The primary purpose of salt spray and wastewater resistance testing for SML PIPE coatings in EN877 is to evaluate the coating’s long-term resistance to chemical corrosion (acids, alkalis, salts), electrochemical corrosion, and microbial corrosion by simulating harsh, real-world corrosive environments (high salinity and complex chemical/biological wastewater). This testing verifies the coating’s ability to effectively protect the cast iron substrate from corrosion throughout the pipeline’s design life. This ensures that the coating maintains adequate integrity and adhesion after extended service.
It indirectly assesses the coating’s ability to maintain the smoothness of the pipe’s interior wall and ensure smooth drainage. This testing serves as a key basis for product quality control and obtaining standard certification.
Resistance to salt spray
The tests shall be carried out in accordance with EN IS0 9227 and after the test period of at least 350h the samples shall be rinsed with demineralized water to remove salt residues.The coatings shall then be examined immediately for blistering and rusting.
Test Process: The salt spray test uses a neutral salt spray of 5% NaCl solution for 350 hours. After the test time is completed, rinse with salt-free water to remove residual salt, and immediately inspect the inner coating for rust and pinholes. The pinhole level does not exceed Class 3, as specified in ISO 4628-2, and the rust level does not exceed Class 2, as specified in ISO 4628-3.
Sand hole degree: Grade3 or above as specified in ISO4628-2; Rust degree: Class 2 or above as specified in ISO4628-3
Resistance to waste water
The samples shall be immersed for 30d in waste water at a temperature of (23 + 3)°C with the composition given in Table 8.
Test Process: At the end of the immersion period, the samples shall be rinsed with demineralized water and dried. They shall be examined immediately for blistering or damage. After 24h at ambient temperature of (23±3)°C the samples shall be examined again.
No loss of adhesion and no rusting shall be accepted.
Post time: Jul-30-2025
