Process Materiality Analysis: Clay Bricks and Roof Tiles Segment
The Value Chain for the Clay Bricks and Roof Tiles Segment
The most important steps in the value chain of the clay block, facing brick and roof tile segments, but not of the clay paver segment, are described in the following. The description applies to the Clay Building Materials Europe business unit and relevant products of General Shale within the North America Division.
Sustainability in the supply chain and in raw material sourcing
Clay and loam are the most important raw materials for brick production. They are either extracted in Wienerberger’s own clay pits or obtained from suppliers. Numerous issues relating to safety and protection arise in the operation of an extraction site. Besides ensuring the safety and health of employees, minimizing noise and dust pollution for local residents is another important aspect. Raw material extraction always constitutes an interference with nature, which is kept as low as possible during operation. Depleted extraction sites have to be re-cultivated, renaturalized or re-used for other purposes. The availability of adequate regional extraction sites is very important for a long-term supply strategy. To obtain the desired product quality, aggregates, such as sand, grit and gravel, as well as additives, such as straw, paper fibers or polystyrene, are added to the base material for the production of clay blocks. Some types of clay blocks are filled with mineral wool or perlite to increase their thermal insulation capacity. For facing bricks various production methods lead to a large range of colors, surface textures and shapes. Special texturing, for example, can be created through sanding, milling, engobing, glazing or brushing. Roof tiles are glazed or engobed to prolong their service life and/or to obtain a variety of surface finishes. The materials used should be free of hazardous substances. Renewable or mineral-based fillers, such as mineral wool or perlite, have ecological advantages. Organic and carbonaceous components in clay (e.g. bitumen) and in additives result in the release of climate-relevant CO2 emissions to the atmosphere during production. While this can hardly be avoided in clay and loam, CO2 emissions from additives and fillers can be reduced through the use of biogenic substances that are considered to be climate-neutral.
Environmental aspects in production
Energy consumption for the energy-intensive processes in ceramic brick production, such as firing and drying, is a major environmental aspect. Climate-relevant emissions are generated either in the production plant itself or by the (remote) electricity generating plant. Emissions can be reduced, above all, through an increase in energy efficiency in the brick plant. At the same time, the use of renewable sources of energy contributes towards reducing CO2 emissions. Direct climate-relevant emissions also have an impact on costs, as ceramic production is subject to the European CO2 emissions trading system (ETS). Resource efficiency is defined as the sparing use of natural resources, such as raw materials or environmental goods. Efforts are made in the production process to avoid scrap and breakage, and most of the remaining production waste is recycled internally. Water consumption in ceramic production can be further reduced through efficiency measures and the introduction of closed-cycle systems.
Social aspects in production
The safety and health of employees as well as business ethics and compliance are important social aspects in production. Protecting employees from exposure to respirable crystalline silica, a substance released primarily during brick grinding and cutting, is a major health issue in the brick segment. Technical and organizational measures as well as the use of personal protective equipment help to reduce the exposure of employees to this hazard. Dust monitoring, health checks and training programs also serve to reduce exposure and, thus, diminish the risk of disease. These and other aspects are described in the chapters “employees” and “social Responsibility”.
Sustainability in period of use and at end-of-life
Bricks are durable and strong. They offer protection in the event of fire, earthquakes or floods. During their service life, bricks provide thermal insulation and thereby help to reduce the energy consumption of buildings, which in turn results in lower CO2 emissions. Moreover, the energy efficiency of buildings can be optimized through smart building concepts. Clay blocks contribute towards a healthy indoor climate and ensure good indoor air quality. Facing bricks and roof tiles are essential elements determining the appearance of a building; they are weather-proof, require little care and are easy to clean. In many regions, brick façades, pitched brick roofs or brick pavings are part of the cultural heritage.
There is also a growing interest in the re-use of historical bricks. When buildings are demolished, ceramic material can be separated from other building debris and re-used. Wienerberger has little influence on the erection and demolition of buildings. Thorough planning of the construction process helps to avoid scrap and reduces the amount of products to be returned. The use of recycled raw materials from construction debris in brick production is technically feasible, but an economic balance cannot yet be drawn up. Nevertheless, with a view to “urban mining”, Wienerberger always keeps the recyclability of its brick products in mind.