What is the life span of a zinc roof?
Usually the life span of zinc is over 100 years in an unpolluted urban environment and between 60 and 80 years in a marine atmosphere.
Why do you say that zinc is durable?
We say that zinc is durable because, in the presence of water, when it comes into contact with carbon dioxide in the air, a compact patina is formed, which adheres to the zinc, and protects the zinc from any later atmospheric corrosion.
What is patina?
Patina is the layer of zinc hydroxycarbonate that forms on the surface of the zinc when it is exposed, in the presence of water, carbon dioxide (CO2) in the air. The patina consists of a compact protective layer, which adheres to the zinc beneath it and protects the zinc from any later atmospheric corrosion.
Does zinc pollute?
The amount of zinc in the environment does not present a risk to ecosystems because it is within a range of concentrations that are optimal for life.
Is zinc harmful to human health or living organisms?
No, zinc is not harmful to human health or living organisms, nor is it toxic in itself since it is necessary, and indeed essential, in small quantities for all living organisms whether they are human, vegetable or animal. They draw it from their food in order to ensure that their metabolism functions properly. Zinc is essential for human health, for example for growth and for the protection of the skin. It also plays an important role in the development of the brain, foetal development, immune functions, sense of taste, sense of smell, etc.
Is rolled zinc recyclable?
Yes it is potentially100% recyclable. In practice, 95% of VMZINC is recycled. Recovered zinc is reused by secondary zinc refiners, and brass and zinc oxide producers. Its use is limited in the production of rolled zinc.
What is white rust?
White rust is the result of a corrosion mechanism that occurs when water condenses on poorly ventilated zinc surfaces. To prevent it from forming, there must be good ventilation between the rolled zinc and its substructure. If it is not possible to achieve such ventilation we recommend using VMZ ZINC PLUS, which is VMZINC® with a backside protective treatment.
What are the main factors that influence the zinc corrosion rate?
The corrosion rate of an exposed rolled zinc surface is influenced by:
* sulphur dioxide (SO2), typically found in very urbanised or industrialised atmospheres,
* chlorides, essentially present in a marine atmosphere,
* the slope and direction of the exposed surface,
* surface treatments.
SO2 has the greatest impact: it is very soluble in rainwater which it acidifies. It attacks the protective layer of zinc hydroxycarbonate (patina) to form a soluble zinc sulphate which is washed off by rainwater. The corrosion rate of zinc is thus higher in highly industrialised areas.
Can zinc be used in a marine atmosphere?
Zinc is a metal that performs extremely well in coastal environments and our normal warranties are valid for these locations. However, as zinc is a natural non painted metal it can react with its external environment including air with a high salt content. When this salty air lands on surfaces such as roofs the rainwater rinses the salt off, however on un-rinsed surfaces such as some facades and soffits this rinsing effect maybe very limited. For these surfaces within 1km of the sea, permanent staining resulting from salt exposure, is likely. The staining will also be more visible on a very dark grey surface such as ANTHRA-ZINC.
In 2005 VMZINC launched the PIGMENTO range which is pre-weathered zinc with an added pigment which is then sealed with a coating. This coating results in elements such as salt in the air adhering and reacting with the zinc far less than with QUARTZ-ZINC and ANTHRA-ZINC. It is also easier to clean the PIGMENTO range. We also offer products without added pigment, called QUARTZ-ZINC STRAT and ANTHRA-ZINC STRAT.
For coastal locations (within 20km of the sea) the use of PIGMENTO and STRAT products will reduce potential superficial staining on building surfaces with limited exposure to rinsing by rainwater. For these surfaces within 1km of the sea, permanent staining resulting from salt exposure, is still likely.
It should be noted that PIGMENTO and STRAT must not be left with bare edges exposed in coastal locations and folding radii must be respected – see General technical recommendations for further information.
Does zinc have to be protected from external attacks?
No, zinc doesn't require any particular protection because it protects itself by forming a patina when it comes into contact with the oxygen and carbon dioxide in the atmosphere. Nevertheless, the use of preweathered zinc may be recommended in particularly aggressive environments such as industrialised areas or industrialised marine environments.
Is zinc compatible with all materials?
The only materials with which zinc is not compatible in the case of direct contact are:
* metals such as copper, brass, steel, cast iron and chrome
* wood with an acid pH, for example: chestnut, oak, larch, birch, Douglas fir, and red cedar
* cement and plaster
* bitumen, even water from a bituminous roof should not run over a zinc roof.
However, if precautions are taken to avoid direct contact, zinc can be used with all types of substructures.
What is sustainable development?
The concept of sustainable development came into being in the Seventies. Public opinion woke up to the close link between the protection of the environment and the ecological, economic and social differences between countries and generations.
Sustainable development is a form of development which "meets the needs of the present without compromising the ability of future generations to meet their own needs." (from the Brundland Report, UN, 1987). It is development which respects the environment and takes into account the economic, technological and human equilibrium on a worldwide scale.
