The Commission for Tunnels and Underground Space (CPT) is a Portuguese professional society. Within CPT, Working Group 4 focuses on BIM and information management for underground infrastructure. This contribution presents the development of a standardized Exchange Information Requirements (EIR), conceived as a reference document to support public procurement of engineering design services for tunnel projects. The proposed EIR is aligned with ISO 19650 and ISO 7817-1, translating strategic information needs into operational, contract-ready requirements. It is organised around Organizational, Asset and Project Information Requirements (OIR, AIR and PIR), which are explicitly linked to decision points and information delivery milestones. Exchange Information Requirements are defined to ensure timely, verifiable exchanges aligned with decision-making and acceptance criteria. Building on existing reference material developed by buildingSMART Portugal, including EIR examples for buildings, this work adapts and extends those principles to the specific context of underground works. The EIR is positioned as a reusable and scalable template, intended to improve consistency, transparency and maturity in public infrastructure procurement, while remaining proportionate to project scale and complexity. Its publication is being institutionally coordinated with buildingSMART Portugal to ensure coherence with national and international openBIM initiatives. From a technical perspective, the EIR adopts openBIM principles, explicitly referencing IFC concepts aligned with forthcoming IFC 4.4. It specifies the Level of Information Need (LOIN) per information requirement and establishes the groundwork for future implementation of Information Delivery Specifications (IDS), promoting unambiguous, machine-readable requirements. The document operationalizes ISO 19650 processes into a practical, implementable framework, demonstrating robustness and practical applicability.

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