Objectives of Sustainable Building
An objective of sustainable building is quality. Sustainable buildings are environmentally friendly and easy on the resources. They offer occupants healthy surroundings that fit within their environment. This is how sustainable buildings retain their high value on a long-term basis – for investors, owners and users.
Sustainable Building with RHEINZINK
- Natural element
- Sustainable resource
- Natural and low to no-maintanance surface
- Long service life
- 100% recyclable
- Low primary energy use
Zinc is one of the most abundant elements in the earth’s crust. Zinc comes second as a main trace element behind iron and plays an important role for numerous physiological and biochemical functions. Zinc regulates hormones, stabilizes the cell membrane, influences growth and plays an important role for nerves, eyes, skin, wound healing and the immune system.
Zinc ore is readily available and mainly mined underground from countries such as Australia, Canada and Peru. Other countries such as Japan, Mexico, Zaire and some European countries, also mine zinc ore. As far as present day usage, zinc ore reserves are estimated at 34 million tons throughout the world – based on the current production quantities this would be a reserve for the next 700 years. This timeframe does not take recycling into account, thus extending the timeframe of zinc even further.
Natural and low to no-maintenance Surface
The PATINA LINE has a natural surface and no permanent coating or phosphated layer. After prolonged periods of wetting and drying cycles, a blue-grey or graphite-grey protective layer forms on the surface of the material. This layer is called the 'patina'. The self-healing properties of the patina is important as it diminishes minor scratches over time.
The patina is responsible for the corrosion protection and the durability of the material. The water-insoluble layer is permanently removed by environmental influences / erosion (both natural and harming environmental influences) and simultaneously the material forms a new patina.
Due to the significant reduction of environmental pollution during the past decades the wear rates, which also depend on the location, the orientation and pitch of the surfaces have considerably decreased. For the central European climate a value of 3.0 g/(m²·a) respectively 0.4 µm per year can be assumed as the average wear rate. According to latest studies this value has to be considered rather to be too high than too low.
If the wear rate is considered in context with the so-called half-value thickness (e.g. 0.35 mm for 0.7 mm sheet thickness) the result would be a statistical life expectancy of several hundred years. However, this statement only represents a theoretical life expectancy. If other influences, like e. g. processing are taken into account, a realistic life expectancy of about 100 to 120 years can be assumed for RHEINZINK roof and 150 + years for wall coverings. A proper planning and a flawless processing are vital for reaching the above-mentioned life-expectancy.
The following institutes and certification bodies confirm the durability of our material:
- The German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety: Zinc as a roof covering has a minimum life expectancy of 50 years (Source: Table "The service live of building elements for the life-cycle analysis based on the Assessment System for Sustainable Building for Federal Buildings")
- The British certification body BRE (Building Research Establishment Ltd.) estimates a life-expectancy of minimum 80 years for RHEINZINK in the context of life cycle assessment.
- The Institute TNO (Built Environment and Geosciences), Breda, Netherlands assumes a service life of minimum 75 yearsfor gutters and downpipes.
Recyclability plays an important role in the field of sustainable building. The demolition process belongs to the life cycle of a building and has to be considered separately. The main goals are the protection of natural resources and the avoidance of high waste rates. Excellent recyclability guarantees the recycling of the parts of the building within the natural energy and material cycle. Therefore construction materials should be used which can be re-used or recycled.
Principally, RHEINZINK products last forever. In case of refurbishment or at the end of its service life, separate collection is possible. All products of the PATINA LINE are 100% recyclable without additional production processes like the removal of coatings or separating composite materials. The scrap resulting from production is re-melted and processed into new products. In Germany, the recycling rate for construction zinc stands at more than 95% - consequently almost no construction zinc gets lost. Today, thanks to the high recycling rate almost one third of the material consists of recycling material – the rate is only limited as to the durability of zinc products.
The energy consumption for recycling RHEINZINK is only 5% of the primary energy content. This means that 95% of the energy can be saved compared to primary production. Considering the economic aspect that scrap metal can garner as much as 60% of the price charged for high-grade zinc as a raw material, the decision for the natural material is extremely sustainable.
Low primary Energy Use
RHEINZINK has a low melting temperature of approx. 520°. The recycled content has a low primary energy content and is comparable to other building metals or conventional roofing materials like concrete or clay tiles.
For more information, please see our Environmental Product Declarations (EPD's).