Regarding the issue of pressure testing equipment on-site

It is of course good to have the conditions for pressure testing on site, as this can help avoid container failure caused by collisions during transportation. It is actually unnecessary to conduct pressure testing on fully assembled pressure vessels at the site.

Under normal circumstances, a pressure test is carried out after the equipment is installed. Whether it is a pneumatic or hydraulic test is determined by the design institute. If it is a hydraulic test, the design institute will take into account the conditions of the foundation; it is recommended to understand those conditions before deciding whether to conduct a hydraulic test on site. Personal opinion, for reference only.

At the construction site, this question should first be asked of the designers – how did they consider it? Generally, the issue of pressure testing is taken into account during the design process. Hydraulic testing was taken into account during the design process. Of course, from a safety perspective, hydraulic testing should be carried out. If the design does not include provisions for on-site hydraulic testing, then the owner, the contractor, and the designer should discuss together how to address this issue. Once the plan is finalized, each person is responsible for verification, coordination, and execution……

Hydraulic pressure testing is an important procedure to determine whether general equipment is qualified. The construction party should pay attention to following the design documents; if there are no specific design requirements, it can discuss and decide on them together with the owner, the designer, and the supervisor

Pressure vessels that have been fully assembled must undergo re-pressure testing on site.

Under normal circumstances, a pressure test is required after the installation of equipment, but it seems that many companies don’t carry out this test these days

1. Check whether it is a Class III container; if so, pressure testing is required. 2. Pressuring must be done using water pressure; unless one doesn’t care about their own safety, there was no one on site who could instruct me to use air pressure. It can be refused; it’s not safe. 3. On-site pressure testing: In addition to checking whether the container itself has been damaged during transportation, it is mainly necessary to check for leaks at the container’s outlet (i.e., the area where it connects to the valve), as well as for internal leaks in the valve.

After the installation of pressure vessels is completed, a hydrostatic test is generally carried out; for vessels of category three, an airtightness test is also required. Personnel from the pressure vessel authority must come and conduct inspections, otherwise a permit for using the pressure vessel will not be issued.

Pressure vessel installation is divided into assembled-installation and bulk-installation types of vessels. In accordance with the \"Safety Technical Inspection Regulations for Fixed Pressure Vessels,\" the pressure testing requirements for assembled pressure vessels have already been carried out at the manufacturing plant; therefore, there is no need to conduct pressure testing at the installation site； Bulk pressure vessels, as they need to be assembled and welded on-site, must undergo a pressure test after installation is complete. Unless Party A is concerned that accidents such as collisions during transportation might pose a risk of rendering the container unusable, it may conduct another pressure test at the installation site. Pressure testing is divided into hydraulic testing, pneumatic testing, and hydro-pneumatic testing, which are carried out under different requirements. If the site and the pressure vessel permit the use of liquid for testing, then hydraulic testing is conducted ； If the container is susceptible to corrosion by liquids or cannot be pressurized with liquids, a pneumatic pressure test can be carried out with the approval of the technical supervisors from both the client and the installer ； In cases where the container is particularly large, a liquid-gas pressure test can also be used. The leak test is primarily applied to pressure vessels containing flammable, explosive, or toxic substances, and it must be carried out after the pressure test.

The option upstairs is the correct one. For equipment that has been fully assembled and welded before leaving the factory, there is no need to conduct a pressure test after it is installed on site; at most, a leak test or similar should be carried out after it is connected to the system, and this applies mainly to the connection seals. If the welding is to be carried out on site, or if the final closing ring weld is to be welded on site for such equipment, then hydraulic pressure at the site is required. But I’ve never heard of the claim that “on-site water pressure equipment won’t crack.” What’s the principle behind that?