FAQs

What is the Lifecycle Database?

The aim of the Lifecycle Database (formerly known as Wood First Plus) project is to create a free online information hub containing all of the environmental and design data necessary to specify timber as a first choice material.

In particular, it will focus on providing generic LCA datasets for key timber products used in the UK.

PE INTERNATIONAL has been engaged to oversee the collection, analysis and review of existing life cycle assessment (LCA) data for a wide range of timber and timber products. The company has extensive experience in the construction materials sector and in working with the timber industry, having previously completed a major LCA project on U.S. hardwood lumber for the American Hardwood Export Council (AHEC). These data will be used to generate generic LCA datasets for key timber products used in the UK.

The project is a result of on-going consultation with timber industry organisations and external stakeholders, including contractors’ groups, architects, professional institutions and many others.

All stakeholders will be able to access whole-life information on timber products free of charge through a dedicated website, managed by Wood for Good. Individual timber companies will be able to use these data as a basis for developing specific environmental product declarations (EPD) for their products.

“With the built environment sector now firmly focused on delivering low-carbon, sustainable buildings, being able to quantify the environmental impact of construction materials is becoming increasingly important. The aim for Wood First Plus is to provide empirical evidence on the performance of specific wood products, making it easier for construction professionals wishing to build with timber to do so, and helping them to adhere to industry regulations.”

David Hopkins, Wood for Good

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Who are the Lifecycle Database Project Sponsors?

Lifecycle Database is a multi-stakeholder project run by the UK’s timber industry. It is headed by Wood for Good and supported by Scottish Enterprise, the Timber Trade Federation, Forestry Commission Scotland, TRADA and AHEC.

Wood for Good is the UK's wood promotion campaign. The Wood for Good campaign works on behalf of the whole timber industry in the UK. It aims to promote the suitability and sustainability of wood as a building material to the construction and logistics sectors and associated professionals such as architects and design engineers.

http://www.woodforgood.com/ 

Scottish Enterprise supports the development of more globally competitive companies and Scotland’s growth sectors that have the biggest opportunity in global growth markets.

http://www.scottish-enterprise.com/ 

The Timber Trade Federation grows the market for wood and wood products through innovative industry representation and business support for its members. Advice and support provided by the TTF covers topics from Chain of Custody to employment law and from technical guidance to ready-made contracts. The TTF is regularly consulted by Government, NGOs and sister organisations on issues affecting the wood industry.  

http://www.ttf.co.uk/

Forestry Commission Scotland (FCS) was created in 2003 as a result of the Forestry Devolution Review.  The FSC serves as part of the Scottish Government's Environment and Forestry directorate, and is responsible to Scottish ministers, advising on and implementing forestry policy and managing the national forest estate.

The FSC’s mission is to protect and expand Scotland's forests and woodlands and increase their value to society and the environment.

www.forestry.gov.uk/scotland 

The Timber Research and Development Association (TRADA) is an internationally recognised centre of excellence on the specification and use of timber and wood products. Its position in the industry is unique with a diverse membership encompassing companies and individuals from around the world and across the entire wood supply chain, from producers, merchants and manufacturers, to architects, engineers and end users. Its aim is to provide members with the highest quality information on timber and wood products to enable them to maximise the benefits that timber can provide.

http://www.trada.co.uk/ 

The American Hardwood Export Council (AHEC) is the leading international trade association for the American hardwood industry, representing companies and trade associations engaged in the export of a full range of U.S. hardwood products including lumber, veneer, plywood, flooring, moulding and dimension materials. 

http://www.ahec.org/

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What sort of data will Lifecycle Database provide?

The online hub at the core of the project will provide a user-friendly portal for information on carbon accounting and life cycle assessment (LCA) for timber.

The Lifecycle Database hub will incorporate both generic LCA datasets for the primary products developed during this project and existing manufacturer-specific datasets identified during a literature review, together with the related evidence base. Over time, it will also provide tools to allow manufacturers to produce their own Environmental Product Declarations (EPD).

The environmental data provided for the primary timber products are intended to be used at the building or end-use-product level, allowing comparisons to be made between different options, taking account of the full life cycle. Data for products themselves can only be compared where the full functionality through the life cycle has been considered.

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What products are covered by Lifecycle Database?

This project focuses on timber and timber products produced and used in the UK, and will provide data for manufacturing and end of life. These timber products, such as kiln dried timber, wood panel products or engineered timber, are themselves the raw or primary materials used in buildings or other end-use products such as furniture; they are rarely an end-use product in themselves.

