This article provides concise answers to the ten most relevant issues for designers of sustainable commercial buildings.
The ten questions were developed through industry consultation - including a cross-industry, cross-geography workshop, telephone surveys, and a series of focus groups in 2005 and 2006. For each question, specialised authors provided brief answers and links to further information. Over time, the ten questions are likely to evolve through additional surveys and in response to your comments on this website.
How can I profit from designing a sustainable commercial building?
Sustainable buildings can incorporate a variety of features that have positive impact on its profitability. Each case is different it is important to identify and communicate where opportunities are for increasing bottom line profit, and also to identify areas where profit may be reduced.
Sustainable buildings are said to have greater public support which may result in a fast planning approval process, thereby reducing the carrying costs of development. An integrated design process can lead to time savings resulting from improved communications, faster exchange of information, and increased innovation. Sustainable building development reflects well on corporate responsibility and as such can help an organisation's marketability. It is a rapidly expanding business sector and is a market differentiator and may give firms competitive advantage opening them up new clients and market sectors.
See Profit and the business case for sustainable commercial buildings and The business case for designers of sustainable commercial buildings for more information.
What are the legislated sustainability requirements for commercial buildings?
The answer to this question is dependent on the meanings of the terms 'commercial buildings' and 'sustainability'. In The legislative context of sustainable commercial buildings article, 'commercial buildings' are generally taken to mean buildings of Class 5 - 9 in accordance with the Building Code of Australia
(BCA) Classification (Section 1.3) and 'sustainability' indicates issues associated with energy efficiency, water efficiency, material usage or indoor environment conditions.
The current mandatory requirements - common to most States and Territories - are the operating Energy Efficiency Provisions of the BCA (Section 2.1 & 2.2) and Existing Building Provisions (Section 2.3). Sustainability requirements and related legislations (Section 2.4) particular to each Australian state and territory are listed under States and Territories Provisions.
Water issues are regulated under Plumbing Code of Australia but its current content is mainly about installation. Material usage regulations are currently mainly about waste disposal which are under state and territory control, well established long before the term sustainability was invented. Similarly, there are long established requirements in the BCA about indoor environment conditions such as indoor air quality, sound, light and disabled access.
See The legislative context of sustainable commercial buildings for more information.
Which rating tool should I use when?
Environmental performance assessment of a building or facility may be undertaken at different stages of its life cycle: at planning and design, during construction, at commissioning, and during occupancy or use. This is usually a decision made by the client. The type and extent of assessment - including the choice of rating tool and the nature and content of the assessment report - will depend on the primary purpose of the assessment and for whom it will be conducted.
The 'Performance setting and measurement for sustainable commercial buildings' article presents the different contexts in which an assessment can be made, provides an overview of a general process for undertaking assessment, and identifies selected tools and methods that can be used for environmental performance assessment, including a comparative guide for selecting the tool(s) appropriate for a building or facility at various stages of its life cycle. A series of tables is presented as a starting point for quick comparisons of selected tools to aid decision making.
Other criteria for selection of a rating tool include its usability (or user-friendliness, which may be a subjective decision) and the cost involved in its use (all the way to certification, if required/desired).
Also, it should be noted that:
- the 'right' tool for one project at a specific stage of the process and for a specific purpose would not necessarily be the right one for another project
- a project can use different tools for assessment at different stages of development, or different tools (with complementary focus) at the same stage of the facility's life cycle.
See the section on Tool selection guide and comparisons in the Performance setting and measurement for sustainable commercial buildings article and the Rating tools rundown by the Centre for Design for more information.
How can I integrate sustainability into my project management?
The sustainable design and management process entails the consideration and design of the building fabric, building elements and services together in an integrated manner from the early concept design phase in order to achieve sustainable outcomes.
In the earlier phases the project manager can help set targets for ESD and allocate the time and resources (consultants) to achieve them.
During the documentation and construction phases the project manager can ensure the ESD priorities are maintained and reported against. Finally at completion and occupation the project manager can ensure that the building is handed over thoroughly so that the building will be operated in the way its designers intended.
See Project management and sustainable commercial buildings for more information.
What are the basic design principles for sustainable commercial buildings?
