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ReUSE - 2013

ReUSE - Repetitive Utilization of Structural Elements

 

A large quantity of waste is generated during the production of building components and after the building demolition. Construction and demolition activities in Europe are responsible for 40 - 50% of solid waste production which was estimated over 460 million tonnes per year in EU-27 (about 1.1 tonnes per person per year) excluding excavations. It contains mostly minerals from the structures.

The construction sector also consumes about half of all natural resources extracted in Europe yearly, that have very high energy demands on their transformation into building products. It has been estimated that 40 - 50% of all extracted raw materials are transformed into building products. The construction sector uses vast amounts of energy in the first three stages of the production process: resource generation, resource extraction and intermediate product manufacture.

Therefore the focus of today’s environmental policy is on the building end-of-life scenarios and material efficiency. Recycling and material re-use becomes the common practice, but it is not always environmentally efficient, and material separation of composite structures is very challenging. Building elements have often longer service life than the building itself and are, therefore, suitable for recovery and re-use after deconstruction. However, component re-use is still not widespread practice because of technological and institutional barriers. Structural components are not usually designed to be re-used, even though they are designed for deconstruction in some cases.

Recycling and material re-use is the common practice nowadays, but it is not always environmentally efficient, and material separation becomes more challenging in case of composite structures. Building elements have often longer service life than the building itself and are, therefore, suitable for recovery and re-use after deconstruction. However, component re-use is still not widespread practice because of technological and institutional barriers. Structural components are not usually designed to be re-used, even though they are designed for deconstruction in some cases. The main barriers for re-using are (a) long service life of building products, (b) their spatially fixed nature, and (c) discrepancy between building owners and users.

 

Sustainability

Reusing of building components has impact on all aspects of sustainability of the built environment.

The business perspective emphasizes the possibility to increase the “green” image of the product, reducing the waste charges, challenging the growing need for housing removal, developing new competences and work possibilities, and application of smart and modular building systems.

The ecological perspective impact will be in reduced waste generation and natural resources consumption that can reflect in higher eco-labelling (BREEAM, LEED, …).

The social perspective challenges the migration to urban centres, the values and living environment change, and new legislation.

Key roles in re-use process

Designers - Designers have one of the most important roles in structural elements re-use. Their documentation, drawings and instructions significantly affects the effort needed at the building deconstruction. Not only selected components and technologies are important, but also the way how the final design documentation availability will be secured for the whole building’s life span. The maximization of environmental, cultural and financial value at the end of building’s life should be considered already in the design stage. Designers have to get access to the information about the actual and potential reclaimed components supply, sizes and material grades and they need to be flexible to adapt to current situation.

Owners and investors - Re-use project can be successful only when it is fully supported by the building owner or investor. Therefore the building owners and investors are equally important as the designers. They need to understand the process and its advantages and drawbacks. Education and demonstration of successful cases should be the way to increase building owners and investors’ motivation.

Raw materials - The increasing demand for building materials is creating great pressure on natural resources. Moreover, the raw materials are becoming scarce and more expensive. Material extractors will have to adapt to this change in order to avoid reducing their operations and profitability.

Material producers (mills) – The production process vary with the material. Raw material and in most cases also recovered waste (e.g. steel scrap) is utilized to produce new building material that is sold to the service centres or fabricators directly.

Service centres - Service centres are businesses that inventory and distribute materials for industrial customers and perform first-stage processing. They act as intermediaries between the producers and the fabricators, and other end users.

Fabricators and erectors - Fabricators purchase materials from service centres or directly from producers and fabricate the individual components that are needed to assemble a building. Some fabricators also have their own erection crews to assemble the components at the building site. Others subcontract the erection to independent organisations. Fabricators may send any waste and offcuts back to mills for recycling, usually through a dealer. Some of the fabricators will occasionally dismantle old structures and re-fabricate the reclaimed elements for new uses. A minority may have a small stock of building parts that has been reclaimed waiting for appropriate new uses.

Buildings – The way how buildings can be assembled to maximize the usefulness and value of components at the end of a buildings life needs to be clearly demonstrated to the construction industry. The growing number of projects successfully shows how components from an old building or structure can be re-used in a new building reducing the environmental impact, but the communication of such successful cases to the construction practitioners is not sufficient at the moment.

Demolition – Current building removal practices predominantly mean a process of destructive demolition by heavy machinery. There is a perception that manual extracting of building elements from buildings for re-use leads to additional problems and costs. However, even separation of re-usable components from the demolition waste may lead to significant recovery amounts.

Disassembly - The re-use of components can be maximized only when careful disassembly is carried out. Many projects have shown that disassembly is possi-ble and should be considered. The volume of disassembled building components will increase as the demand for them increases.

Salvage yards - Salvage yards store building elements for re-use and recycling. A few salvage yards will extract components when they recognise potential for re-use.

Material dealers - Dealers sell waste materials for recycling and re-use. Material is sorted, graded, batch, and sold back to producers for recycling. These organisations will also often buy waste materials arising during fabrication and from other sources. Material dealers will often try to sell reclaimed material directly from the demolition site.

Design codes - The benefits of re-use can be greatly improved if building codes emphasize the environmental aspects of the construction and give designers more opportunities for material sourcing. The immediate goal should be to enable structural elements re-use by establishing clear rules for the material grading and safety of structures designed from reclaimed components.

Design tools – The rapidly developing area of design software is currently able to offer many useful tools for the environmental optimization of buildings. As the buildings components are physically re-used, they can be re-used also digitally. The implementation of building information models (BIM) is essential to manage smooth transfer of building elements between two different projects.