Life cycle assessment (LCA) of adhesives used in ...

Life cycle assessment (LCA) of adhesives used in wood constructions

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Master Thesis Ecological System Design Prof. Dr. Stefanie Hellweg Institute of Ecological System Design ETH Zürich Annika Messmer May 2015

Supervisor:

Abhishek Chaudhary

Acknowledgement I would particularly like to thank Abhishek Chaudhary and Prof. Dr. Stefanie Hellweg for the supervision of my master’s thesis. Further I would like to thank Dr. Joseph Gabriel from Purbond for his support on the topic of PUR adhesive production, Dr. Ari Setyan from the EMPA and Prof. Dr. Jing Wang for their high commitment on the part of the emission measurement as well as the two companies where I could kindly measure the emission during application of the adhesive. Finally I thank everyone else who was involved in different ways in the success of this study.

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Abstract The demand for wood construction has increased in recent years, and two main reasons are responsible for that: on one hand, the increasing awareness of environmental issues such as fossil depletion and climate change, and on the other hand, the support of adhesive technologies that enable wood to be used for new and demanding construction tasks. A very promising and new application of wood in construction is cross laminated timber (CLT). However, the environmental performance of wood as the only known renewable and sustainable construction material is impacted from the use of synthetic adhesives. Recent studies have already highlighted adhesives as a hotspot of the environmental performance of composite wood products. Traditional formaldehyde-based adhesives, such as melamine urea formaldehyde (MUF), phenol formaldehyde (PF) and phenol resorcinol formaldehyde (PRF), were used for wood construction. Today, new formaldehyde-free adhesives such as polyurethane (PUR) are also available for the production of wood construction. Polyurethane has two benefits. First, there is the environmental performance, i.e. the replacement of formaldehyde, which is suspected to have a negative impact on human health; and second, a lower amount of PUR adhesive is required for the production of CLT. Therefore, PUR adhesive is suspected to have lower environmental impacts compared to the traditional adhesives. At present, however, no study comparing the environmental impacts of wood adhesives used in wood construction is available. Hence, the object of this study was to compare the environmental impact of the different adhesives using the methodology of life-cycle assessment and ReCiPe. Data for the production of MUF, PF and PRF adhesives was collected from different sources in the literature, and the data for PUR was provided by a company in Switzerland. The emissions in two different companies were measured to observe the impact and the occupational risk from the application of the adhesives in a glue laminated timber manufactory. To complete the life-cycle assessment, the impacts from the adhesive during the use phase and final disposal were also assessed using data and models taken from the existing literature. For the production of CLT, PUR has the lowest environmental impact. This is mainly because a low amount of adhesive and no additional hardener is required. However, the endpoint result of the ReCiPe method includes a subjective weighing which has a high influence on the result. In addition no uncertainty analysis was performed as some of the data was aggregated and the differences between most of the adhesives are too small to be significant. For all adhesives the production of raw material has the highest impact on the endpoint result of the ReCiPe method. During the application, no high emissions were measured and none of the substances exceeded the threshold of the maximum workplace concentration (MAK). But still the calculated impact on human toxicity with the Usetox method resulted for MUF in higher impacts for the application than for the production. For all adhesives higher impacts on human toxicity were observed for the use phase then for their production and also the impact from the final disposal determined with the LCA4AFR tool was lower compared to the production of the adhesives. According to the findings of the life-cycle assessment with the ReCiPe method and in order to reduce the impact of adhesives used in wood construction, a possibility would be to focus on the raw materials. There are several different options: one would be to substitute the synthetic raw materials with renewable materials such as lignin, tannin, cashew nutshell liquid and castor oil. These materials have already been tested for composite wood products, but have not yet been tried for wood constructions.

Master’s Thesis FS 2015

Annika Messmer

Contents 1 Introduction

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2 Wood Adhesive and Engineered Wood Products: Literature Review 2.1 Wood Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Engineered Wood Products (EWP) . . . . . . . . . . . . . . . . . . . . . . 2.3 Environmental Impact of Adhesive used in Engineered Wood Products . .

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3 Research Objective 4 Method 4.1 Life Cycle Assessment of Adhesive Production . . . . . . . . . 4.2 Risk Assessment of Occupational Exposure in Glulam Factory 4.3 Assessment of the Use Phase . . . . . . . . . . . . . . . . . . 4.4 Assessment of Final Waste Disposal . . . . . . . . . . . . . .

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5 Results and Interpretation 5.1 The Impact Assessment of the Production of 1kg Adhesive with a solids content of 100% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Result of the second Impact Assessment for the Production of Adhesive and Hardener in Relation to their Use in CLT Production . . . . . . . . . 5.3 Result of Occupational Risk Assessment and Environmental Impacts of the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 The Result of the Environmental Impact Assessment of the Use Phase . . 5.5 The Result of the Environmental Impact Assessment of Final Disposal . .

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6 Discussion 37 6.1 Environmental performance of PUR compared to formaldehyde-based adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 6.2 Potential to Improve the Environmental Performance of Wood Adhesives . 41 6.3 The limitation of the validity of this LCA . . . . . . . . . . . . . . . . . . 41 7 Conclusion

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8 Appendix

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List of Figures Figure 1: Figure 2: Figure 3: Figure Figure Figure Figure Figure Figure

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Figure 10: Figure 11: Figure 12: Figure 13: Figure 14: Figure Figure Figure Figure Figure Figure Figure Figure

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Figure 23: Figure 24: Figure 25:

Wood use in the past, present and future (Sathre & Gustavsson, 2009) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Global market share of different wood adhesives (Transparency market research, 2014) . . . . . . . . . . . . . . . . . . . . . . . . 2 The global glulam consumption in the recent years (UNECE FAO, 2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 The structure of cross laminated timber (Karacabeyli et al. , 2013) 7 The cradle to gate system boundary of the first assessment . . . . 14 The cradle to gate system boundary of the second assessment . . 14 The sketch of the production process in company A . . . . . . . . 20 The sketch of the production process in company B . . . . . . . . 20 The result of the first assessment of the adhesive production for the three endpoint categories . . . . . . . . . . . . . . . . . . . . 25 The endpoint result per impact categories of the first assessment of the adhesive production for all datasets . . . . . . . . . . . . . 25 The midpoint result of the first assessment of the adhesive production for all datasets . . . . . . . . . . . . . . . . . . . . . . . . 26 The LCA endpoint result for adhesive and hardener used in the production of CLT differentiated by midpoint indicators of the ReCiPe methodology. . . . . . . . . . . . . . . . . . . . . . . . . . 32 The impact of the production of 1kg of the different raw materialsXIII The impact of the production of 1MJ with the different production mixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .XIII Midpoint result of MUF Brazil . . . . . . . . . . . . . . . . . . . . XIV Midpoint result of MUF Wilson . . . . . . . . . . . . . . . . . . . XIV Midpoint result of PF Wilson . . . . . . . . . . . . . . . . . . . . XV Midpoint result of PF Ecoinvent . . . . . . . . . . . . . . . . . . . XV Midpoint result of PRF Wilson . . . . . . . . . . . . . . . . . . . XVI Midpoint result of PUR Wilson . . . . . . . . . . . . . . . . . . . XVI Midpoint result of the second assessment . . . . . . . . . . . . . X . VII The sensitivity of the impact from final disposal on the C-content of the adhesive . . . . . . . . . . . . . . . . . . . . . . . . . . . . X . XX The LCA of CLT production with MUF adhesive . . . . . . . . XXXI . The LCA of CLT production with PRF adhesive . . . . . . . . . XXXI . The LCA of CLT production with PUR adhesive . . . . . . . . . XXXI .

Index of Abbreviations

MUF

Melamine urea formaldehyde

PF

Phenol formaldehyde

PRF

Phenol resorcinol formaldehyde

PUR

Polyurethane

UF

Urea formaldehyde

EWP

Engineered wood products

glulam Glued laminated timber CLT

Cross Laminated Timber

MDI

Methylene diphenyl diisocyanate

VOC

Volatile organic compounds

ISO

International organization of standardization

LCA

Life cycle assessment

LCI

Life cycle inventory

DALY Disability-adjusted life years MAK

Maximal work place concentration

TVA

Technische Verordnung für Abfallbehandlung

DNPH 2,4-dinitrophenylhydrazine

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1 Introduction

1 Introduction Wood construction has been undergoing a revival in recent years. During the technological development of the nineteenth century wood lost its pioneering role and modern construction materials like concrete and steel became more important (Glos et al. , 2008). The building industry has a large environmental impact due to the extensive use of natural resources and the huge energy demand. Today the building sector accounts for about 42% of energy use and produces 35% of the total greenhouse gas emissions in Europe(EC, 2007). The increasing awareness of policy makers and society about the depletion of natural resources and climate change has heavily influenced the building sector over the last two decades, and the demand for sustainable and renewable building materials has increased (Glos et al. , 2008). Wood, the only known renewable building material, has therefore gained importance and furthered the development of new adhesives technologies (Figure 1).

