Abstract
The increasing adoption of modular plant concepts in process engineering requires new strategies for design and safety evaluation. Conventional hazard analysis methods, such as HAZOP are time-consuming and must be repeated whenever a configuration changes, which contradicts the flexibility that modularization aims to achieve. This work combines concepts from the modular HAZOP method and the preHAZOP method to enable an automated, early-stage safety assessment for modular plants based on P&IDs. A workflow is developed that generates a combined P&ID for a modular plant from individual module (PEA) P&IDs provided in DEXPI format and performs an adapted preHAZOP analysis on the resulting plant representation.A key motivation is that P&IDs are always created during plant or module design and already contain relevant piping information, which can be reused for automated module interconnection and plausibility checks. In the proposed workflow, standardized interfaces enable automatic connection generation and validation. The safety assessment is performed by rule-based deviation propagation on a DEXPI-based P&ID graph and can operate with, without, or alongside process data. The workflow outputs structured scenario tables and selected design consistency checks and is implemented as a Streamlit web application, validated on a modular example system.