HORshe: A novel-systematic method for safety risk assessment using shell and hierarchy of control

Current safety risk assessments, such as HIRA (Hazard Identification and Risk Assessment) and FMEA (Failure Mode and Effect Analysis), have several weaknesses. Meanwhile, the House of Risk approach (HOR), commonly applied in the supply chain, has the potential to be adapted to the safety context. Therefore, this study aims to propose a new method called HORshe (House of Risk for Safety, Health, Etc.). As the extension and further development of the original House of Risk (HOR) framework, HORshe is designed to implement SHELL (Software, Hardware, Environment, Liveware), a human factors-based model, and Hierarchy of Control. HORshe consisted of three stages, where stage #1 used SHELL to facilitate the identification of Risk Event (E_i) and stage #2 adapted the Hierarchy of Control and an AHP-style scoring system to determine the priority of Preventive Actions (PA_k). Finally, stage #3 was used to conduct a residual risk assessment. To validate the HORshe method, a case study of maintenance activities was carried out at a steam power plant in Indonesia, posing a high risk to worker safety. The results showed 8 Risk Events (E_i), 6 Risk Agents (A_j), and 12 alternative Preventive Actions (PA_k), which collectively represent the general risk profile of the scenario. The case study explained that 3 main Risk Agents (A_j) and 3 corresponding Preventive Actions (PA_k) aligned with available resources were identified. While the existing HOR method does not include residual risk assessment, HORshe incorporates this step, and the results demonstrated that it reduced average risk exposure by 82.42% compared to the existing condition. Although specific Risk Event (E_i), Risk Agent (A_j), and Preventive Actions (PA_k) may differ between case studies, the three-stage framework remains applicable across contexts. Furthermore, HORshe has the potential to be used for assessing risk outside the context of safety, including project risk management, lean manufacturing, and other domains. The key insights from this method include: HORshe implement SHELL, a human factors-based model, and Hierarchy of Control with AHP-style scoring system to determine the priority of Preventive Actions. HORshe consisted of three stages and adaptable for assessing risk outside the context of safety.