Development of Fire Hose Coupling
Fire hoses with a diameter ≥ DN100 used screw coupling in the past, which was very difficult to construct. This is due to the large diameter, shallow thread at the pipe interface, weak connection, easy to leak, and deep thread, the thread at the interface The wall of the tube is too thin to withstand the working pressure of the system and it is easy to break. That is to say, the old fire protection design code requires that the pipeline behind the alarm valve, regardless of the diameter of the pipe, require the use of screw couplings to be defective, which is also the main reason why this code needs to be modified. So, what solution has this always had in the engineering practice afterwards?
1. Pipes with a diameter of <DN100 use a threaded coupling. Pipes with a diameter of ≥100 use a welded or flanged interface. The inner wall of the pipe near the weld is no longer treated for corrosion protection.
2. Pipes with a diameter of <DN100 use a wire-bonded interface, and pipes with a diameter of ≥100 use a welded interface. After welding, a second galvanizing treatment is used (first welded installation, pipe number and marked, and then disassembled and sent to the factory The galvanizing workshop is galvanized, and then the number is seated and installed), which is a mandatory local regulation in Beijing and Shanghai.
3. Pipes with a diameter of <DN100 use a threaded coupling, and fire pipes with a diameter of ≥100 use a clamp-type connector interface.