Material requirements of steam pipeline

The selection of pipeline materials shall meet the following requirements:

Seamless steel pipes shall be used for steam pipes with pressure greater than 1.0 MPa gauge and temperature greater than 200℃ and hot water pipes with pressure greater than 1.6 MPa gauge and temperature less than or equal to 180℃. Seamless steel pipes or welded steel pipes can be used for steam pipes, hot water pipes and condensation pipes with pressure less than 1 and 6 6MPa (gauge pressure) and temperature less than 200℃;

2. When heating pipes are laid in impassable ditches or buried directly, seamless steel pipes should be adopted. When overhead, semi-channel or channel trench laying is adopted, seamless steel pipe or welded steel pipe can be adopted, and it shall comply with the provisions in paragraph 1 of this article.

Basis: Code for Design of Boiler Room (GB 5004 1—2008)

18.4 pipes and accessories

18.4. 1 The selection of pipeline materials shall meet the following requirements:

Seamless steel pipes shall be used for steam pipes with pressure greater than 1.0 MPa gauge and temperature greater than 200℃ and hot water pipes with pressure greater than 1.6 MPa gauge and temperature less than or equal to 180℃. Seamless steel pipes or welded steel pipes can be used for steam pipes, hot water pipes and condensation pipes with pressure less than 1 and 6 6MPa (gauge pressure) and temperature less than 200℃;

2 When the thermal pipeline is laid in an impassable ditch or buried directly, seamless steel pipe should be adopted. When overhead, semi-channel or channel trench laying is adopted, seamless steel pipe or welded steel pipe can be adopted, and it shall comply with the provisions in paragraph 1 of this article.

18.4.2 The nominal diameter of outdoor heat pipe shall not be less than 25mm.

18.4.3 valves shall be installed on the branch pipes of hot water, steam and condensate pipes leading to each user. When the length of the branch pipe is less than 20m, it may not be installed.

18.4.4 The high point and low point of hot water, steam and condensate pipes shall be equipped with a bleed valve and a drain valve respectively.

18.4.5 start-up drainage devices shall be set at intervals of 400-500m along the straight slope and 200-300m on the reverse slope of the steam pipeline. Before the low point and vertical elevation of steam pipeline, a constant drainage device should be set up.

18.4.6 The steam pipeline shall be discharged into the condensate pipeline when conditions permit.

18.4.7 check valves or other inspection accessories shall be installed at the place where the steam trap is installed. A filter should be set before the trap without a filter device.

18.4.8 In the area where the calculated outdoor heating temperature is lower than -5℃, overhead laying shall be carried out in the area where the calculated outdoor heating temperature is lower than-1O℃ on the intermittently running pipeline.

Gray cast iron equipment and accessories should not be installed on the pipeline. In areas where the calculated outdoor heating temperature is less than or equal to -30℃, valves and accessories installed on overhead pipelines shall be made of steel.