Traditional design methodologies do not effectively extend to consider a resilient system capable of absorbing disruptions and recovering from their consequences. This highlights the need for a practical resilience analysis model which can be used at the design stage. While the concept of resilience is widely discussed, there is currently no agreed-upon methodology to quantify it. From a review of existing works, this paper presents a specific definition of resilience as a process safety concept. A novel model for assessing and scaling process system resilience during the early design stage is proposed in line with this definition. The proposed methodology entails a standardized analysis for measuring and comparing resilience, allowing for the simplified and accessible analysis of resilience across industry. The model combines analyses of resilient design by an index-based quantification, vulnerability to high-impact unexpected events (beyond design basis events), and assesses the potential for severe impacts due to such events. The model facilitates cost-benefit assessments for design improvements towards resilience and presents an effective tool for introducing resilience as a design concept.