Pipework, valves and associated equipment in dams,London

Overview

The average age of UK reservoirs is circa 125 years, and this also generally applies to the associated pipework systems. Pipework systems in dams is a collective term for pipes, valves, gates and associated equipment, along with fittings, joints, jointing materials, supports, restraints and drainage pipework, which are critical to the safe operation of a dam. The failure of such elements to operate properly, whether routinely or in an emergency, can have severe consequences.

The new CIRIA report is an update, review and extension of the Report 170: Valves, Pipework and Associated Equipment in Dams – Guide to Condition Assessment (Reader et al, 1997) published by CIRIA. This subject was ranked fourth in the 2016 Defra reservoir safety research strategy review due to the gaps in available guidance with respect to selection and operation of valves and gates for dam structures and because there is no consistent recent UK guidance for this subject. This report is of paramount importance to dam safety in existing assets and draws on a further 20 years’ experience of good practices and incidents, along with challenges that have been overcome. An overview to the new guide will be followed by two case studies:

1. The Canal & River Trust is responsible for many very old dams. The challenges which would result from their draw-off arrangements were not appreciated at the time of construction. Pressurised pipelines with downstream control have been updated by lining using a variety of techniques and by installing upstream valves. The Trust has a duty to conserve its heritage. Where appropriate, original equipment is restored and remains in use. Sometimes it must be replaced but may be conserved, interpreted and displayed on site or at a museum.
2. SSE Renewables refurbish critical gates and valves, typically on a 24-year cycle. A number of examples of these refurbishments were presented as case studies in the guide. Since these case studies were submitted SSE have undertaken further refurbishment projects. Stuart will provide some examples of what works were undertaken, what issues were found, and how these were resolved.