Life cycle assessment and environmental profiling of building materials
Abstract:
Sustainability is a complex challenge facing the world today. It requires a holistic approach to thinking which brings together social, economic and environmental dimensions. The built environment, with its vast consumption of energy and resources, and resultant emissions has an important role to play in meeting this challenge. It follows that the manufacture and supply of building materials must contribute to this. Within this context, life cycle thinking and the examination of materials’ embodied impact must go hand in hand with a broader agenda including healthy and safe materials, responsible sourcing and good resource management. This chapter examines these issues taking a focused look at embodied impacts and the use of life cycle assessment (LCA) as an important tool with which to address the environmental sustainability of our building fabric.
7.1 Materials sustainability
Sustainability in the context of modern development is a term that transcends the original definition of the word. It is therefore briefly important to examine what it means. From a qualitative perspective, sustainability is, by definition, something that has the ability for continuance, in essence, the ability to keep itself going. This is a simple concept to grasp. However, within the context of our developing society it has developed into a hugely complex debate and agenda. The reason for this is that the term has become synonymous with the very existence of humanity, and with our (logical and rightful) desire for continuance.
To sustain life on earth, the global environment must be sustainable, for, as Sarah Parkin (2000) bluntly puts it, ‘if the environment cannot support life, then we are dead’. For hundreds of millions of years, the world has successfully supported and sustained life (and more recently, human life). Unfortunately, evidence now indicates that the global environment could be losing its qualities of sustainability. Indeed, it is now widely recognised that humanity’s existence as we know it is threatened.
This has prompted concern that the world will develop into an unattractive and perhaps uninhabitable place in which to live. The underlying blame can be attributed to human activities and their burden on the environment. It follows that human activities are unsustainable; they are causing potentially irreversible damage and it is now widely recognised that this problem must be addressed. This is a complex and global challenge that requires a reexamination of how we do things in all walks of life.
The built environment, with its vast consumption of energy and resources and resultant emissions, in construction, operation, and at end-of-life has an important role to play. This is well recognised and the drive is now on to design, construct and manage our built environment in a way that is sustainable.
The manufacture and supply of materials has an important contribution to make to this objective and the sustainability of building materials and construction products has become an issue against which we should judge our building fabric. But what does this mean and how do we allow for this complex agenda in materials selection, specification and procurement?
The start point is to recognise that sustainable decision making requires that environmental, social and economic dimensions are brought together in a holistic approach considering multiple criteria within a life cycle context. Therefore this enables technical performance of a material to be examined alongside its impacts. Within this context it should be recognised that both the benefits and impacts a material has occur across all three environmental, social or economic dimensions.
Slowly the industry is establishing tools and methods for this new framework of assessment. This chapter takes a focused look at one of these tools called life cycle assessment (LCA), as well as introducing the concepts of healthy materials, responsible sourcing and resource management and how they are expected to play an increased role in the next period in the assessment of sustainable materials.
7.2 A life cycle approach to selecting building materials
Commonly referred to as ‘cradle-to-grave’ or ‘cradle-to-cradle’ assessment, life cycle assessment, or LCA, examines the life cycle of a product, system or process and evaluates the environmental impact it has over its life or a defined study period. In this regard LCA follows two key principles important to sustainable decision making. These are a ‘systems’ approach to assessment, i.e. it assesses life cycle performance; and secondly evaluation across multi-criteria, i.e. performance is measured across multiple environmental impact categories (Fig. 7.1). Both are fundamental to making environmentally sustainable decisions.
7.1 Life cycle assessment has two key strengths as an environmental sustainability assessment tool. These are that it can follow a cradle-to-grave or even a cradle-to-cradle assessment approach, i.e. it works on a ′life cycle′ basis; and secondly it can study a system against a broad selection of environmental impacts, which can include headline issues such as climate change (i.e. as commonly recognised by ′embodied carbon′ or ′embodied CO2′); but also embodied waste, embodied water, etc. Life cycle thinking and multi-criteria are fundamental to making environmentally sustainable decisions.
