1. LIFE CYCLE ENVIRONMENTAL IMPACTS FROM REFURBISHMENT PROJECTS
– A CASE STUDY
Freja NYGAARD RASMUSSEN, Harpa BIRGISDÓTTIR
Danish Building Research Institute, Aalborg University Copenhagen,

2. Introduction
LCA is becoming more commonly applied in the building sector in Denmark
Mandatory in sustainable building certification (DGNB)
Voluntary sustainability class in building regulations is being discussed, including possible requirements for embodied impacts

3. Introduction
Danish Transport and Construction Agency and Danish Building Research Institute:
LCAtool for buildings has been developed for the industry and is free to use (LCAbyg)
Guideline and LCA studies have been published in order to raise the knowledge
The methodological framework for LCA on existing building is not as clear as for new construction

4. The aim of the study
Illustrate the life cycle environmental impacts of a large refurbishment project based on case study
Evaluate the environmental pay-back time of energy efficiency measures installed
Compare the refurbishment impacts with the life cycle impacts of a new construction

5. The case study
Refurbishment of residential complex with a 50-year assumed service life after refurbishment
Three residential 14-storey buildings erected in 1960
428 flats ( m2 GFA)
41,991 m2 total GFA
One of the three Sorgenfrivang blocks prior to refurbishment. Illustration by DOMINIA Consulting Engineers.

6. The case study Refurbishment measures include:
Building shell: insulation of roof and new roof covering, gable and socket insulation, façade element replacements, low energy windows, new balconies
Interior: new stairwells, elevators, new kitchen and bathroom units
Technical: new heating distribution system, new ventilation system, new electrical installations, photovoltaics
One of the three Sorgenfrivang blocks prior to refurbishment. Illustration by DOMINIA Consulting Engineers.

7. The case study Annual energy consumption Before renovation
District heating: 112 kWh/m2
Electricity: 5.7 kWh/m2
After renovation
District heating: 52 kWh/m2
Electricity: 6 kWh/m2
One of the three Sorgenfrivang blocks prior to refurbishment. Illustration by DOMINIA Consulting Engineers.

8. Building life cycle, EN15978

9. Results: Environmental impacts – material types
Other
Gypsum
Glass
Plastic and bitumen
Tiles and bricks
Insulation
Metals
Cement based materials
Wood and wood based
materials

10. Results: Environmental impacts – building elements
Technical equipment
Windows
Roof
Slaps
Inner walls
Outer walls
Foundation

11. Comparison with new building
Allocation approach – existing structure
Allocation I: where the impacts are regarded as offset (hence “burden free”) at the time of the refurbishment, i.e. the existing structure comes for free in the refurbishment project
Allocation II: where the impacts from the existing building structure is temporarily allocated in accordance with the expected service life of the existing components. E.g. when slabs have expected service lives of 100 years in total and the refurbishment takes place after 56 years, % = 44 % of the embodied impacts from the slabs are allocated to the refurbishment project

12. Comparison with new building
Operational energy (module B6)

13. Comparison with new building
Embodied impacts of material use

14. Environmental pay-back time

15. Conclusions
Pay-back time of less than 20 years for all environmental impacts (except for ODP)
Operational energy is on similar level as new construction
Life cycle embodied impacts are 45% or 25% of a new construction depending on the allocation method
The question that I would like to raise is, what do you think about the allocation approaches we assessed?
And do you have any other input to how refurbishment should be treated in LCA?