What are the main environmental guidelines for the building industry worldwide?
There are 4, each with its own specifications:
* HQE in France
* LEED in the USA
* Eco-devis in Switzerland
* BREEAM in the UK
The purpose of all four is to optimise the environmental performance of buildings.
Why is rolled zinc an asset in sustainable development?
Zinc is an asset with regard to environmental guidelines because some of its properties contribute to protecting natural resources, reducing greenhouse gases and limiting costs related to waste management and building maintenance. These properties are:
* low energy consumption for the production of rolled zinc
* high recovery and reuse rate (90%)
* extremely durable
Moreover, the variety of textures and colours (natural, preweathered, bilacquered) allows the building to blend into its surroundings, which is also an asset.
Where is zinc found in the environment?
Rocks, many minerals, soil and water and the air naturally contain variable concentrations of it.
There is an average of 80 g of zinc per ton in the earth's crust.
In some areas of the earth's crust, as a result of geological and geochemical processes, there are particularly high concentrations of zinc. In areas where the concentration of zinc is generally over 5% the ore is extracted.
Is there a risk of a zinc shortage in the future?
Taking into account the efforts made to recycle it and with an estimated 1,900 million tons of mining reserves, mankind's requirements for zinc will be met for over a century.
Do the zinc production plants pollute?
In the industrialised countries, production plants have to obey very strict environmental regulations. The French Umicore plants are all committed to meeting ISO 14001 standards: the Umicore plant in Viviez obtained ISO 14001 environmental certification at the end of 2003. The Auby plant obtained this certification at the beginning of 2004 and the Bray-et-Lû plant obtained it in December 2004.
What are the main countries or regions where zinc is mined?
The main regions and countries where zinc ore is mined are:
* Asia (China, Kazakhstan, India and Japan) and Australia: 44%,
* North America (Canada, USA, Mexico) and South America (Peru, Bolivia, Brazil): 43%,
* Europe (Ireland, Poland, Spain): 10%,
* Africa (Morocco, Tunisia): 3%.
How much energy does zinc consume in comparison with the other metals used in the building industry?
Less energy is used to produce metallic zinc from ore or from recycled materials than for any other metal, such as aluminium, copper or stainless steel, used in the building industry.
In addition, less energy is used to transform zinc into rolled zinc than to process other metals. In fact, zinc's mechanical properties make it easier to roll and transform it into finished products for the building industry because these properties allow the zinc to be rolled at a low temperature compared to most other metals, thus reducing energy consumption.
How does the rolled zinc recycling market work?
Rolled zinc recycling is a traditional market in Western Europe where old rolled zinc is recovered during light building renovation work such as the replacement of rainwater systems or from bigger renovation projects such as the replacement of a roof and, occasionally, the demolition of an old building.
Systematic collection is facilitated by the ease of dismantling old products, the existence of a large local network of buyers and an advantageous purchase price. In fact, the long-term trend for the price of old zinc is relatively constant and equal to 60 to 75% of the London Metal Exchange price for pure zinc ingots.
The main users of old rolled zinc products are secondary zinc refiners (56%), zinc oxide producers (35%) and brass producers (5%), all located in Europe. This recovered zinc cannot be reused to make rolled zinc: very pure (99.995%, therefore with a maximum of 0.005% impurities) primary zinc is required to make rolled zinc.
What are the consequences of zinc deficiency on human health?
Zinc deficiency can cause serious health problems. Zinc is the 3rd most important trace element after magnesium and iron in the human body. As such, it participates in a great number of metabolic reactions. A lack of zinc in the diet can give rise to serious health problems such as skin problems, slower healing of wounds, reduced senses of taste and smell, increased risk of infection, retarded growth in children, mental lethargy, lack of appetite, hair loss, etc.
Is zinc a dangerous heavy metal like cadmium for example?
No, zinc is not a dangerous heavy metal in the same sense as cadmium for example. Metals are commonly divided into two groups: "heavy" metals (with a density of over 5 g/cm3 * "Effets des métaux lourds sur l'environnement et la santé" (Effects of heavy metals on the environment and health) G. Miquel, Rapport 261 - Office parlementaire d'évaluation des choix scientifiques et technologiques.) and light metals (with a density of less than 5 g/cm3). Since the density of zinc is slightly higher than 5 g/cm3 it can certainly be classified as a "heavy metal" because of its density.
But the term "heavy metal" is often associated with "toxic". While this association is true for certain metals such as cadmium (if even a small quantity of these elements is inhaled, ingested or enters the human body through the skin, it can cause death or chronic or acute problems * Décret n°97-517 du 15 mai 1997 relatif à la classification des déchets dangereux. (Order 97-517, May 15 1997 regarding the classification of dangerous waste.)). This is not true for other metals such as zinc or copper. Zinc is not toxic because it is a trace element which is indispensable for all living organisms.
What is ecotoxicology?
Ecotoxicology is the science that studies the potential effects of various substances on ecosystems (ecosystem = biological community of interacting living organisms and their physical environment, for example: a tree trunk, a field, an ocean, etc).
