Design for Sustainability
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Revision as of 07:01, 22 June 2017
Contents |
Abstract
This article addresses sustainability in construction managed during design phase. It is discussed how proper management in this stage of the project can help providing structures that are sustainable throughout all its life time. Nationalities all around the world are concerned about global warming effects. Thus, many countries are creating plans to construct only sustainable buildings in near future.
This trend will require change of the way that designer thinks. There are plenty of sustainable design principles that can lead humanity to achieve this aim. Many of those strategies apply to the construction sector.
Further, application of design for sustainability in design is described. How appropriate planning can influence the construction sustainability? Early integration of construction planning can detect and eliminate problems sooner, cheaper and most importantly without negative effects on the environment. Construction works leave behind solid waste, that contributes to landfill and pollution. Some of the materials delivered on the site are never used and disposed immediately. Planning of the works in the initial phase of the project could bring better results in overall sustainability. Optimised delivery of new constructions is discussed. Operation is also influencing sustainability. The initial choice of the energy source has a huge impact as well as user pattern, e.g. energy and water use. Demolition has even greater impacts than construction. Enormous volume of waste is generated. Proper choice of materials for the construction would result in more efficient utilisation of them in demolition or refurbishment.
Finally, some limitations and critique on sustainable design are presented.
Introduction
There is a growing need to build sustainable structures. In fact, there is the demand to do so. In year 2020 according to European Performance of Building Directive (EPBD) [1] all buildings constructed in Europe must be net zero Energy (nZEB). It not only means that the energy demand will be close to zero but also the constructions will be environmentally – neural e.g. the carbon emissions of those buildings must be reduced. Moreover, in the USA there is a similar plan till year 2030. It is not only Europe but all around the world there will appear sustainable buildings.
With that requirements, it will be crucial to manage the design process so that the structure remains sustainable not only when constructed but also during operation and after demolition in the end of its service life.
Big idea
Definition
Sustainability has number of definitions, among them is “meeting the needs of the present without compromising the ability of future generations to meet their own needs” by Brundtland Commission. Not only term “sustainability” has different explanations but “sustainable design” [link] is described by a few names, for instance eco design, environmentally-friendly design, etc. In the simplest worlds:
"Sustainable design is the philosophy of design that complies with the principles of sustainability".[reference]
Among 17 Sustainable Development Goals[2]are some relevant for construction industry. They are presented in the figure x.
Sustainable design strategies
Many strategies apply to sustainable design, although they represent different approaches the final goal is common for all of them, sustainable design. The designer should not just choose one of those methods, their combination shall serve for achieving the best results. Here are presented some of possible methods relevant for construction management:
Integrated approach to design brings together all the specialists responsible for the structure. It requires collaboration between architect, structural, HVAC and other engineers. All of them work together to do sustainable architecture. One of the most commonly used tool for that purposes is BIM.
It is an approach to design that is inspired by nature. Solutions found in environment were evolving since thousands of years. Thus, they are believed to be most reasonable and efficient.
- Design for Dematerialise
Reducing amount of material needed for functionality of the product. For instance, in construction it could be replacing concrete structure with reinforced concrete or using more resistant one.
- Design for Durability
Choosing materials that will increase overall durability of the structure.
- Design for Longevity
Use of the materials that are long lasting. It reduces need to exchange for new product and even enables reuse of them after building operation life. This strategy also aims to design in the way that the product is still attractive to people after years.
- Design for Disassembly
Following the concept of reusing materials for construction, components of the building should be assembled in the way that it will be easy to disassemble them without any damages
- Design for Recyclability
It is about using materials that are easy to recycle, a bit like previous idea. The components of building should be easy to segregate. For instance, the consideration is how to separate frame of window from pane so that any of material is not destroyed so that cannot be reused/recycled afterwards.
- Design for Multifunctionality
Design in the way that product has multiple uses. Spaces in the building should be easily adjustable for other uses. For instance, open office space constructed without columns inside can be converted in to concert hall.
Sustainability Assessment
There are three types of assessment methods for buildings’ sustainability Cite error: Invalid <ref> tag;
invalid names, e.g. too many
- Performance based design
“Performance Based Building is an approach to building-related processes, products, and services, with a focus on the required outcomes”
Whole life assessment refers to procurement, construction, operation, maintenance, renovation and demolition, in other ways to all life stages of the structure.
- Building rating and certifications
The following list addresses most of the well-known sustainability asssesment tools that can be used for the buildings.
