The industry standard for ceramic disc durability testing is 150,000 cycles. Our new test bench runs to 500,000. The first batch of cartridges from the Xiamen line completed the full run last month. None failed.
Ceramic disc cartridges are the mechanism inside nearly every quarter-turn tap and shower valve manufactured in the last thirty years. Two flat ceramic discs — one fixed, one rotating — seal against each other. The tolerances are measured in microns. When they work correctly, they work for decades. When they fail, they drip.
The failure mode is almost always wear. The discs grind against each other with every turn of the handle. The rate of wear is determined by the flatness of the discs, the quality of the ceramic compound, the lubrication between them, and the water quality they operate in — hard water accelerates abrasion in a way that soft water does not.
Why 500,000 Cycles
The EN 817 standard requires 70,000 cycles for quarter-turn fittings. The ISO 15083 standard goes to 150,000. We have been testing to 150,000 since 2021. The new bench runs to 500,000 because our hospitality clients operate in buildings where a tap may be turned 50 times a day, 365 days a year. At that rate, 150,000 cycles is approximately eight years. 500,000 cycles is twenty-seven years — which is closer to the design life of the building.
"We test to the life of the building, not the life of the warranty."
The Test Bench
The new bench runs 48 cartridges simultaneously. Each cartridge is cycled through the full range of motion — open to close to open — at the rated operating pressure for its specification class. Water temperature cycles between 15°C and 60°C every 2,000 cycles to simulate the thermal expansion and contraction the disc experiences in service. The bench logs torque, leak rate, and temperature continuously. An automated system flags any cartridge that exceeds the leak threshold or requires more than 15% more torque than baseline to turn.
First Run Results
Forty-eight cartridges from our current production batch ran the full 500,000-cycle programme over thirty-eight days. Results:
- Leakage failures at any point: 0
- Torque increase above 15% threshold: 2 cartridges (at cycle 480,000 and 497,000 respectively)
- Mean torque increase at 500,000 cycles vs. baseline: 6.3%
- Maximum torque increase: 11.8%
The two cartridges that triggered the torque alert were disassembled for analysis. Both showed minor surface scoring on the fixed disc, attributed to particulate matter in the test water. We are reviewing our inlet filter specification as a result.
What Partners Receive
From March 2026, all SUSOS ceramic disc cartridges ship with a test certificate referencing the 500,000-cycle programme. The full test report — including the torque and leak data for every batch — is available to distribution partners and project specifiers under NDA. We do not publish batch data publicly, but we share it with the partners who need it for their own warranty commitments.
The 500,000-cycle programme is currently running on our quarter-turn range. We will extend it to thermostatic cartridges in Q4 2026 when the thermal-cycling equipment is installed.
