Posts By: tbsl

Roof is the most essential part of your structure. Done professionally, it seals your building, protects it from water leaks and increases your property value. Most importantly, your roof brings your entire structure to life for many years to come! The metal roofing or wall cladding is one of the principles building components that act like protective envelope.

But have you ever wondered what kind of material goes into making a steel roof?

Selection of the right material would increase building life, incur low maintenance, enable thermal comfort in hot or cold seasons, provide design flexibility and improve overall aesthetics that last longer.

While there are many roofing materials available, ZINCALUME® steel and Galvanized steel may find themselves at loggerheads during a purchase decision.

Let us see what the differences are between the two:
Fact file: When the steel surface is coated with an additional layer of organic or metallic material to protect from rusting, is called coated steel. Usually, a coating layer is added to flat steel when they are in a coil form.

What is Galvanized steel and ZINCALUME® steel?
Galvanized steel is coated with almost 100% zinc while ZINCALUME® steel is coated with an alloy of approximately 55% Aluminium, 43.5% zinc and 1.5% silicon.

If you’re new to the world of steel, you may have heard the word galvanize thrown around a few times. But what does galvanize mean? Galvanizing is the process of applying a protective coating to steel or iron. The coating is made from zinc and is used to halt the formation of rust. Galvanization is important because it provides protection for steel and iron products.

Developed by technology inventors, ZINCALUME® steel on the other hand is world’s leading Al-Zn alloy coated steel product. It is an outcome of extensive research and continues to set standards for corrosion resistance and long life. It is designed to withstand the rigors of nature and the product’s performance is well-established across a wide range of climatic conditions and geographies using exposure test sites and infield inspections.

The rate of corrosion of ZINCALUME® steel is initially very similar to that of galvanized steel. However, the longer life of ZINCALUME® steel is attributed to the rapid slowing down of this corrosion rate shortly after the initial exposure to the environment. This is due to the formation of Aluminium-containing corrosion products that consequently add to the barrier protection of the coating. All the while, the zinc present in the ZINCALUME® steel coating is available to sacrificially protect the steel at cut edges.

Application areas & Advantages of ZINCALUME® steel over Galvanized steel
Galvanized steel finds its presence in Automobile, telecom & electricity towers to name few. Even in construction industry, GI sheets are practically used for carrying heavy loads. Generally, steel decking, mezzanine or primary structures like beams, columns are common applications in steel building. 1.5mm to 3.00mm are common thicknesses used for these applications. Historically, Galvanized roof panels are also being used for residential & commercial segments. Generally, Z120, Z180 & Z275 are common coating thicknesses used for construction application

With increased awareness for selecting the right material, today Architects & Developers choose ZINCALUME® steel; which has grown as a widely accepted building material over Galvanized steel especially for projects segment. Scope of ZINCALUME® steel can also be extended to LGFS, Solar mounting structures, Silos etc. where high strength & light weight along with durability is of utmost importance.

With technological development in building materials, ZINCALUME® steel is an advanced Al-Zn formulation over standalone Zn coated Galvanized steel as it offers extended corrosion protection & superior aesthetics. Having High strength to weight ratio, ZINCALUME® steel requires lesser tonnage over galvanized steel without compromising on other design aspects, resulting in reduced capital investment. For ZINCALUME® steel, AZ150 & AZ200 are most prominent coating thicknesses used for projects ie non-residential segment applications like Metro stations, Airport, Industries & warehouse as cladding material

Technical benefits of ZINCALUME® steel
Tests have demonstrated that corrosion protection of ZINCLAUME® steel can last up to four times longer than corrosion protection provided by traditional Zinc coated steel with similar coating thickness in roofing and wall cladding applications under similar environmental conditions.

Special Resin & Passivation Coating:
Specially developed Resin & Passivation, double layer protection is key differentiator for ZINCALUME® steel when compared with other coated steel peers. It adds anti darkening property by which your roof and wall cladding looks newer for a longer period. It gives excellent adhesion to substrate, very good impact resistance & forming flexibility

Self-healing properties:
ZINCALUME® steel inherently offers self-healing characteristics for cut edges. The problem with galvanized metal, painted or not, is that once it starts to red rust, it doesn’t eventually stop as it does in case of ZINCALUME® steel. The rust on galvanized surface will just continue to spread and get worse because it doesn’t have the self-healing property.