The science that studies the potential effects of various substances on human beings is called toxicology.
Do current zinc emissions present an ecotoxicological risk for the environment?
No, in the developed countries, current emissions of zinc into the environment present no ecotoxicological risk.
Zinc is a natural element which is found throughout the environment (water, air, soil and rocks).
Localised emissions of zinc into the environment can be from natural sources such as volcanic emissions, or be of human origin, for example: worn tires, atmospheric corrosion from galvanised steel or rolled zinc, from fertilisers and cattle fodder.
In the developed countries, the amount of zinc measured in sensitive ecosystems shows that current emissions of zinc into the environment do not present any ecotoxicological risks because they are within the limits required for optimal conditions for life.
Do living organisms assimilate all the zinc emitted into the environment?
Not all the zinc emitted into the environment can be assimilated by living organisms. Only 10% in the ground and 30% in European rivers can be assimilated, the rest is in bound form and cannot be assimilated. Zinc that can be directly assimilated by living organisms is classified as "bio available".
What is the connection between sustainable development and environmental quality in the building industry?
In the areas of energy, waste and water the building industry has ecological (energy consumption, emission of greenhouse gases, production of waste, etc.), economic (energy costs, waste management costs, water treatment costs, creation of employment, etc.) and social (organisation of living space, sanitary conditions, durability, etc.) impacts.
These impacts are all related to the three fundamental pillars of the concept of sustainable development.
The environmental quality approach in the building industry, the aim of which is to reduce the negative impacts and optimise the positive impacts of this sector on the quality, environment and economy of society, is therefore a form of application of the concept of sustainable development in the building sector.
How does the use of zinc in building applications contribute to sustainable development?
The use of zinc in building applications contributes to sustainable development because:
* when zinc is used as a galvanising agent to coat steel it considerably lengthens the life span of steel products, reduces their maintenance costs and economises on the natural resources used to produce steel,
* zinc contributes to the durability of infrastructures and transportation systems on which modern society depends. Zinc thus contributes to social progress, 90% of all rolled zinc products are recovered. Natural resources are thus protected, there is less building waste in waste storage centres because of recycling, and jobs are created in the recycling market.
What is HQE (high environmental quality)?
HQE (Haute Qualité Environnementale: high environmental quality) is a French approach the aim of which is to incorporate the environmental, social and economic concerns arising from the concept of sustainable development, into development, rehabilitation and construction projects.
This approach is applied throughout the life cycle of the building (from construction to demolition) in order to reduce the impact on the outside environment, participate in the protection of natural resources, and, at the same time, create a healthy, comfortable interior environment.
HQE has established objectives for the improvement of the environmental quality of buildings. These objectives are broken down into 14 targets divided into 4 major themes: ecological construction, ecological management, comfort and health.
Is there an HQE label?
No, HQE is not a label, a standard or a regulation. The high environmental quality approach is voluntary and evolving. The different players in the building industry are involved in this approach which is usually initiated by the owners.
Certification under HQE in the service industry is being tested, but if it becomes official it is nevertheless intended to remain voluntary.
Is it more expensive to carry out a project using the HQE approach?
No, for, although the straight investment cost is often estimated to be 10% higher, the overall extra cost can be greatly reduced, by incorporating the possible savings in running costs particularly for energy, water, maintenance and transport.
For communities there should be a reduction in cost because costs generated by pollution, health, consumption of resources and investments in energy in particular should be avoided.
How is the use of rolled zinc an asset for a building designed according to the HQE approach?
It is an asset because it allows: a harmonious relationship between the building and its immediate environment (conforms to target 1): the rolled zinc products provide a wide choice of systems and a varied range of textures (natural, preweathered) and colours (lacquered).
Limitation of environmental impact (conforms to target 2): the amount of energy required to produce rolled zinc products is the lowest in the non-ferrous metal market. 90% of these products are recyclable at the end of their life.
A low pollution factor on the building site (conforms to target 3): fast installation of rolled zinc products, no on-site pollution and very little waste from the site.
Limitation of impact related to maintenance and upkeep of the building (conforms to target 7): rolled zinc products are very durable.
Protection from noise inside the building (conforms to target 9): zinc is a non-ferrous metal that does not act like a drum; its acoustic attenuation index is comparable to that of slate.
What is LEED?
Leadership in Energy and Environmental Design is an American guide created by the US Green Building Council for players in commercial construction. Its aim is the development of durable, "green" architecture.
How can the use of rolled zinc contribute to obtaining LEED certification?
The use of rolled zinc in an American commercial building can contribute to obtaining LEED certification in the Materials and Resources category because it contributes to the protection of natural resources: rolled zinc is 100% recyclable. Because products can be recovered easily at the end of their life and there is an extensive network of buyers offering advantageous prices, the recycling rate for zinc at the end of its life is extremely high (90% in western Europe).
What is BREEAM
see separate section