The products to be studied include:

A. Sawn Timber (produced and consumed in the UK)

  • Planed timber
  • Fresh sawn softwood
  • Kiln dried sawn softwood
  • Kiln dried sawn hardwood

B. Panel Products (all UK consumed)

  • Temperate Plywood
  • Chipboard/particleboard
  • Melamine coated particleboard
  • Orientated strand board (OSB)
  • Medium density fibreboard (MDF)
  • High density fibreboard (HDF)

C. Engineered Timber (all UK consumed)

  • Glulam (glued laminated timber)
  • Laminated timber (laminated strand lumber (LSL), laminated veneer lumber (LVL), parallel strand lumber (PSL))
  • Cross laminated timber (CLT)
  • Typical Timber frame (both open and closed system)
  • Trussed rafters

D. Proprietary Products (all UK consumed)

  • Galvanised steel (for hangers, plates, joist webs, fixings)
  • A typical joinery adhesive

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What is Life Cycle Assessment (LCA)?

All products, not just construction products, have an impact on the environment. 

A construction product can have environmental impacts from the extraction of raw materials, their processing and manufacture, packaging and delivery to site, installation, maintenance and refurbishment and eventual recycling or disposal. This sequence of stages is known as the life cycle of the product. Calculation of the environmental impact of a product at all stages of the life cycle is called Life Cycle Assessment (LCA). LCA should report on all the significant environmental impacts associated with a product or pro cess by considering a broad range of environmental issues. 

The scope of LCAs can vary, but the manufacturing stage of the construction product will always be included; this is known as a ‘cradle to gate’ assessment. Some LCAs will also take into account transport of the product to the construction site and its installation; this is a ‘cradle through construction’ assessment. LCAs that also include the impacts of maintenance, refurbishment and eventual recycling or disposal are termed ‘cradle to grave’ assessments.

There are two types of traditional construction product LCA. Industry Average assessments use data from several manufacturers of the same type of product to create an industry average LCA for that product. Manufacturer Specific assessments use product-specific data provided by a single manufacturer, and apply only to the specified products.

LCAs should comply with ISO 14040:2006 [1] and ISO 14044:2006 [2] and a peer review is often undertaken to confirm this. Any LCA that is intended for publication and that compares products must be critically reviewed by a panel of independent experts to ensure that the relevant standards have been adhered to and that the assessment is robust (this is a requirement of the ISO standards). 

A particular type of LCA study is an Environmental Product Declaration or EPD.

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[1] ISO 14040:2006 Environmental Management – Life Cycle Assessment – Principles and Framework

[2] ISO 14044:2006 Environmental Management – Life Cycle Assessment – Requirements and Guidelines

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What are Environmental Product Declarations (EPD)?

Environmental product declarations are standardised documents used to communicate the environmental performance of a particular product based on LCA. 

EPD in general are covered by the ISO 14025:2006 standard, although the construction industry has also developed ISO 21930:2007 [1] and EN 15804:2012 to define how construction products should be assessed and reported using EPD. EN 15804:2012 [2] sets out how LCA should be used to consistently determine the environmental impacts associated with a construction product, generating results in a common format to enable building level assessment and comparison across Europe. Many hundreds of EPD are freely available from a number of European schemes and cover a very wide range of construction products, with most being for specific manufacturer’s products, although trade association EPD are also available. EPD schemes aligning to EN 15804:2012 include BRE’s new EN 15804 EPD Verification scheme [3] within the UK, FDES using the French Standard, NF P01-010 presented in the Inies database [4] in France, IBU in Germany and EPD Norge [4] in Norway.

All EPD are manufacturer declared data but should have been independently verified by an expert in LCA and the construction product itself before publication.

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[1] ISO 21930:2007 Sustainability in building construction – Environmental declaration of building products

[2] EN 15804:2012 Sustainability of construction works – Environmental product declarations – Core rules for the product category of construction products 

[3] http://www.greenbooklive.com/search/scheme.jsp?id=260

[4] http://www.inies.fr/IniesConsultation.aspx

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Why are these issues important?

This section summarises the reasons why these issues are important. 

Climate change

There is compelling evidence that the Earth’s climate is changing rapidly, at a rate not seen for thousands of years. This can be seen in well-known phenomena such as rising sea levels and melting ice caps, but also in a rise in extreme weather events such as hurricanes, cyclones, droughts and flooding events [1]. Moreover, it is very likely that these changes in our climate are being caused by human activity, specifically the increase in the concentration of greenhouse gases, such as carbon dioxide or methane, in the atmosphere as a result of industrial activity. 

