Repeat Bowie-Dick failures are a specific signal: the vacuum stage keeps failing to remove air. In the dental office we reviewed, the test failed on the same unit three mornings in a row. A single failure is often procedural, but a repeating pattern is almost always mechanical or supply-related, and treating it as bad luck wastes time and puts loads at risk.
What Did the Repeating Failures Look Like?
The first failure was put down to a hot chamber, and the test was re-run on a cool unit and passed. The next morning it failed again, and this time a cool re-run also failed. On the third morning the same result appeared, with the failure concentrated in one corner of the test sheet rather than spread across it.
That pattern is diagnostic. A localised patch of colour change means air was trapped in a specific area, which points to a leak or a chamber geometry issue rather than a uniform temperature problem. By the third failure the office had stopped using the unit for routine loads, which was the correct call.
How Was the Fault Traced?
The office worked from the machine outward. The door gasket was inspected first and showed a small flattening along one edge, which can let air back into the chamber during the vacuum stage. A gasket in that condition often passes a visual glance and fails the test only intermittently, which is exactly what the three-day pattern suggested.
Rather than jumping to the gasket as the answer, the office also checked the drain and the steam supply, as the requirements for air removal testing suggest, so that a single obvious suspect did not hide a second cause. The drain was clear, and the steam supply was normal, which left the gasket as the consistent explanation.
How Was It Resolved?
The gasket was replaced, and the air removal test was re-run and recorded as a pass before the unit returned to routine use. Any load processed after the first failed test was treated as suspect and reprocessed. Keeping the failed results in the log, rather than erasing them after the fix, is what made the repair traceable.
The office then added a monthly gasket inspection to its maintenance routine, since a worn gasket produces exactly this intermittent failure pattern. Recording the inspection date in the equipment file turned a repeated surprise into a scheduled check, and the following quarter had no repeat failures.
What Is the Lesson for Other Clinics?
Distinguish a one-off failure from a pattern. A single failure on a hot chamber can be procedural; three failures in a row on a cool chamber is a fault. And when a fault is found, keep looking until the evidence points to one cause, because stopping at the first plausible answer is how a second cause survives the repair.
Logging every result, including the failures, is the foundation. The three-day pattern only became visible because the office recorded each attempt. Without that record, the gasket would have been blamed on the first day, replaced on the second, and the intermittent nature of the fault would have been missed.
| Day | Result | Reading |
|---|---|---|
| 1 | Fail, pass on cool re-run | Possible procedural cause |
| 2 | Fail on cool re-run | Fault suspected |
| 3 | Fail, patch in one corner | Leak or geometry issue |
| Repair | Gasket replaced, pass recorded | Cause confirmed |
Related reading
Sterilization compliance hub; daily air removal and Bowie-Dick requirements; how often autoclave door gaskets should be replaced.
Download the printable sterilization log sheet and use the autoclave log generator. Ask a Sterilization Compliance Specialist at the compliance desk. Ordering for a clinic, lab or care home? Wholesale and multi-site ordering and the B2B wholesale collection cover case pricing and account setup. Clinics can also 24-hour biological indicator 25-pack. Reselling? become a distributor.
Frequently Asked Questions
What does a repeating Bowie-Dick failure mean?
A repeating failure on a cool chamber points to a mechanical or supply fault, most often a worn door gasket, a drain issue or a steam supply problem, rather than a procedural error.
What should a clinic check first after a repeated Bowie-Dick failure?
Inspect the door gasket, drain and steam supply, because a localised patch of unchanged colour points to a leak or geometry issue rather than a uniform temperature problem.
Should failed Bowie-Dick results be kept in the log?
Yes. Keeping every result, including failures and re-runs, is what makes an intermittent pattern visible and makes the repair traceable.
CliniEco Medical is a licensed medical device establishment (MDEL #35334).
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