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EDIPTEX - Environmental assessment of textiles

Annex 4: Blouse made of viscose, nylon and elastane

• The blouse - summary and conclusions
• Introduction
• Method
  • Comments to the method
  • Data
• The blouse
  • Functional unit
  • Reference product and main scenario
  • Product system
  • Main scenario - results
  • What-if discussion
• Background data
  • System structure in the EDIPTEX database for the blouse
  • Details of the blouse model in the EDIPTEX database

The blouse - summary and conclusions

Firstly, it is important to stress the following conditions with regard to lack of data for the model used as the basis for the environmental assessment of the blouse.

• Data on manufacture of elastane fibre was not available. Instead, the model includes a process for elastane in which EDIP data for the process to manufacture polyurethane (flexible foam) is used. Elastane is composed of 85 per cent polyurethane.
• Furthermore, within the framework of the project it has not been possible to calculate an equivalency factor for carbon disulphide, which is used in the manufacture of viscose fibres.

For general, and not product-specific conditions regarding quality of EDIPTEX data, see chapter 4.

The first aspect of data quality is not deemed to have a significant impact on the results statement, as:

• Elastane only makes up 5 per cent of the total weight of the blouse.
• There is no knowledge of elastane giving rise to emissions of more problematic chemicals than those in other synthetic fibres (for which there is data).

On the other hand, there is no doubt that the lack of data for human toxicity, ecotoxicity and persistent toxicity for carbon disulphide could be significant for the overall toxicological environmental profile of the product. Relatively large amounts are used and emitted in the manufacture of viscose.

Because of the lack of data it is difficult to draw any definite parallels to case group I in the scenarios (T-shirt, jogging suit and work jacket).

The only relatively certain standard of reference is the environmental profile for consumption of primary energy. This is very different from the corresponding aspects of case group I products. Energy consumption in the manufacture of fibres is by far the most significant. Compared with the corresponding figures for the main scenarios for case group I products, it is apparent that although fibre manufacture is also very important here, the use phase (washing, drying and ironing) has an even greater significance.

The message to a producer wanting to improve the environmental profile of the blouse is therefore clear: work with reuse of the fibre material - primarily viscose.

Introduction

Lifecycle assessment is a method for identification and evaluation of environmental impact potentials of a product or a service from cradle to grave. This method enables the user to make an environmental assessment and focus on the most important environmental impacts.

Lifecycle assessment is an iterative process. The first definition of purpose and delimitations often need to be revised during work with lifecycle assessment. The amount of data available sets limits, and consequently the limits of the system are changed.

The method used in this case for assessment of products is "Environmental Design of Industrial Products" (EDIP) and the associated database and PC tool.

In the EDIPTEX project, sector-specific data have been prepared for the textiles sector in connection with the existing EDIP database. The reports contain environmental assessments for the following textile products:

• A T-shirt of 100 % cotton
• A jogging suit of nylon microfibres with cotton lining
• A work jacket of 65 per cent polyester and 35 per cent cotton
• A blouse of viscose, nylon and elastane
• A tablecloth of cotton
• A floor covering of nylon and polypropylene.

These environmental assessments are intended to illustrate the scope for application of the EDIPTEX database by using the PC modelling tool and, at a more general level, application of the EDIP method.

Method

The six case stories vary a lot in scope. They can be divided into two main groups - with variations within these two main groups. The two main groups are:

• Group I: The T-shirt, the jogging suit and the work jacket.
• Group II: The floor covering, the tablecloth and the blouse.

The division into groups I and II relates to the scope of the collection of data as well as the quality of data.

For group I, it was possible to collect (and process) data for all significant processes. The data are of such quality that these three products have been selected to illustrate how far it is possible to take lifecycle assessment for textiles and to illustrate all relevant aspects of the EDIP method.

Each of the three group I cases contains:

• Definition of functional unit and reference product
• Modelling of main scenario
• Preparation of producer and consumer references
• Simulation of environmental impacts caused by choices made by producer and
• consumer respectively.

Work with these cases has been divided into phases as illustrated in figure 4.1.