Figure 1: Wood use in the past, present and future (Sathre & Gustavsson, 2009) In the past, wood properties strongly depended on tree species, climate zone of origin and the individual trees. Today it is possible to produce engineered wood products of more predictable performance and homogeneity thanks to new adhesive technologies. Therefore, wood can be used for completely new applications and more demanding construction tasks (Pacheco-Torgal et al. , 2014). Traditionally, thermosetting adhesives based on formaldehyde, such as amino-formaldehyde adhesives (melamine urea formaldehyde (MUF) and phenolic adhesive (phenol formaldehyde (PF) or phenol resorcinol formaldehyde (PRF)), are used in wood construction. These synthetic adhesives have the advantage that they provide strength, durability and enhance the use of wood for construction (Pacheco-Torgal et al. , 2014). The high formaldehyde emissions from the wood products engineered in the early stage and the health impact on people exposed to the formaldehyde discredited the traditional adhesives in the 1960s. As a result, the industry was forced to lower the formaldehyde content of the traditional adhesives, and new formaldehyde-free adhesives have been developed (Marutzky, 2003) in recent years. Polyurethane (PUR) is a formaldehyde-free adhesive approved for application in wood constructions. Polyurethane uses methyl-diphenyl-diisocyanate as a binding agent instead of formaldehyde (Gabriel, 2015). Compared to the traditional adhesives, a lower amount of adhesive is required to be applied in wood constructions for PUR, and no additional hardener is necessary. Due to the lower amount of adhesive and the elimination of formaldehyde, PUR adhesive is expected to cause less environmental damage than


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1 Introduction

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traditional adhesives (Gabriel, 2015). But there are today still no studies available about a direct comparison of the environmental performance of the several adhesives used in wood construction. The relevance of the environmental performance of wood adhesive is also ensured by the fact that according to Pizzi & Mittal (2011) more than two-thirds of all wood products used across the world are today either totally or partly bonded using a variety of wood adhesives. The global consumption of adhesives used for overall woodworking was almost 2 million tons in 2014 (including furniture, building products and other applications), and the consumption of wood adhesives is expected to increase in the future (Transparency market research, 2014). The present global market share of PUR (Figure 1) is still small compared to traditional adhesives (Transparency market research, 2014). However, newly engineered wood products, such as cross-laminated timber (CLT), are mainly produced with PUR adhesive. Therefore, the market share of PUR is expected to increase until 2020 due to the predicted rise in the demand for engineered wood products (Committee on Forests and the Forest Industry, 2015).

Figure 2: Global market share of different wood adhesives (Transparency market research, 2014) The main goal of this thesis is to compare the environmental performance of the production, application, use phase and final deposition between the new formaldehyde-free PUR adhesive and the traditional formaldehyde-based wood adhesives.


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2 Wood Adhesive and Engineered Wood Products: Literature Review

2 Wood Adhesive and Engineered Wood Products: Literature Review Bonding wood dates back to the ancient Egyptians (3500 years before Christ), who already knew the art of veneering wood and used adhesives to attach decorations to wood (Skeist, 1990). They used adhesives of natural origin, mainly casein made of a protein isolated from milk (Nicholson, 1991). Casein was not the only adhesive used for bonding wood in this early stage of human history, other varieties made from animal blood or vegetable starch were also known. Synthetic adhesives were introduced just before the start of the Second World War (Eckelman, n.d.). Synthetic adhesives have the benefit being suitable for applications that are far to demanding for the natural adhesives. This explains why the use of synthetic adhesives has surpassed that of natural adhesives and why they have become indispensable for engineering tasks (Eckelman, n.d.). The use of engineered wood products (EWP) for diverse purposes involving structural elements began in 1980.

2.1 Wood Adhesives Today, wood adhesives can be broadly classified as either synthetic-based or based on natural material. 2.1.1 Natural Adhesives For long time natural adhesives were the only known adhesive for wood bonding. They were made of natural polymers from plants and animals, produced from animal blood, hide, casein, starch, soybean, dextrin and cellulose (American wood council, n.d.). The first commercial natural adhesive plant was founded 1690 in Holland. But casein was also produced in Switzerland and Germany in the early nineteenth century (Delmonte, 1947). The introduction of synthetic adhesives in the 1930s replaced natural based adhesives, since they can’t provide the necessary strength and durability required for the structurally engineered wood products of today. However, for non-structural applications, such as indoor furniture, etc., natural adhesives are still used and produced in small quantities (American wood council, n.d.). 2.1.2 Synthetic Adhesives Urea formaldehyde was the first synthetic adhesive to be introduced in the 1930s. This was the start of a successful and fast growing global industry (Keimel, 2003). In a few years, new synthetic adhesives for specific applications (not only wood bonding) were continuously developed and established adhesives improved. Today several different adhesives are available on the market for a range of very specific applications (Skeist, 1990). The synthetic adhesives can be classified into two types: thermoplastic and thermosetting. The two types differ in their chemical structure and response to heat (Nitthiyah, 2013).


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2.1.2.1 Thermoplastic Thermoplastic adhesives are adhesives of homogenized liquid whose aggregate state depends on the temperature. The process of curing and melting is reversible, which means it can be reheated to form a liquid after being cured for some time (Plastics Europe, 2015). The application range for thermoplastic adhesives is limited due to their chemical characteristics. They can only be used for non-structural applications in low temperature climate and they are not resistant to heat or fire. Thermoplastic adhesives are not used in wood construction, and therefore are of no relevance to this thesis. 2.1.2.2 Thermosetting Thermoplastic adhesives, by contrast, are cure irreversible. The curing process can be induced by heat (over 200 degrees), through chemical reaction or suitable irradiation. Adding energy or a catalyst cause the molecular chains to react at the chemical activity site. This process is called a cross-linking process, which results in a molecule of a larger molecular weight and with a higher melting point. Thermosetting adhesives are generally stronger than thermoplastic adhesives and better suited for high temperature applications (Zeppenfeld & Grunwald, 2005). For bonding wood constructions thermosetting adhesives are mainly used. Different thermosetting wood adhesives are available. These are presented in the following section. Urea Formaldehyde (UF) Urea-formaldehyde is a low-priced adhesive. It is mainly used for indoor applications. The characteristics of UF adhesive are fast hardening, high dry bond strength and colourless glue joints. UF adhesives can be hardened hot or cold, but for rapid hardening an additional hardener has to be applied. The glue joints of UF adhesive are high-strength, but brittle and inelastic. Therefore, tension in the wood, caused from changes in humidity and temperature, harm the glue joints and decrease the performance of the adhesive. UF adhesives are only applicable for indoor products. The ratio of formaldehyde and urea influences the strength of the glue joints and has to be between 0.9:1 and 1.3:1. The more formaldehyde the adhesive contains, the higher the content of reactive groups is and the better the performance. But with a higher amount of formaldehyde more emissions also given off from the adhesive during the application, hardening and use phase. The ideal molar ratio F:U is between 0.9:1 and 1.1:1 (Zeppenfeld & Grunwald, 2005). Melamine Urea Formaldehyde (MUF) Melamine urea formaldehyde is similar in composition to the UF adhesive, but melamine provides additional amino groups to the adhesive. MUF adhesive can be hardened hot or cold and the glue joints are colourless and light resistant. The additional melamine makes the glue joints of MUF more elastic than those of UF. Therefore, MUF glue joints have a greater resistance to humidity and moisture. But as melamine is expensive, the molar ration of melamine is kept as low as possible. Not yet hardened MUF glue joints contain free-formaldehyde, which can be emitted during the hardening process. But hardened glue joints are completely harmless. The process of cold hardening can be accelerated with ammonium-containing hardener. MUF adhesives are applied in large amounts in the engineered wood product industry (Zeppenfeld & Grunwald, 2005).


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Phenol Formaldehyde (PF) Phenol-formaldehyde is applied in a broad spectrum of engineered wood products. It is very strong and highly durable in dry and wet conditions and exhibits a very high adhesion to wood. Hardening can occur under both hot and cold applications. PF adhesives are mainly applied in moist and climate-resistant particle- or fiberboard, plywood, pressed laminated wood and glued laminated timber. PF is traditionally not used for cross-laminated timber production, but as the characteristics are similar to the other wood adhesives it is still included in this study. PF can be hardened hot without additional hardener. For the cold hardening process additional acid hardener is required, such as p-toluene sulphonic acid, aralkyl phosphoric acid, aralkyl-sulfonic acid, maleic anhydride, sulfuric acid or phosphoric acid. Depending on the manner of production, two types of PF adhesives can be produced: resole or novolac adhesive. Resole are produced by an alkaline condensation of phenol and formaldehyde, whereas novolac are produced by an acid condensation of phenol and formaldehyde. For the production of glued laminated timber (similar but not as strong as CLT) novolac PF is mostly used. Phenol adhesives are toxic, and skin contact should be avoided. Workers exposed to the adhesive have to wear gloves and skin protection. The content of free formaldehyde emitted from PF adhesive in engineered wood products is lower than that emitted by MUF and UF adhesives (Zeppenfeld & Grunwald, 2005). Phenol Resorcinol Formaldehyde (PRF) Phenol resorcinol formaldehyde is similar to PF adhesive, but contains an additional compound of resorcinol. Resorcinol increases the strength and the resistance of the glue joints in wet conditions. Therefore, PRF is mainly applied in outdoor wood constructions and in the surface gluing required for climate resistant joints. To achieve a fast curing process, additional hardener (paraformaldehyde) has to be used. PRF is toxic to the skin and dermatosis can’t be avoided after multiple skin contacts. Therefore, workers exposed to uncured adhesive have to wear protecting clothing. However, the cured adhesive is harmless (Zeppenfeld & Grunwald, 2005). Polyurethane (PUR) PUR is a formaldehyde-free adhesive used in engineered wood products mainly in crosslaminated timber. The curing process of PUR is induced by the moisture in the wood. The cured glue joints are moisture and hydrolysis resistant. During the process of curing, a low amount of CO2 is created and emitted. In place of formaldehyde, it contains isocyanate. Isocyanate can theoretically also be emitted into the indoor environment during the production and use phase of CLT (Zeppenfeld & Grunwald, 2005). The application specification and the price of each adhesive are summarized in Table 1. The environmental impacts associated with the adhesives, including a detailed description of formaldehyde and isocyanate, are presented later in this chapter.


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Table 1: Overview of the application and price of the different adhesives (Vick & Adherends, 1999; Gabriel, 2015)

Adhesive MUF PF PRF PUR

Application structural, limited exterior structural-/ non-structural, fully exterior structural, fully exterior structural, fully exterior

Price per kg (€/kg) 2.20 3.00

Price per kg 100% solids content (€/kg) 3.75 5.00

3.50 5.50

5.80 5.50

2.2 Engineered Wood Products (EWP) Engineered wood products are value-added wood products made by bonding lumber, veneers, strands or fibers together with glue. High performance products that are structurally stable and of unlimited sizes, can be produced. The demand for engineered wood products in the construction industry strongly depends on general construction activity, and therefore on the global economic situation. It has been observed that the demand for engineered wood products used in construction increased despite the downturn of the economy in the past few years, and it is expected to drastically increase in the near future. For example, the consumption of glued laminated timber (glulam) almost doubled in Europe in the last decade and reached a value of about 3 million m3 in 2012 (in the same year the global consumption was 5 million m3 ) (Manninen, 2014). The development of glulam consumption in Europe in recent years is shown in Figure 2.2.

