Above Ground Installation Integrity Decision Support Tool: Final Report

Abstract:

National Grid operate Pressure Reduction Installations (PRI) on the transmission system in the UK and the US. These installations are predominantly maintained and operated to generic procedures which do not fully take into account location or site specific risks. National Grid has initiated work to develop decision support tools (DST5) which take into account location and site specific risk.

This report describes the PRI DST risk ranking model and scoring logic. The model development has been informed by Take and Regulator Station models and advice provided by the National Grid US operator. The PRI DST provides a qualitative assessment of the supply and safety risks associated with PRI design based on factors which affect the ability to continue to supply gas under fault conditions and the installation's reliability, integrity and condition. The qualitative risk model assigns numeric scores to each factor and calculates an overall risk score which reflects the likelihood of a supply failure or a loss of containment incident. The qualitative risk model will enable an assessment of the sites which are most vulnerable to failure against consistent criteria and allow these sites to be prioritised for more detailed consideration.

Ranking of risk scores will enable efficient and reliable sites to be identified, and the learning obtained can be applied to new sites and sites targeted for investment.

The use of qualitative risk models in the development of maintenance requirements is established good practice, but it is recognised that the availability and access to data can be problematic and can limit the use and application of such models. To address this, the tool is structured to efficiently use the experience and knowledge of National Grid operational personnel and accessible data.

Publication Year:

2016

Publisher:

Ofgem

DOI:

No DOI minted

Author(s):

National Grid Gas Transmission