Human Reliability Analysis of a Pig Receiver Operation: A Case Study Using Petro-HRA
Authors: Morais Caroline Pinheiro Maurieli de 
Published: October 2023

Abstract
It is common sense that it is better to prevent than cure. The same applies to oil & gas industry, which stakeholders have recently coined the expression ‘learn from normal work’ to highlight that there are other ways rather only learning from accidentes. The International Association of Oil and Gas Producers (IOGP) has recently issued a report showing how to implement the concept in the oil & gas installations (IOGP, 2023). The Energy Institute (EI) has chosen to call the concept ‘learning before incidentes’, and has also issued some material, including videos (EI, 2022).
The IOGP guideline points several tools to learn from normal work. Two of them are frequently requested and assessed by the brazilian oil and gas regulator (ANP) auditors during their safety audits: Walk-through (or VCP – verification of conformities with procedures) and the human reliability analysis. The human reliability analysis is a methodology that proposes to systematically consider human factors in risk analysis. By not adopting a method to consider the context in which the workforce is inserted, risk analysis participants tend to issue opinions based only on common sense (Raio et al., 2018). Validated human reliability analysis methods are a better option because they were created by engineers, psychologists and sociologists and consider data from scientific experiments on how human error can be triggered by various factors in the context of the task performed (Kirwan, 2017).
In the Brazilian oil industry, the human reliability analysis methodology is still not used on a large scale. Although clearly stated by ISO 31010 as the right technique to assess human factors in risk analysis, the failure to use it might be possibly due to the lack of knowledge dissemination or clarity in safety regulation which stated that ‘the methodology of risk analysis should consider human factors’ (ANP, 2007). This has prompted the regulator to change the text in the new regulation still under public consultation (ANP, 2022). Usually, in existing installations, the probability of human error is considered when using the LOPA (layer of protection analysis) methodology (Willey, 2014), which considers the human error probability fixed and immutable, when the most appropriate would be to consider the probability according to the task performed and the context in which the worker is inserted. This relationship between context and task factors that can influence human performance is the most important basis of all human reliability analysis methods (those accepted by safety regulatory bodies and scientifically validated). Popular and scientifically acceptable methods can be found in the publication of the UK safety regulator, HSE (Bell & Holroyd, 2009). The methods with the greatest potential for application in the oil and gas industry, according to the criteria used by (Ramos et al., 2020), are (in order of greatest suitability for the oil and gas industry): Phoenix-PRO (high suitability), Petro-HRA (high), CREAM (high), SPAR-H (medium), HEART (medium), ATHEANA (medium) and THERP (low).