Heathrow Airport HV Ducts

Location: Heathrow

Summary: Main electrical cable route ducting.

Specification: To design a fully sealed suspended, fire rated duct system which would eliminate very costly road closures and allow cable pulling to take place internally

Challenges of the task: The geometry of this project in regard to the pipe routes was challenging. 32 pipes set at a lower geometric pattern that not only sloped vertically but had a plan offset shape then arrived at the top geometric pattern that did not match the bottom so each and every pipe varied to its neighbouring pipe.

This setting out was made more difficult by the fact that the supporting hanging frame had to be designed not only fitting around the pipes into very small gaps but in a way that it could be systematically erected on site – so sequence became key.

On top of all these design constraints all the pipes have to be drainable at the top entry point to protect against water ingress from the outside elements, plus all pipes had to be airtight and pressure tested.

The final result was arrived at using manufactured stainless steel curved sections and plastic straight sections. This was hung in a frame and then fireclad in durasteel. The use of the proprietary plastic sections dramatically reduced cost on this project.

The whole unit was fully assembled in a factory upside down prior to site erection to ensure the whole system assembled correctly.