Pressure testing of non-metallic expansion joints is a critical step to ensure that they can operate safely under the design and operating conditions. Such testing typically includes compression strength testing and tightness testing with the aim of verifying the structural integrity and sealing performance of the expansion joint. The following are the general procedures and criteria for pressure experiments:
Compression strength test
Test pressure: Non-metallic expansion joints typically need to withstand at least 1.5 times the design working pressure for testing. However, for gas testing, this ratio may be reduced to 1.1 times the design pressure. In some special circumstances, the test pressure may require further adjustment.
observe: During testing, the appearance of the expansion joint needs to be closely observed to ensure that there is no obvious mechanical damage or structural deformation.
Inspection after pressure relief: After the pressure has slowly dropped to atmospheric pressure, the expansion joint should be checked for any leakage or permanent deformation.
Sealability test
Test Conditions: Carry out at 2 times the design pressure to check the tightness of the expansion joint.
Leakage amount: The amount of leakage should not exceed the threshold specified by the design, usually no more than 10% of the total leakage.
Experimental Precautions
Temperature influence: When performing pressure tests, the effect of temperature on the material should be considered, ensuring that the stress generated during the test does not exceed the limit of the material, especially for non-metallic materials, whose properties may change at high or low temperatures.
Test media: Depending on the actual working environment of the expansion joint, the appropriate test medium is selected, usually water or air, but in certain cases, other media may need to be used.
Other tests
In addition to pressure testing, non-metallic expansion joints may also require other types of testing, such as:
Airtightness test: Check the sealing performance of the expansion joint under gas pressure.
Fatigue testing: To evaluate the durability of the expansion joint in the case of repeated displacement.
Acceptance criteria
Acceptance of non-metallic expansion joints generally follows a stringent set of criteria, which may include the test results described above, as well as the physical and mechanical properties of the material, the properties of the band, etc. If any non-compliance is found during the test, the expansion joints may need to be redesigned, repaired or replaced.
Before performing the pressure test, ensure that all necessary safety measures are in place and that manufacturer's guidance and relevant industry standards are followed to ensure the effectiveness of the test and the safety of personnel. Testing should be conducted by trained professionals and record all test data for subsequent analysis and reporting.