7.3 A brief history of life cycle assessment (LCA)
The history of LCA is well documented (Hunt and Franklin, 1996); Boustead, 1996). As a concept, it has its roots in the late 1960s and early 1970s when the idea was first envisioned to quantify the environmental consequences of Coca-Cola beverage packaging options over a life cycle in terms of energy, transport, waste, materials, etc. Despite this, it was not until the 1990s that a recognised methodology for LCA emerged. This was largely delivered through a body of work supported by The Society of Environment Toxicology and Chemistry (SETAC).
Following these initiatives international standards for LCA started to emerge in the mid-1990s through work organised by the International Organisation for Standardisation (ISO). The subsequent BS EN ISO 14040 Series entitled ‘Environmental management – life cycle assessment’ represents the first complete and internationally accepted standardisation of LCA technique and methodology.
Despite these developments and the fact that the concept of LCA is more than 40 years old and hence is relatively mature, its use to model and communicate the environmental impact of different assessed scenarios until recently remained relatively unusual. This is perhaps due to its complexity, and data intensive nature which makes any programme of assessment a time- and capital-intensive exercise.
All this is starting to change, and in the last five years LCA has started to move into the mainstream with many construction industry stakeholders taking an interest. Before we move on to consider the Standards framing this context, it is first worth briefly exploring ‘environmental labelling’ and where LCA sits within this.
7.4 Environmental labelling
The ISO 14000 series is the family of standards which have been developed to address environmental management. Their scope is broad and encompasses many different strands, but generally speaking two key branches can be identified. These are standards which are organisation oriented, and those which are product oriented. The organisation orientated standards provide guidance for establishing, maintaining and evaluating environmental management systems (EMS). By contrast, the product oriented standards are primarily concerned with determining the environmental aspects and impacts of products and have been developed for the application of environmental labels and declarations associated with them.
The framework for product environmental labelling and declaration is standardised in BS EN ISO 14020. This is a general principles document which further identifies three ‘Types’ of label/declaration/claim. A summary of this framework is provided in Table 7.1. Each declaration ‘Type’ is supported by a separate ISO Standard which has been developed to further harmonise practice. BS EN ISO 14020 and its complementary standards are intended to help an organisation gather the information needed to support planning for, and decision making on, its product/service and to communicate specific environmental information about that product/service to its stakeholders.
Table 7.1
Environmental labelling and declaration according to BS EN ISO 14020
| Type I | Third Party Environmental labelling BS EN ISO 14024:2001 | Label: a voluntary, multi-criteria based third party programme/standard that awards a licence which authorises the use of environmental labels on products indicating overall environmental preference of a product within a particular product category based on life cycle considerations. These are commonly referred to as ′ecolabels′ (e.g. environmental labels like Blue Angel, Nordic Swan and European Eco-Label) |
| Type II | Self-declared environmental claims BS EN ISO 14021:2001 | Claim: a self-declared environmental claim is a statement, symbol or graphic that indicates an environmental aspect of a product (e.g. self-declaration claiming a material or product such as a brick or concrete block to be recyclable, or alternatively to incorporate recycled content) |
| Type III | Third Party verified Environmental Product Declaration (EPD) BS EN ISO 14025:2006 | Declaration: a set of quantified environmental data consisting of pre-set parameters (so-called ′nutritional label′) based on LCA according to the BS EN ISO 14040 series of standards, with at least a minimum set of parameters for the product group (e.g. EPD with a mandatory third party validation: IBU or BRE Environmental Profiles). |
It is important to recognise that LCA information might form content in any of the three identified label or declaration Types, but that with Type III labelling, an LCA approach must be used. Of the three Types of environmental label, it is Type III and its use of LCA which lends itself most readily to considering environmental sustainability of materials. This is because it can take account of life cycle impacts and assessment across multiple issues.
The chapter now looks at LCA and the steps for undertaking an assessment.
