In order to remove condensed water, steam and other water-containing gas pipelines should have a certain slope, generally not less than two thousandths. For underground drainage pipes that use gravity flow, the slope is not less than five thousandths. Steam or other water-containing gas pipelines are equipped with drainage pipes or traps at the lowest point. Some gas pipelines are also equipped with gas-water separators to drain water in time to prevent water hammer and obstruction of gas flow in the pipes. The water supply or other liquid pipeline is equipped with an exhaust device at the highest point to remove the air or other gases accumulated in the pipeline to prevent air resistance from causing malfunctions.
If the pipeline cannot expand and contract freely, huge additional stresses will be generated. Therefore, it is necessary to install expansion joints on pipelines with large temperature changes and normal temperature pipelines that require free displacement, so that the expansion and contraction of the pipeline can be compensated and the influence of additional stresses can be eliminated.
For steam pipes, high-temperature pipes, low-temperature pipes, and pipes with anti-scalding and anti-freezing requirements, it is necessary to coat the outside of the pipes with insulation materials to prevent the loss of heat (cold) or freezing in the pipes. For some liquid pipelines with high freezing points, heating and insulation are required to prevent the liquid from being too viscous or solidifying and affecting the transportation. Commonly used insulation materials include cement perlite, glass wool, rock wool and asbestos diatomaceous earth.
