Incident Report

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Incident Report 2020-05-01T16:26:00+00:00

Manta 5000ST Freeflow - Filter Failure

Incident Date


Incident Description

At a point 150m from the surface a 1988 model Manta 5000ST DIN valve started to free-flow in an excessive fashion. The cylinder tap was closed and an exit made on the alternate supply. On stripping the valve it was discovered that the fibrous first stage filter had ruptured and blown fibres across both the first stage and second stage valve seats. Further investigation recreated this failure mode when the following two conditions were both met; 1) the valve seat was wet and 2) the cylinder valve was opened quickly.

Lessons Learned

When diving with a Manta 5000ST DIN (or any DV with a fibrous 1st stage filter) it is important to keep the filter dry. If the filter becomes wet then the valve must be pressurised very slowly. If possible fit a sintered filter to the unit or use valves with sintered filters as standard.
Line Management Negligible
Gas Management Negligible
Equipment Management Minor
Equipment Failure Major
Training Negligible
Medical Negligible
Planning Negligible
Procedural Error Negligible
Cave Environment Negligible
Weather Negligible
Other Factor Negligible