Tripod-BETA: Incident investigation and analysis
Authors: Doran J.A. , van der Graaf G.C. 
Published: December 2007

Shell companies have their own separate identities. In this paper the collective expressions 'Shell' and 'Group' and 'Royal Dutch/Shell Group of Companies' may be used for convenience where reference is made to the companies of the Royal Dutch/Shell Group in general. Those expressions are also used where no useful purpose is served by identifying the particular company or companies.

Tripod-BETA is a methodology for conducting an incident analysis in parallel with the investigation, supported by a PC based tool. Interaction between these two processes provides the investigators with confirmation of the relevance of their fact gathering and highlights avenues of investigation leading to latent failures. The benefit to the analysis process is that logical anomalies can be highlighted and resolved while the investigation is still active.

Tripod-BETA focuses initially on the accident mechanism - the physical process of the accident - and uses it as a structure to identify the controls and defences that should have been in place. For the incident to happen these controls and defences either were missing or failed. The investigation then examines the immediate and latent failures behind each missing or failed defence, following the Tripod theory of accident causation.

Tripod-BETA software provides the means to collect and assemble investigation facts and manipulate them on screen into a graphic representation of the event and its causes - an incident tree. The logic of the tree structure (labelling and connections) can be tested to ensure that it conforms to the concepts of the Hazard and Effects Management Process (HEMP) and the Tripod theory. When anomalies and omissions have been resolved, a draft accident report can be auto-generated for final editing using a word processing package.

Introduction

Incident investigation is an important source of feedback on the effectiveness of HSE management systems. It can provide managers with evidence of system failures, their actual consequences and, more importantly, the potential consequences, so that remedial actions can be prioritised in relation to business risk.

A comprehensive investigation will identity the active failures: immediate causation factors that are often the result of human error. Also the underlying or latent failures that indicate system defects will be identified. Although the remedies for latent failures often take time to implement they have wider implications in terms of incident prevention.

In a Company culture where HSE management is clearly a line responsibility, the lead in incident investigation will naturally be taken by the line, and the 'customer' for the investigation findings and recommendation is line management. Investigation using entirely internal resources can have drawbacks such as lack of independence and the relatively amateur status of line staff as investigators. A line supervisor may only be involved in a complex incident investigation a few times in his working life. Tripod-BETA was developed to provide a structure for investigation that will enable investigators to apply their technical know-how and knowledge of HSE management systems to best effect.

Background

Tripod is an approach to safety aimed at the underlying problems that lead to incidents.

P. 645