Sustainable commercial building design should consider the following items:
- Integrated building fabric design and building services
- Climate responsive design and operation
- Energy conservation, generation and management
- Water conservation, recycling and management
- Resource efficiency
- Waste minimisation
- Sustainable transport opportunities
- Efficient land use
- Enhanced biodiversity
- Reduced pollution emissions
- Improved Indoor Environment Quality (IEQ)
- Improved social amenity, health and wellbeing
- Re-use of materials, façade, structure, building services and building components (refurbished buildings)
See Design and sustainable commercial buildings and Six steps to sustainable commercial buildings for designers for more information.
Energy
The main techniques for the minimisation of energy consumption in the design stage are:
- passive design - the name given to any design technique that requires no active (energy using) intervention. An example of passive design is the use of thermal mass (e.g. a large slab of concrete) to absorb heat generated in a building during the day and then using night purging to cool the thermal mass.
Passive design makes use of natural energy flows as the primary means of harvesting solar energy. Passive design systems can provide space heating, cooling load avoidance, natural ventilation, water heating and daylighting. Passive design is an approach that integrates building components, exterior walls, windows and building materials, to provide solar collection, heat storage and heat distribution
- appropriate sizing of lighting, heating and cooling systems - ensuring lighting and HVAC systems are fit for purpose. Over sizing of these systems is common and can lead to inefficiencies in operation.
- appropriate zoning and sensors to maximise efficiency of HVAC and lighting, and to take advantage of passive design features - smart zoning of systems, especially where mixed user patterns are anticipated (ie weekend occupation in some zones).
- appropriate building management, including equipment purchasing
- use of renewable energy
- minimising embodied energy in materials - careful consideration of the types of materials selected and minimising waste during construction.
- Commissioning - effective commissioning of all systems to ensure optimal performance standards are achieved.
- operation - ongoing monitoring and tweaking of operational energy use to ensure that design standards are being achieved
- maintenance - ongoing maintenance and repair of systems to ensure efficiencies are maintained.
See the section on Key building design criteria for energy in the Opportunities for improving energy performance in commercial buildings for more information.
Water
Water efficiency design principles for commercial buildings target the three biggest consumers of water, cooling towers, amenities and leakage.
The following building design options will result in less cooling being required, and therefore less water being used in cooling towers or evaporative air conditioners:
- Reduce the heat load - this can be achieved through following the well accepted principles of solar passive design, careful selection of materials, management of the indoor environment including occupancy levels and energy efficient equipment, etc;
- When outside air conditions are favourable, use an outside air economy cycle instead of relying solely on air conditioning plant;
- When outside air conditions are favourable, use a hybrid type air conditioning system involving a natural ventilation system through openable windows; and
- Design the building layout to use passive or convection cooling ventilation
Specifying minimum 4 star WELS rated fittings, considering waterless urinals and setting a water intensity target for the building against benchmarks will help cut amenities water consumption.
Design principles that can reduce leaks include:
- Install water meters and sub-metering on buildings, check water usage (unaccounted and abnormal water consumption) and discover leaks;
- Install leak proof piping and leak detection systems;
- Minimise the diameter of hot water lines and plumb separate lines to major end users to ensure pressure is maintained at the point of use. In the present situation, AS/NZS 3500.1 has generally increased pipe sizes to limit velocity and to minimise wear and water hammer (Master Plumbers and Mechanical Services Association of Australia 2006); and
- Isolate zones in a building for potable water.
See the section on Opportunities for improving performance in the Water use and sustainable commercial buildings articles for more information.
How can I cut through the greenwash when choosing building products and systems?
Cutting through 'greenwash' when choosing building products and materials is often difficult. Suppliers rarely intentionally mislead, but are often unable (due to trade secret constraints or inability to access detailed information) or unwilling (due to time and cost implications) to provide a full life cycle understanding of a product, including upstream and downstream impacts.
Seek independent advice from specialists, comparing costs and benefits with competing technologies where possible. Additionally request case studies of local examples from the supplier, backed up by monitored performance. Discussing your experiences with the materials and technology at industry meetings can assist your colleagues as well.
Independent, professional, third-party assessment is another good means of comparing product sustainability.
See the sections on Products and materials policies and Implementing and operating for improved performance in the Products and materials and sustainable commercial buildings article for more information.
Why doesn't the building perform to its designed levels?
