6D BIM and construction sustainability

How to manage building sustainability information with 6D BIM modelling

In this article, we’ll be taking an in-depth look at 6D BIM, the dimension of BIM that deals with the sustainability aspects of construction assets, a current and widely debated topic.

What are the dimensions of BIM? What is 6D BIM all about? Let’s find out.

6D BIM and sustainability

The dimensions of BIM

“BIM dimensions” refers to all aspects and information that come into play in the process of construction digitalization.

When referring to the graphical representation of a building, the terms 2D (two-dimensional representation of the model through plans, elevations and sections) and 3D (representation of the model in space) are commonly used. 2D and 3D are ‘dimensions’ that characterise the geometry of a model.

However, there are other BIM dimensions (4D, 5D, 6D, etc.) that express other characteristics of the same model.

In fact, BIM is much more than simple geometric modelling in 3D and encompasses many other aspects (or dimensions) that serve to add useful information to the project to be carried out or managed.

That said, the more commonly used ‘dimensions of BIM’ are:

• 3D – Three dimensional graphical information
• 4D – Duration, Timeline & Scheduling information
• 5D – Cost information and analysis
• 6D – Sustainability and energy efficiency assessment
• 7D – Facilities management information (Facility Management software).

In addition to the 7 standard dimensions, there is an open debate on the three “new dimensions of BIM”:

• 8D – Safety during design and construction
• 9D – Lean construction
• 10D – Industrialisation of construction.

The 10 dimensions of BIM

6D BIM, the dimension of sustainability, is looked at in this article.

6D BIM definition

6D BIM is the dimension of BIM that adds sustainability information to the geometric model of the building.

The concept of sustainability can be split into:

• environmental sustainability – the ability to enhance the environment
• economic sustainability – the ability to generate income and employment
• social sustainability – the ability to generate human well-being.

But what is exactly meant by sustainability?

The Bruntland Report at the World Commission on Environment and Development in 1987 defined sustainability as:

“Development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

In simple terms, the sixth dimension of BIM makes it possible to analyse and estimate the energy performance of the building right from the design stage, to adopt technical solutions that guarantee lower energy consumption and to assess the compliance of the building’s characteristics with the performance targets.

This essentially involves a lot of integrated information such as manufacturer data, maintenance schedules, energy requirements, data on the disposal of each building component, etc. This method requires an interdisciplinary approach as the technological and construction solutions must be based on the maximum interrelation between the building, the environmental system and the plant system.

All these aspects converge in a single BIM model that simulates the real behaviour of all the physical asset.

In the process of digitising information, data on energy consumption, greenhouse gas emissions, the recyclability of materials used on the construction site and those produced during demolition, and much other information that can also be implemented during the maintenance of the asset, are added to the model.

Energy model of a building | 6D BIM

The aim of 6D BIM modelling is to determine complete and accurate energy estimates at an early stage in order to achieve an overall reduction in the energy consumption of the building throughout its life cycle and to realise a fully sustainable building.

6D BIM goes beyond the conventional approach that focuses only on initial project costs but helps to estimate the full cost of operating an asset to meet certain sustainability and efficiency criteria.

The benefits of 6D BIM

The benefits of using 6D BIM in a construction project are:

• fast and accurate decision-making processes from the earliest design phases
• improved communication flow and information exchange between the different actors involved in the process
• possibility to rapidly evaluate different solutions
• less impact of the building on the environment
• reduction of energy consumption
• detailed analysis of the impact on economic and operational aspects during the entire life cycle of the asset
• greater savings on any changes on site
• better management of the building after delivery
• more conscious and planned management of the flow of investments in the asset.

6D BIM and sustainability

The concept of sustainability defines the optimal balance between man and nature: from the use of natural resources, to the development of technologies and products, to the development of cities and land use.

Among the greatest challenges for sustainable development, a fundamental role is played by the construction industry.

Often in construction, sustainability is only associated with the energy requirements of a building: a building intervention is only defined as sustainable when it leads to energy savings.

However, sustainability is multifaceted and concerns the achievement of a sustainable balance between economic, environmental and social requirements.

BIM can provide the framework for bringing together all these aspects by offering the possibility to manage a complex information system in an integrated way, referring to the various technological systems, the building components and the different phases of its life cycle.

In this regard, the integration of Life Cycle Assessments (LCA) and BIM is aimed at assessing the environmental impact of civil works throughout their life cycle “from cradle to grave” (from the production of individual materials, to installation, to decommissioning).

The BIM methodology allows you to manage a large quantity of complex and multidisciplinary data (as in the case of environmental impact assessments with LCA analysis) guiding the decision-making process straight from the design phase.

Furthermore, the speed of BIM procedures and information correctness which are obtained directly from the model allow you to quickly evaluate different alternatives that ensure greater efficiency and increased user satisfaction.

6D BIM, energy modelling and building quality

One of the most important aspects of 6D modelling is the energy model of the building, with which it is possible to study possible alternatives to improve energy efficiency, comfort and well-being for users and also include other more efficient and sustainable forms of energy (such as renewables).

The development of useful models to verify the feasibility of the building project and the project compliance requires an interdisciplinary approach. In fact, the technological and construction solutions used must ensure interrelation between the building organism, the environmental system and the building-installation system.

Quality in building can be defined as “entirety of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs” and is divided into 7 areas:

• spatial functional
• environmental
• technological
• technical
• operational
•  use
• maintenance.

As a matter of facts, the objective of BIM modelling should be offering a tool for the evaluation of multiple solutions analysed according to a series of quality indicators and parameters defined by the standards, according to the concept of performance-based building design (PBBD).

6D BIM modelling software

To manage 6D modelling, specific software is needed to create a three-dimensional model of the building and insert parametric objects with data and information relating to the energy performance of each element (fixtures, envelopes, systems, etc.), using up-to-date and customisable libraries of objects.

This type of model is also known by the acronym BEM (Building Energy Modeling) and enables you to:

• obtain automatic calculation of thermal bridges and heat losses
• control the thermodynamic behaviour of the building-installation system
• monitor, update and implement data on the performance characteristics of the building throughout its life cycle
• evaluate the most efficient design solutions
• analysing the effects of shading and natural lighting effects
• carry out static or dynamic energy simulations.

If you’re looking for a software for 6D BIM modelling, download the free trial version of TerMus-PLUS, the BIM software for energy simulation, verification of building energy performance and design of energy efficiency measures.