Existing Buildings as Material Banks: Material Passport ́s Suitability Towards the Existing Building Stock
Translated title
Existing Buildings as Material Banks
Author
Vånge, Erling
Term
4. term
Publication year
2020
Pages
83
Abstract
Bygge- og anlægssektoren har et stort klimaaftryk og udfordrer de globale klimamål. Som svar er der sat gang i cirkulærøkonomiske tiltag, fx design for adskillelse (design for disassembly). Mange af disse giver først miljøgevinster efter de fastsatte klimafrister. Specialet bygger derfor på hypotesen, at den eksisterende indlejrede energi i bygninger (den energi, der er brugt til at fremstille og installere materialer) skal udnyttes bedre gennem cirkulære principper. Projektet undersøger, hvordan den eksisterende bygningsmasse kan kortlægges som materialebanker – oversigter over bygningsdele og materialer, der kan genbruges – for at effektivisere processen og bedre bevare indlejret energi. Den indledende analyse identificerede tre trin i kortlægningen med EU-initiativet Buildings as Material Banks’ mønsterpraksis for materialepas (standardiserede data om materialers egenskaber og oprindelse) som ramme: 1) inspektion, 2) beregning og 3) modellering. Arbejdet blev afgrænset til præfabrikerede betonelementer, og tretrinsprocessen blev præsenteret for den norske og danske byggebranche gennem en spørgeskemaundersøgelse. Formålet var at vurdere realistisk tidsforbrug og kompleksitet for de tre trin med udgangspunkt i en fiktiv to-etagers bygning på 300 m2, ældre end 40 år. Analysen viste, at trin 2 (beregning) og 3 (modellering) har størst behov for effektivisering. En nærmere gennemgang pegede på to forudsætninger for at effektivisere: gentagelse, som muliggør automatisering, og relevans, som sikrer korrekt prioritering af ressourcer. Det lykkedes ikke at forbedre tretrinsprocessen internt, hvilket rejste spørgsmålet, om det i stedet er selve bygningerne, der skal udvælges, så gentagelse og relevans er til stede. Som svar blev der foreslået en kvantificerbar metode til at identificere sådanne bygninger ved hjælp af udvalgte parametre, der beregner en Repetitive and Relevancy Score, hvor en høj score indikerer effektiv kortlægning. Undersøgelsen fandt dog ingen vej uden om at inddrage originalt projektdokumentation. Specialet konkluderer, at bygninger kan kortlægges som materialebanker mere effektivt ved selektivt at vælge bygninger, der opfylder gentagelseskriterier, men at gentagelse kun kan identificeres tilstrækkeligt ved brug af originalt projektmateriale. Uden adgang til dette forbliver kortlægning af eksisterende bygninger som materialebanker meget omkostningstung.
The construction sector has a large climate footprint and challenges global climate targets. In response, circular economy measures such as design for disassembly have been introduced. Many of these measures deliver environmental benefits only after key climate deadlines. This thesis therefore starts from the hypothesis that existing embodied energy in buildings (the energy used to produce and install materials) must be used more effectively through circular principles. The study examines how the existing building stock can be mapped as material banks—overviews of components and materials suitable for reuse—in order to streamline the process and better preserve embodied energy. An initial analysis identified three steps for mapping, using the EU initiative Buildings as Material Banks’ best practice for material passports (standardized data on material properties and origin) as a framework: 1) inspection, 2) calculation, and 3) modeling. The work was limited to prefabricated concrete elements, and the three-step process was presented to the Norwegian and Danish construction industries through a survey. The aim was to assess realistic time use and complexity for the three steps with reference to a fictitious two-storey, 300 m2 building more than 40 years old. The analysis showed that steps 2 (calculation) and 3 (modeling) need the most efficiency improvements. Further examination highlighted two prerequisites for efficiency: repetition, to enable automation, and relevance, to ensure proper resource prioritization. No internal improvements to the three-step process were found, which raised the question of whether selecting the right buildings could instead ensure repetition and relevance. A quantifiable method was therefore proposed to identify such buildings using selected parameters that produce a Repetitive and Relevancy Score, where a high score indicates efficient mapping. However, the study could not avoid the need to involve original project documentation. The thesis concludes that mapping buildings as material banks can be made more efficient by selectively choosing buildings that meet repetition criteria, but that repetition can only be identified effectively with access to original project material. Without it, mapping existing buildings as material banks remains very costly.
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