Technical support:
Tata BlueScope Steel receives extended R&D Support from BlueScope Australia and Tata Steel for special developments as per application. Full technical assistance provided by Tata BlueScope to architects, consultant, owners, Govt./Pvt organizations on recommendation of product suitability in various environments and process assistance to end users.

Since your roof is a long-term investment, it’s important to choose the best option. With decades of experience in manufacturing best-in-class steel products and solutions; we at Tata BlueScope Steel exactly know how important it is to choose the right product for your steel building. Our expert team from Tata BlueScope Steel can guide you for making the right decision, well-suited for your desired application.

For more information, please visit: https://tatabluescopesteel.com/products-solutions/zincalume-coated-steel/

‘First impression is indeed the last impression’ is an old cliché that even today stands true, especially when it is our own factory, warehouse or a commercial structure. Selection of the right cladding material sets a perfect tone for the rest of the structure followed by its interiors. External material and colour choice is much more ‘permanent’ decision and any compromise in that can affect both aesthetics and performance. An impactful ingredient that contributes immensely towards the overall life of the cladding material thereby the longevity of the steel structure, is its colour coating. Colour coatings are used to give painted steel long-term protection under corrosive conditions, maintaining its strength and integrity.

Painted steel sheets are generally referred to as colour coated sheets. The sheets used particularly for roofing and walling in the construction industry are mostly pre-painted. These pre-painted steel sheets usually have metallic coating beneath the paint. The substrate i.e. metallic coated steel coil is processed on a continuous paint line to get the pre-painted steel coil. A typical paint line involves activities like uncoiling, cleaning, pre-treatment, primer application, painting (top and backer coat), baking and recoiling (Refer Fig. 1).

The pre-painted steel has substrate, conversion coating, primer and paint coats on both the surfaces. For best performance, there needs to be synergy and compatibility among different components of the paint system and the substrate. Normally, the paint coats for the two surfaces of a coil are different because of the difference in performance required. The surface to be exposed to weathering is referred to as top coat and other side as backer coat. However, the paint coats for both surfaces could be same. Such pre-painted steel is called double sided. Structural stability is function of base metal thickness & steel grade, whereas corrosion resistance is contributed by type of metallic coating & paint system

It provides aesthetics, protection of substrate and thermal efficiency to structure. Paint shade determines Solar reflectance Index (SRI), hence crucial parameter while building material selection. There are various paint systems available in pre-painted systems

• Regular Modified Polyester (RMP)
• Silicon Modified Polyester (SMP)
• Super Durable Polyester (SDP)
• Polyvinylidene fluoride (PVDF)

Thickness of base substrate known as Base metal Thickness (BMT),while the thickness of metallic coated substrate is termed as TCT, i.e. total coated thickness (Base steel + metallic coating), the thickness of painted steel is called TPT, i.e. total painted thickness (steel + metallic coating + paint film).

Tata BlueScope steel expert team can guide you for right material selection that suits your building environment

COLORBOND® steel is one of the world’s most advanced pre-painted steel products for the building and construction industry. COLORBOND® steel has been designed to provide an excellent strength of the steel base, the corrosion resistance of 55% Al-Zn Alloy coated ZINCALUME® steel and the superior aesthetics of an advanced top & backer paint system. COLORBOND® steel coils are typically supplied in various colours in grade G300 and G550 with base metal thickness ranging between 0.30 mm to 1.30 mm and widths of 900 mm to 1250 mm.

