Is it only necessary to purge after the pressure pipeline testing is completed?
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Is it only necessary to purge after the pressure pipeline testing is completed?
All pipes need to be pressure-tested and purged! ! !
There is no explicit regulation for this, but generally it follows this order. We have carried out a project before where purging was done first followed by rinsing; since deionized water is used for pressure testing, purging later on can easily lead to contamination. The specifics in this regard can vary
No, it depends on the requirements. If it is of high purity, in addition to purging and pressure testing, tests for water/oxygen/particulates, etc., are also required
This was also something we struggled with on site. According to our owner’s specifications, purging and flushing before pressure testing are carried out to remove debris from the pipes, thereby preventing blockages in the instruments used for pressure testing; there may also be other purposes for this ； But on-site, it’s not necessary to first perform pressure testing before purging and flushing, because in this way they can skip the purging step, simply drain the water used for pressure testing, and that’s it.
I assume that pressure testing and purging are the responsibilities of the construction team, right?
For those not in the chemical industry, it is the responsibility of the construction company to develop the programming plans, submit them for the owner’s approval, and carry out the actual work. The owner’s representative and third-party inspection agencies are responsible for approving the programming plans in accordance with the owner’s specifications and overseeing the work on site.
According to the installation regulations, pressure must be applied first; only after it is confirmed that there are no leaks can purging be carried out
Generally, the sequence follows purging, flushing, and pressure testing!
1. You should think this way: what is being purged? Some slag and debris need to be blown out. After welding is complete and everything is cleaned, a pressure test is carried out; however, there are many leaks due to various reasons. So, welding has to be done again, new slag appears, and cleaning with gas is required once more... 2. The hydrostatic test is safer, as water is incompressible. If cleaning is done first using gas, air will start leaking everywhere as soon as it’s released, which is not acceptable. Therefore, the hydrostatic test should be conducted first, followed by cleaning – this is what the standards dictate
In principle, a hydrostatic test should be conducted first to ensure there are no leaks, before proceeding with the purging process. Since purging involves issues such as gas volume and flow rate, explosive purging is sometimes required. Just imagine: how can one carry out explosive purging without something to use to suppress leaks with water pressure?