7.5 Life cycle assessment (LCA) of building materials
LCA can provide a holistic and comprehensive method for assessing environmental performance because it can apply a life cycle-based approach to investigation. It can be used to identify where environmental impacts are arising within a system’s life cycle, and offer a process for examining opportunities for improving performance. In this context, LCA is best described as a form of ‘systems analysis’.
In construction, the system could be a material manufacture process; the fabrication of a building; a building element such as an external wall; an entire building or civil asset over its life; or even a neighbourhood consisting of all of the above. This flexibility means that LCA can be applied to specific built assets or service requirements such as waste management practice, transport scenarios or energy provision.
7.5.1 LCA methodologies and product category rules (PCR)
An LCA methodology, or more specifically a PCR, is a record of the specific rules which govern how an LCA should be undertaken for one or more ‘product categories’. Commonly, a PCR is developed for a defined product category which is a ‘group of products that can fulfil equivalent functions’.
The PCR will be developed with a specific goal and scope in mind. It should be followed to ensure that the LCA is fair, consistently applied, and that the results can be used comparatively. The PCR will define:
• the predetermined LCA environmental impact categories
• rules on reporting additional environmental information
• calculation process, including requirements for data quality, verification procedure, allocation method, declared and functional units, inventory analysis method, cut off rules, boundary conditions, etc.
• general requirements for reporting and communicating the LCA.
Importantly, the PCR will also state the three-step process for undertaking an LCA including characterisation, normalisation and weighting procedure.
7.5.2 Characterisation
In very simple terms LCA is about modelling system flows. Called ‘inventory flows’, these are the environmental interventions that take place between the study system, and the environment around it. They consist of all the inputs and outputs to the study system and include extraction of raw materials and fuels, requirement for heat and water consumption, and emissions to air, discharges to water and emissions to land. The linkage of these inventory flows to environmental impacts happens through a process that ‘characterises’ inventory flows (also known as inventories or interventions), into predefined categories of environmental impact (e.g. CO2, methane, CFCs and N2O all contribute to global warming potential). An important component of characterisation is the use of characterisation factors which recognise that emissions have different contribution levels to impact categories (Fig. 7.2). In this step of an LCA it is possible to determine the magnitude of environmental impacts attributed to a system.
7.5.3 Normalisation
Normalisation is the calculation of the magnitude of the impact category characterised data as set against a relative reference value. Normalisation can be used to bring a degree of relativity to LCA findings. Typically this is done by dividing the characterised impact figure values by comparable impact category figures, but determined for a reference geographic area per head of population over a defined time period. This figure could be used to normalise characterised impact data for global warming potential (climate change).
An outcome of normalisation is better understanding of the relative magnitude of each impact result of the studied system, but also preparation of the LCA findings for an additional procedure of weighting.
7.5.4 Weighting
Weighting, also known as valuation, is a process of assigning a degree of significance to the normalised impact category data. This is done by multiplying the normalised data by numerical factors (i.e. from a total of 100%). These factors are typically based on value choices, i.e. an opinion on which environmental impact category is more important than another. Weighted impact category results can be left disaggregated or added together to a single ‘score’ of environmental performance. It is important to recognise that weighting steps are based on value choices which may not be scientifically based. BRE conducted a weightings exercise for its LCA environmental profile methodology in 2007 (Aizlewood et al., 2007; Hamilton et al., 2007). The weightings derived from this are shown in Table 7.2.
7.5.5 LCA data/life cycle inventory (LCI) information
The input/output data defined in LCA models is called life cycle inventory (LCI) data. There are many commercially available LCI datasets which can be accessed for LCA modelling. Key databases include:
• Ecoinvent: produced for the Swiss Government
• Boustead: produced by a UK-based LCA consultancy
• GaBi: produced by PE Consulting
• IDEMAT: produced by TU Delft
• IVAM: produced by the University of Amsterdam
• Franklin: produced by Franklin Associates in the USA
In addition there are numerous sector specific, and regionally specific, initiatives which have developed to gather LCI or assist with the harmonisation of LCA. From an EU perspective, the Platform project on LCA delivered through the European Commission Joint Research Centre: Institute for Environment and Sustainability (http://lca.jrc.ec.europa.eu/lcainfohub/directory.vm) is a significant initiative. It has the twin objectives of developing an international reference life cycle database as well as an international resources directory and discussion forum for LCA. It also provides links to more widely available LCA data and tools:
7.6 Life cycle assessment (LCA) standardisation
Undertaking environmental life cycle modelling using LCA is a complex process which provides the practitioner with great flexibility to define and set specific methodological rules. The disadvantage with this flexibility is the potential to create LCA models which are not comparable; or in worst case scenarios, develop LCA which are inherently biased, but which appear at face value entirely sound.
