In-situ Remediation of OHL Tower Steelwork
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Gas Distribution Networks
National Grid is in the process of investing over £150m on the refurbishment of
OHL lattice steel work towers over the RIIO period.
Current asset policies require the replacement of steel work identified as Grade 4
(in accordance with TG4) or worse and this policy is being reviewed by a
steel work strategy team. One of the outputs of this team has been the
identification of a need to consider the in-situ remediation of Grade 4 tower
steel work on main structural members as the volumes of steel work involved are
extensive and current methodologies require several circuit outages or a lengthy
double circuit outage to complete the works.
Faced with a growing capital programme and the need to minimise circuit
outages, it is necessary to consider alternative methodologies to resolve this
The key issues to be addressed by this project are therefore the identification,
recording and remediation of Grade 4 steel work on primary structural members
of National Grid's lattice steel towers under outage & non-outage conditions.
This project will consider a range of technologies, as employed in other
industries, for the remediation of structural steel work. It will assess the suitability
of these technologies for use on lattice steel structures carrying live 275kV and
The 3 key deliverables of this project will be:
- The adaptation of recognised methodologies (techniques for cleaning the
steel and combinations of products for re-coating it) for remediation of
structural steel work and the demonstration of the effectiveness of this
solution (through trials and accelerated weathering tests) for use on National Grid's overhead line towers during outage & non-outage conditions
- The creation of a procedure/manual to support ongoing implementation of
the techniques developed
- Development of a training package to ensure consistent recording &
communication the condition of the steel work prior to and after remediation.