Precautions for hot-dip galvanized steel pipe for firefighting
In automatic sprinkler systems, when dn ≤ 80 and using a threaded connection, the minimum pipe wall serial number requirements for sch40 steel pipe, and the thin wall and ordinary steel pipe wall is thinner, need to use thicker steel pipe or seamless steel pipe, Because of the large amount of steel needed, it is of great economic importance to explore the pressure, the wall thickness and the connection method.
1.Pipes, Fittings and Connections
Galvanized welded steel pipes for liquid transport: galvanized welded steel pipes for fluid transport are divided into thin-walled, plain and thick galvanized welded steel pipes according to the wall thickness; According to the connection method is divided into non-threaded and threaded galvanized welded steel pipe. Carbon steel. Alloy steel seamless steel tubes: hot-rolled (extruded, expanded) seamless steel tubes, cold drawn (cold rolled) seamless steel tubes. The minimum pipe wall serial number: China's current steel pipe standards, the minimum pipe wall serial number is recommended for the carbon steel, alloy steel seamless steel pipe size range, the smallest pipe wall serial number is divided into sch20, sch30, sch40, sch60, sch80, etc. The higher the serial number, the thicker the wall thickness of the pipe. Due to the difference in pipeline pressure and connection method, the minimum wall thickness of different specifications for the “measures” and “manual” requirements shall comply with the corresponding minimum wall serial number. Fittings: Hot dip galvanized steel pipe or hot dip galvanized seamless steel pipe with pipe diameter dn 100 in the system can be threaded. However, when the system uses hot dip galvanized steel pipe, the pipe fitting adopts malleable cast iron threaded pipe fittings; when the system uses hot dip galvanized steel seamless pipe, the pipe fitting adopts forged steel threaded connection. The threaded pipe fittings product standard refers to the forged threaded fitting “gb3287-3289”, and the forged steel threaded fitting refers to “gb/t14626”. Connection method: Pipe connection is divided into clamp connection, screw connection, welding and flange connection.