General rules for valves and piping

1, when the fire pump outlet diameter is greater than 300mm, should not adopt a single manual opening and closing function of the valve. Valve should have obvious opening and closing signs, remote control valves should have quick opening and closing function, and reliable sealing.

2. Normally open or normally closed valves should be equipped with locking devices, control valves and valves that need to be opened and closed should be equipped with opening and closing indicators. The control valve of the remote control gun linkage control system should be transmitted to the control room of the system.

3. Valves on dry powder pipes should be ball valves. The diameter must be in line with the inner diameter of pipes.

4, pipes should be made of corrosion-resistant materials or anticorrosive treatment of outer walls of pipelines.

5, suitable flushing interface should be provided in the proper position of foam liquid, foam mixture or seawater pipeline. An automatic exhaust valve should be set at the top of the pipe segment where air may be trapped.

6, after the foam mixing device, a bypass test interface should be set up.

General requirements for common materials of GB valves

1) The material of valve body, valve cover and flange shall be selected according to the operation conditions and manufacturing requirements, and shall comply with the provisions of GB 12228, GB 12229, GB 12230 and GB 3077.

2) The bolts and studs can be made of A5, 25, 35, 30CrMoA and 40MnVB, which should be selected according to the pressure and temperature, and should be in accordance with GB 700, GB 699 and GB 3077.

3) Nut material can be used A3, 20, 30, 35, 45, 30CrMoA and 40MnVB, should be selected according to the use of pressure and temperature, and should comply with the provisions of GB 700, GB 699 and GB 3077.

4) precision casting shall not be used for valves of nominal pressure PN>10.0MPa.

5) attention should be paid to graphitization of materials in the following situations.

A. carbon steel is about 425 degrees above zero.

B. carbon molybdenum steel is about 470 degrees above zero.

C. chrome molybdenum steel (below 0.6% chromium) is about 525 degrees above zero.

6) attention should be paid to possible peroxisome reactions in the following situations:

A. is about 1Cr-0.5Mo steel, 1.25Cr-0.5Mo steel, 2Cr-1Mo steel and 3Cr-1Mo steel above 565 degree.

B. is about 5Cr-0.5Mo steel above 595 C. (source: Internet)

(Jiangsu valve, Changzhou valve, valve manufacturer)