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

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

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

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

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 (26-130 m2 GFA) 41,991 m2 total GFA One of the three Sorgenfrivang blocks prior to refurbishment. Illustration by DOMINIA Consulting Engineers.

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.

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.

Building life cycle, EN15978

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

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

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, 100-56 % = 44 % of the embodied impacts from the slabs are allocated to the refurbishment project

Comparison with new building Operational energy (module B6)

Comparison with new building Embodied impacts of material use

Environmental pay-back time

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?