- -Leadership in Energy and Environmental Design (LEED)
- -Building Research Establishment Environmental Assessment Method (BREEAM)
- -Sustainable Building Challenge Framework (SBTool)
- -WELL Building Standard (WELL)
- -Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB)
- -Energy performance certificates (EPCs)
Application
This section describes how design for sustainability applies on the example of building construction. Listed above techniques are helpful to achieve sustainability in construction. Considerations on influence of the design are presented in following stages of project life:
Pre-design
Designers must know that the client might not have enough information about possible sustainable solutions. It is important that design team introduce those tools and benefits of using them to client during briefing process. Having that knowledge client can make better decision on the order he/she makes.
Before actual design, appropriateness of the project must be evaluated. The site and local situation like available resources or existing structures as well as natural environment should be reviewed. E.g. perhaps there is already structure on the site that could be used or rebuilt or some of those components could be reused to create new building. It should be assessed whether the project is rational. Possibilities on sustainable construction in the localisation should be investigated, for instance local renewable energy sources or government support for green energy production.
Before starting the design, it should be assured that proper people are chosen for the project. The team of managers, designers and contractors should be aware of the sustainable targets of the project and work together from the first stages to achieve the goal.
Initial planning
After gaining knowledge on the local conditions it is time to implement proper strategies. The consideration in this stage is building positioning on the site. It must be done in such a way to ensure maximal utilisation of passive design strategies and minimise impacts on local fauna and flora. It is also important to consider how the connections to media (water, electricity) are located on the plot and how to utilise sun conditions and what will be the access to the construction site and building afterwards. Another important aspect of the design is influence on neighbourhood, if the structure will put shadows on other buildings, generate pollutions and what visual appearance it will have. The influence on surroundings should be considered for both construction and operation period.
At that point, a discussion appears how to reuse or recycle locally available resources, e.g. on the site there is an old brick house, that will be demolished. How the brick could be reused in new construction? Here is where cooperation between architect and structural engineer should start. They need to agree if the bricks will serve as load-bearing structure, where they will be placed, if the structure will be visible or not (aesthetics).
Concept design
Further development of the design brings more sustainability issues to concern. The orientation of the building influence inner conditions like daylight availability or natural ventilation. External envelope must be designed carefully to ensure good thermal performance of the building. For that reason, window shapes and sizes are also relevant. The distribution of the rooms will be influenced by orientation and shape of the structure. It is also important part to integrate all services in the building in the initial state of the design. As an example: early discussion on the layout of the mechanical systems and structural parts could result in decreased need for suspended ceiling height. That will result in decreased building height and so reduction of the initial investment cost as well as lowered energy demand (less space to heat equals less heat needed).
Detail design
Material selection
Choice of the materials for the project has a great impact on the sustainability of the structure. It is relevant throughout all life cycle of the product. The impact on the environment starts form the extraction of raw materials to produce building materials. If the choice is brick for instance, the impacts depend on: how clay is extracted, how it changes the local site, if during production of brick there is a lot emissions, how much heat is used during process. Moreover, there are additional concerns: transportation of the product form factory to the site, what treatment it needs to be assembled to become a wall, how it influences building indoor climate during operation, what happens after disassembly, is it reused or goes to landfill. In the end there is a question to be answered by designer: is there other material that has less impact? Maybe it is possible to reuse already available material or perhaps it is possible to find new one that can be recycled after building life and still serve people for other purposes.
Local material might be better choice as the significant impact from the products is transportation. Even though one product might seem more environmentally-friendly, in bigger perspective it could turn out that importing the more sustainable material (i.e. bamboo) from distant part of world does not pay off in terms of sustainability.
People spend more of their time inside than outside. All materials that are components of our homes, schools and work places could be emitting particles, that have possible negative impacts on humans. The proper choice of materials influence health and well-being. For instance, concrete helps to clean the air.
Physical properties of materials are also relevant. Some of them might need to be replaced several times during building operation. It is a good question to be asked whether it is better to use longer lasting substitution. It must be also mentioned that thermal mass of materials can significantly enhance thermal performance of the building.
Depending on the material sizes and characteristics it might need special equipment for the construction purposes. Renting additional crane might be an option, but does it pay off? Choice of the materials also influences the use phase. Some materials are easy to maintain, while others need special treatment. It could increase for instance water use for cleaning purposes.
Another aim of the design could be to decrease amount of material required for construction. One of the approaches is modularisation. Using typical sizes of the smaller structural elements can eliminate need for adjustments like cutting the tiles. In this way, there are no waste produced on the site.
