(1)The cylinders designed and approved for filling with a particular gas shall not be used for filling with any other gas unless specific approval is obtained from the Chief Controller:Provided that inert gas, oxygen and compressed air cylinder made to the same specification and design, tested and certified as per rule 26 may be converted from one gas to another after fitting with appropriate valve and painting with appropriate identification colour without prior permission from the Chief Controller, with approval of the cylinder owner by following ISO: 11621 or any other code accepted by Chief Controller for such conversion of the cylinders:Provided further that the gas filler and the owner of the cylinder shall maintain proper records of conversion for examination of the Chief Controller or Controller as and when needed.
