Issues with the inlet and outlet pipeline setup and valve installation in storage tanks
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This post was last edited by Desert Fish on 2016-10-15 at 22:15. Dear experts, according to the regulations, storage tank inlet and outlet pipelines must be equipped with two valves, namely a main valve and an operating valve. I have three questions. First, must the inlet and outlet pipelines of the storage tank be separate, that is, must the feed pipeline and the loading pipeline be connected through openings in the tank wall separately? Is it acceptable to use just one pipeline instead of two – namely, using a single DN200 feed pipeline to fulfill the functions of both the feed and loading pipelines? Does the specification permit this? Second, the method of installing dual valves on the pipeline at the base of the storage tank is not specified in detail in the plans. Is it acceptable to install the emergency shut-off valve as the primary valve in the first stage, or to use the emergency shut-off valve as an operating valve in the second stage? Do the dual valves at the base of the tank include an emergency shut-off valve? Third, is the metal hose at the base of the tank installed between the two valves or after them (on the outermost side)? ?
I’m not in the design field, but I’d like to share with you what I’ve encountered on site: 1. On site, it’s common to provide a separate opening for incoming and outgoing pipelines; I’ve also seen cases where there’s only one opening for both, but this makes operations less flexible. Unless there are special requirements, it’s better not to design just one opening. 2. At the site, measurement starts from the opening of the tank; in sequence, it is the valve – metal hose – isolation valve – valve. This design allows for isolation and maintenance in case of problems with either the isolation valve or the metal hose. 3 The metal hose is located between the two valves.
In fact, the regulations are quite clear: the size of the inlet and outlet pipes is determined based on the volume of flow, it’s not arbitrary. I posted the installation regulations for piping valves in a resources post; you can download and take a look
The response on the 2nd floor refers to a very classic installation method, which makes sense. The problem is that we are trying every means possible to reduce costs; we want to simplify the process based on that classic method you mentioned, by reducing the number of valves and piping. Is this in conflict with the relevant standards?
I think that if one wants to save on investment, it’s fine to create an opening, but it’s not convenient to operate. Due to the hazardous nature of the medium, efforts should be made to minimize the number of openings; the inlet and outlet are designed as one
I would like to ask the original poster: which specific standard specifies the requirement to install dual valves at the tank base? I looked everywhere but couldn’t find it