Details regarding the density of insulation materials and the span of supports and hangers
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What is used as a basis for determining the density of insulation materials? I see that the specifications provide only a range; for example, the density of rock wool insulation tubes ranges from 60 to 200, which is a very large difference； Another issue is that the code does not specify whether, in the formula for calculating the span of supports and hangers mentioned in the standards, the unit length pipe load q should take into account only the working medium or also the hydraulic test pressure, with the maximum value of these two values being used All of these have a significant impact on the outcome.
When it comes to insulation materials, this topic involves a great deal of moisture. Especially regarding this ambiguous thickness of the rock wool: its thickness at the time of delivery was 8 mm, but in reality it was less than 10 mm after installation. Therefore, when signing the contract, be sure to use the thickness verified after construction as the standard. As for the need for a hydrostatic test, the weight of this part must be taken into account. But ordinary pipes are usually pressure-tested for leaks. For reference.
First, regarding the density of insulation materials, this is something that is easily overlooked in the design process. When designing pipe insulation, attention is usually given only to the thickness of the insulation, while requirements such as the density of the insulation materials are determined according to standards, with no detailed specifications provided; instead, it is up to the client to purchase and use materials in compliance with those standards. This also leads to the owners always claiming that the insulation thickness is insufficient, causing the pipes to freeze. Really, it’s not that the designed thickness is insufficient; rather, the insulation material is of poor quality. Of course, freezing will occur if the design thickness is followed. For the calculation formula of the span of the second hanger, I took into account the weight of the water filled in the pipeline, as when conducting strength tests on pipelines, more water pressure is used than air pressure. Furthermore, when filling the pipeline with water for recalculation, there is a large margin of safety, ensuring high reliability
Yes, some of the regulations in the design specifications are too vague
When designing, the most severe operating conditions during use and testing should be taken into account. The density of the fluid flowing through the pipeline, whichever is higher than that of water, should be used as the basis for strength calculations. For insulation materials with a thickness of 50 millimeters or less, their mass can generally be ignored; if the mass of such insulation materials is to be included, I recommend using the maximum density value
What you say makes sense, but the standards don’t even specify these most basic principles you mentioned. I’m also drunk; sometimes domestic standards aren’t rigorous enough