That is wrong. It is this for testing of bottlesa 4500PSI will hold another 50% more than a 3k if they are the same volume
ontop of this 3k tanks are generally steel meaning they need testing every three i think years and they way alot more.
4.5k tanks are carbon fibre on the other hand meaning they only need testing every five years and they weigh a lot less
Which is taking from the UKPSF website.FIVE YEARS FOR FULL-FIBRE WRAPPED BOTTLES - EN12245 and Pi certified.
THREE YEARS FOR FULL WRAPPED BOTTLES - HSE-AL-FW2 manufactured before July 2003 then five years after retesting for SCI and Luxfer cylinders
THREE YEARS FOR FULL WRAPPED BOTTLES - HSE-AL-FW1
FIVE YEARS FOR HALF WARP BOTTLES
FIVE YEARS FOR ALUMINUM OR STEEL BOTTLES