Practices

OVERVIEW | Possibilities and challenges of BIM with respect to the assessment of the energy performance of buildings

Share this Post:

Shutterstock / nopporn

By Peter Wouters, INIVE

 

BIM (Building Information Modelling) is in many EU countries high on the agenda. This article is focusing on the potential of BIM in relation to the energy performance of building assessment and also in relation to a better quality of the works.

 

ISO 29481-1:2016 (en), defines BIM as the “use of a shared digital representation of a built object (including buildings, bridges, roads, process plants, etc.) to facilitate design, construction and operation processes to form a reliable basis for decisions”.

 

BIM developments in Europe

 

The future market uptake of BIM is difficult to predict with great accuracy, but it clearly is a development with great potential.

 

In terms of requirements, an increased number of countries impose the use of BIM for certain types of projects, e.g.:

 

  • Since 2010, obligatory in Norway for new buildings;
  • Since 2011, mandatory in the Netherlands for public works of more than €10 M;
  • Sine 2016 mandatory in the UK for public buildings above £5 M;
  • Since 2008 mandatory in the USA by the general services administration for the submission of government projects.

Global perspective of BIM implementation throughout the world (Source: Roadmap Proposal for Implementing Building Information Modelling (BIM) in Portugal. Maria João Falcão Silva, Filipa Salvado, Paula Couto and Álvaro Vale e Azevedo. Open Journal of Civil Engineering (OJCE), Vol.6 No.3, June 2016)

In its 2016 report ‘Shaping the Future of Construction – A breakthrough in mindset and technology’ by the World Economic Forum, prepared in collaboration with the Boston Consulting Group, the market view on a whole range of new technologies has been collected. From this survey, it appears that BIM has the highest likelihood and an expected extreme high impact on the building sector.

 

In practice, there are a lot of initiatives at international level and in the individual countries, e.g.:

 

What can BIM mean for EPC calculations?

 

At present, the calculation of the Energy Performance Certificate (EPC) of a building is an activity on its own. One has to collect all data, introduce all these data (surfaces, volumes, product and system data …) into the software tool. This can be very time consuming. Therefore, it is important/necessary to have the possibility of simplified procedures. Examples of such simplified procedures are e.g.:

 

  • to treat a dwelling as a single zone;
  • to have default values for various systems;
  • to have simplified procedures to deal with thermal bridges.

With BIM, and of course depending on the Level of Development (LoD) of the BIM approach, there is no need for collecting all these data for EPC calculations as they are part of the BIM model. Of course, specific tools have to be developed for the EPC calculations. Such BIM approach can reduce the required efforts for obtaining an EPC substantially.

 

What can be the impact on the calculation procedures themselves? An interesting example are thermal bridges: with a detailed BIM model, and given the calculation power or modern computers, it becomes possible to have a 3-dimensional transmission analysis of the building shell, meaning that there is no need any more to speak about a ‘thermal bridge’.

 

Another example is the assessment of overheating risks. At present, most countries use simplified procedures which only give a rough indication of the risk of overheating and/or the related energy consumption for achieving appropriate thermal comfort. With a detailed BIM model, much more refined assessment methods become possible without requiring specific efforts for collecting input data.

 

With respect to HVAC systems, most countries have at present (very) simplified procedures to assess the energy performances of such systems. With BIM, a more refined assessment becomes possible.

 

BIM and standardisation

 

In order to accelerate the market uptake of BIM, standardisation of protocols is important. Within the context of CEN, Technical committee 442 (Building Information Modelling) was created in September 2016. At ISO level, Technical Committee 59 is also dealing with BIM.

 

In order to develop on the short term data structures for providing data from CE marking in BIM compatible formats,  CEN has set up a ‘Smart CE marking’ workshop agreement.

 

With the market uptake of BIM, and assuming that BIM models will be used for EPC calculations, there might be also new tasks for standardisation in relation to EPBD related standards. BIM offers the possibility to have a better physical modelling of energy processes (see examples before for thermal bridges, overheating assessment, HVAC modelling). It is important that the (CEN and ISO) standards reflect such development.

 

BIM and convergence of national EPC calculation procedures

 

At present, there are still major differences in the national calculation EPC processes. With the new set of CEN standards, one can expect more convergence in the EPC calculation procedures. However, one observes sometimes very big differences in the visions on the need for simplification and this is often a barrier for further convergence.

 

With BIM, there is the possibility to come with limited or no efforts for the user to a more accurate physical modelling of the energy performances and therefore the possibility of nearly no differences in views between member states. If the thermal bridges are automatically calculated due to the fact that the BIM model has all relevant information, why should countries have different procedures?