Figure 3: The global glulam consumption in the recent years (UNECE FAO, 2013) The focus of this study however will be on a relatively new, engineered wood product used in construction called cross-laminated timber (CLT).


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Cross-Laminated Timber Cross-laminated timber is made of several layers of wood boards glued crosswise together (see Figure 2.2). The number of layers varies, but there have to be a minimum of three layers. This makes CLT to a very strong and stable material. The size of the produced CLT-panels is unlimited during the production, but transportability regulates it. The production of CLT was introduced in Germany and Austria in 1990, and the demand has increased significantly over the last few years. It can be used as substitute for concrete and steel construction (Manninen, 2014). The production of CLT in Europe in 2012 was 560’000m3 , whereof 65% was produced in Austria, and only 4% of the whole European production was produced in Switzerland (Kutnar, 2013).

Figure 4: The structure of cross laminated timber (Karacabeyli et al. , 2013)

2.3 Environmental Impact of Adhesive used in Engineered Wood Products Recent studies show that wood adhesive is an environmental hotspot of the lifecycle of composite wood products. Significant contributions to the following impact categories have been found: global warming, photochemical oxidant formation, acidification, eutrophication, toxicity (Pacheco-Torgal et al. , 2014; Silvaa et al. , 2013). For example, the production of the petroleum-based raw material for amino adhesives primarily effects fossil depletion, acidification, global warming, abiotic depletion and eutrophication. The formaldehyde emissions of the adhesive, on the other hand, have an impact on photochemical oxidation, ecotoxicity and human toxicity (Silvaa et al. , 2013). Similar impacts are also expected for all other synthetic wood adhesives. Raw Material Synthetic adhesives used for engineered wood production have a fossil feedstock mainly based on petroleum, and the production of the raw material requires a lot of energy, which is mainly produced from fossil fuels. Fossil fuels, and especially petroleum, are the most obvious and important example of a finite resource, which is being rapidly depleted (Leggett, 2006). Therefore, the adhesives used for the production of wood constructions have an impact on the depletion of finite resources. Emission The use of fossil feedstock is only one aspect of the environmental impact of wood adhesives. The other aspect that should be considered when assessing the environmental impact of wood adhesives are the emissions that occur during the application of the engineered wood production and the use phase of the wood product. These emissions


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have potential negative impacts on the indoor environment, and therefore pose a health risk for people being exposed to them in the workplace or at home (González-García et al. , 2011). The traditional wood adhesives contain formaldehyde, which can be partially emitted during the application and the early stage of the use phase of the wood product. The problem of formaldehyde emission from engineered wood products was identified in the 1960s. After the initial discovery, threshold values were introduced and the formaldehyde content of the adhesives was lowered (Gomez-Bueso & Haupt, 2010). Since the trend of constructing air-tight modern buildings began in recent years, the issue of formaldehyde emissions from wood products in the indoor environment has increased (Less et al. , 2015). But also emissions from the formaldehyde-free adhesive PUR would be possible. There the emissions of isocyanate are mainly supposed to have an impact on indoor air quality (Streil, 2006). Generally, the emissions from engineered wood products used in construction, such as CLT, are considered to be much lower than the emissions from wood composite products such as particle boards. For the production of engineered wood products used in construction, less adhesive is required and only a small amount of adhesive is located directly on the surface of the product. Therefore, for wood products used in construction, the emissions are expected to be greater during the manufacturing process than in the use phase (Barr et al. , 2010). In the following, the health impact and the threshold value of substances emitted from adhesives are described in detail. Volatile organic compounds (VOC) Volatile organic compounds are used as organic solvents in various products, such as paint, adhesives and varnish. They easily evaporate in the gas phase and, as air pollutants, have harmful effects on human health by contributing to respiratory illnesses. Some VOCs are also mutagenic or toxic to reproduction and harmful to the unborn (Environment et al. , 2013). The threshold limits for work place exposure to the individual VOC substances are defined by SUVA (2012). Formaldehyde Formaldehyde is a VOC, which is suspected to cause irritation to the eyes, nose and throat. It is characterized as a human carcinogen causing nose and throat cancer by the department of health and human services (ATSDR, 2015). The maximal concentration at workplaces (MAK) has ben defined by SUVA (2012) to have a threshold limit of 0.37mg/m3 . The amount of formaldehyde emissions emitted from wood adhesives (MUF, PF and PRF) depends on the adhesive type and molar ratio. For MUF, higher emissions were observed than for PRF and PF adhesives (Funch, 2002). Isocyanate Isocyanates are a family of highly reactive chemicals with low molecular weight. The most commonly used compounds are diisocyanates, such as MDI and HDI, which are also used in PUR adhesive. Direct contact with high isocyanate emissions can cause irritation of the respiratory track and eyes. Direct skin contact can cause marked inflammation, and there is evidence that both skin and respiratory exposure can lead to sensitization of the workers (CDC, 2014). The hazard of exposure is directly related to the volatility and molecular weight of the isocyanates. Diisocyanates have a higher molecular weight than other isocyanates, and their volatility, vapor pressure and toxicity is therefore much lower than other isocyanates (Sullivan & Krieger, 2001). The highly reactive NCO-group of the molecule is suspected to have an impact human health. In order to determine the air quality the total concentration of the NOC-group is measured. The defined maximal workplace concentration (MAK) for the total NCO-group is 0.02mg/m3 (SUVA, 2012).


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2.3.1 The Methodology of Life Cycle Assessment (LCA) in general The methodology used to assess the environmental impact of a given product is known as life-cycle-assessment. It includes the complete life-cycle of the product, i.e. the extraction and processing of raw material, the manufacturing of the product, all transportations and distribution measures, as well as the use and maintenance, recycling, reuse or final disposal of the product (Consoli, 1993). For the performance of an LCA the International Organisation of Standardization (ISO) provides guidelines within the series ISO 1404 and 14044. These guidelines describe the main steps of a LCA (Consultants, 2014) : Goal and Scope In this first step of a LCA, the intended use (goal) and scope have to be clarified. This includes: the definition of the functional unit and the system boundaries, a description of the system and the method used for the impact assessment, a description of the data and data quality requirements, as well as a description of all assumptions and limitations of the LCA. Inventory Analysis The second step of a LCA is to set up the life-cycle inventory (LCI) of the system. This includes the collection and calculations of the input/output data associated with the product. Therefore, all resources, emissions used and produced during the production and life cycle of a product are collected in an inventory. Impact Assessment In the impact assessment the emissions and resources collected in the life-cycle inventory are transformed into a limit number of impact categories. Different methods can be used to predict the potential environmental impact of a product or a process. Interpretation The interpretation of the results includes different checks to ensure that the conclusion and procedure used for the study are sufficiently supported by the data. Checks and analyses of uncertainty, sensitivity and contribution are recommended.


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3 Research Objective

3 Research Objective The objective of this master’s thesis is to compare the environmental impacts of four different wood adhesive types (melamine urea formaldehyde (MUF), phenol formaldehyde (PF), phenol resorcinol formaldehyde (PRF) and polyurethane (PUR)) used in wood construction by using the methodology of life-cycle assessment (LCA) and focusing on the following aspects: Quantifying the environmental impact of the adhesive production (cradle to gate) • The production of 1kg of adhesive with a solids content of 100% – Which adhesive production has the highest/lowest environmental impact? – To which impact categories do the impacts mainly belong? – Which process or input causes the most environmental impact? – How high are the environmental impacts in relation to the cost? • The production of adhesive and hardener used in cross-laminated timber production: – Which adhesive has the best environmental performance when producing 1m2 of cross-laminated timber with three layers and a thickness of 30cm? – How much does the performance of the adhesive change when considering the amount and hardener used and their specific solids content? – How high are the environmental impacts in relation to the cost? Quantifying the environmental impacts of the application in the engineered wood production – Risk-assessment: How high are the emissions of the different adhesives during the application? Are workers in a glulam factory exposed to a risk? – What is the environmental impact for each adhesive induced from the measured emissions? Quantify the environmental impact of the use phase – What emissions can be expected during the use phase of cross-laminated timber? – What are the environmental impacts of these emissions? – How much does the use phase contribute to the overall performance? Quantifying the environmental impact of the final disposal – What emissions occur during the final disposal? – What are the environmental impacts of these emissions? – How high is the environmental impact of the final disposal compared to the production and use phase?


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4 Method

4 Method As first step, a literature research for the life-cycle inventory data of the four adhesive types was performed. For PUR, the life-cycle data of the production were provided from a company in Switzerland. In a second step, the production process was modelled in SimaPro8 for each dataset, with consideration given to resources and emissions used and produced. The impact assessment of the production was performed in two steps based on the process models: First, the impact assessment was performed for the production of 1kg of adhesive with a solids content of 100% in order to observe the differences of the environmental impact between the adhesives and to find out which process or raw material contributes the most to the overall performance. Second, the amount of adhesive and hardener used to produce cross-laminated timber was taken into account and a second impact assessment was performed. The emissions (formaldehyde, VOC and isocyanate) were measured during application in two different companies to assess the environmental impact of the adhesive applied in the CLT factory and to assess the occupational risk for the workers. In oder to be comprehensive, the environment impact of the use phase and the final disposal were also considered by using emission data and models from the existing literature on the subject.

