Case Studies

Countess of Chester Chilled Water Pipe Replacement

Countess of Chester Chilled Water Pipe Replacement

Client: Countess of Chester NHS Hospital
Location: Chester
Project: Chilled Water Pipe Replacement
Value: £175k
Project Manager: Matt Clare


Having completed the upgrades to the Chillers back in 2022, The chilled water pipes that fed them, needed to be replaced as they had suffered from corrosion. The external pipework was mild steel and the vapour wrap had failed, so exposure to the elements meant that corrosion was inevitable. This pipework is mild steel, which is not the same as the very thin walled Carbon Steel, that suffers similar issues. These pipes, even though they are fully welded rather than press fitted, do still suffer from rust and will eventually fail.

In this case, the seepage caused by the corrosion meant that the Glycol levels fell below that which would offer frost protection for the pipework and the chillers themselves, so there was little choice but to replace the damaged pipes. These were replaced in mild steel, fully painted in red oxide, insulated and aluminium clad.

The work

The whole system consisted of two roof top plant rooms with eight chiller units. Two of these feed the operating theatres and the remaining six feed the general wards and common spaces. The pipework reaches into the heart of the building.

As is normally the case within a live hospital environment, the work had to be programmed to cause absolute minimal disruption to patients and staff. This in itself meant we had to look for a different approach to the project.

The solution was to install all of the new pipework alongside the damaged pipework, which took around eight weeks. When this was finished, we were left with only one pipe to change per system to enable the new system to be put into operation. This was done over one day of a weekend, when the hospital was at its quietest.

All of the existing fluid within the system had to be drained off and nearly 3,000 litres was removed and pumped down from the roof into IBCs, to be able to be properly recycled.

All of the valve sets were replaced throughout and the motorised heads from the old system transferred across. When our installation work was complete, Honeywell came in to commission the controls and the system was live with less than two days of disruption.

A new dosing system was also installed to protect the system going forwards.

When the project was fully operational, we then stripped out all of the old pipework for recycling.

Project Management

The project was managed by Matt Clare who is very familiar with the site.

“I did work on the installation of the Chillers when they were replaced a few years ago, so it gave me a great insight to the site and how the place works. We had to think little differently to make the project work well for the hospital, but overall, I’m delighted with how it went and the finished job.”


This Turnkey project involved the following trades:

– Pipefitting
– Lagging
– Plumbing
– Electrical
– Builders Work



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