First published April 2013. Revised and updated August 1 2017.
PART 1 - INTRODUCTION DEFINITIONS OF ESD
There are a number of definitions of the acronym ESD
- Ecologically Sustainable Development
- Environmentally Sustainable Design
- Environmentally Sustainable Development
The first one is a broad all encompassing macro level description defined along the lines of
"… using, conserving and enhancing the community's resources so that
ecological processes, on which life depends, are maintained, and the total
quality of life, now and in the future can be increased".
In the building industry, ESD is also used as an abbreviation for Environmentally Sustainable Design. Masterspec adopts the broader meaning of ESD, using the term 'development', to cover issues beyond design, such as construction and maintenance.
This report outlines how a Masterspec based specification can be used to give effect to ESD principles and opportunities in the building context.
The principles of Environmentally Sustainable Design can be expressed as;
- Client commitment:
- The single most important principle for achieving ecologically sustainable building design is client commitment.
- Whole of life thinking:
- About the life cycle of the building; that is, its design, construction, use, refurbishment and demolition.
- Design influence:
- It is at the design stage that many of the impacts of a building are locked in
- Life Cycle Assessment (LCA):
- The whole of life impact of various initiatives on the environment.
From these, it identifies a number of opportunities for ESD in building design:
- Social sustainability and occupant satisfaction
- Indoor environment quality
- Energy management
- Commissioning and operations
- Ozone layer depletion
- Choice of materials
- Waste minimisation
- Water use reduction
These principles include not only the more familiar environmental factors such as energy and waste reduction, but also broader social factors such as accessibility by the whole community and provision of public space.
ROLE OF THE SPECIFICATION IN ESD
A basic principle of building contract documentation is that the specification puts into effect design decisions. In order to produce an ESD specification, appropriate design decisions must first be made. A non-sustainable design cannot be transformed into a sustainable one just by specifying. For example, it is not possible to achieve thermal efficiency through the specification alone, it must be designed in. The role of the specification, in this instance, is to enable the full ESD potential of the design to be achieved.
It is, however, possible to improve on the environmental impact of any design through the specification by mandating low toxicity materials, energy and water efficient appliances, and so on.
In summary, an ESD specification focuses on:
- Giving effect to ESD design decisions not shown on the drawings.
- Specifying ESD appropriate materials and methods of construction.
- Specifying components and products that permit the implementation of ESD
Masterspec, as a master specification system, is not written as an exclusively green specification. It is a specification system that can be customised to give effect to a green design on specific projects.
ESD AND THE BUILDING CODE (NZBC)
The NZBC incorporates a number of mandatory environmental provisions. These primarily relate to energy conservation (NZBC H1 Energy Efficiency), restrictions on contaminates (e.g. NZBC G13 to G15) and improving the comfort and amenity of buildings for their occupants (e.g. NZBC G4 to G8).
Although the NZBC does not have a lot of direct ESD provisions, it is possible to use Acceptable Solutions (e.g. minimum timber treatments), to meet the ESD objectives. However, the limited direct ESD provisions of the NZBC means, the ESD commitments made by designers will often far exceed the NZBC and/or push toward Verification Method or Alternative Solution answers, rather than the Acceptable Solution provisions of the NZBC.
ESD AND ENVIRONMENTAL RATING SCHEMES
ESD and environmental rating schemes incorporating ESD into a project, start with the client’s commitment, either initiated by the client or suggested by the designers. Since ESD decisions can have implications such as increased project cost, designers should ensure they have the client's agreement to ESD rather than acting unilaterally.
Although ESD can be on an generic ad hoc basis, a more structured approach, such as the adoption of an established voluntary environmental rating schemes, is more likely to result in the desired outcome that may be more beneficial to the client. With the latter approach, designers make appropriate ESD design decisions to conform to the chosen scheme (and, of course, in compliance with the NZBC ESD provisions).
In New Zealand a number of rating schemes are available for evaluating the environmental design and performance of various types of buildings based on a number of criteria including management, indoor environmental quality, energy, transport, water, materials, land use and ecology, and emissions etc.
Rating schemes available in New Zealand include:
- New Zealand Green Building Council (NZGBC)
- Green Star (Masterspec has supporting sections)
- HomeStar (Masterspec has supporting sections)
- Circular Economy Model Office
- CEMO (Masterspec has supporting sections)
- International Living-Future Institute (ILFI)
- Living Building Challenge (LBC) (Masterspec has supporting sections)
- Passive House
In addition to a buildings performance, there are systems for assessing the ESD performance of materials/products and services. In New Zealand such a system is eco-label by Environmental Choice New Zealand (ECNZ). ECNZ license products and services based on a life cycle analysis, unfortunately the range of products is limited. There are a number of overseas systems, but relating the results to New Zealand can sometimes be difficult, unless they use a local rating assessment organisation such as EnviroSpec.
