University of Cambridge saves downtime with in situ inspection and testing of high pressure gas cylinders


The Integrity Management team at Chesterfield Special Cylinders (CSC IM) has completed the periodic inspection and testing of a high pressure gas cylinder installation at the Cavendish Laboratory at the University of Cambridge, without the need to remove them. The in situ project has reportedly saved the University’s Cryogenics Facility many weeks of downtime.

The ‘M’ Type Tubes were inspected and tested using specialist acoustic emission (AE) techniques in accordance with BS 8562:2011. 

Stephen Butler, director of CSC IM, says: “This helium gas installation consists of 72 cylinders and is vital to the University’s Cryogenics Facility. Their re-certification period was imminent, so we were asked to conduct the inspection and test without actually removing the cylinders, saving a great deal of downtime.

“This is a task we have conducted worldwide, at universities and process plants, on submarines, even onboard a ship crossing the Atlantic. We began with visual internal and external inspections of each cylinder, then tested using AE techniques, documented our findings and re-certified each cylinder as it passed.”

A scaffold was erected over the entire installation to protect the cylinders from the weather whilst under test. Once pressures were checked manifolds and valves were removed, threads cleaned and inspected, and an external visual inspection was completed. Utilising an endoscope, a detailed internal visual inspection was conducted, with images of the current internal condition being captured to aid in future re-tests. 

AE tests identify any growing defects within the cylinders. Once the AE sensors were applied, each cylinder was taken up to 50% test pressure using helium. Leak testing and flow checks were conducted before the system was filled with helium to complete the test while monitoring the sensor output. 

Daniel Cross, Cryogenics Facility Manager at the Cavendish Laboratories said: “This project was thorough and fast, saving the University a great deal of downtime. Had the CSC IM team been unable to conduct this in situ, the time required would have been far longer, as it would have involved the cylinders’ removal by crane, transportation for factory testing and then returning back to the University for re-installation.

“These cylinders are well over 40 years old, so it was important for the University to have full working knowledge of the status of each cylinder and that has all now been fully documented. I cannot recommend the CSC IM team’s in situ service highly enough.”