What Does Flushing Test Mean?
Flushing test is carried out to determine a sewer liner's flushing resistance under specific conditions. Trenchless rehabilitation techniques utilize high strength liners to rehabilitate damaged pipelines.
Sewers undergo regular flushing and cleaning to keep them functional by removing buildup and debris. Any liner installed should be capable of withstanding the cleaning process without causing wear and tear. The test can be conducted on an installed liner or on a section of liner in a laboratory.
Trenchlesspedia Explains Flushing Test
The Hamburg model of testing requires the use of a liner length at least 20-meters long for the flushing test. The test determines the long-term behavior of a liner including the opened connections when subjected to cleaning at high pressure of about 120 bar. Based on 30 years of useful life and assuming annual cleaning, 30 rinsing cycles are carried out with eight nozzles of 2.6 mm each. Also, three random points on the liner are subjected to permanent loading condition by keeping the nozzle pointed at those particular points.
The DIN 19523 test is based on the jet energy density of 330 w/mm square (not the water pressure) for 60 cycles. The liner in either test has passed quality checks if no signs of damage are detected.