The construction industry and built environment

The built environment makes a significant contribution to global greenhouse gas emissions over its life cycle, with estimates of between 38% and 48% of total global emissions being attributable to buildings. In the UK, Government targets [2] outlined in the Climate Change Act [3] to reduce greenhouse gas emissions by 34% by 2020 and by 80% by 2050 are unachievable without a significant contribution from the construction industry to improve the performance of new and existing buildings. This has led to Government plans to make all new homes “zero carbon” by 2016 and all new non-domestic properties zero carbon by 2019 [4].

Embodied or Capital Carbon is the total greenhouse gas emissions (not just carbon dioxide) associated with extraction and manufacturing of construction materials, and in some instances, with their transportation, installation, maintenance and disposal. Production, delivery and disposal of construction materials and operation of construction and demolition sites for the UK market is estimated to produce 33.6 million tonnes of carbon dioxide equivalent per annum [5], around the same amount as for domestic hot water [6] and over 3% of total UK greenhouse gas emissions.

The majority of embodied carbon for construction materials is carbon dioxide emitted from the use of fossil fuels in extraction and manufacturing of construction materials and process emissions from manufacturing. Some studies of embodied carbon consider only the embodied emissions in the manufacturing supply chain (extraction, manufacturing, transport). These are termed “cradle-to-gate” studies. Other studies of embodied carbon consider transport to site and installation (cradle to site) and others also include maintenance and replacement over the building life, and the disposal of demolition waste through recycling, landfill or incineration (cradle to grave or cradle to cradle). 

Global warming potential

Emissions of greenhouse gases contribute to climate change by trapping heat in the atmosphere through a process known as radiative forcing. The degree of radiative forcing caused by a given quantity of gas varies according to the specific gas emitted. 

Carbon dioxide is well known as being the most important greenhouse gas, with the biggest influence on climate change. However, compared to most other greenhouse gases the radiative forcing associated with carbon dioxide is small. The reason that carbon dioxide dominates is simply because it is emitted in much greater quantities than other greenhouse gases.

The primary indicator of climate change is “global warming potential (GWP)”. GWP is calculated by normalising the potential impact on climate associated with emission of a particular gas to the impact of carbon dioxide. This allows all greenhouse emissions to be reported in the same units, known as “carbon dioxide equivalents (CO2e)” that can then be summed to give a single value for GWP accounting for all types of emission. 

For example, emission of 1 kg of methane, another common greenhouse gas, has the same impact on global warming as 25 kg of carbon dioxide. Hence 1 kg methane = 25 kg CO2e. The GWP of some other greenhouse gases are given in the table below. 

Table: GWP for common greenhouse gases [7]

Greenhouse Gas

GWP

(kg CO2e)

Carbon dioxide (CO2)

1

Methane (CH4)

25

Nitrous oxide (N2O)

298

Sulphur hexafluoride (SF6)

22800

Perfluorobutane

8860

HFC 134a (tetrafluoroethane)

1430

 

 

 

 

 

 

 

 

 

When referring to greenhouse gases and climate change, the term “carbon” is often used as a catch-all and can mean

  • carbon dioxide (CO2) alone
  • a basket of all greenhouse gases

In recent years the number of studies and publications that report carbon dioxide alone has decreased and it is more common for the GWP of all greenhouse gas emissions to be reported. 

Sources of embodied carbon

With the exception of process emissions such as the release of carbon dioxide from the calcination of limestone or the release of some blowing agents during manufacturing of insulation foams, most carbon emissions normally result from the use of energy. However, emissions also occur during the extraction of fossil fuels, their transport and processing, and from distribution losses such as gas leaks (natural gas is predominantly methane, a more potent greenhouse gas than carbon dioxide). Carbon is also released when bio-based products such as timber are burnt or decay in landfill or compost. Where the decay is anaerobic (when access to oxygen is limited, for example, in landfill) then some of the carbon may be emitted as methane. 

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[1] http://climate.nasa.gov/evidence/

[2] http://www.decc.gov.uk/en/content/cms/emissions/carbon_budgets/carbon_budgets.aspx

[3] http://www.theccc.org.uk/home

[4] http://www.communities.gov.uk/publications/planningandbuilding/zerocarbondefinition

[5] (Green Construction Board, 2013) – UK capital carbon emissions for 2010

[6] Environment in your pocket 2009, DEFRA

[7] IPCC 4th Assessment Report 2007

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What is Carbon Sequestration?