4.1 Life Cycle Assessment of Adhesive Production 4.1.1 Goal and Scope Definition Four different types of adhesives are used for cross laminated timber production. They have similar functionality, but different chemical compositions and methods of application. The goals of this assessment are to investigate the environmental impact of the production for each adhesive and to compare their environmental performance relative to each other. This is carried out in two steps: First: The production of 1kg of adhesive with a solids content of 100% is analysed to determine which process or raw material contributes the most to the overall performance of each adhesive. The environmental impacts of the different adhesives can be compared to each other. Second: In the second assessment, both differences in manner of the production and differences in the amount of adhesive and hardener used for the production of CLT are considered. Through this assessment, the impact of the hardener and the different amount of adhesive can be observed, and the adhesive with the lowest impact on the environmental performance of CLT can be identified. 4.1.1.1 Functional Unit The functional unit creates a reference level for inputs and output and also provides a way to compare the different adhesives. Different functional units are used for the two assessments: First: the production of 1kg of adhesive with a solids content of 100%. Second: the production of the amount of adhesive/hardener used in the production of 1m2 CLT with three layers and a thickness of 30cm.


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4.1.1.2 Description of the Production System The production process is similar for all adhesive types. The raw materials of the adhesive are mixed together in the factory using small amounts of electricity and heat. Both the production process and the raw material inputs are similar. All adhesives are based on petrochemicals produced from natural gas, crude oil or coal. Formaldehyde is a part of all adhesives, either as feedstock for the production of raw materials, or as a binding agent in the adhesive. Formaldehyde is mainly produced from the oxidation of methanol using Fe/Mo catalysts (Gayathri & Muthamilarasi, 2005). In the following, the production process of each adhesive type is described in detail. Production of Polyurethane The main raw material for the production of polyurethane adhesive is a binding agent based on 50% methylene-diphenyl-diisocyanate (MDI) and 50% polypropyleneglycol. During the manufacturing process, the binding agent is mixed in a reactor at ambient temperature with several small amounts of other additives (including HDI trimerisat, silica fume and polyglycol). Methylene-diphenyl-diisocyanate is produced in two steps: first, aniline and formaldehyde are made to react with hydrochloric acid as catalyst to a diamine-precursor. And second, the precursor forms together with phosgene MDI. Polypropylenglycol is produced through the polymerization of propylenoxide and ethylendiamine (Gabriel, 2015). Production of MUF For the production of MUF, melamine is mixed with UF adhesive. To produce urea, natural gas is reformed into ammonia in a steam reforming process at high temperatures and high pressure. Together with CO2 the produced ammonia is later reacted and urea is formed. Formaldehyde, as described above, is produced from the oxidation of methanol, which in turn, is produced through a catalytic reformation of natural gas. Melamine is produced from urea with a catalyst at high pressure and temperature. The by-products of the melamine production are CO2 and ammonia, which can be recycled (CMP, 2003). Production of PF The raw materials for PF adhesive are phenol and formaldehyde. The process of producing phenol is called the Hock process and includes several steps: in a first step, cumene is produced from benzene and propene (both produced from crude oil) at 600 K by means of pressure and an acid catalyst. In a second step, cumene is oxidized with air at a temperature of 350-390K and 1-7atm pressure to cumene-hydroperoxide, which is then in a third step, mixed with sulfuric acid at 313-373K to decompose and produce phenol and propane. Propane is the co-product of this process, with 6 tons of propane produced per 10 tons of phenol. (Zeppenfeld & Grunwald, 2005). Production of PRF For the production of PRF, adhesive resorcinol is mixed with phenol-formaldehyde resin. There are two main processes used to produce resorcinol. In the US the benzene-disulfonation process is still used, whereas in Japan a new process, called hydroperoxidation of meta-diisopropylbenzene (m-DIPB), is used. For this study, the newer process of hydroperoxidation of meta-diisopropylenbenzen is considered. The m-DIPB is produced with the Friedel-Crafts alkylation of benzene and propylene using a catalyst to attain a high purity of m-DIPB. In a second step, the m-DIPB are oxidized with air to dihydroperoxid (DHP) in a pressurized reactor and a catalyst at 80-120 degrees. The last step in the production of resorcinol is the cleavage of DHP, which is achieved using a strong acidic catalyst such as sulfuric acid, sulfur trioxide, phosphoric acid, hydrochloric aid, boron trifluoride, p-toluene sulfonic acid, acid clays or ion-exchange resins (Durairaj, 2005).


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Production of MUF Hardener The MUF hardener is produced from a mixture of raw materials consisting of: resorcinol, kaolin, formic acid, thickener and water. Resorcinol, benzene and propene are produced from crude oil (in a similar process to that described above). Kaolin is directly extracted from the earth. Formic acid is produced from sulphuric acid and sodium formate. And cellulose derivative is used as thickener. All the raw materials are mixed in the factory at ambient temperatures (CMP, 2003). Production of PF Hardener For PF adhesive maleic anhydride is used as a hardener. Maleic anhydride can be produced by two means. One is the partial oxidation of benzene, and the other is the oxidation of n-butanes. For both processes slightly elevated pressure, and temperatures between 350-450 degrees, are required. In the first method, benzene is mixed with compressed and heated air over a catalyst. In the second, superheated butane is fed into a reactor containing a catalyst. For both processes, the off-gas contains maleic anhydride. In Europe, 75% of the maleic anhydride production is produced using the first method and 20% by the second (Althaus et al. , 2007). Production of PRF Hardener The hardener for PRF adhesive is paraformaldehyde, which is a polymere formaldehyde (Zeppenfeld & Grunwald, 2005). Paraformaldehyde is produced through vacuum evaporation of an aqueous solution of formaldehyde (Naujoks & Fuchs, 1934). Production of Cross Laminated Timber The amount of adhesive used for the production of 1m2 CLT with 3 layers and a thickness of 30cm varies depending on the type of adhesive used for the bonding. In Table 2 the different amount of adhesive used in CLT, as well as their specific solids content, are listed. Table 2: The amount of adhesive used to produce 1m2 CLT with 3 layers and a thickness of 30 cm Adhesive

Amount (g/m2 CLT) 800 900 900 360

MUF PF PRF PUR

solids content (%) 65 45-55 55-60 100

source Kläusler (2014) Gabriel (2015) Kläusler (2014) Kim et al. (2013)

For MUF, PF and PRF adhesives additional hardener has to be used to accelerate the process of curing. PUR adhesive can be applied cold, without additional hardener. In Table 3, the amount of hardener and adhesive used for the production of 1m2 CLT with 3 layers and a thickness of 30 cm is listed for each adhesive. Table 3: The adhesive-hardener ratio used for CLT production Adhesive

Ratio

MUF PF PRF PUR

100:60 100:10 100:20 100: 0


Adhesive (g/m2 CLT) 500 810 750 360

Hardener (g/m2 CLT) 300 90 150 0

Source Holzbau (2014) Zeppenfeld & Grunwald (2005) Wang et al. (2014) Gabriel (2015)

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4.1.1.3 Description of the System Boundaries The system boundary for the assessment of the adhesive production is cradle to gate. The assessment considers not only the impacts of the adhesive production in the factory, but also all the impacts which are associated with the production of raw materials, including their extraction and production as well as their delivery to the factory. Not included in this assessment is the infrastructure of the factory and the labor involved, nor the packing, application, use phase and final disposal. During the production of adhesives no co-products are generated, and a black-box approach considering only in- and outflows was selected for modelling the production process. The system boundary for the second assessment of the production only includes the production of the amount of adhesive and hardener used to produce 1m2 CLT with three layers and a thickness of 30cm. Other resources used for CLT production, such as wood, electricity, heat, etc., as well as any on site emission involved in the production of CLT, are not included in this assessment. In Figure 5 and 6, the system boundaries of the two assessments are presented. The only differences between the two assessments concern the amount of adhesive and the presence or absence of hardener- theses are only considered for the second assessment.

Figure 5: The cradle to gate system boundary of the first assessment


Figure 6: The cradle to gate system boundary of the second assessment

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4.1.1.4 Data Quality and Assumptions Input data such as raw material, water use, energy use and output data such as emissions to the air, water and soil were collected for each adhesive. The LCI data were found in literature, with the exception of the LCI data on PUR, which was provided from a company in Switzerland. In Table 4, all the different datasets are listed together with their source: Table 4: The source of the datasets included in the life cycle assessment Adhesive name MUF Brazil MUF Casco MUF Wilson PF Wilson PF ecoinvent PRF Wilson PUR MUF hardener PRF hardener PF hardener

Location Brazil Sweden USA USA Europe USA Switzerland USA USA Europe

Source Silva et al. (2014) CMP (2003) Wilson (2010) Wilson (2010) Althaus et al. (2007) Wilson (2010) Gabriel (2015) NREL (2013) NREL (2013) Althaus et al. (2007)

In the following paragraphs the datasets are described in detail: Melamine Urea Formaldehyde (MUF) Three different datasets for MUF were found in literature. The datasets are taken from different places in the world: USA, Sweden and Brazil. A detailed description of each dataset follows: Melamine Urea Formaldehyde produced in Brazil (MUF Brazil) The data for the MUF produced in Brazil are taken from the environmental performance assessment of the melamine urea formaldehyde resin manufactory from Silva et al. (2014). He collected data of raw material, electricity and energy use and air emission in a factory in Brazil. The data for the soil and water emissions were taken from the inventory data of Wilson (2010). The data for the background flows were also collected from the literature: The data for the production of urea in Brazil are described in the study of Ribeiro (2009), and the data for the methanol production in Brazil has been taken from Camargo (2007). The data for Brazilian diesel were taken from Ecoinvent 2.2 (2010) and adapted according to the higher content of sulfur (500ppm), which leads to higher sulfur emissions (Brasil, 2009). The data for melamine, sodiumhydroxide, formic acid and water were taken from Ecoinvent 2.2 (2010), as well as the data for the electricity (Brazilian mix). For transport, typical values used in Ecoinvent 2.2 (2010) have been assumed. Melamine Urea Formaldehyde produced in Sweden (MUF Casco) This data is available from CMP (2003). The data is aggregated so that it can’t be assigned to any previous processes or products other than the production of MUF. The data from the raw materials have been taken from Ecoinvent 2.2 (2010), has all the emission and the transport data. The production of urea formaldehyde adhesive, melamine formaldehyde adhesive and formaldehyde takes place in the same factory in Sweden. Sodium hydroxide is also produced in Sweden, but in a different factory, and is therefore transported a