To help harmonise LCA application and set common rules, the International Standards Organisation has developed a series of standards for the use of LCA. In addition, the European Committee for Standardisation (CEN) is coordinating the development of a construction sector set of LCA standards. A brief summary to the ISO and CEN work is now provided.
7.6.1 International Standards Organisation (ISO)
ISO has been active in the development of LCA standards since the mid-1990s. There now exist a range of standards for the generic application of LCA, through to its specific use in the construction sector.
ISO 14040 series: Environmental management – life cycle assessment
The ISO 14040 series were originally published in 1997 to harmonise the application of LCA. There are currently two1 standard documents2:
• BS EN ISO 14040:2006, Environmental management – life cycle assessment – principles and framework.
• BS EN ISO 14044:2006, Environmental management – life cycle assessment – requirements and guidelines.
The difference between the two documents is that ISO 14040 provides a general introduction to the principles of LCA and LCI; by contrast, ISO 14044 sets out specific requirements. Both documents adopt a similar structure organising content under a consistent set of key issues including:
ISO 14025: Type III environmental declarations and programmes
As the use of LCA has evolved, and its reporting has become more widespread, specific labelling programmes which model production systems and label products have been established. These programmes are known as Type III Environmental Product Declaration (EPD) labelling schemes. The requirements for their establishment, management, delivery and reporting are set out in BS EN ISO 14025 (2006).
LCA product data can be a useful source of environmental information to the building designer and Type III labelling schemes are a potential source for this information. ISO 14025 supports this through providing a set of ‘principles and procedures’ for establishing such labelling programmes and how their operators should use the LCA ISO 14040 series. In this regard, ISO 14025 sets out guidance for developing the PCR, programme operator responsibilities, ensuring comparability, verification procedures, transparency, reporting requirements; to name a few issues.
ISO and LCA in construction
Although LCA is now widely used across many industrialised systems, very few are supported by standards. The construction industry is an exception as it benefits from a suite of international standards dealing with sustainability in building and construction that include:
• ISO 15392 Sustainability in building construction – general principles
• ISO 21932 Buildings and constructed assets – sustainability in building construction – terminology
• ISO/TS 21929-1 Sustainability in building construction – sustainability indicators – Part 1: Framework for development of indicators for buildings
• ISO/TS 21931-1 Sustainability in building construction – framework for methods of assessment for environmental performance of construction works – Part 1: Buildings.
Figure 7.3 shows the relationship of these different documents and how they relate to ISO 21930, a standard that sets out the principles for using LCA for the environmental declaration of building products. This means it provides a useful additional focus from the ISO 14040 series, by addressing specific issues of relevance to construction such as the service life of the building products as seen over a building’s life cycle. ISO 21930 is designed to be used in combination with ISO 14025 as the basis for establishing Type III environmental declaration programmes.
7.3 Suite of related international standards for sustainability in building construction and construction works (BS EN ISO 21930, 2007). Permission to reproduce extracts from BS EN ISO 21930 (2007) is granted by BSI. British Standards can be obtained in PDF or hard copy formats from the BSI online shop: www.bsigroup.com/Shop or by contacting BSI Customer Services for hard copies only: Tel: + 44 (0)20 8996 9001, Email: [email protected].