Figure 4.1 EDIPTEX case group I flow diagram

For group II, it was not possible to complete all sub-processes. Although only 1-2 sub-processes for each product have considerable lack of data, these processes are deemed potentially significant for the overall lifecycle assessment. The group II case stories are therefore of an entirely different character than those of group I. The group II cases illustrate that it is possible to tell an interesting and exciting "environment story" based on lifecycle assessment (and EDIP) even though it has not been possible to analyse all aspects of lifecycle assessment data. This situation will arise very often in lifecycle assessment work. However, there is a significant difference in this EDIPTEX connection; it is possible to draw on results from the three lifecycle assessments from case group I (and this has been done), which improves the quality of the case stories.

Comments to the method

Product references

The "what-if" simulations were carried out to elucidate the consequences of possible changes in the product's lifecycle. A special product reference has been defined for the producer scenarios in some of the case stories. The producer only has limited influence on the use phase. In order to take this into account, a product reference has been prepared for the producer scenarios where only a limited part of the impacts from the use phase has been included in relation to the product reference from the main scenario. This was done in order to give producers a clearer picture of the influence of the production phase on the product's environmental profile in the "what-if" producer scenarios.

Data

With regard to data, it should be noted that the validity of the data in the database varies, depending on the processes considered.

This difference has not been taken directly into account in the EDIPTEX database, but a representative level for the data has been defined. Therefore, the data are very general and not necessarily representative for all lifecycle assessments. Some processes are more exact, such as extraction of crude oil for nylon (nylon is contained in the blouse). This process is well documented, both as regards industrial accidents and as regards resource consumption.

Production data primarily come from Danish enterprises. The number of enterprises involved represents limitations in this connection. For example, only one reactive dye has been studied thoroughly (the dye for the viscose part of the blouse). This substance represents the entire group of dyes, despite the major differences that may occur.

A large proportion of the environmental impacts come from the consumption of electricity. The data currently used in the database originate from the EDIP database, and the reference year is 1990. This area is being studied in order to update this part of the database. It is important to note that this lifecycle assessment was carried out using the 1990 data in all processes that consume electrical energy.

This product is different in that data for the manufacture of elastane fibres were not available. However the model does include a process for elastane in which EDIP data is used for the process of manufacturing polyurethane (flexible foam).

Elastane is composed of 85 per cent polyurethane. Furthermore, within the project budget it has not been possible to calculate equivalency factors for carbon disulphide, which is used in the manufacture of viscose fibres. These aspects of data quality mean that focus for this case is on primary energy and environmental impacts for the main scenario. The significance of the lack of data for the statement of results for the main scenario is discussed. Moreover relevant parallels have been drawn with the scenarios in the three group I cases.

The blouse

Product description: the blouse is composed of 70 per cent viscose, 25 per cent nylon and 5 per cent elastane. The assessment does not include multicoloured patterns or prints on the product.

Functional unit

The performance assessed can be described as a "functional unit", comprising a qualitative and a quantitative description, including the product's lifetime. The qualitative description is to define the quality level for the performance, so that products can be compared at a somewhat uniform quality level. The quantitative description is to determine the size and duration of the performance.

In this project, the functional unit is defined as:

"25 days' use of blouse over the course of one year"

Maintenance is assumed to be a wash at 40°C. It is assumed that 25 days correspond to the number of days a consumer wears the blouse over the course of 1 year. Some consumers have an entirely different consumption of blouses. Some almost never wear a blouse, while others often change blouse according to fashion. Therefore the blouse may be discarded because of a change in fashion long before it wears out.

Reference product and main scenario

The reference product is a product that meets the criteria of one functional unit. The project uses a coloured blouse of viscose, nylon, and elastane.

The calculations are carried out for "1 blouse", these need to be converted in relation to lifetime, and the calculations need to be converted to "per year".

It is assumed that the blouse can be washed 25 times before it is discarded.

It is assumed that the consumer wears the blouse 25 days per year.

It is assumed that the blouse is used 1 day and is then washed.

If the blouse is washed after each use, 25 days' use of the blouse means that 1 blouse is completely used up in one year - or more likely - that a person has 5 blouses that together last 5 years.

The following assumptions apply to the assessment and are thus included in the modelling of the main scenario.

Assumptions for the assessment

• The blouse is knitted from 70 per cent viscose, 25 per cent nylon and 5 per cent elastane.
• Viscose is dyed with reactive dyes.
• Nylon is dyed with acid dyes.
• Elastane is dyed like nylon.
• Washing 40°C.
• Drip drying on a clothesline.
• Ironing not necessary.
• Lifetime: 25 washes.
• Weight: For this environmental assessment, the assumption is that the blouse weighs 200 g and 125 g per m².