Depending upon aesthetics & environment conditional requirement, Tata BlueScope steel offers COLORBOND® steel with multiple variants as

• COLORBOND® XRW
• COLORBOND® Spectrum Series
• COLORBOND® Ultra
• COLORBOND® XPD
• COLORBOND® Metallic

Successfully tested for over five decades, COLORBOND® steel has withstood challenging weather conditions; ranging from extreme cold, dust, cyclonic, saline coastal environments to heat zones exceeding 50 deg C. Best in class paint system helps to resist chipping, peeling and cracking, ensuring COLORBOND® steel delivers a long lasting performance for generation to come. Widely accepted by most progressive sectors like manufacturing, warehouse, infrastructure etc., COLORBOND® steel is most preferred choice of Architects to transform landscape around us

Intensity of Urban heat island (UHI) effect

Around half of the world’s human population lives in urban areas. In the near future it is expected that the global rate of urbanization will increase by 70% of the present world urban population by 2030, as urban agglomerations emerge and population migration from rural to urban/suburban areas continues. Thereby, it is not surprising that the negative impacts related to urbanization is an increasing concern capturing the attention of people worldwide.

An urban heat island (abbreviated as UHI) is where the temperature in a densely populated city is as much as 2 degrees higher than suburban or rural areas. Why? This happens because of the materials used for pavements, roads and roofs, such as concrete, asphalt (tar) and bricks, which are opaque, do not transmit light, but have higher heat capacity and thermal conductivity. UHI is also decrease air quality in the cities, due to pollution generated by industrial and automobile exhaust, higher extent of particulate matter and greater amounts of dust. Extensive research activities being conducted to mitigate risks related to UHI

What is Solar reflective index (SRI)?

The Solar Reflectance Index (SRI) is a measure of the solar reflectance and emissivity of materials that can be used as an indicator of how hot they are likely to become when solar radiation is incident on their surface. The lower the SRI, the hotter a material is likely to become in the sunshine.

SRI is a scale from 0 to 100. Materials that absorb and retain solar radiation (and so become hotter in sunshine) have a lower number, whilst highly reflective materials (which remain cooler in sunshine) have a higher number.

COLORBOND® steel with Thermatech® solar reflectance technology

For more than 40 years, COLORBOND® steel has revolutionised building design, transforming our workspaces along the way. COLORBOND® steel with Thermatech® solar reflectance technology sets new benchmarks, providing architects, builders and developers better choices to meet the challenges of a changing world. With the Indian summer soaring above 50 degree Celsius; roof is your structure’s first line of defence. And the climatic impacts within the building could be controlled with a thermally efficient roofing system.

Thermal reflective roofing materials with suitable SRI values in its paint system, have been a big focus in recent times and is one of the many vital components considered while planning a structure. Addressing the changing requirements of a roofing system that demands greater climatic considerations. Tata BlueScope Steel, leading coated steel manufacturer offers an innovative energy efficient solution; THERMATECH™ Solar Reflectance Technology that is incorporated in COLORBOND® steel. This High strength light weight colour coated steel provides thermal protection, by optimising solar reflectance properties, which is inbuilt in its material due to the paint system

Saves Energy

Thermatech® technology helps your roof and your building stay cooler by reflecting more of the sun’s heat. When heat is reflected away from your building, air-conditioning has an easier job keeping your building cool. Using less energy to cool your building can help occupants save money on energy costs as well as potentially reduce emissions from electricity generation. In moderate to hot climates COLORBOND® steel with THERMATECH® Technology can reduce annual energy consumption by up to 20%, compared to ordinary Pre-painted steel (ordinary PPGL) roofing materials of similar colour but with a lower solar reflectance.

Help Structures Lasts Longer

COLORBOND® steel with Thermatech® technology absorbs less heat from the sun, protecting your roof and its supporting structure from extremes in heat. As a result, the stresses placed on your roof and its materials are reduced and your roof lasts longer.

Even Darker Colours Reflect More Heat

It’s widely known that lighter colours are better at reflecting heat. Now with Thermatech® technology, even the darker colours in the COLORBOND® steel range perform better without changing their appearance. So you can choose from a wider range of colours and still enjoy a thermally efficient roof.

Minimising Environmental Impact

With Thermatech® solar reflectance technology, we help in creating a future that is comfortable not just for people, but for the environment too. THERMATECH® Technology is an effective way to reduce the energy load of your building. COLORBOND® steel is a GreenPro certified product by IGBC (Indian Green Building Council). This certification requires the product to undergo a rigorous sustainability assessment. Tata BlueScope Steel is committed to design and manufacture sustainable products and solutions, that are lighter, last longer and use fewer natural resources to produce them.