Inherent in LCA modelling is the consideration of the study system ‘life cycle’. For buildings and building components this is particularly challenging because they can exhibit long service lives, sometimes extending over tens or hundreds of years. To bring consistency to this complex area, LCA practitioners are increasingly using the ISO 15686 series of standards on ‘service life planning of constructed assets’. The relationship of these standards and ISO LCA frameworks is shown in Fig. 7.4. In this context perhaps the most important standard for LCA is BS ISO 15686-8:2008 Buildings and constructed assets – service-life planning Part 8: Reference service life and service-life estimation.
7.4 Inputs and influences on service life planning of buildings. Permission to reproduce extracts from BS EN ISO 15686-1 (2000) is granted by BSI. British Standards can be obtained in PDF or hard copy formats from the BSI online shop: www.bsigroup.com/Shop or by contacting BSI Customer Services for hard copies only: Tel: + 44 (0)20 8996 9001, Email: [email protected]. (adapted from BS EN ISO 15686-1, 2000)
This standard provides guidance on how to select or determine a construction component ‘reference service life’ (RSL) and how to use this for the purposes of calculating an ‘estimated service life’ (ESL). As a defined time period, ESL can be used to represent the service life period of a construction component and when it will reach its end-of-life in an LCA model.
ISO and comparability
A key observation of the ISO work is that despite providing a useful framework for modelling, the standards still provide significant room for interpretation by the user (they are designed in this way due to the international and multidisciplinary context in which they will be applied). This means that although studies conducted within their standardised framework should follow a logical path and offer a degree of consistency, they still offer significant opportunity:
• to adopt entirely valid, but differing approaches
• to introduce bias through manipulation of the LCA methodology towards a particular outcome
• for Type III labelling schemes to apply LCA in different ways.
In conclusion, LCA conducted by different practitioners within the ISO standards are unlikely to be directly comparable (and this includes construction focused standards).
7.6.2 European committee for standardisation (CEN)
Many ‘built environment/construction works’ EPD schemes now exist in Europe following the ISO standards. Most of these incorporate common elements but due to the flexibility of the ISO standards, the PCR they follow and the EPD that they produce are different from country to country.
To avoid barriers to trade of goods and services, European harmonisation is necessary. This agenda became the subject of a CEN Mandate, under instruction from the EU Enterprise Directorate. The Mandate was written to develop a harmonised approach for ‘sustainability of construction works’ of which LCA would be an important part. The mandate was accepted in late 2004 and work on the standards began in 2005.
In response to the mandate, Technical Committee TC350 was established by CEN to develop ‘horizontal standardised methods for the assessment of the integrated environmental performance of buildings’. Although the original mandate extended only to ‘environmental performance of buildings’, the work has subsequently been broadened to consider socio-economic aspects as well.
TC350 consists of five Working Groups under the leadership of a single Task Group; the work programme is split horizontally into framework, building and product levels; and vertically into environmental, social and economic dimensions. The initiative will deliver European Standards (EN), Technical Reports (TR) and Technical Specifications (TS).
Through TC350 the goal of the Commission is to provide a method for the voluntary delivery of environmental information that supports the construction of sustainable works including new and existing buildings.
7.7 UK context
LCA is increasingly being used in the UK construction sector. Material suppliers use it to assess the environmental impact of their supply chains and production systems; and building designers and constructors are applying it to understand the impact of their constructed assets. Clients are increasingly becoming familiar with the data LCA can present and are considering it in their procurement decisions.
Building ratings systems including BREEAM and the Code for Sustainable Homes also indirectly apply LCA through their use of the Green Guide to Specification as a compliance tool. Even CEEQUAL the civil engineering assessment methodology provides reward for the application of LCA to measure embodied impacts of civil works. There is no British Standard or commonly ‘regulated’ approach. The work most widely applied has been that conducted by BRE.
7.7.1 UK BRE Environmental profiles methodology
The Environmental Profiles methodology is an LCA approach, i.e. a PCR developed for applying LCA to built environment scenarios. The methodology is designed and scoped to provide a ‘level playing field’ approach for all construction materials, i.e. an approach which is not biased to any particular type of material. The Environmental Profiles methodology allows direct comparison of the environmental impacts of functionally equivalent products, building specifications and buildings or even infrastructure.
