Case Studies

Commissioning Problem with Heating System

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The project involved the refurbishment of a large office building. During the course of the works a number of problems arose, which led to a number of legal claims including fire safety systems, clashes of services, finishes in toilets and washrooms, placement of lighting fixtures. These matters were addressed in our report.

One of the main difficulties was encountered during commissioning and balancing of the new heating system. Balancing involves setting valves on each floor and at each heating unit to ensure even heating of all parts of the system. When the valve settings were checked some time after the commissioning the system was found not to be properly balanced and the process had to be repeated. This occurred several times.

During the course of our investigations we came to the conclusion that the problems were caused by 'micro-bubbling'. Small quantities of air dissolved in the water were coming out of solution and forming minute bubbles on the valve seats. This restricted the flow of water through the valves and upset the balance of the system. The bubbles could be dislodged by closing and opening the valve.

This problem is not encountered very commonly. In this case it was exacerbated by a design feature which caused low pressure drops across the valve seats. In addition, the deaerator originally specified had not been installed in order to save costs. In many cases problems such as this would not come to light as the balancing of systems is rarely repeated.

Our expert attended the hearing and gave evidence. Our Client's case was successful.

Engineering Discipline

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