Question: This question relates to container size and type codes. “Some of my tanks say T6 and some say T8. What is the correct marking?”
Tank Guru: If you are referring to the “Type Code” of the tank container, as in 22T6 or 22T8, it will depend on the pressure rating of the tank. For a typical 4 bar MAWP chemical tank with a Test Pressure of 6 bar, the correct code would be T6 and would be appropriate for any tank with a Test Pressure equal to or greater than 6 bar, but less than 10.5 bar.
T8 (or 22T8) would normally be found on gas tanks. And in the Size Code the first “2” indicates that it is a 20′ container, and the second “2” indicates the 8.5′ height. See the image here for a detailed explanation on container size and type codes, courtesy of the now-defunct Tank Container Association.