A more detailed description of the processes, calculations of volumes, waste, etc. can be found in the section "Background data".

Product system

Figure 4.2 Lifecycle, flow and phases

In the following, all phases of the blouse's lifecycle will be described from extraction of raw materials through production to the making-up of the finished blouse.

Manufacture of raw materials

Viscose fibres, which comprise 70 per cent of the weight of the blouse, belong to the group of regenerated fibres. Regenerated fibres are made on the basis of natural chemical compounds - for viscose (and for many other types of fibre such as lyocell and acetate) this is cellulose. Cellulose can be recovered from wood, cotton waste, and similar parts of plants with high cellulose content.

Nylon, which comprises 25 per cent of the weight of the blouse, and elastane, which comprises 5 per cent, are in the group of synthetic fibres and are produced on the basis of crude oil and natural gas, which are converted into plastic through a number of chemical processes. The raw material is a limited resource, and production may lead to impacts on humans and the environment at local, regional and global levels. During processing of the materials into fibres, lubricants are usually added in the form of spindle oil and antistatic agents. Bactericides and fungicides may be added.

Data for the manufacture of elastane fibre have not been available. However, the model includes a process for elastane in which EDIP data for the process to manufacture polyurethane (flexible foam) is used. Elastane is composed of 85 per cent polyurethane. Furthermore, within the framework of the project it has not been possible to calculate an equivalency factor for carbon disulphide, which is used in the manufacture of viscose fibres.

Production of the blouse

Production is divided into several sub-processes: yarn manufacturing, knitting, pre-treatment, dyeing, finishing, making-up and distribution.

Yarn manufacturing

As the blouse is made exclusively from artificial fibres, an actual yarn manufacturing process is not always necessary, as it is to manufacture textiles such as cotton, for example. The model assumes that the yarn is obtained directly from the fibre producer and goes straight to the knitting process.

Distribution

The blouse is packed in polyester bags and then on a wood pallet. Finally, it is distributed to retail suppliers throughout Denmark.

Use phase

The consumption of washing agents and fabric softeners and the consequential discharge of detergents and nutrient salts lead to possible local and regional impacts in the aquatic environment.

Transport

The mode of transport when the blouse is transported from the shop to the buyer's home is also important in connection with the overall environmental profile of the product. Options like driving a car, using public transport or a bike make a significant difference in this part of the product's lifecycle.

The disposal phase

Textiles may not be landfilled. On final disposal, they must be incinerated so that the energy content is recovered and replaces non-renewable energy sources like oil and natural gas. In some situations, the used blouse will be reused in a third-world country. In such situations, it is not possible to recover energy by incineration in Denmark.

Main scenario - results

The problem with quality of data already mentioned means that there is some reservation regarding the results in the two paragraphs below. The comments to the figures are neutral, i.e. the comments are on the basis of what can be read from the figures, as they appear. The subsequent section (What-if) discusses the significance of the lack of data for the statement of results.

The results of the main scenario are presented according to processes. The negative contributions that occur in some processes are due to estimated reuse potentials and contribution to environmental impact potentials. In the processes in question, the contributions can be allocated to other products and thus appear as negative contributions in the blouse's environmental profile.

The values in the four figures are not immediately comparable, as the unit is not the same for the four categories. The consumption of primary energy is calculated in mega-joules (MJ). The environmental impact potentials are presented as "milli-person equivalents" and are directly comparable. Milli-person equivalents are calculated as the direct impact for the year 2000. The weighting factors are based on global (w) or Danish (DK) discharges in the year 2000.

Consumption of primary energy

The consumption of primary energy reflects the processes that require a lot of electrical energy or heating air or water.

Figure 4.3 (consumption of primary energy per functional unit) shows that manufacture of fibre is primarily responsible for large energy consumption because energy consumption in the industrial manufacture of artificial fibres is so large. Manufacture of viscose fibres is especially significant. Primarily because it makes up 70 per cent of the total weight of the blouse. But also because the calculations using the original EDIP data show that 196 MJ primary energy must be used per kg viscose fibres; a factor approx. two-times larger than, e.g. polyester fibre. The figure is about 30 per cent larger than stated in several places in the literature. EDIP control calculations show that there are primarily inconsistencies in aspects related to the energy content in wood (the basic material for manufacturing viscose). The conclusion to the control calculations is that the correct figure is 196 MJ/kg.

