General regulations for valves and pipelines

1. When the outlet pipe diameter of fire pump is greater than 300mm, the valve with single manual opening and closing function shall not be used. The valve should have obvious opening and closing signs, and the remote control valve should have a fast opening and closing function and reliable sealing.

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

3. The valve on the dry powder pipeline should use a ball valve, and its diameter must be consistent with the inner diameter of the pipeline.

4. The pipeline should be made of corrosion-resistant materials or undergo anti-corrosion treatment on the outer wall of the pipeline.

5. Flushing interface should be set at proper position of pipeline using foam liquid, foam mixture or seawater. Automatic exhaust valves should be installed at the top of pipe sections that may trap air.

6. A bypass test interface should be set behind the foam proportioning device.

General requirements for materials commonly used in national standard valves

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

2) The materials for bolts and studs can be A5, 25, 35, 30CrMoA, and 40MnVB, which should be selected according to the usage pressure and temperature, and should comply with the provisions of GB 700, GB 699, and GB 3077.

3) Nuts can be made of materials such as A3, 20, 30, 35, 45, 3030CrMoA, and 40MnVB, which should be selected according to the pressure and temperature used and comply with the provisions of GB 700, GB 699, and GB 3077.

4) Precision castings shall not be used for valves with a nominal pressure PN>10.0MPa.

5) Attention should be paid to the possibility of material graphitization in the following situations:

a. When carbon steel is above approximately 425 ℃;

b. When the temperature of carbon molybdenum steel is about 470 ℃;

c. When the chromium molybdenum steel (containing less than 0.6% chromium) is about 525 ℃.

6) Attention should be paid to possible peroxide reactions (scaling) in the following situations:

a. 1Cr-0.5Mo steel, 1.25Cr-0.5Mo steel, 2Cr-1Mo steel, and 3Cr-1Mo steel above approximately 565 ℃;

b. 5Cr-0.5Mo steel above approximately 595 ℃. (Source: Internet)