Bannister 2006, identifies a series of reasons why buildings don't perform at the level predicted during design:
- HVAC controls programmed inefficiently or incorrectly
- Commissioning issues
- Loss of design intent
- Complexity
- Poor build quality
- Net Leases
- Cheap, unreliable components
- Poor Maintenance and operation
- "Invisible" Problems
- "Bad" tenants
Source: "Why Good Buildings Go Bad While Some Are Just Born That Way" - Dr Paul Bannister, accessed from http://www.airah.org.au
Good design isn't enough - a building's sustainability performance is greatly influenced by facilities managers and tenants. It's important that both groups are aware of the design intent and the behaviour required to optimise performance. Best results are achieved by an 'integrated design process' that includes input by building users and managers in the design phase, and by developing tailored learning and awareness raising programs for facilities managers and tenants.
See Education, awareness and training for sustainable commercial buildings for more information.
What is "good" and "best" practice?
"Good" and "best practice" are relative terms for performance of the industry at any one point in time. They are usually defined by benchmarks such as those outlined for energy and water.
Energy
Office buildings can be rated for their energy efficiency using the Australian Building Greenhouse Rating (ABGR) scheme. Energy efficient buildings have lower operating and life cycle costs, giving a very competitive advantage to owners and tenants.
The Australian Building Greenhouse Rating scheme assists office building owners and tenants to reduce energy use, reduce energy costs and reduce greenhouse emissions. ABGR was developed and is managed by Government, is endorsed by the Property Council of Australia and supported by other major Industry associations and property owners.
The scheme benchmarks a building's greenhouse performance on a scale of one to five, one having the worst greenhouse performance and five the best. Three stars represents current market best practice. The rating system is derived from the actual amount of energy (electricity, gas, coal or oil) your building/tenancy consumes in a year. This means the rating reflects the way energy is managed as well as how efficiently the building is designed. The benchmark allows comparison with the greenhouse performance of other buildings within the state. The stars are arranged as follows:
- 1 Star - Poor energy management or outdated systems. Building is consuming a lot of unnecessary energy. There are cost effective changes that can be implemented to improve energy consumption, cut operating costs and reduce greenhouse emissions.
- 2 Star - Average building performance. Building has some elements of energy efficiency in place and reflects the current market average. There is still scope for cost-effective improvements, and minor changes may improve on this building's energy and operating costs.
- 3 Star - Current market best practice. Building offers very good systems and management practices and reflects an awareness of the financial and environmental benefits of optimising energy use.
- 4 Star - Strong performance. Building demonstrates excellent energy performance due to design and management practices or high efficiency systems and equipment, or low greenhouse intensive fuel supply.
- 5 Star - Best building performance. Building is exceptional due to integrated design, operation, management and fuel choice.
See the section on Australian Building Greenhouse Rating (ABGR) scheme in the Planning, implementing and operating for improved energy performance in commercial buildings article for more information.
Water
National water intensity benchmarks have been developed for office buildings and public buildings. These benchmarks, referred to as NABERS benchmarks, identify what are average, better and best practice water intensities for these building types. Water intensity refers to the water consumed per square metre of space. Similar work has been conducted in the United Kingdom public estate as part of the Water Mark programme. The benchmarks provide guidance to building owners, managers and tenants on how their buildings measure up against similar sites nationwide, and are now available at Water benchmarks for offices and public buildings.
See the section on National water intensity benchmarks in the Water use and sustainable commercial buildings article for more information.
Are there computer modelling tools I can use for sustainability?
There are a number of tools available to designers that can assist them to integrate sustainability into design. Sustainability consultants, architects and engineers, can undertake building information modelling using computer simulation software to test the sustainability performance in terms of thermal comfort, visual comfort, daylighting etc.of various fabric and services options. This has the advantage of bringing the engineering agenda forward in the design process and allowing decisions to be made to ensure optimal sustainability performance.
See the section on Tools in the Design and sustainable commercial buildings for more information.
How do I do a life cycle analysis?
The International Organisation for Standardisation (or ISO) has a suite of standards in the ISO 14000 series (ISO 2007) that provide a full and detailed guide for undertaking Life Cycle Analysis (LCA). The methodologies can be applied to the manufacture and delivery of individual products ('product LCA') that constitute a building, or directly to the construction of a specific building ('building LCA').
One option is to do the analysis from first principles following ISO standards. Another is to use generic LCA software (e.g. SimaPro, Boustead, GABI, etc) and apply it to building products and processes. Another way is to use a software like LCADesign or similar tools that have been developed for specific application to buildings.
The 'Performance setting and measurement for sustainable commercial buildings' article provides further information and references related to LCA and the use of Eco-indicator in the environmental performance assessment of buildings and facilities.
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