Tripod Beta is an incident and accident analysis methodology made available by the Stichting Tripod Foundation via the Energy Institute. The methodology is designed to help an accident investigator analyse the causes of an incident or accident in conjunction with conducting the investigation. This helps direct the investigation as the investigator will be able to see where more information is needed about what happened, or how or why the incident occurred.
Early development Tripod Beta was developed by Shell International Exploration and Production B.V. as the result of Shell-funded academic research in the 1980s and 1990s. Such research contributed towards the development of the Swiss cheese model of accident causation, and in the late 1990s and early 2000s, towards the development of the Hearts and Minds safety culture toolkit. The research was based on the following hypotheses:
Accidents happen because controls fail (a concept now known as the Swiss Cheese model). Control failures stem from deeper, underlying issues in how systems are managed. These underlying causes, metaphorically comparable with 'pathogens', are present long before an accident occurs. Some individuals are aware of these systemic imperfections prior to the incident. People are generally well-intentioned and strive to complete their tasks despite flaws in the system Identifying and addressing these failures can significantly reduce the likelihood of accidents. The early research focused on a predictive tool to identify underlying causes of incidents before they occurred rather than an incident investigation methodology. This would later become the basis for Tripod Delta. The incident investigation methodology whilst always part of the research came later around 1990. Initial Tripod Investigation followed a tabular approach as graphical program was not yet available Following the 1988 Piper Alpha disaster and Lord Cullen report in 1990, Shell International created a team to look at safety management systems and safety Cases. That team worked until 2004. They developed a number of approaches, including the E&P Forum's guidance on safety cases (later adopted by the International Association of Oil & Gas Producers). The team worked closely with Leiden and Manchester universities to advance the understanding of accident causation that had been developed in the 1984–2000 research programme. In 1992, Microsoft released Windows version 3.1. That gave the team the ability for the first time to create graphical representations of the theories developed. Two software-based tools were developed: Bow Tie and Tripod Beta.
Stichting Tripod Foundation In 1998, following the publicity surrounding Tripod Beta, Shell International Exploration and Production B.V. transferred copyright of the Tripod Beta methodology to the Stichting Tripod Foundation, a charitable body under Dutch law. The Foundation's purpose is to promote best practice in industry through the sensible usage of Tripod technologies to aid in the understanding and prevention of accidents and incidents. In 2012, the Foundation partnered with the Energy Institute in the UK to help achieve this goal. The Energy Institute currently publishes the official guide on using the Tripod Beta methodology. The Stichting Tripod Foundation also accredits training courses, and assesses the competence of users in applyingTripod methodology. Users who are assessed as competent in Tripod Beta are accredited as 'Tripod Practitioners'.
The methodology Tripod Beta is a methodology that can be conducted via pen and paper or using specialized software. The methodology combines a number of theories of accident causation to generate a single model of an accident or incident, known as a 'Tripod tree'. It draws most notably from the Swiss Cheese model (barrier-based risk management) and human factors-oriented theories such as GEMS (Generic Error-Modelling System). as well as the globally recognized GOP model (Gap, Outcome, and Power) developed by Martin Fishbein and Icek Ajzen, expanding on the Theory of Reasoned Action (TRA). A Tripod tree is divided into three sections.
What happened unexpectedly? An event in terms of Tripod Beta is the unexpected, unwanted, or adverse outcome of a willfully carried out and intended process. The sequence of such events in an incident is shown in the tree as a series of trios, a simple logic (AND) gate that tells how the combination of two events led to an outcome. The outcome can then become an event that can combine with another event to cause a subsequent outcome, and so on. As the sequence of trios goes forward in time, the tree ends when the last incident occurs, but, if relevant, can also take into account what happened after the incident (such as emergency response). Potential events may also be investigated; such events that did not materialize, either because a barrier prevented them, or due to sheer randomness, which is less likely.. As the sequence goes backwards in time, the tree usually begins with the last 'normal' event, i.e. an event that was a normal part of business operations. This represents a logical place at which to start investigating an incident, as everything that happened after this was unusual and therefore worth investigating ‘what went wrong?’ A trio has three elements: the event (the outcome, a change in state to an object, causing an effect such as an injury), the object (the person or thing that was changed or damaged), and the agent of change (the energy, driving force or hazard that caused change or damage to the object). A logic test is used to ensure the correct identification of these elements: 'agent of change' acts upon 'object' and results in 'event'. For example, 'fire' acts upon 'person' and results in 'person burnt by fire'. The Tripod practitioner first models the incident by constructing a series of trios that explain 'what happened'. Trees usually contain two to five trios connected by interlinking nodes. In these, an event may become an agent of change in a subsequent trio, or an object may become an event if affected by another agent of change.
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