Accumulators consist of cylinders that are calibrated for storage of oil, gas or water under high pressure and is an integral part of hydraulic activated systems. In the context of BOP, the function of this device is to feed hydraulic power to BOP stack and facilitates opening/closing of the stack under normal as well as emergency situations. For this purpose to be carried out smoothly, these units should have sufficient volume to open/close all preventers and alongside accumulator pressure has to be strictly maintained at the required gauge throughout the process.