I own 1 500 Gal., 2-100 pound, 2-40 pound and 1-20 pound Propane tanks they all have something in common with the 1 pound tanks The burst strength is 450 PSI or better and a safety valve that is set for 250 PSI Using the 20 pound tank at apx 60 deg. F and the 1 pond at 0 Deg. F the most I have gotten is at filling with out touching the safety vale in a time of 1.5 Min. apx 11.5 OZ of Propane in the cyl. (Spring type scale not sure how precise it is) So you can see how hard it is to blow your self up by over filling the tank. If you go by weight and do not exceed 1 pound you will be ok. Your 1 pound tank has the capacity of 19.2 OZ the 3.2 OZ is your vapor area and safety expansion zone.