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short distance to the adhesive factory. The other raw material for the adhesive production is produced at different sites in Europe. Urea and methanol are transported in bulk transport by sea and melamine by truck in big bags. Melamine Urea Formaldehyde produced in US (MUF Wilson) In the life-cycleinventory of Wilson (2010), data for the MUF production such as raw material use, emission of the factory and energy use were collected at 6 different plants in the US. This inventory also considers the transport of the raw materials to the factory. The back ground data for the production of the raw materials such as urea, melamine, formic acid, sodium hydroxide, etc. were taken from the Ecoinvent 2.2 (2010) database. Phenol Formaldehyde (PF) For the production of phenol formaldehyde adhesive two datasets were found in literature one for the US and one for Europe. Phenol Formaldehyde produced in US (PF Wilson) The life cycle inventory data of phenol formaldehyde from Wilson (2010) were collected in 13 different plants in the US. The collected data contain information about the raw material and energy use and the emissions in the factory. Also the transport of the raw material is considered in the data. Again, the back-ground data for the production of the raw material were taken from the Ecoinvent 2.2 (2010) database. For the production of the electricity, the US mix from Ecoinvent 2.2 (2010) was chosen. Phenol Formaldehyde produced in Europe (PF Ecoinvent) This dataset is provided from Althaus et al. (2007), and considers the production of PF in Europe. The data, however, is not collected from any companies, but in stead generated and rough estimations. Therefore, this dataset does not represent a real production situation and is not recommended for the use in a comparative LCA. Nevertheless, this dataset is still included in the assessment to observe the difference between the two PF datasets. Phenol Resorcinol Formaldehyde (PRF) For phenol resorcinol formaldehyde only one dataset was found in the literature. Phenol resorcinol formaldehyde produced in US (PRF Wilson) The inventory data for PRF from Wilson (2010) has been collected in 8 different plants in the US. It contains information about the use of raw material, energy and electricity for the production of PRF in the factory as well as the transport of the raw material to the factory. The background data for the production of the raw materials was taken from the Ecoinvent 2.2 (2010) database. For resorcinol, no LCI data could be found, neither in the Ecoinvent 2.2 (2010) database nor in literature. As the research in literature on the production process of resorcinol shows, however, the hydroperoxidation process of meta-diisopropylenbenzen (first step to produce resorcinol) is quite similar to the production process of phenol (with the intermediate product cumene). So for resorcinol, the data of phenol production in Ecoinvent 2.2 (2010) was adapted for resorcinol production by doubling the input of cumene. Polyurethane (PUR) Polyurethane is the only adhesive included in this study that is not based on LCI data from literature, but rather based on data from a Swiss company producing PUR in Germany and Switzerland. The company provided data for raw material and energy use. The major raw material for the production of PUR is


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methylene-diphenyl-diisocaynate (MDI). Together with polypropyleneglycol (produced through polymerization of propyleneoxide and ethylenediamne), it reacts to the binding agent of the adhesive. The background data for the production of MDI is taken from the Ecoinvent 2.2 (2010) database. For polypropyleneglycol, no data could be found in the Ecoinvent 2.2 (2010) database, but LCI data for the polymerization of propylenoxide and ethylenediamine were reported in ISOPA (2012). The background data for propylene oxide and ethyelenediamien production were taken from the Ecoinvent 2.2 (2010) database. Aside from the MDI and propyleneglycol, small amounts of several other additives are also added. No reported lifecycle-inventory data could be found for these chemicals. To quantify the cumulative energy demand and the global warming potential based on the chemical structure for these adhesives, the tool Finechem (Wernet et al. , 2009) was used. Hardener for MUF, PF and PRF For the MUF and PRF hardener, data from the USLCI database (NREL, 2013) was used. The data of both datasets is aggregated so that the emissions and resources can’t be allocated to different background processes like resorcinol production or kaolin extraction. In the data, all the resources and the emissions for the production of the raw material, and all the emissions emitted from the production in the factory are included. Also included is the energy needed for both the production or extraction of raw materials, as well as the production of the hardener in the factory. The transportation of the raw materials to the hardener factory likewise considered in the data. Different hardeners can be used for the PF adhesive. For this assessment, maleic anhydride was selected, and the LCI data for its production were taken from the Ecoinvent 2.2 (2010) database. Summary of the assumptions Table 5 summarizes all the assumptions taken for the assessment of the adhesive production. Table 5: The list of all assumptions taken for the production assessment Dataset PRF Wilson PUR PF MUF Brazil

Assumption LCI data for resorcinol production adapted from phenol production process No emissions in adhesive factory Impact of the production of the additives calculated with the Finechem tool Typical transportation distances of raw material taken from Ecoinvent 2.2 (2010) Estimation of the adhesive and hardener amount used for the CLT production LCI data for diesel production adapted from Ecoinvent 2.2 (2010) with 500ppm sulphur

4.1.2 Inventory Analysis A short list of the input of raw materials for each dataset is presented in Table 6. The detailed inventories for all adhesives can be found in the Appendix (8). According to the differences of the raw materials, also the molar ratio of the adhesive varies between the datasets. Table 7 presents the molar ratios of the adhesives considered in this study.


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Table 6: Inventory of the raw materials of the different datasets

Melamine Urea Phenol Resorcinol Formaldehyde Polypropylene glycol MDI

MUF Brazil (kg/kg) 0.10 0.39

MUF Wilson (kg/kg) 0.08 0.39

0.16

0.26

MUF Casco (kg/kg)

PF Wilson (kg/kg)

PF Ecoinvent (kg/kg)

PRF Wilson (kg/kg)

0.24

0.95

0.17

0.151

0.28 0.19 0.09

PUR (kg/kg)

0.402 0.491

Table 7: The molar ratio of the adhesives Adhesive MUF Wilson MUF Brazil MUF Casco PF Wilson PF Ecoinvent PRF Wilson PUR

F:(M+U) F:(M+U) F:(M+U) F:P F:P F:(P+R) -

Molar ratio 1.16 1.35 n/a 2.23 0.5 0.61 -

Free formaldehyde (%) 0.45 0.6

-

4.1.3 Impact Assessment using the Method of ReCiPe The method used in this study to transform the list of the life cycle inventory results into a limited number of impact categories is called ReCiPe. In the methodology of ReCiPe, two indicator levels are determined: midpoint (18) and endpoint (3). Environmental mechanisms are used as the basis for the modelling. This can bee seen as a series of effects that creates a certain level of damage to a certain impact category. The longer the environmental mechanism is, the higher the uncertainties become. The benefit of only taking the first step into account, is the relatively low uncertainty, as this is based on chemical/physical parameters which are easy to measure or determine. The midpoint categories in ReCiPe are, therefore, calculated with less uncertainty than the three endpoint categories. But the benefit of the endpoint categories is that they are much easier to interpret. In contrast, the midpoint categories are more numerous, have very abstract meanings and are difficult to compare. The idea behind the midpoint and endpoint categories is that each user can choose between the uncertainty of the categories or the uncertainty of the correct interpretation of the categories (Goedkoop et al. , n.d.). Both midpoint and endpoint categories contain factors influenced by the three cultural perspectives (individualist, hierarchist and egalitarian). Each perspective represents a set of choices for issues such as time and the expectation that the proper management or future technology development can avoid future damages. For this impact assessment the hierarchist perspective was selected. The results of the impact assessment are presented in Chapter 5. For the determination of the impact on human toxicity aside the ReCiPe an other method is used, called Usetox (Rosenbaum et al. , 2008). This method includes effect factors for substances having a harmful impact on human health.


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4.2 Risk Assessment of Occupational Exposure in Glulam Factory MUF and PUR are the main adhesives used for the production of wood construction products such as CLT and glulam in Switzerland. For glulam production the adhesive is, similar to CLT production, applied on the surface of the wood. The only difference is that for glulam the wood layers are glued lengthways together whereas for CLT production the layers are glued crosswise together. Emission measurements were performed during the application in two factories in Switzerland to observe the environmental impacts of the adhesive application. Both factories produce glued laminated timber but use different kinds of adhesives. Company A uses MUF, and company B uses PUR for the glulam production. 4.2.1 Production Process in Glued Laminated Timber in Factory Company A produces 10-15 m3 of glued laminated timber per day. The adhesive is applied in glue lines on the wood. For one charge this process takes about 5-10 min. Between 200-250g/m2 of MUF adhesive is applied to the wood per layer. After the application, the glued laminate timber is pressed for 20 min at 80 degrees and 250 bar. Only one worker is needed for the production. He has to place the wood correctly into the machine and to control the adhesive application. He works about 30- 50 cm away from the nozzles during the application. No ventilation is installed close to the glued laminated timber production area, and the worker wears no protective gear other than gloves when cleaning the nozzles or touching the glued wood. The production runs nonstop from 7 am till 5 pm in the afternoon. The company B produces 60 m3 per day. It is much bigger than company A, but the adhesive application is very similar. The adhesive is also applied in glue lines on the wood. For one charge the process takes between 10 and 20 minutes, depending on the length of the wood. 200 g/m2 PUR adhesive is applied to the wood. After the application, the glued wood is pressed vertically for 90 min at 22 degrees, 70-100 bar and high humidity (65%). Similar to company A, company B also has no ventilation installed close to the application area. There are several workers in the factory but only one has to work close to the application area and to control the application process. In this factory too, the workers wear no other protective gear aside from gloves when cleaning the nozzles or touching the glued wood. After each break, the nozzles have to be cleaned from the curing glue with a towel.