When trees and plants grow they take carbon from the atmosphere and incorporate it in molecules such as cellulose and carbohydrates. 

This “biogenic” or “sequestered” carbon removes carbon dioxidefrom the atmosphere and has benefits, particularly for long life products such as construction materials, as the carbon stays “stored” in the product until disposal. However, disposal processes may release the carbon back into the atmosphere, either as carbon dioxide from combustion or aerobic decomposition processes, or as both carbon dioxide and methane from anaerobic decomposition.

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What are Forest Carbon Sinks?

A forest contains carbon not just in the living trees you can see above the ground, but in litter on the forest floor, and below ground in roots and soil.

These carbon stores, known as “carbon pools”, are shown in the figure below and include both living biomass and dead organic matter. Over time, the various parts of the forest can both emit carbon and remove carbon from the atmosphere. For example, as a tree grows, it creates new branches and roots which require carbon removal and sequestration within the tree. When leaves fall to the ground however, they decay causing emissions of carbon dioxide and methane. The overall balance of emissions and removals will result in an increase in carbon in the forest (a carbon sink), or a decrease in carbon in the forest (a net emission).

Quantifying these emissions and removals to calculate the balance requires an understanding of how natural processes and human actions interact.

Illustration of the carbon pools and naturally occurring greenhouse gas dynamics associated with land use, land use change and forestry, taking the example of forest land. After Morison et al. (2012), taken from (Robert Matthews, 2012)

 

The main greenhouse gas involved in forestry is carbon dioxide (CO2) from carbon stock changes. Other greenhouse gases often associated with agriculture include nitrous oxide (N2O) from, for example, nitrogen inputs (although applying fertiliser to forest land is not common practice in the UK), and methane (CH4) which is involved in the greenhouse gas balances of forests growing on highly organic soils such as peatlands.

Human management of forests can have a strong influence on the pattern of emissions and removals but managed forests are always susceptible to natural disturbances such as forest fires or storms which can lead to substantial release of carbon to the atmosphere or reduced sequestration from the atmosphere. 

Understanding forest carbon balances as stock changes

The range of carbon pools involved in forest greenhouse gas balances and the types of issues raised in the preceding discussion can lead to the impression that forest greenhouse gas balances are difficult to understand and quantify.  However, for most purposes forest carbon or greenhouse gas balances can be understood and modelled more simply by considering changes in carbon stocks.

The chart below shows how carbon stocks would change if a Scottish field were planted with Sitka Spruce.  Before the trees are established the existing vegetation carbon stocks might typically comprise no more than 20 tonnes carbon per hectare (tC ha-1). The small initial loss of carbon stocks due to removal of existing vegetation is not shown in this chart. The land is assumed to be managed without any harvesting (either through thinning or clearfelling), effectively being allowed to develop into a ‘wilderness forest’.

An illustration of the change in vegetation (tree) carbon stocks that can occur on an area of land by planting a stand of conifer trees. a: establishment phase; b: full-vigour phase; c: mature phase; d: long-term equilibrium phase. Taken from (Robert Matthews, 2012)

This text is based on (Robert Matthews, 2012).

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How does the IPCC treat carbon in forestry and timber products?

The IPCC Guidelines were developed for the purpose of producing national greenhouse gas inventories rather than for considering sequestration or emissions associated with particular products. Hence this perspective is different to that of life cycle based greenhouse gas accounting methods.

Wood harvested from forest land, cropland and other types of land use will remain in products for differing lengths of time. Harvested Wood Products includes all wood material (including bark) that leaves harvest sites and constitutes a carbon reservoir. The time carbon is held in products varies depending on the product and its uses. For example, fuelwood and mill residue may be burned in the year of harvest; many types of paper are likely to have a use life of less than 5 years which may include recycling of paper; and sawnwood or panels used in buildings may be held for decades to over 100 years. Discarded Harvested Wood Products can be deposited in solid waste disposal sites where they may persist for long periods of time. Due to this storage in products in use and in solid waste disposal sites, the CO2 emissions from harvested wood products in a given year could be less, or potentially more, than the total amount of wood harvested in that year. Worldwide the amount of carbon held in harvested wood products is likely to be increasing.

Given that inputs do not in general equal outputs and that carbon can remain stored in Harvested Wood Products for extended periods of time, this storage time needs to be taken into account when providing guidelines for estimating the contribution of Harvested Wood Products to carbon dioxide emissions/removals associated with agriculture, forestry and other land use projects.

