Design details
GRE was contracted, by one of the UK’s leading M and E contractors, to design, manufacture and install a liquid nitrogen distribution system to feed two freeze driers used in the vaccine manufacture and storage process.
The project challenges
The largest and most obvious challenge for GRE’s engineers at the start of the contract, was that the building that the SIVL was to be installed in, wasn’t even built! In the first instance, our engineering team, worked in parallel with the M and E contractor to incorporate our vacuum jacketed lines into the CAD model of the building, working around spaces where the many other building utilities would be located. As building progressed, periodic 3D scans were undertaken by GRE, to ensure that the SIVL runs were in the correct position and unencumbered by other utilities.
Another significant challenge was that, due to the application being pharmaceutical, GRE had to design the SIVL to be able to achieve a high level of safety – in this case, HSG 253, Cat II Proved isolation (double block and bleed).
In addition to being able to demonstrate a high level of safety in the system design, GRE also had to provide full material compatibility justification and certification, and all welds had to be undertaken by GRE’s coded welders, to prescribed procedures.
As a brand new / experimental production line, the clients were unable to give accurate estimates of the flow requirements of the freeze dryers, so the distribution system had to be flexible enough to cope with widely varying mass flows.
As the site was in a built-up area, the system also had to comply with very strict sound limits. With this in mind, GRE modelled the exhaust gas outlet, based on a wide variety of flows and custom-designed/built a silencer that reduced exhaust gas noise to acceptable limits.
Finally, part of GRE’s scope was to provide an ongoing support, comprising of a spares package and multi-year service agreement.
As with all of GRE’s vacuum insulated pipework/systems the client was then presented with a comprehensive document package including:
- Full system P & ID with mechanical drawings for each component
- Material Test Certificates
- Individual line/component factor test reports (Vacuum Conditioning, Helium leak and positive pressure tests)
- Site Acceptance test report (Helium leak and positive pressure tests)
- Installation and operation manuals
- Declaration of conformance documentation
All actuated and manual isolation valves were from the Stohr range of cryogenic equipment, provided by Gas and Liquid Controls Ltd www.gasandliquidcontrols.com