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The following substances are considered essential for the two adhesives: formaldehyde (mainly for MUF), isocyanate (mainly for PUR) and VOC (for both). The emissions only occur when the adhesives are still reactive. Therefore, the emissions were measured close to the application station and the press. Formaldehyde and isocayante emissions cause hazardous impacts to human health (as described in Chapter 2). For both substances, threshold values for the maximum workplace concentration (MAK) are defined from SUVA (2012) (see Table 8). The MAK values for the individual VOCs are present in Table 42 and 43 in the Appendix. Table 8: MAK-value for formaldehyde and isocyanate

MAK

Formaldehyde mg/m3 0.37

Isocyanate mg/m3 0.02

4.2.2.1 Measurement setup Figure 7 and 8 present the sketch of the production area and the positions of the three measurements of both companies.

Figure 7: The sketch of the production process in company A

Figure 8: The sketch of the production process in company B

The first measurement has been performed close to the worker who controls the application process. The second measurement was performed close to the press, due to the different climate condition. And the third measurement was performed 5m away from the application area in order to observe how the substances disperse in the air. The measurement was repeated for each company on a second day. In addition, a background measurement has been performed when no production took place in the factory. For company A, the background measurement was performed on a day with no production, where as for company B the background measurement was performed in the evening 30 minutes after the production had stopped.


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4.2.2.2 Measurement Method The three substances were measured at each point. In addition the particle concentration (mass and number concentration) was also measured to observe the air quality in the factory. Sample Collection Air was pumped with a velocity of 200 ml/min for 30 min through the cartages which had different sorbent inside. For formaldehyde DNPH was used, for VOC Tenax TA and Carbopack C and for isocyanate a filter was used. During this 30 minutes the emitted substances accumulated on the sorbent. Parallel to the emission, the humidity and temperature were also measured, as they influence the emission from the adhesive in engineered wood products. Sample Analysis After the sampling, the adsorbed substances were resolved and were analysed in a chromatograph. 4.2.2.3 Risk Observation and health impact assessment from application To observe the risk for the workers in the factory the measured concentrations of the different substances were compared to their corresponding MAK-value. A risk for the workers is only expected if measured concentrations exceeded the threshold values. The results of the measurements are presented in Chapter 5. The average emission measured 5 m away minus the background measurement was considered to be the representative emission occurring from the adhesive application and which is inhaled by the worker during the 8 hours of shift. With the average amount of adhesive applied during the measurement (presented in Table 9) the emission per gram adhesive can be calculated for each substance. Table 9: The amount of adhesive applied during the emission measurement Company A Company B

(g) (g)

Formaldehyde 19375 46603

VOC1 35000 30958

VOC2 19375 23280

Isocyanate 48958

Considering the amount of adhesive applied on the wood for CLT production the emission of the application of adhesive can be determined for the production of CLT. For the estimation of the impact on human health on one hand the amount of emission inhaled by the worker has to be determined for each substance (0.5 m3 /h during 8 hours) and on the other hand the effect factor (EFi ) from UseTox has to be known for each substance (see Appendix, Table 46). With these information the impact of the emission on human health can be determined for each substances by multiplying the amount of emission inhaled and the effect factor.


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4.3 Assessment of the Use Phase Different studies show that the air quality in wooden buildings is negatively impacted by the emissions from the adhesive in engineered wood products (Funch & Clorius, 2002). 4.3.1 Total Emission from CLT in the Use Phase The emission rates (µg/m2 /h) from MUF and PRF adhesives used in glued solid wood were measured in a chamber experiment over the course of 28 days at three different points in time in the study of Funch (2002). In a similar chamber experiment, the emission rate from PUR adhesive used in glued solid wood was also measured by Bremer Umweltinstitut (2011) (see Table 48 to 50 in the Appendix). No emission rate measurements were found in literature for PF adhesive. PF adhesive is not commonly used for CLT, and therefore PF adhesive was excluded from the assessment of the use phase. The focus of the LCA methodology is on the total input and output, rather than on the emission rate of a product (ISO, 2006). For the calculation of the total output of emissions from the use phase of adhesive in 1 m2 CLT, a time-dependent emission model has to be integrated over a defined period of time. Different models have been reviewed from Guo (2002) and Skaar & Jørgensen (2013). But only three of the models were considered applicable for general emission modelling. All three are decay models based on emission rate, are controlled by internal diffusion and are not limited by vapour pressure. Of the three possible models, the first-order decay model (Guo, 2002) was selected for this study (2).

E = E 0 ∗ e-k*t

(1) (2)

The decay model was fitted to the emission rate data from each substance and adhesive (MUF, PRF, PUR) using nonlinear regression. The decay model with the generated parameters was integrated for each substance and dataset over the time of the use phase (3). The time goes from t0 (time when the product was installed in the house) to tf (end of service life of the product). The use phase of CLT is about 40 years (Aktas & Bilec, 2012). The total amount of emission from each adhesive in 1 m2 CLT can be found in Table48 to 50 in the Appendix. ˆ mtoti =

tf

E i (t) dt.

(3)

t0


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Chaudhary & Hellweg (2014) and Hellweg et al. (2009) proposed an approach for the calculation of the impact on human health from the use phase of engineered wood products (4, 5):

impactindoor =

n X

mtoti ∗ iF ∗ EF i =

i=1

n X

mtoti ∗ CF iindoor

(4)

i=1

impactoutdoor =

n X

mtoti ∗ CF ioutdoor

(5)

i=1

Only a portion of the emissions remains indoors and has an impact on the indoor air quality. The rest of the emissions can escape outdoors due to ventilation or air exchange. The emissions from the use phase of CLT, therefore have both indoors and outdoors impacts on human health. The Impactindoor and impactoutdoor in Equation 4 and 5 are the impacts on human health [cases per functional unit], EFi is the human health effect factor for inhalation of a certain substance [cases per kg substance] and iF is the intake fraction describing the fraction of the emission inhaled by people exposed to the emission in a room. The intake fraction can be calculated using Equation 6.

iF =

IR ∗ h ∗ P V ∗ 24 ∗ N

(6)

IR is the inhalation rate (0.5 m3 /h), h is the exposure time (assumed to be uniformly distributed over the day), P is the number of people in the room (assumed to be only one), N is the ventilation rate (assumed to be 0.5/h) and V is the volume of the room (standard room assumed to have volume of 17.4m3 ). The approach for the calculation of the intake fraction is based on Hellweg et al. (2009)’s recommendation to use a one box model with the following assumptions: homogeneously mixed air, connection to surroundings by ventilation, disregard of adsorption and desorption and inhalation as the most significant means of exposure. The portion of emissions escaping outdoors was calculated from the total emissions emitted minus the amount inhaled. The indoor characterization factor CFi can be calculated for each substance from the effect factor (EFi ) and the intake fraction. The effect factors and the outdoor characterization factor CFioutdoor were directly taken from the Usetox model (an environmental fate, exposure and effect model developed by UNEP/SETAC (Rosenbaum et al. , 2008)). They are listed in Table 51 in the Appendix. The conversion factors suggested by Huijbregts et al. (2005) were used to convert the unit of the effect factors and the characterization factors from [cases per kg] into [DALY] (disability adduced life years, a concept developed by the world health organization and a powerful concept to address human health damages). The impact from the use phase of MUF, PRF and PUR adhesive used in 1 m2 CLT on the human toxicity are presented in Chapter 5.


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4.4 Assessment of Final Waste Disposal Thermosetting wood adhesives are not recyclable, therefore glued scrap wood from buildings has to be treated in an appropriate incineration plant according to the TVA(Swiss Federal Council, 1990). In the past, the emissions in the flue gas of the incineration plant were considered harmless due to high dilution. But Marutzky & Schriever (1986) have already showed the environmental impact of the emissions arising from the incineration of particleboards in in their paper 1986. In the mean-time other studies have also observed the emissions occurring from the incineration of particle boards and composite wood products (Marutzky & Schriever, n.d.; Karlsson et al. , 2001; Risholm-Sundman & Vestin, 2005). The decision support tool LCA4AFR for resource use and waste management was taken in order to calculate the environmental impact from the incineration of adhesives used in wood construction. The Excel-based computer program was developed at the ETH Zürich by the group Ecological-Systems-Design to provide environmental information on waste treatment processes. The tool evaluates all emissions and resource consumption of the waste treatment process (at the facility and in the supply chain). It is based on the elemental mass flow entering and leaving the system with environmental indicators regarding different impact categories such as climate change, resource consumption, or toxicity (Boesch et al. , n.d.). Table 10 presents the elemental composition of the different adhesives. The net heating value of the different elemental composition was calculated using the equation (4.4) of Boie (1953):

N HV (kcal) = 83.22 ∗ C + 276.48 ∗ H − 25.8 ∗ O + 15 ∗ N + 94 ∗ Cl + 18.5 ∗ F + 65.0 ∗ P + 12.2 ∗ F e (7)

Table 10: The elemental composition of the different adhesives C N O H S NHV

(%) (%) (%) (%) (%) (MJ)

MUF 30 33 31 6

PRF 60

16

24

34 6

PUR 61.2 9.7 22 6 1.1 27

In Chapter 5 are the results presented of the calculated environmental impacts from the final deposition of the adhesive used in CLT.


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5 Results and Interpretation

5 Results and Interpretation 5.1 The Impact Assessment of the Production of 1kg Adhesive with a solids content of 100% Figure 9 and 10 present the endpoint results (for the three endpoint categories and for the different impact categories) of the impact assessment of the production of 1kg of adhesive with a solids content of 100%.

Figure 9: The result of the first assessment of the adhesive production for the three endpoint categories

Figure 10: The endpoint result per impact categories of the first assessment of the adhesive production for all datasets


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Only five of 18 possible impact categories contribute to the endpoint result of the overall performance of the adhesives: fossil depletion, climate change human health and ecosystem, particle matter formation and human toxicity. The impact category of fossil depletion (more than 40%) contributes the most to the overall performance, followed by climate change human health and ecosystem (more than 14% resp. 8%). For all adhesives, these three impact categories together make the largest contribution to the environmental performance (more than 85%). The impact categories particle matter formation and human toxicity make a much smaller contribution. The production of PRF adhesive has the greatest impact (572mPt) on the environment of the various adhesives. And the production of MUF (Wilson, 2010) has the lowest impact (321mPt). In Figure 11 presents the midpoint results of the assessment for all adhesives. These results are not yet weighted or normalized and have therefore less uncertainty.