The following data are required for calculating greenhouse gas withdrawals and emissions at the national level:

  • Annual change in carbon stock in Harvested Wood Products in the reporting country, including Harvested Wood Products stocks from both domestic harvest and imports
  • Annual change in carbon stock in Harvested Wood Products made from wood harvested in the reporting country including annual change in carbon stock in Harvested Wood Products exported to other countries
  • Annual imports of all types of wood and paper material to the reporting country
  • Annual exports of all types of wood and paper material from the reporting country
  • Annual harvest for wood products in the reporting country.

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Why is Lifecycle Database needed?

Regulatory and legislative frameworks for construction and manufacturing are becoming ever more restrictive.

As such, in future it is expected that assessment of environmental impacts will be increasingly important customer drivers alongside cost and performance criteria throughout the construction sector.  This in turn means that there will be increasing demand from clients in the construction and manufacturing industries for robust, accessible data showing measurement and assessment of supply chains, performance of products in design, construction, whole-life assessment and end-of-life considerations among other factors.

Many other industries, including competing material sectors, recognise the importance of these changes and have taken the lead in promoting positive information to their target audience. The timber industry is determined to do the same. Without it, specifiers and buyers will choose the products and materials for which clear data exists and ignore those which cannot back up their claims.

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What is the methodology used to generate the Lifecycle Database generic data?

PE’s approach to the generation of GHG and LCA data for the primary products to be assessed in the project (see above) is informed by similar work which they have undertaken to develop generic construction databases for Germany, Europe (as a region), Brazil, China, and Ukraine and generic national LCA databases for Malaysia and France.

This approach uses existing underlying data from LCA models, within the highly regarded GaBi Life Cycle Database, adapted to compensate for differences in a particular region by considering the particular mix of technology used and making use of relevant regional data for the most sensitive input/output variables to the model to provide “generic data” for the region.

This adaptive, or compensatory approach must be distinguished from a more conventional LCA based approach where all, or a selection of manufacturers supplying a region, provide complete data on their processes which are then modelled and averaged, to generate “average data” for the region.

Because “average data” will more accurately represent a typical product than “generic data” can, it should always be used in preference if available. There are also limitations to the claims that can be made for the representativeness of “generic data”. However, given the number and geography of suppliers to the UK market, the costs of data collection and modelling to generate “average data” for the number of products in the brief cannot be accommodated in the available project budget.

Although the work will be guided by the review of regulation and policy, the intention at this stage would be to provide a generic LCA database for timber and timber products aligning with the CEN/TC 350 standards, and which could be pre-verified according to CEN/TR 15941:2010 for use in building-level assessment to EN 15978, and for use as generic data for input materials in the preparation of EPDs to EN 15804 where specific data are not available. CEN/TR 15941:2010 is the CEN/TC 350 report covering generic data, which provides guidelines on the required quality of data, and gives provision for the pre-verification of generic data. Relevant text from the standard is presented below:

“CEN/TR 15941:2010 4.1

Generic data are used instead of system specific data to describe the environmental impacts and aspects of a product's life cycle in an LCA study. Generic data are used for calculations where system specific data LCI/LCA data are not available or where other non-system specific LCI or technical data are required”.

“CEN/TR 15941:2010 4.3.4 Compensating with generic data for differences in local conditions

Often generic data will not directly reflect the local conditions (i.e. the actual situation) under study. Data compensation then has to take place. Compensation on a quantitative empirical basis for local conditions is always the best option. This however presupposes the practitioner's detailed understanding of the information under the local conditions and therefore understanding the different measures to be taken for compensating any bias in the information. When informed compensation of the data is not possible, informed assumptions have to be made. These kinds of assumptions are common in LCA since often no other option is available. Such assumptions should always be reported in the LCA-report and the sensitivity of the analysis resulting from such assumptions should be evaluated.CEN/TR 15941:2010

The process described here allows for the provision for a single generic dataset for both production (based on a consumption-weighted average of species, technologies and imports/UK produced if relevant), and with typical UK end of life data for all the products listed in “What products are covered by Lifecycle Database?”

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How is the forest used the make timber products?

Diagram showing the use of different forest outputs taken from (Robert Matthews, 2012).

The diagram shows the common sources of harvested wood products used to product timber products and biofuel. In addition, the “blue” boxes show the main products which are not required if timber is used.

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User Guide

An overview of the lifecycle assessment work

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Glossary

Definitions of commonly used terms

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