BIM – Route for the QS into the 4D and 5D Digitised Workflow TU

This information paper has been compiled for Quantity Surveyors (QSs) in relation to
Building Information Modelling (BIM). The purpose of the paper is to discuss BIM as a
technology, presenting how data contained within a 3D model differs from 2D drawings
and specifi cations, and how BIM models can be consumed by the QS.

It is envisaged by reading this information paper, as well as the documents and media content
mentioned therein, that the QS will gain a greater degree of confi dence, enabling them to
communicate as an informed participant in an emergent digitised construction workflow.

An understanding of model objects and data is critical because the QS must have the know-how to
map 3D design information to their Work Breakdown Structures (WBSs) such as the National Standard
Building Elements (NSBE) and the Agreed Rules of Measurement 4 (ARM 4). The fundamentals
of a 3D model are therefore detailed, including data contained in the objects of the model.

The paper outlines the basics in 4D BIM (time/clash) and 5D BIM (cost management),
and particularly how the QS can leverage the model to effectively manage client
requirements, especially time and cost management. It also describes a number of mapping
methods, linking data of the model, in incremental complexity, to the QS WBSs.

It is acknowledged that BIM is not currently a panacea for instantaneous cost/plan or
BOQ production, but a technological process that is creating opportunities for QSs to add
value, while also maintaining their high level of services. The paper therefore addresses
some of the issues that QSs may encounter when generating and using BIM quantities,
and outlines diffi culties when transitioning from a 2D workfl ow to a BIM process.

This information paper does not deal in detail with BIM as a ‘process’, in terms of the International
Standard Organisation’s series of BIM standards (ISO 19650); the level 2 mandate in the
United Kingdom (UK); or Ireland’s BIM road-map. Even though these policies and documents
are important and collaboration across all stakeholders is a key underpinning of BIM.

The paper is structured such that it may be read from start to fi nish (depending on the readers
understanding and capabilities with BIM) or it can utilised on a sectional basis, as required.