IES Consulting performed analysis of the LEED v4 IEQ Daylight credit on the Project De Bureaux in Paris.
Projet De Bureaux is a structure composed of 9000m² of office space, 600 m² of shops and a private nursery. The project is located in a developing urban area, which is a homogeneous mix of housing.
IES Consulting performed analysis of the LEED v4 IEQ Daylight credit on the Project De Bureaux in Paris. The analysis utilised Option 1 of the credit with performance against sDA (spatial daylight autonomy) and ASE (annual sunlight exposure).
The consultants used RadianceIES climate based daylight modelling (CBDM) technology to model the space performance. CBDM utilises an annual simulation linking location, shading, climate data (including solar intensity and cloud cover) together with the building properties. This provides a complete overview on how the daylight performance varies throughout the year due to changes in these factors.
The analysis included performance against sDA (spatial daylight autonomy) and ASE (annual sunlight exposure).
CBDM is more detailed than a static calculation which provides only a snap shot approach. Daylighting varies throughout the year, primarily due to the solar position, so it is essential daylighting variance is properly considered toward the impact on building design.
The analysis was performed for sample spaces and assessed the potential for full credit performance was not currently possible. However, inference on the needs to meet the credit was possible from the analysis conducted.
LEED criteria specifies achieving a maximum threshold of 10% equates to Exemplary performance. Following credit feedback LEED issued guidance noting a relaxation on the criteria and a maximum of 20% will meet the credit. The >10% and <20% banding equates to Acceptable performance. In addition a minimum floor area of 250 sqft (~23 m2) is necessary for the space to be included within the analysis but its ASE must still be reported.
The same applies for spaces including automated dynamic façade systems, however the LEED clarification does not clearly stipulate if this system must cover all external glass or whether a minimum glass percentage is needed. For the purposes of the assessment it has therefore been assumed that the presence of an automated dynamic façade system with a room’s glass is enough to meet this criteria. The results from the analysis undertaken by IES Consulting demonstrated a mix of spaces meeting satisfactory conditions.
For sDA 300, 50% must be achieved for at least 55% of the example regularly occupied floor space. Unlike for ASE this still includes for all spaces regardless of floor area and automated dynamic façade system. The results from the analysis undertaken by IES Consulting demonstrated that no spaces at the time met the satisfactory conditions, with further design evolution expected.