BRE developed the first edition of the Environmental Profiles methodology and its associated database in 1999 (Howard et al., 1999). A research programme through 2006–8 has culminated in its update, and the publication of a second edition of the Environmental Profiles methodology. The methodology provides the UK with an approach to the environmental life cycle assessment of all types of construction materials. It was developed with the UK material supply sector through close coordination with the Construction Products Association and its members.
The Environmental Profiles methodology reports using the 13 environmental impact categories summarised in Table 7.2. It also applies a weightings step which enables a single score of environmental impact to be derived called the Ecopoint. The methodology has enabled BRE to develop three key LCAbased initiatives. These are now summarised.
7.7.2 Green guide to specification
The Green Guide to Specification is now in its fourth edition. It is a specification aiding tool aimed at providing the building professional with easy-to-use guidance on how to make the best environmental choice when selecting construction materials and components. The fourth edition is available online and provides environmental ratings for more than 1200 specifications across various types of building. It is underpinned by the Environmental Profiles methodology and a LCI data collection exercise across a broad range of UK material suppliers. The environmental impacts for discrete specifications are presented as Ecopoint scores which have been converted into A +, A, B, C, D and E ratings. The online tool is expected to grow in functionality as BRE continue to develop it.
7.7.3 Envest
This is a BRE commercial building software tool that combines LCA and whole life costing (WLC). It allows both environmental and financial tradeoffs to be considered in the design process. The user assigns their building design parameters (height, number of storeys, glazing area, etc.) and material specification choices (external wall, roof covering, etc.) into the tool. Envest then assesses the environmental impact (with LCA) and cost (with WLC) of the design. The tool reports on environmental impact using the Environmental Profile impact categories and Ecopoints, and costs in pounds sterling.
7.7.4 The environmental profiles certification scheme
This is a Type III EPD certification scheme managed by BRE Global (the certification company of the BRE group). The scheme uses the Environmental Profiles methodology to produce EPD of manufacturer specific construction products and publishes Type III EDP declarations on behalf of the manufacturer. Each EPD is based on verified LCI for the manufactured product which has been audited by a certification officer through visiting the manufacture facility and reviewing production documentation. EPD are then listed in the GreenBookLive and also used to generate Green Guide to Specification ratings.
7.8 Other issues
The sustainability of a material or product is more than how it performs in a life cycle assessment. This section looks at three additional aspects and how they contribute to considering the sustainability of a material.
7.8.1 Healthy and safe materials
Materials and their constituent components can contribute to a range of human health problems including carcinogenicity, endocrine disruption, and skin and mucous membrane irritation and sensitisation (to name but a few). From a safety perspective, material specification can have implications towards personal injury, accident, trauma or loss for stakeholders.
Both health and safety aspects need to be considered throughout the building life cycle including extraction of basic material ingredients, the manufacture of these into a product, installation/construction, the maintenance requirement it demands in service and the implications for deconstruction and disposal at end-of-life.
Therefore different materials and the way a design uses them will exhibit different health or safety levels. Generally government legislation exists to govern material impacts across these. However, this topic is important because many materials originate in places where human health and safety are not well regulated, or where the legislative frameworks might be considered too tolerant. Beyond legislation, various frameworks for considering these issues exist and are formalising.
7.8.2 Resource management
Resource management recognises that within a finite global system, there are limits to be respected by human activities. These will vary significantly from material to material, but resource management indicators can be used to determine performance including:
• abiotic depletion: depletion of non-renewable material resources
• renewability (or even rapidly renewable)
Different strategies exist for driving good resource management and efficiency. The most common is that presented within the waste hierarchy of prevention, minimisation, reuse, recycling, energy recovery and disposal. LCA has the capacity to include a range of resource management based indicators and generally the issue should be considered in life cycle terms.
On a practical level in the UK construction Site Waste Management Plans offer a mechanism to reduce waste arising on site and dispose of it efficiently when it arises.
