.2 Strength of parts
35.2.1 A part of an alarm accessory that is subjected to pressure during intended usage shall function as intended and remain within the limits for calibration after being subjected for 1 minute to a hydrostatic pressure of 150 percent of its maximum pressure rating and shall withstand, without rupture, a hydrostatic pressure of 875 psig (6033 kPa) applied for 1 minute.
35.2.2 Specimens of polymeric material used (or gong protectrve devices are to be subjected to air-oven aging and compared with unaged specimens. The average tensile strength of five aged specimens shall be at least 80 percent of the average tensile strength of five unaged specimens. The average resistance to impact of five aged specimens shall be at least 80 percent of the average resistance to impact of five unaged specimens.
35.2.3 For tensile strength tests, specimens are to be prepared from the polymeric part and the tensile strength determined in accordance with the Standard Test Method for:
b) Tensile Properties of Plashcs by Use of Microtensile Specimens. ASTM Dl 708
The specimen dimensions will depend on the size and shape of the part, but are to be in accordance with one of the specified ASTM test methods.
352.4 For impact resistance tests, specimens are to be prepared from the part and tests conducted in accordance with the Standard Test Method for:
a) Impact Resistance of Plastics and Electrical Insulating Materials, ANS(!ASTM D256; or
b) Tensile-Impact Energy to Break Plastics and Electrical Insulating Materials, ASTM 01822. depending upon the type of material and the size and shape of the part
352.5 The specimens to be aged are to be suppo.led In a full draft circulating air oven that has been preheated at full draft to 70 ±1.0CC (158 ±1.8°F). The manner of support is to prevent the samples from touching one another or the sides of the oven. Specimens are to be aged for 30 and 60 days at full draft and then allowed to cool In air at 23 ±2°C (73.4 ±.6°F) for at least 24 hours before conducting tensile strength and resistance to impact tests.
35.2.6 Specimens of the polymeric material used for gong protective devices are to be subgected to light and water exposure and compared with unexposed specimens. The average tensile strength of live exposed specimens shall be at least 80 percent of the average tensile strength of five unexposed specimens. The average resistance to impact of five exposed specimens shall be at least 80 percent of the average resistance to impact of five unexposed specimens.