Hydrostatic Testing of CNG Cylinder is a nondestructive test procedure used to check cylinders for leaks, structural flaws, durability, and corrosion. It is used to check a cylinders structural integrity.
CNG Cylinder Testing consists of enclosing a cylinder filled with water inside a test jacket filled with water. Pressure is then applied internally to the cylinder, causing the cylinder to expand. The total and permanent volumetric expansions of the cylinder are determined by measuring the amount of water displaced by the expansion of the cylinder when under pressure and after the pressure has been released. An external and internal visual inspection of the cylinder is also performed, along with a dead-ring test for steel cylinders.