How much heat loss does a steam pipeline have at its supports and hangers?
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It seems that the heat loss through the steam pipes at the supports and hangers could be greater than that due to the insulation around the pipes. If welded pipe supports are used and the pipes are mounted directly on steel beams, how large is that loss usually? What is the typical loss per kilometer at 160°C, 250°C, and 350°C?
The heat loss of welded pipe supports is usually negligible; if high requirements are placed on heat loss, insulated vermiculite pipe supports can be used.
In the situation you mentioned, the heat loss of the pipes at the supports is indeed significant, especially when welded metal pipe supports are in direct contact with the steel structure. This will result in a significant heat bridge effect, with local losses potentially being several times higher or even more so than in areas with ordinary insulation. Typical empirical data show that: when no insulation measures are taken and metal supports are welded directly in contact with the steel structure, the heat loss at those specific locations of the supports and hangers can account for approximately 10% to 20% of the total heat loss of the entire pipeline. In some special cases (such as dense scaffolding or short spans), the heat loss at a single point can be 3 to 5 times greater than the loss in a normally insulated area at that location. For general industrial steam pipelines in various temperature classes, when there are no special insulation measures and the ordinary welded steel pipe supports come into direct contact with the supporting structure, the approximate heat loss values are as follows: for a pipeline medium at 160°C, the heat loss is around 300–500 W per support point. Assuming a spacing of 4 meters between supports, there are approximately 75–125 support points per kilometer; thus, the total heat loss per kilometer is around 22–63 kW. - Pipeline medium at 250°C: Heat loss per support is 600–1000 W, approximately 45–125 kW per kilometer. - Pipeline medium at 350°C: The heat loss per support is approximately 800–1500 W, and it can reach 60–188 kW per kilometer. The actual heat loss depends highly on site conditions, such as the type of supports and hangers, ambient wind speed, ambient temperature, and the quality of insulation used. To reduce risks, it is generally recommended to install thermal insulation pads or pre-fabricated thermal insulation supports at the supports and hangers in order to significantly minimize the heat bridge effect. If no measures are taken and only welded metal supports are used, heat loss becomes very significant over time. .