 

BIM and EPC compliance

 

At present, data collection for calculating the EPC of a building is in most cases an autonomous activity not linked to other design and execution processes. This might fundamentally change when BIM will become mainstream. All relevant product and system data can then be directly coupled to the BIM objects (brick, thermal insulation, fan, heat pump …).  There still we be a challenge for compliant data, but this will not be any longer a specific challenge for the energy related performances.  Moreover, one can expect that the BIM model will be updated once design or execution modifications are decided and this not driven by the energy concerns but by the need that the BIM model effectively represents what is constructed.

 

As a result, it might mean that, once the BIM approach has become mature, there is nearly no need for specific compliance efforts related to EPC compliance.

 

BIM and quality of the works

 

Quality of the works is frequently reported problem. An advantage of the market uptake of BIM is the possibility to come to a better quality of the works. This can be illustrated for ventilation systems. If the BIM model of the installation includes all components, it will be possible to assess if the required air flow rates can be achieved, if the acoustical performances can be reached.

 

Several Horizon 2020 projects are dealing with BIM and quality of the works (see further).

 

BIM and smartness indicator

 

The implementation of the concept of a smartness indicator is proposed in the revision of the EPBD. With the expected market uptake of BIM, it probably becomes also possible to set up in a cost effective manner more refined assessment methods for the smartness indicator of buildings.

 

European projects related to BIM and energy performance

 

Within the context of Horizon 2020, 3 BIM related projects are running with a strong link to building works focusing on the energy performance of buildings:

 

1. BIMPLEMENT “Towards a learning building sector by setting up a large-scale and flexible qualification methodology integrating technical, cross-craft and BIM related skills and competences“.

 

The main aim of BIMPLEMENT is to achieve an improved quality for NZEB construction and renovation by setting up a large scale, training, Continuing Professional Development (CPD) and qualification schemes. This is done by addressing the entire process phases in a cross-crafts and cross level multidisciplinary approach, strengthened with hands-on and BIM-enhanced workplace learning tools by following objectives:

 

  • to improve the overall quality of renovations and new constructions, based on a BIM-enabled workplace learning, addressing the entire process phases in a cross-crafts multidisciplinary approach;
  • to create a new generation of professionals and craftsmen, equipped and enabled by BIM skills, to enhance the overall quality of construction and renovation across the entire process;
  • to foster interactions between different trades and professions enabled by a flexible qualification, certification and accreditation methodology for implementing BIM as a workplace learning environment;
  • to sustain the qualification and training schemes a replication and exploitation strategy will be developed and validated.

2. BIMEET “BIM-based EU-wide Standardised Qualification Framework for achieving Energy Efficiency Training”.

 

The BIMEET project aims to leverage the take-up of Information and Communications Technology (ICT) and BIM through a significant upgrade of the skills and capacities of the EU construction workforce.

 

Through its actions the project will:

 

  • pave the way to a fundamental step change in delivering systematic, measurable and effective energy efficient buildings through BIM training with a view to effectively address European energy and carbon reduction targets;
  • promote a well-trained world leading generation of decision makers, practitioners, and blue collars in BIM for energy efficiency;
  • establish a world-leading platform for BIM for energy efficiency training nurtured by an established community of interest.

3. Net-UBIEP “Network for Using BIM to Increase the Energy Performance”.

 

The project proposes BIM Qualification Models integrated with energy competences, to widespread a better comprehension of energy issues along all the value chain of building industry so that both existing and new buildings will have better energy performances. The definition of the BIM Qualification Models will pass through the identification of specific energy BIM competences needed to implement BIM models during the whole building life cycle.

 

During the project the “integrated” BIM Qualification Models will be validated by stakeholders thanks to the delivering of different training activities. Once the schemes will be validated, they will be proposed for standardisation to find a broader acceptance at European and international level through regulatory organisations (CEN / ISO).

 

There are also other BIM related EU funded projects with a link to energy, e.g. the BERTIM project (developing a BIM tool for renovation) and the P2ENDURE project (using BIM to model the predicted behaviour of a range of technologies for the renovation of existing buildings using thermal and acoustic scanning technologies as well as 3D scanning).

 

Conclusions

 

A lot of developments are taking place in the field of BIM. There probably will be major differences in speed of implementation between countries and for various building types, but there is no doubt that its importance will substantially grow in the coming decade. BIM can offer major opportunities in relation to the energy performance assessment of buildings, including compliance and enforcement. Moreover, it can at the same time contribute to better quality of the energy systems and the market uptake of smart building systems.