Definition

Building Information Modelling (BIM) is defined in ISO 19650-1 as the "use of a shared digital representation of a built asset to facilitate design, construction and operation processes to form a reliable basis for decisions." BIM is a collaborative working method underpinned by an information management framework. The essential output is structured, reliable information that supports decisions throughout the asset lifecycle. The UK adopted the ISO 19650 series as the governing standard, superseding the earlier PAS 1192 family, and mandated compliance on centrally procured public sector projects from 2016.

Why this matters for Data Management

  • Level 1 knowledge: you must be able to define BIM, identify the principal standard (ISO 19650) and explain the surveyor's role within a BIM project team.
  • BIM is the defining development in built environment information management; a candidate who cannot discuss it competently will be at a disadvantage on construction and project management instructions.
  • The CDE concept underpinning BIM is the most sophisticated implementation of project information storage principles covered in this competency.
  • The Building Safety Act 2023 "golden thread" obligation for higher-risk buildings is a mandated form of BIM-type information management for the operational phase.

Key principles

The ISO 19650 information management framework

ISO 19650 sets out an information management process built around the client's information requirements — Organisational Information Requirements (OIR), Asset Information Requirements (AIR) and Exchange Information Requirements (EIR) at project level. The project team responds with a BIM Execution Plan (BEP) documenting how information will be produced and delivered. Information flows through a Common Data Environment with defined workflow states, ensuring only approved information is acted upon. The standard covers both the delivery phase (ISO 19650-2) and the operational phase (ISO 19650-3).

The surveyor's role in BIM

Different surveying roles engage with BIM differently. A quantity surveyor sets the cost-related elements of the EIR and uses model-extracted quantities to inform cost plans. A project manager may act as information manager on a smaller project, maintaining the CDE. A building surveyor uses the as-built model to support planned maintenance programmes. A valuation surveyor may use BIM data to assess whole-life cost implications on investment value.

BIM Execution Plan and Level of Information Need

The BIM Execution Plan documents how information will be produced, by whom, to what standard and in what format. The Level of Information Need (LOIN) specifies how much information needs to be included in a model element to support the decisions it must inform — replacing the older Level of Detail concept with a more purposeful, decision-driven approach. Over-specifying the LOIN adds cost without value; under-specifying means the model cannot support the decisions required.

Relevant RICS guidance and legislation

  • ISO 19650-1 — concepts and principles for information management using BIM.
  • ISO 19650-2 — delivery phase of assets, including CDE, BEP and EIR requirements.
  • ISO 19650-3 — operational phase of assets; particularly relevant to facilities management and asset management surveyors.
  • Building Safety Act 2023 — the golden thread requirement for higher-risk buildings operationalises BIM-type information management principles for the building's ongoing life.
  • RICS Rules of Conduct (effective 2 February 2022) — Rule 5 requires surveyors to maintain digital competence, including BIM literacy appropriate to their practice area.

Ethics and Rules of Conduct angle

BIM creates specific professional ethics challenges. The Honesty and Integrity rule applies to the reliability of information shared through the CDE: a party that knowingly introduces inaccurate data into a shared model, or fails to flag known errors, is in breach of their professional obligations. The Competence rule requires surveyors to be honest about the limits of their BIM capability; taking on BIM coordination responsibilities without the necessary skills is not in the client's interest. The Responsibility rule applies to cyber security and data protection in the CDE.

APC-style Q&As

Q (Level 1)What is BIM and what is the primary UK standard that governs it?

Building Information Modelling is the use of a shared digital representation of a built asset to facilitate design, construction and operation processes, providing a reliable basis for decisions throughout the asset lifecycle. The primary UK standard is the ISO 19650 series, which sets out information management requirements for BIM from the delivery phase through to asset operation.

Q (Level 1)What does EIR stand for and what is its purpose?

EIR stands for Exchange Information Requirements — the client's project-level specification of what information the project team must produce, in what format, at what level of detail, and at which project stage. They define information deliverables at each gateway, so the design team knows what to produce and the client knows what to expect.

Q (Level 2)How does a quantity surveyor use BIM to support cost management?

A QS extracts quantities directly from the BIM model — areas, volumes, component counts — reducing measurement error and keeping cost plans aligned with evolving design. The QS sets the cost-related elements of the EIR to specify data attributes needed at each stage. At later design stages, 5D modelling links cost data directly to model elements so the cost implications of design changes are visible in near real-time.

Q (Level 2)What is the Level of Information Need and why does it matter?

The Level of Information Need (LOIN) defines how much information a model element must contain to support the decisions it must inform. It replaces the older Level of Detail concept with a purposeful approach: information should be produced at the level of geometrical detail and data appropriate for the decision, and no more. Over-specifying the LOIN adds cost without value; under-specifying means the model cannot support the decisions required.

Q (Level 3)You are acting as project manager on a new office development. The design team is using BIM but the main contractor has limited BIM experience. How do you manage this?

(example) I would address this at pre-contract stage by including BIM capability as a scored criterion in the tender evaluation. If the selected contractor has limited experience, I would agree a proportionate BIM Execution Plan focused on the CDE for document management and clash detection, and agree a realistic programme for building capability during the contract. The EIR would specify minimum deliverables — for example, an as-built model at handover — and I would document all decisions, flagging the limitation to the client so they can make an informed choice about whether to appoint a BIM coordinator as additional project resource.