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     Occasionally I see a post where someone refers to "overfilled tanks" 
     or "overpressurized tanks".  I've even heard of people disabling their 
     valve's overpressure plugs by doubling the discs.
     
     I wonder just how much over the rated pressure people are talking 
     about?  I routinely fill my 2250 tanks to 2600PSI, and my 3000 PSI 
     tanks to 3400 PSI.  I get the feeling that other people may push the 
     envelope alot further than that.
     
     Blow out discs on a 2250 PSI tank are rated at 3750PSI.
     Blow out discs on a 3000PSI tank are rated at 4800PSI.
     
     New steel tanks can be overfilled by ten percent (legally) provided 
     that a + sign follows the hydro stamp.  Normally this only applies to 
     new tanks, and the + sign is not re-affixed after the first retest.  
     Aluminum tanks are not supposed to be overfilled at all, per the 
     manufacturer's recommendations and CGA guidelines.
     
     I noticed in an OMS catalog that had a chart showing the working 
     pressure and the "bursting pressure". Does that imply that it's OK, if 
     not condoned to overpressurize tanks?
     
     I spoke with Bill High of Professional Scuba Inspectors about 
     overfilling tanks.  Bill probably knows more about cylinders, their 
     filling, construction, maintenance, inspection and testing than anyone 
     in the world.  He adamantly maintains that cylinders should not be 
     filled one ounce more than they're supposed to be filled.
     
     I'd be interested in hearing abut how much you guys overfill, and what 
     affects, if any, the overfilling had on tank life, etc.
     
     Andy Cohen

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