The attached report was written for the Navy who use a lot of SCBA tanks on ships for fire fighting. The purpose of the study was to assess the feasibility of extending the life of the tanks another 15 years and assessing tank integrity using a non-destructive test. Apparently thread damage during hydrostatitic tests was their most frequent cause of having to retire a tank. They pull the valve to thread the tank onto the test apparatus. Their conclusion is that a 15 year life extension is fully feasible and use of the NDE technique is also fully feasible. I don't think either has been adopted, however. It is not a terribly difficult paper to read but the NDE discussion is a bit of a distraction.
One interesting comment is they see no correlation of age or number of pressurization cycles to damage to the tank. Physical damage to the carbon fiber or contamination of the tank with water due to failure to remove it after a hydro are the ways their tanks have been damaged. They looked at data from the entire 16 years the Navy has used these tanks. This paper is a key reason I am not worried about continued use of my "expired" Scott SCBA tank.
They also address failure mechanism. No violent ruptures have been experienced. Only slow leaks.
View attachment navy-self-contained-breathing-apparatus-scba-composite-cylinder-life-extension-research-project.pdf
One interesting comment is they see no correlation of age or number of pressurization cycles to damage to the tank. Physical damage to the carbon fiber or contamination of the tank with water due to failure to remove it after a hydro are the ways their tanks have been damaged. They looked at data from the entire 16 years the Navy has used these tanks. This paper is a key reason I am not worried about continued use of my "expired" Scott SCBA tank.
They also address failure mechanism. No violent ruptures have been experienced. Only slow leaks.
View attachment navy-self-contained-breathing-apparatus-scba-composite-cylinder-life-extension-research-project.pdf
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