Other related schemes have narrower focus like WEERS (Window Energy Efficiency Rating System), WELS (Water Efficiency Labelling Scheme) and MEPS (Minimum Energy Performance Standards) which provide for labelling with star ratings for efficiency of products like, windows, appliances and fixtures.
PART 2 - INCLUDING ESD CONCEPTS IN SPECIFICATIONS
The ways in which the specification can be used to implement specific ESD principles can be divided into a number of broad categories.
- Energy conservation and greenhouse gas reduction
- Conserving other consumables (like water).
- Using ESD appropriate materials e.g. materials with low volatile organic compounds (VOC) emissions.
- Creating a quality environment, both inside and outside the building, by incorporating ESD principles.
ENERGY CONSERVATION & GREENHOUSE GAS REDUCTION
Reducing building energy use reduces operating costs and the greenhouse gas emissions caused by that energy use. Initially this involves appropriate design to reduce energy dependence and make use of free natural sources through thermally efficient, passive design. The most direct way in which the specification can enhance this is by including energy efficient equipment such as for lighting, water heating and mechanical plant. The specification is also used to document design decisions intended to reduce the need for energy, such as glazing and insulation performance and air leakage.
Given this broad application and the fact that not all clients express an ESD commitment, Masterspec does not impose ESD. Instead it provides a framework in which clients and designers who wish to incorporate ESD principles and consider life cycle costs can do so while also enabling appropriate choices to be made for clients whose priority is lowest initial cost. For example:
- The Glazing work section can be used to document minimum performance to the NZBC, or ESD performance that exceeds NZBC minimum requirements.
- The Fans work section can be used to specify a higher efficiency and quieter fan or a cheaper fan with lower efficiency and higher noise level. Which of these is achieved depends on the fan selected or the performance criteria the designer/specifier inserts in the respective fan schedule.
There are a quite a number of sections in Masterspec that can aid energy conservation, like 7125 SOLAR WATER HEATING SYSTEMS or 7717 PHOTOVOLTAIC POWER SYSTEM.
There is considerable potential for conserving water by specifying water efficient fixtures and equipment. The Sanitaryware and tapware work sections can be used to specify higher efficiency fixtures. Like most other ESD provisions, appropriate design is the first step in water conservation.
In addition, where authorities permit the use of recycled water and rainwater, Masterspec includes the work sections 7142 GREYWATER SYSTEMS and 7112 RAINWATER STORAGE TANKS for specifying these systems, as well as the related section 7462 WASTEWATER TREATMENT SYSTEM.
The most frequent use of the specification is to prescribe specific materials to meet design objectives, including ESD.
The Australian Department of Environment and Heritage notes that:
- The extent of knowledge gaps [about environmental impact] means that it is currently not possible to say that a given material is "sustainable"
They consequently recommends use of the term 'environmentally preferable'.
The specifier needs to select the materials to suit their particular design objectives, including ESD, and delete others. Among the ESD issues to be considered are:
- Toxic and hazardous materials: If used, they must conform to manufacturer's recommendations, usually contained in the manufacturers' Material Safety Data Sheets (MSDS).
- Alternatives: When considering materials to avoid known ESD problems, they should be assessed for the possibility of other undesirable properties. The knowledge gaps about environmental impact and an absence of evidence, at this time, means it should not be assumed that alternative materials are safer or more environmentally preferable.
- Durability of materials: Premature failure of materials can be a significant determinant of the useful life of a building. To this end Masterspec provides many opportunities for specifying materials for greater durability. For the purposes of ESD the durability requirements of materials would usually be beyond those required by NZBC B2.
ALTERNATIVE CONSTRUCTION METHODS
In addition to alternatives for materials there are also alternative methods to conventional construction some of which are included in Masterspec work sections for instance:
- Adobe brick earth building (Masterspec section 3351 ADOBE BRICK EARTH BUILDING)
- Rammed earth building (Masterspec section 3352 RAMMED EARTH BUILDING)
- Straw bale
There are many other alternatives, but like straw bale in its uncompromised form, without some coverage in the NZBC Acceptable Solutions it can be a challenge to get BCA acceptance.
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