TECHNICAL ARTICLE case
TESTS EXECUTED BY EXPANSION JOINT COMPANIES
Expansion Joints can be subject to any kind of tests and inspections. The scope of tests executed by Expansion Joint companies meets the requirements of the design code and/or the customer’s specification. Some of the tests are executed by Expansion Joint companies and some are performed by third parties. There are two different test types: non-destructive and destructive testing. By testing, Expansion Joint companies verify if products are suitable for the intended use. Non-destructive testing is most commonly used, as it does not permanently modify the tested subject.
Description of tests executed by Expansion Joint companies
- Visual test: a visual inspection of the bellow convolutions for any cracks and irregularities, surface finish, weld and paint imperfections.
- Leak tightness test: is used to verify conformity of Expansion Joints. There are several ways to execute a leak test. The most commonly used by Expansion Joint companies is soap-water solution that should indicate the presence of a leak.
- Dye penetrant test: is the method to locate cracks in a welded surface, lack of welding fusion, leaks and fatigue cracks.
- Radiographic examination: is used by Expansion Joint companies to inspect discontinuities and imperfection of butt welds by using electromagnetic gamma rays.
- Hydrostatic pressure test: by using this test Expansion Joint companies verify Expansion Joint for its strength and leak resistance. The test pressure is always higher than the operating pressure to give a factor of safety. Belman is able to perform the test up to DN 3000 and 500 tons.
- Magnetic particle examination: is a non-destructive testing for detecting discontinuities in surfaces and sub-surfaces in ferromagnetic materials and alloys.
- Ultrasonic testing: is used to transmit sound waves into the test material. It determines all imperfections in welds. This test is used by Expansion Joint companies on carbon steel, stainless steel, alloys and other materials.
- Positive material identification (PMI): is performed by Expansion Joint companies to determine the qualitative and quantitative composition of the material being tested.
- Helium leak testing: where a normal leak test with water or soap solution has a limited leak detection rate, helium leak test passes through and determine any leak in inspected area.
- Eddy Current test: uses electromagnetic induction to detect very small cracks in the surface of the material.
- Destructive testing: Expansion Joint companies perform destructive tests to understand and prove structural and material performance under load. Belman has equipment to carry on: burst test, cupping test, movement test and fatigue test.
Belman Quality & Test
Focus on quality had always been a part of Belman’s mission. We strive to provide Expansion Joints of highest quality. Therefore Belman treats test and quality procedures as an important process, which adds value to our products, but most importantly, it guarantees the quality and gives the product confidence to our customers. Testing of our Expansion Joints is always carried on according the client and/or project requirements and relevant standards.