The impact tests described in ISO 21809-1 and ISO 21809-2 are crucial for evaluating the mechanical durability of pipeline coatings, simulating the physical damage that can occur during handling, transportation, and installation. Both standards utilize a falling-weight impact tester, where a hammer with a specified mass and impact surface is dropped from a controlled height onto the coated pipe. The energy of the impact, calculated by multiplying the mass of the hammer by the drop height, is what determines the severity of the test. After the impact, the coating is examined for signs of failure, such as cracking, chipping, or flaking, either visually or through the use of a holiday detector to find any hidden pinholes or breaches in the coating that would compromise its corrosion protection.
For ISO 21809-1, which covers multi-layer polyolefin coatings, the impact test is a crucial measure of the overall system’s ability to absorb energy and resist damage. The test is typically carried out at various temperatures, as the properties of plastics and coatings can change significantly with temperature. The results are used to qualify the coating system by determining the minimum impact energy the coating can withstand without failure. Similarly, for ISO 21809-2, which applies to Fusion-Bonded Epoxy (FBE) coatings, the test assesses the toughness of the single-layer FBE system. The test parameters, such as the specific drop height and hammer mass, are defined in the standard to ensure consistent and comparable results between different coating products.
At 4ward Testing, our expertise in Mechanical Testing UK guarantees these critical impact tests are performed with accuracy and reliability, helping clients meet and exceed industry standards.