In the use phase, the electricity consumption for washing causes the impacts. When the T-shirt is incinerated in an incineration plant, some energy is recovered and this is credited in the energy accounts.

Figure 4.3 Consumption of primary energy per functional unit – for translation of Danish terms see glossary in annex 11

Environmental impact potentials

Figure 4.4 (Toxicological environmental impact potentials per functional unit), figure 4.5 (Environmental impacts related to energy per functional unit) and figure 4.6 (Environmental impacts, waste per functional unit) show that the contributions to the environmental impact potentials primarily originate from the fibre-manufacturing and washing processes.

In the use phase, primarily detergents in washing agents result in potential persistent toxicity. It has been assumed that no users add fabric softener when washing, and therefore the figures probably do not tally with the actual conditions in private Danish households.

Click here to see the Figure.

Figure 4.4 Toxicological environmental impact potentials per functional unit – for translation of Danish terms see glossary in annex 11

Click here to see the Figure.

Figure 4.5 Environmental impacts related to energy per functional unit – for translation of Danish terms see glossary in annex 11

The environmental impact potentials related to energy are primarily due to burning fossil fuels.

Click here to see the Figure.

Figure 4.6 Environmental impacts, waste per functional unit – for translation of Danish terms see glossary in annex 11

The contributions to the waste categories shown in the figure originate primarily from generation of electricity. They are relatively limited in size compared with the above impact categories.

What-if discussion

This section will discuss the significance of the lack of data for the statement of results for the main scenario. Furthermore relevant parallels will be drawn to scenarios in the three group I cases (see the section on Method).

The significance of lack of data for the statement of results

As mentioned above, data for manufacture of elastane fibres have not been available and equivalency factors for carbon disulphide have not been included.

As elastane only makes up 5 per cent of the total weight of the blouse and as there is no knowledge of elastane manufacture causing emissions of especially problematic chemicals compared with other synthetic fibres, it is deemed that this has no significant impact on the statement of results.

As all other relevant energy data have been included in the model, it is deemed that the lack of data has no significance for the appearance of figure 4.3 - consumption of primary energy.

The same applies for figures 4.4 and 4.5, which for EDIPTEX primarily relate to environmental impacts resulting from consumption of energy.

On the other hand there is no doubt that the lack of data for human toxicity, ecotoxicity, and persistent toxicity of carbon disulphide can be relevant for the appearance of figure 4.6. It is used and emitted in relatively large quantities in the manufacture of viscose.

Parallels to case group I scenarios

Because of the lack of data, it is difficult to draw definite parallels to case group I scenarios (T-shirt, jogging suit, and work jacket).

The only relatively certain standard of reference is the appearance of figure 4.3 - consumption of primary energy. This is very different from the corresponding aspects of case group I products. Energy consumption in the manufacture of fibres is by far the most significant. Compared with the corresponding figures for the main scenarios for case group I products, it is apparent that although fibre manufacture is also very important here, the use phase (washing, drying and ironing) has an even greater significance.

The message to a producer wanting to improve the environmental profile of the blouse is therefore clear: work with reuse of the fibre material - primarily viscose.

Background data

System structure in the EDIPTEX database for the blouse

The figures in column on the right of the table refer to the ID numbers used in the original EDIP PC tool.

Details of the blouse model in the EDIPTEX database

Assumptions:

• The blouse is knitted from 70 per cent viscose, 25 per cent nylon and 5 per cent elastane.
• Viscose is dyed with reactive dyes.
• Nylon is dyed with acid dyes.
• Elastane is dyed like nylon.
• Washing 40°C.
• Drip drying on a clothesline.
• Ironing not necessary.
• Lifetime: 25 washes.
• Weight: For this environmental assessment, the assumption is that the blouse weighs 200 g and 125 g per m².

Functional unit

For the blouse, the functional unit is defined as:

"25 days' use of blouse over the course of one year"

Maintenance is assumed to be a wash at 40°C. It is assumed that 25 days correspond to the number of days a consumer wears the blouse over the course of 1 year. Some consumers have an entirely different consumption of blouses. Some almost never wear a blouse, while others often change blouse according to fashion. Therefore the blouse may be discarded because of a change in fashion long before it wears out.

The calculations are carried out for "1 blouse", this needs to be converted in relation to lifetime, and the calculations need to be converted to "per year".

