Belgian Building Research Institute

Wood and other bio-based building materials are often perceived as a good choice from a climate mitigation perspective. This article compares the life cycle assessment of the same multi-residential building from the perspective of 16 countries participating in the international project Annex 72 of the International Energy Agency to determine the effects of different datasets and methods of accounting for biogenic carbon in wood construction. Three assessment methods are herein considered: two recognized in the standards (the so-called 0/0 method and −1/+1 method) and a variation of the latter (−1/+1* method) used in Australia, Canada, France, and New Zealand. The 0/0 method considers neither fixation in the production stage nor releases of biogenic carbon at the end of a wood product's life. In contrast, the −1/+1 method accounts for the fixation of biogenic carbon in the production stage and its release in the end-of-life stage, irrespective of the disposal scenario (recycling, incineration or landfill). The −1/+1 method assumes that landfills offer only a temporary sequestration of carbon. In the −1/+1* variation, landfills and recycling are considered a partly permanent sequestration of biogenic carbon and thus fewer emissions are accounted for in the end-of-life stage. We examine the variability of the calculated life cycle-based greenhouse gas emissions calculated for a case study building by each participating country, within the same assessment method and across the methods. The results vary substantially. The main reasons for deviations are whether or not landfills and recycling are considered a partly permanent sequestration of biogenic carbon and a mismatch in the biogenic carbon balance. Our findings support the need for further research and to develop practical guidelines to harmonize life cycle assessment methods of buildings with bio-based materials.

The purpose of this report is to provide support to the design decisions-makers during the design process. For each of the defined design step decision the important topics to consider were identified, the key stakeholders are declared and the purpose of LCA at the selected design step is defined. The report covers: The definition of the design steps, the definition of the tasks in each design step and an overview of the relevant milestones for performing LCA; An overview of the systematic building decomposition methods and the appropriate levels at each design step; An overview of the tools that can be used for LCA and a selection process for choosing the right LCA tool. A special emphasize is given to the topic of Building Information Modelling (BIM), how the BIM tools can facilitate the LCA assessment and what information should be implemented in the BIM model; Strategies on how to reduce the design-related uncertainties; An overview of the visualization of the LCA results and which are appropriate in the selected design steps.

Noise caused by mechanical ventilation systems in dwellings remains a common problem in practice. To help designers and installers, a simplified acoustic calculation tool has been developed which can be used without detailed acoustic knowledge. The tool is based on the prediction models in EN 12354-5 and VDI 2081 and takes into account the airborne duct sound. The model has been validated by multiple case studies in dwellings. For each case study, the noise levels and airflow rates of the mechanical ventilation system have been measured in each room. Generally, the global A-weighted noise level is predicted with an accuracy of ± 3 dB, on the condition that the airborne duct sound is dominant and sufficiently accurate acoustical input data are available for key components like fans, silencers and air openings. However, some measurement results cannot be predicted by the simplified calculation framework, e.g. when turbulence in two closely placed fittings leads to additional flow noise. The uncertainty also increases when the fan sound is dominated by tonal components.

The growing importance of a circular economy also holds possibilities for concrete. Some of the principles of circularity, like the re-use of "waste" as secondary raw material and the optimisation of the design with regards to lifespan, environmental impact and re-use, can be applied. Several technological innovations in this domain are in an advanced stage of development. However, the transition from research to full commercial applications is held back, mostly due to the absence of documented experience and the lack of a technical framework (prescriptions). In order to accelerate the adoption of new technologies, the Belgian Building Research Institute (BBRI) started the project "Circular.Concrete". In this paper, the results are presented of validation tests regarding 1) smart crushing technology, 2) the carbonation of recycled aggregates, 3) concrete using only recycled aggregates and 4) the use of alternative binders and supplementary cementitious materials.

In order to achieve carbon neutrality in the building field as expected by the Energy Performance of Buildings Directive, it is important to not only be able to calculate energy performance during design but also to be able to measure the actual energy performance of buildings during occupancy. However, there is currently no approved methodology for assessing the energy performance of the building envelope of an occupied building independently of its occupants, its systems and the climate. We applied a mathematical method to determine the heat loss coefficient (HLC) of the building envelope, from data collected in occupied buildings. The paper describes the in-situ measurement protocol and the mathematical models that contributes to address this challenge. Our methodology is demonstrated on a new semi-detached house, more insulated than the regulatory level, located in Brussels from a full year of monitoring data. For this case study, the results are promising. Indeed, some mathematical models show results of the same range value for the occupied insitu HLC and the reference HLC, obtained from in-situ measurements but without occupancy. However, more case studies should be evaluated, in order to validate the methodology.

Manufacturers of LED luminaires promise very long lifetimes for their products.This is a main advantage compared to traditional light sources.Long operational lifetimes are particularly interesting for reducing maintenance efforts and to ensure the ecological and economical relevance of this technology.However, Light Emitting Diodes typically show a gradual depreciation of their characteristic photometric performances.The key point is thus to make sure that the luminaires still meet the expected performances after many hours of operation.The main objective of this study is to identify the relative light output of luminaires over long running times in realistic conditions and to identify the course of the depreciation.Secondly it is intended to extend the lifetime evaluation to other indicators.The current standardized lifetime definition takes only the variation of light flux into account as a parameter.Nevertheless, complementary performance issues such as colour shift and the changes of the input power should also be considered.Just as the lumen depreciation these characteristics can also render a product gradually obsolete.This paper addresses the results of an experimental endurance test on photometric performances and electrical parameters for a selection of luminaires of various types and price categories.It was found that the lumen depreciation shows a relative consistent path over time, while colour shift tends to show more irregular patterns and thus it is more difficult to predict.Colour shift is also much more perceptible than lumen depreciation in any typical application case so more attention should be paid to this problem.Meanwhile it was observed that the energy efficiency of the luminaires depreciates in a similar way to the loss of light output.As different causes for depreciation coexist, lifetime claims should always consider the whole luminaire system in order to determine the operational service time.