Energy
There is a list of elements that affect energy performance of the building. The proper design and construction of building envelope has great impact on the energy demand. There should be chosen sufficient thickness of insulation and the building should be raised in the way that it is tight.
Not only envelope is important but also choice of energy source, certainly solar heating system is more sustainable than coal furnace. Choice of artificial light type and bulbs used as well as appliances energy class are contributing to overall sustainability of the building.
Daylight design has also influence on the building. There are solar heat gains and heat loses through glazing. Depending on the design, those could have positive or negative impacts.
Water
Water consumption is second issue after energy that impacts environment. To save water there are designed rainwater collection, greywater and back water systems. Those can significantly reduce building demand for water or even reduce it completely. It may seem that the tanks can be just added at the construction process. However early implementation into design can result in better water collection efficiency, for instance by dedicated roof design to gather more rainwater.
Water efficient sanitary equipment chosen for the project can help reduce needs for water use. Depending on the location water might be very valuable resource, that is why right choices should be done as soon as possible.
Construction management
Although it seems that nothing can be done while designing to ensure sustainability during construction, it can influence the works substantially. Having discussed site challenges between designing team and construction managers is crucial. It may not only make worker’s life easier but also contribute to savings and most importantly save environment from the impacts of the actions.
Planning of the construction works should start with beginning of design process. The site conditions might determine some aspects of the construction works. In difficult plots, access to the construction site might determine location of the building.
To ensure sustainability during the works, the construction manager should be aware of the amounts of the materials needed. Precise numbers provided by the architect can help to decide about quantities to be ordered and it will reduce number of left-overs. Recycling on the site will also contribute to the sustainability. To assure that workers do segregate materials, the access to the trash bin should be easy.
Operation and Maintenance (O&M)
The design can strongly influence operation and maintenance. As mentioned before material choice has an impact but also careful design can make the building to be easy in use. If it would be foreseen by the architect that there will be needed additional space for storage or access to shafts, he/she can implement it into design and in this way, decrease O&M costs. Analysis of use phase before even constructing the building can detect problems and prevent them.
Limitations
Aesthetics
There are claims that sustainable buildings are not architecturally beautiful. Frank Gehry said that green buildings are “bogus” [3]] and Perter Eisenman that they are “having nothing to do with architecture”. [Inter…] It is right that first sustainable houses were not impressive in terms of aesthetics. The reason for designing simple square or rectangular houses is that the more compact building’s envelope is, the more energy efficient it is. [picture of passive house] However, there is a hope for the sustainable buildings in future. There already are created structures that are both environmentally friendly and look attractive. [for instance] Thus, in following years there could be expected that new constructions will be more and more pleasant to look at.
Complexity of the sustainable improvements
Sustainable solutions require unconventional thinking and sometimes they may seem complicated. To achieve the goal the choices of the designer must be careful. The decisions should be made not only based on architect’s opinion but also other specialists’ opinions. As an example: the sizes and location of windows are not only depending on aesthetical outcome but also on amount of daylight provided indoors and heat gains. This may be an obstacle for designers and contractors who did not experience this kind of collaboration before.
Implementation of new technologies
Certainly, sustainable design is new and requires new solutions and technologies. New technologies like windows are rising costs of initial investments. Though the component are often the same, they must be used in different way. Thus, for insulation it is still used Styrofoam and mineral wool, but it needs to be assembled in thicker layers. It requires slightly different treatment than in traditional construction.
Stubbornness
As mentioned before, sustainable design brings high expectations towards people who create them. It is natural that humans tend to use known solution and are not willing to implement new solutions into their buildings. The novelties are usually faced with some resistance.
Annotated bibliography
ISO 15392: “Sustainability in building construction – General principles”
http://library.uniteddiversity.coop/Ecological_Building/Strategies_for_Sustainable_Architecture.pdf
"Strategies for Sustainale Architecture" describes in details implementation of sustainable approach for architects.
...
References
- ↑ [https://ec.europa.eu/energy/sites/ener/files/documents/nzeb_full_report.pdf /Towards nearly zero-energy buildings. Definition of common principles under the EPBD ] Towards nearly zero-energy buildings. Definition of common principles under the EPBD
- ↑ https://sustainabledevelopment.un.org/sdgs
- ↑ [link/title] “Architect Gehry on LEED buildings: Hamburg
https://www.designingbuildings.co.uk/wiki/Sustainability_in_building_design_and_construction