7.8.3 Responsible sourcing
Responsible sourcing is an approach of supply chain management, responsible manufacture and product stewardship, and encompasses social, economic and environmental dimensions. The concept is broad and many different variations of the concept exist. Within the construction products sector, the aspect is most mature within the timber industry with sustainable timber supply schemes like the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification schemes (PEFC) leading the way.
The reality, however, is that responsible sourcing should be an objective of all material supply sectors. A company demonstrating good responsible sourcing practices is likely to be contributing to all the materials sustainability issues outlined in this chapter including addressing embodied impact, working to good heath and safety standards and ensuring good resource management practice.
Sector schemes to drive corporate social responsibility of manufacturing practice, exercise good supply chain management, and product stewardship, are starting to evolve. These commonly require that manufacturers address the following objectives:
7.9 References
Aizlewood, C., Edwards, S., Hamilton, L., Shiers, D., Steele, K. Environmental weightings: their use in the environmental assessment of construction products. Bracknell: IHS BRE Press; 2007. [Information Paper IP 4/07].
Boustead, I. LCA – how it came about. The beginning in the UK. International Journal of LCA. 1996; 1(3):147–150.
BS EN ISO 14020. Environmental labels and declarations – general principles. Geneva: International Standards Organisation; 2002.
BS EN ISO 14021. Environmental labels and declarations – self-declared environmental claims (Type II environmental labelling). Geneva: International Standards Organisation; 2001.
BS EN ISO 14024. Environmental labels and declarations – Type I environmental labelling – principles and procedures. Geneva: International Standards Organisation; 2001.
BS EN ISO 14025. Environmental labels and declarations – Type III environmental declarations – principles and procedures. Geneva: International Standards Organisation; 2006.
BS EN ISO 14040. Environmental management – life cycle assessment – principles and framework. Geneva: International Standards Organisation; 2006.
BS EN ISO 14044. Environmental management – life cycle assessment – requirements and guidelines. Geneva: International Standards Organisation; 2006.
BS EN ISO 15686-1. Buildings and constructed assets – service life planning – Part 1: General principles. Geneva: International Standards Organisation; 2000.
BS EN ISO 21930. Sustainability in building construction – environmental declaration of building products. Geneva: International Standards Organisation; 2007.
BS ISO 15392. Sustainability in building construction – general principles. Geneva: International Standards Organisation; 2008.
BS ISO 15686-8. Buildings and constructed assets – service-life planning Part 8: Reference service life and service-life estimation. Geneva: International Standards Organisation; 2008.
BS ISO/TS 21931-1, Sustainability in building construction – framework for methods of assessment for environmental performance of construction works – Part 1: Buildings. Geneva, International Standards Organisation.
BS ISO 21932, Buildings and constructed assets – sustainability in building construction – terminology. Geneva, International Standards Organisation.
Hamilton, L., Edwards, S., Aizlewood, C., Shiers, D., Thistlethwaite, P., Steele, K. Creating environmental weightings for construction products: Results of a study, BR 493. Bracknell: IHS BRE Press; 2007.
Howard, N., Edwards, S., Anderson, J. BRE Methodology for Environmental Profiles of construction materials, components and buildings, BR370. Bracknell: IHS BRE Press; 1999.
Hunt, R.G., Franklin, W.E. LCA – how it came about – personal reflections on the origin and development of LCA in the USA. International Journal of LCA. 1996; 1(1):1–4.
ISO/TS 21929-1, Sustainability in building construction – sustainability indicators – Part 1: Framework for development of indicators for buildings. Geneva, International Standards Organisation.
Parkin, S., Sustainable development: the concept and practical challenge. Proceedings of ICE, Civil Engineering, 138, November, 3–8, 2000.
1There are actually three documents but ‘DD ISO/TS 14048:2002 Environmental management – life cycle assessment – data documentation format’ is only a draft for development (DD) technical specification (TS) which outlines formatting requirements for LCA data documentation.
2ISO 14040:2006 and ISO 14044:2006 supersede EN ISO 14040:1997, EN ISO 14041:1998, EN ISO 14042:2000, EN ISO 14043:2000.