How To Use This Book

The Ecology of Building Materials is an attempt to present the possibilities for existing materials, as well as evaluating new materials. A number of partly abandoned material alternatives have also been evaluated. In particular, we will look at vegetable products, often with traditional methods of preparation. In their present state these methods are often of less relevance, and these reviews must therefore be regarded as tentative.

Many factors relating to the materials discussed depend upon local conditions; this book is primarily based on the climatic and topographical conditions in northern and central Europe. However, when considering the Earth as a whole, it will become clear how little the overall use of materials varies; and the principles underlying better solutions to a large extent are universal.

The materials dealt with are those that are generally used by conventional builders such as bricklayers, masons, carpenters and locksmiths. Under this category, all fixed components and elements that form a building are included, with the exception of heating, ventilation and sanitary installations. Materials providing high environmental standards are presented most thoroughly, whilst less attractive and often conventional alternatives are given less attention.

The book is divided into three Parts:

Part 1: Eddies and water-level markers. Environmental profiles and criteria for assessment covers the tools which we shall use to evaluate and select materials on the basis of production methods, raw material availability, and energy and pollution aspects. Tables illustrate important alternatives available and key information on their environmental profile is presented. The information derives from many different, reliable sources, mainly European. They show quantifiable as well as qualitative environmental effects and should be read in conjunction with more comprehensive presentations in Parts 2 and 3. The final chapter in this section gives an introduction to the chemical and physical properties of building materials.

Part 2: The flower, the iron and the sea. Raw materials and basic materials presents the materials at our disposition. The term 'raw materials' denotes the materials as they are found in nature, either as a single chemical compound or as a combination of several compounds. They form the basis for the production of 'basic materials' such as iron, cement, linseed oil and timber. These materials form building blocks in complete products. The section is divided into chapters that present the different organic and mineral materials and discuss the ecological consequences of the various ways of utilizing them.

Part 3: The construction of a sea-iron-flower. Building materials discusses usage, such as roofing and insulation, and assesses the usability of the various alternatives from an ecological perspective. Descriptions are given of the practical uses of the best alternatives. This Part is divided into seven chapters:

1. Structural materials that support and brace.

2. Climatic materials that regulate warmth, humidity and air movement.

3. Surface materials that protect and shield structures and climatic materials from external and internal environments.

4. Windows, doors and stairs.

5. Fixings and connections that join different components.

6. Paint, varnish, stain and wax that improve appearance and provide protection.

7. Impregnating agents, and how to avoid them: the different impregnating substances and the alternatives.

The structural, climatic and surface materials covered in the first three chapters in Part 3 represent 97-99% of the materials used in building, and environmental evaluations are given for each. The evaluations are mostly based on information given in Part 1 of the book. In addition to conventional environmental issues, human ecological aspects are also discussed, primarily through questions such as the feasibility of local production of building materials.

The evaluation tables in Part 3 are ordered so that each functional group has a best and a worst alternative for each particular aspect of the environment. In the concluding summarized evaluation, priority is given according to the standing place of the author. In such processes, political, cultural and ethical aspects come strongly into play. In Africa for example, the raw material question is usually given high priority; in New Zealand and Argentina, factors that affect the ozone layer are taken very seriously; in Western Europe high priority is likely to be given to human toxicity. Today however, in most regions one is likely to find that global warming is the most important environmental parameter (Anderson, 2000; Lippiatt, 2007). A separate column in the tables is therefore devoted to the global warming potential (GWP) of each product. An added reason for presenting the potential climate effect of the products is that this often provides an excellent indicator of other environmental effects. A product causing high greenhouse gas emissions is very likely to be resource intensive and a source of emissions of other toxic chemicals and by-products during the production process. Studies show a clear correlation between climate-related results and results of broader environmental analyses (Strand Hansen, 2002).

It is necessary to emphasize that information provided in this book represents the state of our knowledge as of the date of publication. The sciences that address the different relationships in the natural environment are complex, relatively young, and in some cases just beginning. New aspects come to light continuously, some of which can affect the whole situation. An example is chlorofluorocarbons (CFCs), which were not considered to be a problem until the 1970s when their effect on the ozone layer became known.

It is also important to underline that the evaluations in this book are based on the precautionary principle. The consequences of using a material, in particular new products, should be well understood before it is taken into use.

It must be emphasized that the evaluation tables describe isolated materials, and not composite constructions consisting of several elements such as often occur in buildings. This may give a slightly distorted picture in certain cases; for example, ceramic tiles and the mortar or jointing mastic used with them cannot be considered independently. In most cases, however, the tables represent a thorough basis for comparisons between products at a fundamental level.

Life span evaluations of building materials

During the last 20 years many methods have been developed to evaluate the lifecycle environmental profile of building materials. After some years of trial and error, several of these are now useful and effective tools. Amongst those to be recommended are ENVEST (England), BEES (USA), ATHENA (Canada), EPS (Netherlands), BEAT (Denmark) and ECOPRODUCT (Norway).They are all based on transforming qualitative into quantitative data that are then collated into a final value expressing the environmental impacts of a material during its life span. Results for any given material may vary somewhat between systems because the evaluations are largely based upon prevailing national regulations presenting acceptable pollution limits, etc. Comparisons are further complicated by the fact that some systems weigh in economic factors, and that there is varying breadth in the environmental factors taken into consideration. The systems also have varying degrees of transparency often including hidden evaluation procedures.

It isto be hoped that there will bean increasing degree of coordination internationally especially in view of the global nature of the environmental issues at hand, in particular climate-related. A good degree of transparency is also important and the reasons for variations of a national character should be easily identifiable.

Was this article helpful?

0 0

Post a comment