Figure 11: The midpoint result of the first assessment of the adhesive production for all datasets The contribution of single background processes or substances to the different impact categories are similar for the midpoint and endpoint results. In the paragraphs below, the contribution of each adhesive to the different impact categories is analysed in detail for the endpoint results. 5.1.1 Fossil Depletion Table 11 lists the contribution of the different raw material inputs to the fossil depletion for all adhesives. The raw material production makes the largest contribution to fossil depletion (more than 80%) regardless the adhesive type and dataset. In the paragraphs below, the impact of the different adhesives on fossil depletion is analysed in detail.


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Table 11: The contribution of the processes and substances on fossil depletion

Raw material

Transport lorry Transport rail Diesel Electricity Substances

Urea Melamine Methanol Phenol Sodium hydroxide Resorcinol MDI Polypropylene glycol

Natural gas Crude oil Coal

MUF Brazil % 97.54 11.87 4.86 79.28

MUF Wilson % 80.00 38.98 16.67 24.35

2.30 1.77 1.47

0.86

89.77 8.75 1.34

76.84 17.97 5.70

MUF Casco %

PF Wilson % 96.70

PF Ecoinvent %

20.77 73.63 2.30

PRF Wilson % 94.10

PUR %

4.68 38.14 51.28 2.28

49.26 49.95

1.12 87.28 8.38 4.34

49.40 43.02 7.26

39.78 52.79 7.45

39.74 53.85 6.52

42.11 40.32 17.05

MUF Adhesive For all three MUF datasets the impact on fossil depletion is mainly caused by the use of natural gas (more than 75% and for MUF Brazil even 97%). Natural gas is, on one hand, the raw material for methanol (about 20%) , urea (about 50%) and melamine production (about 10%). And, on the other hand, it is also used for energy production (20% dataset of Wilson (2010)). Especially for methanol production in Brazil, natural gas is the main energy source (544.94MJ). This explains the high impact of methanol production in Brazil (almost 80%). Crude oil is used in the ammonia steam reforming process (the prior process to urea and melamine production). It is used alongside coal for heat production. Coal is not only used for heat production but also for the electricity production. 46.5% of the US electricity mix is produced due to coal burned in a power plant. PF Adhesive Both phenol and formaldehyde are petrochemicals produced from crude oil and natural gas. Therefore, the impact on fossil depletion comes mainly from the production of raw materials (over 90%). Crude oil is the main feedstock for phenol production. Natural gas is used for phenol production as an energy source and as raw material for formaldehyde production. These differences between the two datasets arise from different inputs (see Table 11): the Wilson dataset has a 2.5 times higher input of methane (equal to formaldehyde) than the dataset of Ecoinvent 2.2 (2010), where as Ecoinvent 2.2 (2010) reports a 1.8 times higher input of phenol than the dataset of Wilson (2010). However, for both datasets the major part of crude oil is used for phenol production (41% in the dataset of Wilson (2010) and 49% in the dataset of Ecoinvent 2.2 (2010)). PRF Adhesive The production of raw material is also the major impact for PRF adhesive. At 51%, resorcinol makes the highest contribution to fossil depletion, followed by phenol at 38%. Crude oil and natural gas is the feedstock for the production of both resorcinol and phenol. Therefore, the extraction of crude oil and the use of natural gas are primarily responsible for fossil depletion. 53% of the impact on fossil depletion is caused from the extraction of the crude oil used as raw material for the production of phenol and resorcinol (21% and 30% resp. ).


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PUR Adhesive The production of MID and the production of polypropylene glycol have a similar impact on fossil depletion (each about 50%). MDI is produced with formaldehyde and anilin. The feedstock for formaldehyde is natural gas and for anilin it is nitrobenzene, which is produced through the nitration of benzene, whose feedstock is, in turn crude oil. Polypropylene glycol is produced with propylene oxide, which is produced with propylene, whose feedstock is also crude oil. All the impacts from PUR adhesive on fossil depletion are, therefore, allocated to the production of the raw materials. 5.1.2 Climate Change Human Health and Ecosystem Table 12 lists the impact for the category "climate change human health and ecosystem". The main impact results from the production of raw materials (more than 83%). The CO2 emission that occur during the production of raw materials are mainly responsible for the impact on climate change (for all adhesives more than 85%). In the following paragraphs, the sources of the CO2 emissions are analysed in detail for each dataset. Table 12: The contribution of the adhesive production on the category climate change human and ecological systems

Raw material


Urea Melamine Methanol Phenol Sodium hydroxid Resorcinol MDI Polyprolylene glycol HDI

CO2 Methan

MUF Brazil % Human Eco 83.33 83.17 43.49 43.42 18.10 18.15 21.74 21.60

8.21

85.42 13.22

MUF Wilson % Human Eco 93.46 94.11 62.93 63.61 19.63 19.67 10.90 10.84

MUF Casco % Human Eco

PF Wilson % Human Eco 93.87 93.95 12.53 75.96 5.38

PF Ecoinvent % Human Eco

12.53 76.03 5.40

PRF Wilson % Human Eco 86.38 89.22

38.00

2.75 38.08

48.38

48.42

3.95

2.94

85.39 6.64

92.83 6.65

92.79 6.64

89.01 11.83

88.84 10.97

87.70 11.83

87.69 11.81

87.83 11.83

87.64 11.94

87.69 12.00

87.35 12.03

PUR % Human Eco

44.27 43.87 9.76

44.37 43.99 9.82

86.37 12.66

86.71 12.72

MUF Adhesive The CO2 emissions of MUF production are primarily emitted from the production process of urea (between 40% and 60% depending on the dataset). CO2 is produced as a byproduct of the ammonia factory process. In the second step of this process, ammonia is reacted to urea with CO2 at high temperatures (180-190 degree) and high pressure (150 bar) (CMP, 2003) . The CO2 emissions from the urea production include both: excess CO2 from the ammonia reformation process and emitted CO2 from the heat and pressure production. The differences between the MUF datasets can be explained by the differences in the raw material inputs. The urea production in Brazil contains less ammonia which leads to lower CO2 emissions (40% less than the process of Ecoinvent 2.2 (2010)).


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PF Adhesive The contribution of the CO2 emissions of PF adhesive to climate change is about 87%. CO2 is mainly emitted from the production of the raw materials (81%). In this case especially from the production of pheno atl 66% in the dataset of Wilson (2010), and at 76% in the dataset of Ecoinvent 2.2 (2010). The production of phenol requires high temperatures and pressure, both of which are produced by burning coal, natural gas and/or crude oil, thereby emitting CO2 emissions. The differences between the two PF datasets are from the the different inputs of formaldehyde and phenol. PRF Adhesive The contribution of CO2 emissions from PRF production is similar to that of the PF adhesives (87%). The CO2 emissions primarily come from the production of raw material 86% (resorcinol (48%) and phenol (38%)). For the production of both resorcinol and phenol, cumene is needed, and the production of cumene emits large amounts of CO2 (70%), due to the need for high temperature (600K) and high pressure. The energy required for the production of cumene comes from fossil fuels that emit CO2 . PUR Adhesive The production of the raw materials MDI and polypropylene glycol requires benzene and propylene. As described above, the production of benzene and propylene emits high amounts of CO2 , and therefore the production of the raw material constitutes for PUR, too, the highest impact on climate change. And in addition to the feedstock for the raw material, the electricity needed to create propylene oxide and polymerize polypropylene glycol also has an impact on climate change (34% of the CO2 emissions). 5.1.3 Particle Formation Table 13 lists the contribution of the raw materials on the impact category "particle matter formation" for all adhesives. Similar to the other impact categories, the main impact of particle matter formation comes from the production of raw materials (more than 73%). Table 13: The contribution of raw materials and processes on particle formation

Raw material


Urea Melamine Methanol Phenol Sodium hydroxide Resorcinol MDI Polypropylene glycol

MUF Brazil % 73.93 35.38 19.24 19.31

MUF Wilson % 91.83 65.87 21.94 4.01

MUF Casco %

PF Wilson % 83.31

PF Ecoinvent %

75.38 7.29

PRF Wilson % 81.05

PUR %

35.30 45.75

15.50 4.76

9.80

50.76 46.59

4.09 Nitrogen oxides Sulfure dioxide Particulates < 2.5 um Ammonia Particulates >2.5,16t, fleet average/RER U Electricity/heat Electricity mix/US U Emissions to air Carbon dioxide, fossil Carbon monoxide VOC, volatile organic compounds Particulates Formaldehyde Methanol Dimethyl ether Phenol Final waste flows Waste, solid* *instead of solid emission to soil


Amount 1 47

Unit kg %

0.3498 0.00821

kg m3

0.244 0.209 0.061 5.889E-09 0.675 0.038

kg kg kg kg tkm tkm

0.0356

kWh

0.0176 0.0000381 0.0000289 0.00000231 0.00000669 0.0000032 0.00000473 0.00000204

kg kg kg kg kg kg kg kg

0.0002

kg

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8 Appendix

Table 27: PF Ecoinvent, process modeled in SimaPro

PF Ecoinvent at 100% solids content PF Adhesive solids content Resources Water, cooling, unspecified natural origin/m3 Water, unspecified natural origin/m3 Materials/fuels Phenol, at plant/RER U Formaldehyde, production mix, at plant/RER U Electricity, medium voltage, production UCTE, at grid/UCTE U Transport, freight, rail/RER U Transport, lorry >16t, fleet average/RER U Emissions to air Heat, waste Carbon dioxide, fossil Phenol Formaldehyde Emissions to water BOD5, Biological Oxygen Demand COD, Chemical Oxygen Demand DOC, Dissolved Organic Carbon TOC, Total Organic Carbon Phenol Formaldehyde