It is assumed that the blouse can be washed 25 times before it is discarded.

It is assumed that the consumer wears the blouse 25 days per year.

It is assumed that the blouse is used 1 day and is then washed.

If the blouse is washed after each use, 25 days' use of the blouse means that 1 blouse is completely used up in one year - or more likely - that a person has 5 blouses that together last 5 years.

Disposal:

It is assumed that the blouse is sold in Denmark and disposed of through waste incineration. This means approx. 140 g viscose, 50 g nylon and 10 g elastane must be incinerated.

Household wash:

It is assumed that the blouse can be washed 25 times in its lifetime. This means that 0.2 kg * 25 = 5 kg must be washed in the lifetime of the blouse. I.e. viscose: 0.14 kg * 25 = 3.5 kg + nylon and elastane (synthetic) : 0.06 kg * 25 = 1.5 kg, washed at 40°C normal without prewash.

Drying:

It is assumed that the blouse is dried on a clothesline. This is also 5 kg.

Packing the blouse:

It is assumed that the blouse is packed in a thin plastic bag. It is assumed the bag weighs 10 g.

Laying out, cutting and sewing the blouse:

There is no company data for a blouse. A new process has been set up: "Blouse - Laying out, cutting and sewing the blouse. TX28-1-04". The process is calculated "per blouse". It is assumed that energy consumption is the same as for a tablecloth (for which there is company data).

According to Laursen et al. 1997, waste is 6-25 per cent. For a blouse it is assumed that waste is 10 per cent as a blouse is one of the simplest garments for cutting and sewing. This means 0.20 kg / (1-0.1) = 0.222 kg textile must be used. It is assumed that the waste is discarded (incinerated at a waste incineration plant).

Fabric - inspection and rolling onto a cardboard roll

There is no company data for knitted fabric for a blouse. It is assumed that data is the same as for woven fabric for a tablecloth. Therefore process no. TX27-3-08-06 is used. Amount: see previous process: 0.222 kg approved textile after the fabric inspection. It is assumed there is no significant waste from this process.

Therefore 0.222 kg textile must be produced (dried and fixed).

Drying, final fixing and setting square-metre weight:

As mentioned above, 0.222 kg textile must be used per blouse. This corresponds to 1.8 m² textile (dried and fixed) per blouse weighing 125 g per m².

It is assumed there is no significant waste from this process. This means 0.222 kg dyed textile must be used.

Dyeing viscose/nylon/elastane textile:

0.222 kg is used by this process per blouse. There is no waste in the process.

Pre-treatment of synthetic woven fabric:

Only washing. No bleaching. It is assumed there is no significant waste from this process. Therefore 0.222 kg is used by this process per blouse.

Knitting:

0.222 kg textile must be knitted per blouse.

1.015 kg yarn is used per kg circular-knitted textile. Therefore 0.225 kg yarn must be used per blouse. The waste is disposed of via incineration.

Viscose fibres

0.225 * 0.70 kg (the blouse is composed of 70% viscose) is used in this process (per 0.158 kg). Note that unlike cotton there is no yarn manufacturing, as filament yarns are used and they come directly from the fibre producer.

Polyamide 6.6 fibre (nylon)

0.225 * 0.25 kg (the blouse is 25 per cent nylon) is used in this process (per 0.056 kg). Note that unlike cotton there is no yarn manufacturing, as filament yarns are used and they come directly from the fibre producer.

Elastane fibres

0.225 * 0.05 kg (the blouse is 5 per cent elastane) is used in this process (per 0.011 kg). Note that unlike cotton there is no yarn manufacturing, as filament yarns are used and they come directly from the fibre producer.

Transport

All transport distances are estimated. See table below.

* Consumer transport: It is assumed that the consumer drives in town by car to buy 1 blouse and 5.8 kg other goods. It is assumed the consumer drives 10 km and the car goes 12 km per litre. This means 0.83 l petrol is used (= 0.61 kg petrol, as petrol weighs 0.73 kg per litre). Of this, 0.61 * 0.2/6 is allocated to the blouse, i.e. 0.02 kg petrol.

Lorry, total: 701.4 kg km (assumed 33 per cent urban, 33 per cent out-of-town, 33 per cent motorway). I.e. total transport:

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Version 1.0 July 2007, © Danish Environmental Protection Agency