For swing check valves, what are the hazards of conducting pressure testing in the reverse direction?
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I recently used a swing check valve that does not have a spring-return function； Before conducting a hydrostatic test, workers are required not to install the valve in reverse for the test; it must either be installed in the correct orientation with the valve fully open, or the valve must be removed ； As a result, it was still installed in reverse for the pressure testing. I just want to know what the hazards of installing it in reverse are? The pipeline hydrostatic test pressure may be greater than the valve opening pressure.
Pressure testing is used to check the pressure resistance of a process system, and it is not merely intended to detect internal leakage in check valves. So, if the check valve is installed in reverse, where does the pressure test behind the check valve come from? Isn’t that nonsense? Is one leaf blocking the view? ? The pressure testing of check valves can be carried out before they are put into use. During system testing, it is difficult to detect any leaks in the reverse direction for check valves; instead, it is necessary to test the flanges connected to the check valves as well as the valve devices downstream of them. Alas, in this vast world, there’s no shortage of strange things. :lol
I’m helpless too; it’s all written clearly in the documents and was also mentioned verbally. They insisted on doing it that way on site. The problem is that the client inspected it but didn’t say anything, so I didn’t dare to object. The inlet side of the check valve is an open space, with seawater ； The opposite direction is the pipeline, used for sampling. For the pressure testing, the connection between the valve and the pipeline is indeed tested, so there’s no need to remove it; however, it still seems strange to include the check valve in the pressure testing in the reverse direction.
If such a thing occurs, someone needs to sign and certify it to leave a record; otherwise, it’s not possible. When I’m in a good mood, I’ll explain the principles to you; when I’m not, I have to handle things professionally. If a problem arises, there must be evidence to support it.
For a check valve, testing in the forward direction checks the housing, while testing in the reverse direction checks the seal; there aren’t that many necessary steps
During the pressure testing of process pipelines, do check valves need to be opened or removed?
Installing a check valve in the reverse direction does not meet the requirements regarding the flow direction of the fluid in the pipeline; it fails to provide any sealing effect at all. This is an extremely poor way of installation. I think these are all issues that need to be resolved before imposing pressure; it’s not possible to exert pressure in this way.
I’ve encountered this before as well: a check valve being installed in the wrong direction, which prevents pressure from escaping, or when a sealing fitting is missing. I just want to figure out exactly how many harms there are
Reverse installation is not intended for testing the check valve; if it is not used in the installation process, a temporary bypass must be created to make a connection. Doing this on the construction site is also done to save effort
In fact, apart from check valves, components that cannot be used during pressure testing include online instrument control valves as well; these need to be removed before the pressure testing is carried out and replaced with temporary pipes for connection. However, engineers should consider providing the construction party with an appropriate compensation. Ignoring costs and focusing only on such requirements is simply unreasonable
It doesn’t pose much harm; it’s not proper