A more respectful architecture with the environment implies, firstly, to become aware of the environmental burdens that generates and, secondly, to adopt measures to minimise them.
The construction and maintenance of buildings consumes a 40% of the total used materials in the European Union. This percentage indicates the great repercussion that a good materials choice can have for the buildings construction and rehabilitation.
The main challenge for building professionals is to meet the functionality, safety and habitability requirements of buildings while minimizing their environmental impacts.
When choosing the construction materials it has to be considered the natural resource consumption and emissions that will represent, the impact on ecosystems and the behaviour as a waste.
Some of the most relevant environmental impacts that are commonly used to compare products are explained below:
It is originated as a result of the return of the sulfur and nitrogen oxides released into the atmosphere to the Earth surface as acids. The acidification can occur as dry or wet deposition (acid rain).
Biodiversity is guarantee of biosphere’s comfort and balance. In each ecosystem, all the living organisms are part of a whole, interacting among each other, but also with the surrounding air, water and soil. The main cause of the biodiversity loss is the habitat deterioration of the affected species.
Water pollution can cause an overabundance of nutrients, mainly nitrogen and phosphorous. This leads to an excess of vegetation and other organisms that, consequently, cause a depletion of the oxygen dissolved in water affecting other species such as fishes.
The responsible gases for the greenhouse effect are those gaseous compounds of the atmosphere, both with natural and anthropogenic origins, which absorb and reemit the infrared radiation, contributing to the increase of the Earth mean temperature.
As heavy metals, those having a relatively high atomic weight and a density of about 5g/cm3 are considered. In general, they are very toxic but without presence in high concentrations in the air or in the water. However, in case of accumulation, they can reach critical or lethal levels.
At the top of the Stratosphere there is the ozone layer, which acts as a filter of the ultraviolet solar radiation. If there is a reduction on its concentration, the amount of ultraviolet radiation that goes into the Earth also increases. When nitrogen dioxide and CFCs reach other regions of the Stratosphere, they dissociate because of the sunlight, producing nitrogen oxide and free chlorine. This last element destroys ozone.
The use of fossil fuels emits sulfur oxides (mainly SO2) and nitrogen oxides (NOx) into the air. These pollutants, when combined with the atmosphere humidity, turn into sulfuric and nitric acids, respectively, that fall as acid rain. The acid rain negatively affects lakes and forests, flora and fauna, cultivable land, water reservoirs and human health.
It refers to the fog with atmospheric pollutants whose main origins are industrial activities and transport. As a consequence of the concentration of dust particles and smoke, when acting as condensation nuclei, they produce water vapor condensation, even when the relative humidity is much less than 100%. The pollutants that contribute the most to this effect are particles, coal, iron dust and sulfur oxide.
The affections can be multiple. Establishing the chronic toxicity levels for each substance is complicated since there are several factors favouring or disadvantaging the effects of the possible toxicity and, as it does not have immediate effects, it is not always possible to correlate the cause-effect relationships.
1. The majority of the materials used in construction are valid since they can not be considered as good or bad. What is good or bad is the way to use them and how they are managed throughout their entire service life.
2. Technicians need to have information about the complete materials’ life cycle to be able to choose constructive solutions based on objective data. This information is provided by the environmental product declarations.
Currently, the construction sector is based on extracting and transforming resources for its use in buildings and, after a while, converting them into wastes.
If the wastes can be converted again into resources, it will be possible to close the cycle of the materials.
Some examples of measures that can help to reduce the environmental impacts of the materials used in buildings are showed below:
|Stage||Aspects to consider during the design of the building|
|Exploitation / Maintenance||
Furthermore, it is recommended to apply a Life Cycle Assessment (LCA) when designing or having to prioritise strategies to reduce the environmental impacts. This methodology allows having a more complete knowledge of products and avoids possible transfers of environmental impacts, such as using low-impact materials in terms of production, but not durable implying a periodic substitution.
The Life Cycle Assessment (LCA) methodology can be useful to compare between products, equipments and systems that have the same function. This tool allows making global balances considering all the environmental impacts produced in the different stages of the materials used to construct a building: the production of materials, transport, service life in the building, uninstallation and final management of the wastes generated.
The main goal of the eco-labels (also known as environmental labels) is to promote the demand of the products that have a lower environmental impact. According to the ISO (International Organization for Standarization) there are three eco-labels types.
Type I eco-labels are environmental certifications that consider the life cycle assessment of a product or service. According to the ISO 14024, the type I eco-labels are part of a voluntary and multi-criteria program, developed by a third party that authorises the use. The type I eco-labels indicates that a product is environmentally preferable dependent on several considerations based on its life cycle assessment. Some examples of type I eco-labels geographically close and that includes construction products are:
|Distintiu de Garantia de Qualitat Ambiental
Generalitat de Catalunya
|Aenor Medio Ambiente
Asociación Española de Normalización y Certificación
|Der Blaue Engel (Àngel Blau)
Ministerio Federal de Medio Ambiente de Alemania
|The Swan (Cigne Blanc)
Northern Ecolabelling (Noruega, Finlandia, Islandia, Dinamarca, Suecia)
AFNOR Certification (Francia)
Type II eco-labels or environmental self-declarations, in accordance with the ISO 14021, focus on positive environmental characteristics of a product that have not been authorised by a third party. According to the ISO 14021, too general and ambiguous phrases about a product like “respectful with the environment”, “ecological”, “does not pollute” or “protects the ozone layer” must be avoided.
The Möbius strip is an example of environment self-declaration widely known by the consumer. According to the ISO 14021, it can be used to indicate that a product or container is recyclable or contains recycled materials. In the absence of a percentage, the symbol is interpreted as the product or container is recyclable. On the contrary, when the percentage is specified, it indicates the amount of recycled material that contains. Some companies make use of symbols to indicate that their own products have a better environmental performance. In accordance with the ISO 14021, these symbols have to be simple, easily reproducible and recognisable. Moreover, in case of using symbols emulating natural objects, they must have a direct and verifiable relation with what is stated.
Type III eco-labels or environmental product declarations, based on the ISO 14025, facilitate the objective, comparable and trustable communication of the environmental performance of products. EPDs neither give criteria for the preference of a product nor establish a minimum criterion to be achieved. However, they promote the products and services demand and offer with a lower environmental impact by comparing between different products. These declarations are based on the life cycle assessment of a product that is developed according to specific requirements. What is more, EPD can be reviewed and validated by accredited organisms. Some examples of type III eco-labels that include construction products are:
|Environmental Construction Product Declaration
Administered by Col·legi d’Aparelladors, Arquitectes Tècnics i Enginyers d’Edificació de Barcelona.
|Environmental Product Declaration
Administered by AUB (Alemania)
|Environmental Product Declaration
Administered by The Swedish Environmental Management Council