Regarding the purpose of the voltage withstand test and the leakage test
Thread Content
In the explanations provided in the GB150 standard regarding the purposes of the pressure test and the leakage test for containers, it is stated that both tests are intended to \"check the integrity of welding joints and verify the sealing performance of sealing structures\". The question is as follows: 1. Since the pressure test already serves to \"check the integrity of welding joints and verify the sealing performance of sealing structures\", is it then unnecessary to conduct a leakage test?； Is it still used for a gas tightness test, especially after a pressure test? 2. Regarding the timing for performing a leak test, the design drawings specify that such a test should be carried out; however, the manufacturer believes that the flange seals need to be removed after the leak test is done, so there is no need to conduct the leak test at the manufacturing facility – it should be done after installation by the end user. What are everyone’s thoughts?
1. The pressure test is primarily used to check the tightness of welded joints as well as the pressure-bearing capacity of the main pressure-bearing components; the pressure applied is 1.25 times the design pressure (for water)； The airtightness test primarily verifies the sealing performance of the sealing structures (joints such as welds, flanges, and threads), with the pressure used being the design pressure. The two cannot replace each other. 2. This is normal. For devices that need to be opened on-site, leakage tests are generally not conducted before leaving the factory, but rather after installation is completed.
The voltage withstand test is a strength test, while the leakage test is a process test
I basically agree with the view on the second floor. Regarding Article 2, ensuring airtightness within the manufacturing facility is a way of showing responsibility for quality; no one wants to find that the airtightness cannot be maintained on site, as that would be very problematic. So if it were me, I would choose to perform a leak test inside the factory.
For hydraulic testing, water and gas have different levels of permeability; therefore, a leak test is still necessary. When conducting a pressure test, it’s important to understand the difference between a pressure test and a tightness test http://bbs.hcbbs.com/thread-1005778-1-1.html (Source: Haichuan Chemical Industry Forum) If repairs are needed after the airtightness test, it will be difficult to conduct another airtightness test after the installation in the workshop, right?
This post was last edited by zhangjuhua on 2016-10-11 at 17:54. A tightness test is just one type of leakage test; it can also be a halogen test, an ammonia test, a helium leak detection test, etc. GB150 specifies that if a pressure test has been conducted, a tightness test may be omitted, but this requirement was later removed. If other methods are used for leak detection, then the tightness test definitely cannot be skipped, as the accuracy of tightness testing seems to be lower compared to those other methods
It’s a clichéd question.....
It’s a clichéd question.....
Purpose of the pressure test: To assess, under pressures higher than the design pressure, whether defects will expand rapidly leading to failure or cracking resulting in leakage, and to evaluate the sealing performance of the sealing structure. Purpose of the leak test: sealing integrity. Sealing components and welded joint areas. Withstand voltage test and leakage test. Withstand voltage test: hydraulic, pneumatic, gas-liquid combination; Leak test: airtightness test, halogen test, ammonia test, helium leak detection. Well, that’s what is clearly stated in the book. For pressure resistance tests, if a gas pressure test is used, and the medium conditions require a leakage test, then a airtightness test will suffice; in such cases, design documents generally do not require such tests to be carried out! And if other halogens, ammonia, or helium are used, then a leak test must be conducted. Because of the medium used in your pressure test. Generally, there are no such types of leakage, and the equipment’s medium is required to have no trace leakage. And your pressure test cannot meet this requirement. So it has to be done! You need to conduct a leak test; first, you must ensure that your equipment is in good condition: 1. Sealing components, 2. Welded joints. If you don’t do this, they will carry out the test on site and discover that there are leaks in the welded joints. What should I do? Besides, after the pipes are installed, they are generally tested for leaks based on the operating pressure. Personal opinion!
My personal opinion is that even if pressure testing is carried out using air, it is not necessarily necessary to eliminate the airtightness test; it depends on whether all safety accessories are installed during the pressure testing. If they are installed properly, then the airtightness test can be omitted; otherwise, the airtightness test must be conducted again
The pressure test is a strength test for pressure vessels, while the leakage test is a tightness test (for media with extremely high hazards, etc.)