A non-metallic expansion joint, also known as a non-metallic compensator, is a device used to absorb thermal expansion, vibration, and displacement in a piping system and is typically made of flexible materials such as rubber, silicone, fluoroplastics, fabrics, and other high temperature resistant materials. They are widely used in various industrial fields, such as electricity, chemicals, oil and gas, etc. Here are some key criteria for manufacturing and acceptance of non-metallic expansion joints:
Cycle testing：
The non-metallic expansion joint shall be cycled under the specified design pressure and displacement conditions, and the number of cycles shall not be less than 2 times of the design fatigue life.
Sealability test：
Sealability test shall be carried out after the specified number of test cycles, and the leakage shall not exceed 15%.
After the blasting pressure test is carried out at 2 times the design pressure, the sealing test is carried out again, and the leakage amount should not be more than 10%.
Blasting pressure test：
The non-metallic expansion joint should be subjected to the test of 2 times the design pressure, and there should be no obvious mechanical damage in appearance and no obvious deformation of structural parts.
Appearance check：
The surface of the ring belt is not allowed to be scratched, cracked, intercalated and peeled.
No braided circumferential seams are allowed, and the surface of all welds shall be free of cracks, unpenetrated, unfused, surface pores, craters, insufficient welding height, slag inclusions and splashes, and the transition between the welds and the base metal shall be smooth.
Nameplates and logos：
The expansion joint before leaving the factory shall be accompanied by a nameplate, including the product name, specification code, size and other information.
If there is a flow direction requirement, the flow direction arrow should be marked in the obvious position of the product.
Installation component inspection：
The surface of the non-metallic skin should be intact and clean, and the assembly gap with the metal frame should be even, without local wrinkles, bulging and twisting.
The position of the guide tube is centered, and the movable gap between the movable end and other structural members is uniform.
The sealing surface of the flange is flat, and there are no defects such as cracks, bumps, scratches and welding splatters.
Materials and Properties：
Follow relevant standards, such as ASTM F1123-87 (2019), which specify minimum requirements for construction, materials, properties and dimensions.
These standards ensure the safety and reliability of non-metallic expansion joints, effectively absorbing displacement and preventing stress buildup in piping systems in practical applications. Manufacturers and users should strictly adhere to these standards to ensure product quality. If you need specific international or national standard documents, such as ASTM F1123 or other relevant ISO standards, you may need to purchase or consult them directly from the appropriate standardization organization.