Amount 1 100

Unit kg %

0.024 0.012

m3 m3

0.95 0.152 0.333 0.661 0.11

kg kg kWh tkm tkm

1.2 0.0468 0.0019 0.000303

MJ kg kg kg

0.00418 0.00418 0.00142 0.00142 0.00171 0.000273

kg kg kg kg kg kg

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8 Appendix

Table 28: PRF Wilson, process modeled in SimaPro PRF Wilson PRF Adhesive solids content Resources Water, unspecified natural origin/kg Gas, natural/m3 Materials/fuels Phenol, at plant/RER U Methanol, at plant/GLO U Sodium hydroxide, 50% in H2O, production mix, at plant/RER U Ethanol, 95% in H2O, from corn, at distillery/US U Propane/ butane, at refinery/RER U Transport, lorry >16t, fleet average/RER U Transport, freight, rail/RER U Resorcinol, at plant/RER U** Electricity/heat Electricity mix/US U Emissions to air Carbon dioxide, fossil Carbon monoxide VOC, volatile organic compounds Particulates Formaldehyde Methanol Phenol Emissions to water BOD5, Biological Oxygen Demand Suspended solids, unspecified Formaldehyde Phenol Final waste flows Waste, solid* **Phenol has been taken instead of Resorcinol *instead of solid emission to soil


Amount 1 60

Unit kg %

0.656 0.0318

kg m3

0.277 0.103 0.00372 0.00744 5.25E-08 0.8338869 0.7947366 0.19

kg kg kg kg kg tkm tkm kg

0.0989

kWh

0.0685 0.000149 0.0000338 0.00000301 0.0000088 0.0000052 0.00000416

kg kg kg kg kg kg kg

0.00281 0.000167 0.000332 0.000114

kg kg kg kg

0.000165

kg

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8 Appendix

Table 29: PUR, process modeled in SimaPro

PUR PUR Adhesive solids content Materials/fuels Methylene diphenyl diisocyanate, at plant/RER U Electricity, medium voltage, production UCTE, at grid/UCTE U Transport, lorry >16t, fleet average/RER U Transport, freight, rail/RER U Polypropylene glycol Additive 1 Additive 2 Additive 3

Amount 1 100

Unit kg %

0.4917 0.021 0.108 0.648 0.4275 0.03 0.0026 0.0011

kg kWh tkm tkm kg kg kg kg

Table 30: Urea Brazil, process modeled in SimaPro

Urea, Brazil Urea Production, Brazil Resources Water, unspecified natural origin/kg Materials/fuels Ammonia, liquid, at regional storehouse/RER U Carbon dioxide liquid, at plant/RER U Electricity, production mix BR/BR U Heat, natural gas, at industrial furnace >100kW/RER U Emissions to air Carbon dioxide Carbon monoxide Nitrogen oxides Particulates, unspecified Emissions to water Nitrogen, total


Amount 1

Unit kg

0.0761

kg

0.561 0.651 0.000541 0.0035

kg kg GJ GJ

0.0166 0.000000499 0.0000467 0.000943

kg kg kg kg

0.000168

kg

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8 Appendix

Table 31: Methanol Brazil, process modeled in SimaPro Methanol, Brazil Methanol Production, Brazil Resources Gas, natural/kg Oxygen Energy, from gas, natural Materials/fuels Electricity, production mix BR/BR U Diesel, at regional storage/RER U Emissions to air Water/m3 Methane Carbon monoxide Carbon dioxide Hydrocarbons, unspecified Nitrogen oxides Sulfur dioxide Particulates Methanol Emissions to water Organic compounds (unspecified) BOD5, Biological Oxygen Demand COD, Chemical Oxygen Demand Sulfur Suspended solids, unspecified Emissions to soil Sulfur


Amount 1000

Unit kg

184 34042 544.94

kg kg GJ

320 2.24

kWh kg

392.18 24.024 3.726 1772.04 3.654 1.726 9.02 0.27 0.000424

m3 kg kg kg kg kg kg kg kg

0.014 0.024 0.17 0.0002 0.17

kg kg kg kg kg

0.02

kg

from volume(m3) to kg factor 0.66kg/m3 (wikipedia 2015) from volume(m3) to kg factor 1.15kg/m3 (wikipedia 2015) from volume(m3) to kg factor 1.98kg/m3 (wikipedia 2015) from volume(m3) to kg factor 0.7kg/m3 (guidechem.com 2015) 95% NO (1.34kg/m3), 5%NO2 (2.62kg/m3) (wikipedia 2015) from volume(m3) to kg factor 2.62kg/m3 (wikipedia 2015)

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8 Appendix

Table 32: Resorcinol, process modeled in SimaPro

Resorcinol Resorcinol, at plant/RER U Resources Water, cooling, unspecified natural origin/m3 Water, unspecified natural origin/m3 Materials/fuels Oxygen, liquid, at plant/RER U Chemical plant, organics/RER/I U Cumene, at plant/RER U Electricity, medium voltage, production UCTE, at grid/UCTE U Heat, natural gas, at industrial furnace >100kW/RER U Transport, lorry >16t, fleet average/RER U Transport, freight, rail/RER U Emissions to air Carbon dioxide, fossil Heat, waste Cumene Emissions to water Cumene BOD5, Biological Oxygen Demand COD, Chemical Oxygen Demand DOC, Dissolved Organic Carbon TOC, Total Organic Carbon


Amount 1

Unit kg

0.024 0.012

m3 m3

0.716 4E-10 2.68 0.333 2 0.34 2.04

kg p kg kWh MJ tkm tkm

0.191 1.2 0.00736

kg MJ kg

0.01288 0.0198 0.0198 0.00579 0.00579

kg kg kg kg kg

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8 Appendix

Comparison of impacts of different raw material production and energy production

Figure 13: The impact of the production of 1kg of the different raw materials

Figure 14: The impact of the production of 1MJ with the different production mixes


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XIV

Midpoint result of the first assessment (kg)

Figure 15: Midpoint result of MUF Brazil

Figure 16: Midpoint result of MUF Wilson


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Figure 17: Midpoint result of PF Wilson

Figure 18: Midpoint result of PF Ecoinvent


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Figure 19: Midpoint result of PRF Wilson

Figure 20: Midpoint result of PUR Wilson


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8 Appendix Result of Usetox assessment for human toxicity (non-carcinogen)

Table 33: The contribution of the process or substances to human toxicity (noncarcinogen) determined with the method of Usetox

Processes

Substance

% Ammonia Benzene Chlorine Propylene glycol Sugarcane Heavy fuel oil Propylene glycol Acetaldehyde Aldrin Toluene Xylene Methane, dichloro-, HCC-30 Propylene oxide water Propylene oxide air Methane, tetrachloro-, CFC-10

MUF Brazil % 2.50 2.11 88.89

3.69 88.89

MUF Wilson % 44.02

MUF Casco %

PF Wilson %

PF Ecoinvent %

PRF Wilson %

19.39 12.99 9.42

30.79 13.46 7.56

23.69 5.02 25.15

35.87

11.14

13.87

10.13

25.77 11.08 7.21 6.82

23.24 18.75 25.30 8.19

27.21 23.77 7.86 11.84 9.19

23.81 22.29 7.24 17.04 13.22

PUR

99.44

10.74 7.84

99.46

Detailed result of the second assessment (CLT)

Figure 21: Midpoint result of the second assessment


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8 Appendix

Table 34: Contribution of hardener and adhesive to the impact on fossil depletion (CLT) Hardener Adhesive Substances

Natural gas Adhesive Hardener Crude oil Adhesive Hardener Coal Adhesive Hardener

CLT MUF, Brazil % 26.14 73.86 78.10 66.40 11.71 15.22 6.46 8.75 15.22 6.46 8.75

CLT MUF Wilson % 45.78 54.22 61.90 41.39 20.50 25.04 9.70 15.33 9.95 0.00 9.95

CLT MUF Casco % 44.46 55.54 68.39 48.48 19.91 19.54 4.65 14.89 12.08 4.47 9.66

PF Ecoinvent % 0.00 100.00 39.85 39.85 0.00 52.64 52.64 0.00 7.45 7.45 0.00

PF Wilson % 0.00 100.00 49.54 49.54 0.00 43.11 43.11 0.00 7.28 7.28 0.00

CLT PRF Wilson % 15.98 84.02 42.03 33.33 8.70 49.79 45.17 4.63 8.13 5.47 2.66

CLT PUR % 0.00 100.00 42.80 0.00 0.00 39.70 0.00 0.00 11.63 0.00 0.00

Table 35: The contribution of hardener and adhesive to the impact on climate change human/ eco (CLT)

Hardener Adhesvie Substances

CO2 Adhesive Hardener Methane Adhesive Hardener

MUF, Brazil human eco % % 32.11 32.12 67.89 67.88 88.46 88.47 57.92 57.93 30.53 30.54 10.40 10.39 8.97 8.96 1.42 1.42

MUF Wilson human eco % % 29.00 29.01 71.00 70.99 93.47 93.47 65.89 65.89 27.58 27.58 6.01 6.00 6.01 4.71 1.29 1.29

MUF Casco human eco % % 34.57 34.57 65.43 65.43 90.96 91.32 60.33 58.44 30.64 32.87 8.88 8.51 7.45 6.98 1.43 1.53

PF Ecoinvent human eco % % 0.00 0.00 100.00 100.00 87.62 87.63 87.62 87.63 0.00 0.00 11.95 11.93 11.95 11.93 0.00 0.00

PF Wilson human eco % % 0.00 0.00 100.00 100.00 87.74 87.76 87.74 87.75 0.00 0.00 11.83 11.82 11.83 11.82 0 0.00

PRF Wilson human eco % % 11.44 11.44 88.56 88.56 88.27 88.28 77.56 77.57 10.71 10.71 11.24 11.22 11.24 10.50 0.73 0.72

PUR human % 0.00 100.00 87.13 0.00 0.00 12.36 0.00 0.00

eco % 0.00 100.00 87.15 0.00 0.00 12.35 0.00 0.00

Table 36: The contribution of hardener and adhesive to the impact on particle formation (CLT) Hardener Adhesvie Substances

Nitrogen oxides Adhesive Hardener Sulfure dioxide Adhesive Hardener particulates 2.5 ,