Pressure switch requirements for Fire sprinkler systems
6.1Exterior
6.1.1 The surface of the pressure switch should not have obvious defects such as corrosion, peeling of the coating, blistering, burrs, and loose structure.
6.1.2 The text symbols and signs marked on the pressure switch are clear and correct
6.2 Fixed working pressure
The rated working pressure of the pressure switch should not be less than 1.2MPa.
6.3 Action pressure
6.3.1 The operating pressure of the ordinary pressure switch is 0.035MPa～0.05MPa.
6.3.2 The operating pressure of the pre-action pressure switch is 0.03MPa~0.05MPa.
6.3.3 The operating pressure range of the special system pressure switch is determined by the manufacturer.
6.3.4 For adjustable pressure switches, the maximum and minimum operating pressure ranges are provided by the manufacturer.
6.3.5 During the test, the normally open contact of the pressure switch should be closed, and the normally closed contact should be disconnected; the pressure switch should not operate when the system pressure increase to 80% of the operating pressure for 3 minutes.
6.4 Strength requirements
Conduct a hydraulic strength test, the test pressure is 1.5 times the working pressure and hold for 5 minutes, the pressure switch should not be damaged and leaked.
6.5 Working reliability
6.5.1 In the reliability test of ordinary pressure switch and Pre-action pressure switch, the action of the pressure switch should be flexible and reliable, and no failure or structural damage should occur.After this test, the contact resistance of the pressure switch should not be greater than 0.5Ω.
6.5.2 The test times and temperature of the pressure switch of the special type system are provided by the manufacturer. During the test, the action of the pressure switch should be flexible and reliable without any failure or structural damage.The contact resistance of the pressure switch should not be greater than 0.5Ω.
6.6 Humidity and heat resistance requirements
During the damp heat test, the pressure switch is not allowed to malfunction, and the insulation resistance value measured according to the regulations should not be less than 1MΩ; after the test, perform the action test according to the regulations, and the results meet the requirements of 6.3.
6.7 Withstand voltage requirements
Under normal atmospheric conditions, keep for 24h to carry out the withstand voltage test. All contacts of the pressure switch (except the grounding point) and the shell should be able to withstand the AC voltage of 50Hz. The test lasts for 60s. During the test, the pressure switch should not appear the surface Flashover, sweep discharge, corona or breakdown phenomenon.
