Man, Technology and Organisation

The Petro-HRA Project


A new method for assessment of human reliability in post-initiating events in the petroleum industry.

Logo for the Petro-HRA project

Click on the logo above to download the Petro-HRA guideline.


Introduction & Background to the Petro-HRA Project

The Petro-HRA method has been developed in an R&D project called “Analysis of human actions as barriers in major accidents in the petroleum industry, applicability of human reliability analysis methods”, Project no. 220824/E30. The sponsors were the Research Council of Norway and Statoil Petroleum AS, and DNV-GL has provided resources as an industrial partner. The method has been developed in a joint effort by: the Institute for Energy Technology (IFE, project owner), the Norwegian University of Science and Technology (NTNU), DNV-GL, SINTEF Technology and Society, the Idaho National Laboratory and Statoil.

The aim of the Petro-HRA project was to test, evaluate and adjust a suitable HRA method to post-initiating events in the petroleum industry. This project chose the Standardized Plant Analysis Risk-Human Reliability Analysis, or SPAR-H method (Gertman, Blackman, Marble, Byers & Smith, 2005), as the primary method to adjust to the petroleum industry. The choice was based on a review by Gould, Ringstad and van de Merwe (2012), which concluded that SPAR-H was the most promising method after having evaluated different methods for analysing human reliability in post-initiating events in the petroleum industry.

The Deepwater Horizon disaster. Source:

The Deepwater Horizon disaster (Source: http://

A main goal for the Petro-HRA project was to adapt the SPAR-H method to make it more suitable for the oil and gas industry. Petro-HRA is a method for qualitative and quantitative assessment of human reliability in the petroleum industry. The method allows systematic identification, modelling and assessment of tasks that affect major accident risk. The method is mainly intended for use within a QRA framework, but may also be used as a stand-alone analysis, e.g. to support a Human Factors engineering analysis. The Petro-HRA method includes context-specific guidance on qualitative data collection and analysis and quantitative analysis, as well as integration in QRA.

The Petro-HRA Method

The Petro-HRA method comprises seven steps, covering both the qualitative and quantitative analysis requirements for a complete HRA method:

    1. Scenario definition: defines the scope and boundaries of the analysis and shapes the subsequent qualitative and quantitative analyses. This step includes reviewing the QRA model to understand the context of the HRA within the overall risk assessment and system for managing safety barriers.
    2. Qualitative data collection: collection of specific and focused data from site visits, interviews and discussions with operators and documentation reviews, to enable a detailed task description, which includes information about factors that may (positively or negatively) affect human performance and the outcome of the scenario.
    3. Task analysis: description of the steps (i.e. human actions) that are carried out as part of an activity. Task analysis provides a systematic means of organizing information collected around the tasks with the aim of translating this into a level of detail suitable for the HRA and QRA.
    4. Human error identification: identification potential errors associated with task steps in the scenario, and description of the likely consequences of each error, recovery opportunities, and the performance shaping factors (PSFs) that may have an impact on error probability.
    5. Human error modeling: modeling of the tasks to logically describe how the HFE can occur in this scenario, and to clarify the links between the errors. The model logic can then be used to calculate the Human Error Probability (HEP) for the Human Failure Event (HFE) in the next step.
    6. Human error quantification: quantification of each chosen task or event based on a nominal value and an evaluated set of PSFs.
    7. Human error reduction: development of risk-informed improvement recommendations to reduce the human contribution to risk. Such improvements aim at either preventing the occurrence of human errors or mitigating their consequences.

The Petro-HRA method figur

The seven steps in the Petro-HRA method.