11 Energiforbrug og klimapåvirkning – Guidance on the Climate Impact of Buildings (BR18)
The official guidance document 11 Energiforbrug og klimapåvirkning provides the regulatory framework for assessing building climate impacts in Denmark. Issued by the Danish building authorities under Bygningsreglementet 2018 (BR18), this guidance details the requirements introduced on January 1, 2023, specifically focusing on § 297 and § 298. It outlines how the life cycle assessment (LCA) of new buildings must be calculated and documented to comply with national sustainability strategies. The document serves as a technical manual for architects, engineers, and developers to ensure that the total climate impact of a construction project is quantified and, for larger buildings, kept within statutory limits.
The scope of the guidance covers all new construction projects subject to energy frame requirements under § 259 or § 260. It defines two primary regulatory elements: the mandatory calculation of climate impact for all new buildings (§ 297) and a specific limit value for buildings with a heated floor area exceeding 1,000 m² (§ 298). The methodology is strictly based on the European standard DS/EN 15978:2012 (Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method). It details the use of life cycle modules from raw material extraction (A1-A3) to end-of-life disposal (C3-C4) and the potential for reuse or recycling (Module D).
This guidance also specifies the data sources permitted for these calculations, including the generic data found in BR18, Annex 2, Table 7, and product-specific Environmental Product Declarations (EPDs). It establishes a standardized reference period of 50 years and a specific unit of measurement: kg CO2-equivalents per m² per year. The following sections detail the core principles of life cycle stages, area calculation weightings, and the documentation required for final building completion.
Calculation Principles and Life Cycle Stages
The climate impact calculation must cover the entire life cycle of the building over a fixed 50-year reference period, starting from the time of completion. The assessment is divided into several modules as defined by EN 15978, though not all modules are included in the compliance limit for § 298.
- Product Phase (A1-A3): Includes raw material extraction, transport to the factory, and manufacturing of building products.
- Use Phase - Replacement (B4): Covers the climate impact from replacing building components that have a shorter lifespan than the 50-year reference period.
- Use Phase - Energy (B6): Accounts for the CO2 emissions resulting from the building's operational energy consumption for heating, cooling, and ventilation.
- End of Life (C3-C4): Includes waste processing and disposal of materials after the building's service life.
- Module D: Quantifies potential environmental benefits or loads from reuse, recycling, and energy recovery, reported separately from the core calculation.
Reference Area and Weighting Factors
The climate impact is expressed per square meter of reference area. This area is based on the floor area defined in § 455, but adjusted with specific weighting factors to reflect the varying material intensity of different building elements.
- 100% Weighting: Applied to integrated basement areas, waste rooms at ground level, and safety rooms.
- 50% Weighting: Applied to integrated garages for single-family houses and terraced houses.
- 25% Weighting: Applied to external ramps, balconies, fire escapes, and integrated carports or sheds.
- Excluded Areas: Detached carports, garages, greenhouses, and terraces are not included in the area calculation or the material inventory.
Data Sources and Documentation
Calculations must be based on verified data to ensure comparability. The primary source is the generic database in BR18, Annex 2, Table 7, but builders may opt for more specific data if available.
- Environmental Product Declarations (EPDs): Valid, third-party verified EPDs according to EN 15804 can be used to replace generic data for specific products.
- Generic Data: Must be used if a specific EPD is not available; these values are generally set conservatively.
- Standard Values for Installations: For technical systems (drainage, water, heating/ventilation), builders can use predefined standard values based on building typology (e.g., offices, schools, housing).
- Documentation at Completion: The final LCA must be submitted as part of the building's technical documentation upon completion, as per § 40.
Limit Values and Special Circumstances
For buildings over 1,000 m², a maximum limit of 12.0 kg CO2-eq/m²/year is enforced. However, certain technical or legal conditions allow for deviations or additional allowances in the energy frame that do not count against this limit.
- Low-Emission Class: A voluntary class where the limit value is reduced to 8.0 kg CO2-eq/m²/year.
- Special Conditions: Buildings with high safety requirements (Consequence Class CC3), high-purity requirements (hospitals/labs), or extreme floor loads may justify higher impacts through professional dialogue with municipalities.
- Local Plans: If specific architectural requirements in a local plan necessitate high-impact materials, this can be considered a valid special circumstance under § 298, stk. 4.
Frequently Asked Questions
What is the mandatory limit value for climate impact in new buildings?
For buildings with a heated floor area over 1,000 m², the limit is 12.0 kg CO2-eq/m² per year, excluding Module D.
Which buildings are exempt from the climate impact calculation requirements?
Exemptions include renovations, transformations, summer houses, and temporary mobile pavilions as defined in § 251, stk. 2.
What is the standard reference period for a building's LCA in Denmark?
The calculation must be performed over a fixed period of 50 years, counting from the time of building completion.
How are reused materials handled in the climate impact calculation?
Reused building materials are assigned a climate impact value of 0 kg CO2-eq throughout their entire life cycle in the calculation.
Which life cycle modules must be documented according to § 297?
Documentation must include modules A1-A3, B4, B6, C3, C4, and Module D.
Can I use standard values for technical installations instead of specific data?
Yes, standard values for drainage, water, and heating/ventilation/cooling are available for typologies like single-family houses, offices, and schools.
What happens if a building has multiple energy frames?
The climate impact calculation is performed per building; if multiple energy frames exist, they are area-weighted to find a single average result.
Are balconies included in the reference area for CO2 calculations?
Yes, balconies and external ramps are included in the reference area but are weighted at only 25% of their actual area.