Watch this video to understand more about Thermatech® solar reflectance technology from COLORBOND steel

Building a structure has many direct and indirect ramifications on nature. Right from manufacturing of its raw material, getting it to the site, while constructing or repurposing the same; buildings consume energy, water, generate waste, and at times also emit hazardous emissions. Such adverse effects on people and environment; has prompted the world to craft an effective policy in form of green building certification and usage of sustainable commercial buildings material to mitigate serious impacts on our lives and ecosystem.

Environmental considerations are becoming increasingly important in the construction of new green buildings. The green concepts and techniques in building sector can help address national issues like water efficiency, energy efficiency, and reduction in fossil fuel use in commuting, handling of consumer waste and conserving natural resources. Most importantly, these concepts can enhance occupant health, happiness and well-being.

In view of this, the Indian Green Building Council (IGBC) has launched IGBC Green New Buildings rating system to address our nation’s priorities. This rating programme is a tool which enables the designer or an architect to apply green concepts and reduce environmental impacts.

COLORBOND® steel and ZINCALUME® steel manufactured and marketed by Tata BlueScope Steel are ‘GreenPro’ certified and are ideal for creating buildings that satisfy environmental rating tool requirements such as the Indian Green Building Council (IGBC), on their sustainability assessment. These are the new age eco-friendly construction solutions for propagating the green building movement.

Green building rating brings together best sustainable practices and solutions to reduce environmental impacts and provides an integrated approach considering life cycle impacts of the resources used.

Let us see how COLORBOND® steel and ZINCALUME® steel conform to the sustainability quotient stipulated by GreenPro certification:

During manufacturing process there has been special care taken for minimum water consumption, energy utilisation and hazardous and non-hazardous waste management system. Obtaining 90% of its raw material (by weight) from regional sources has further added to its green credentials. With adequate quality management system the plant has been effective in reducing rejection rates after sales. In addition to that an efficient manufacturing process, usage of energy sensitive machinery, solar energy, recycling and disposal management system further contributes to qualifying to a green manufacturing process.

Recyclability refers to how effectively and efficiently a product or material can be recycled into a new product. Recycling prevents the waste of potentially useful materials; reduces consumption of raw materials and energy; and reduces overall pollution. COLORBOND® steel and ZINCALUME steel are water harvestable materials with RoHS compliance. Being lead free it has acceptable levels of volatile organic compounds.

Roofs made from COLORBOND steel have high solar reflectivity reducing solar radiation and heat absorbed into the buildings. The paint technology known as THERMATECH technology, consists of high solar reflectance index that contributes to energy performance improvement in the built environment. An effective way to reduce a building’s energy load through less reliance on air-conditioning to maintain a comfortable internal temperature, Thermatech technology potentially saves occupants money on energy as well as reduces emissions from electricity generation.

COLORBOND® steel with its advanced paint technology uses fewer metal resources and offers excellent corrosion resistance with an increased lifespan resulting in a smaller environmental footprints.

IGBC’s accreditation for COLORBOND® and ZINCALUME® steel as green products, further increases the green rating points of the overall project; thus granting of government incentives. Both COLORBOND steel and ZINCALUME steel are sustainable products manufactured by a responsible establishment. Being durable and resilient to India’s harsh climatic conditions and coastal environments with its long life helps conserve resources and energy that may otherwise be invested in products with a shorter life span. It is a lightweight material which can mean a lower cost to transport to site and enables a lighter roof structure. It is a perfect combination of beauty, strength and environmental performance that makes it a responsible choice for a greener and a sustainable future.

Internationally, the Melbourne Convention and Exhibition Centre (MCEC) was the first convention centre in the world to have achieved a 6 Green Star rating back in 2008. This recognition was accredited by the Green Building Council of Australia (GBCA) with an objective to develop a sustainable property industry in Australia and drive the adoption of green building practices through market-based solutions. The entire roofing solution at the Melbourne Convention and Exhibition Centre; was made of COLORBOND® Steel (with THERMATECH™ technology).