Water jacket volumetric expansion method

The direct expansion method is applicable when only total and permanent expansion determinations are required. However, its use has practical limitations because this method is less accurate than the water jacket volumetric expansion method. Therefore, regulations forbid the use of this method to qualify U.S. or TC cylinders for charging up to 10 percent in excess of marked service pressure [1,2]. 

Water jacket volumetric expansion is the standard method of testing high pressure cylinders in the compressed gas industry. This method is applicable when volumetric expansion determinations are required that is, total, elastic, permanent, and percent permanent expansion measurements. It consists of enclosing a... 

Water jacket volumetric expansion is the standard method of testing high pressure cylinders in the compressed gas industries. This method is applicable to all hydrostatic tests when volumetric expansion determinations are required, that is, when expansion, elastic expansion, permanent expansion, and percent permanent expansion measurements are required. It consists of enclosing the cylinder, full of water, in a vessel completely filled with water. The measurement is done with a suitable device, such as a leveling burette, attached to the jacket vessel. This measures the volume of water forced from the jacket upon the application of pressure to the interior of the cylinder, which causes expansion of the cylinder, and the volume remaining displaced upon release of the pressure. These volumes represent the total and permanent expansions of the cylinder, respectively. 

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