55% Aluminium–Zinc Alloy Metallic Coated Steel

Rajesh Maheshwari, Head -Technical Support (Coated Steel), Tata BlueScope Steel Limited

Metallic coated steel as a building material offers strength, great flexibility and is durable. It is light, quick to install, insect/ mold resistant and also relatively inexpensive. Today, metallic coated steel can be made to look traditional or contemporary. Metallic coatings with high reflective values increase thermal efficiency of buildings thereby reducing energy costs. For these features, metallic coated steel is the most preferred engineered building material.

Metallic Coated Steel for Roof & Wall Cladding
55% Aluminium–Zinc Alloy Metallic Coated Steel
Of the various applications of metallic coated steel, maximum usages is for roofing and wall cladding of buildings. For the high strength (minimum Yield Strength of 550 MPa), it is used in thinner sections and is much lighter than other construction materials therefore requires lighter structure. The high strength also helps in larger purlin spacing i.e. savings in material and installation costs. Metallic coated steel roofs are very tough and highly resistant to hail damages, much more than asbestos/fiberglass sheets. In fact, high strength coated steel roofing products have the highest impact resistance to hail. Similarly coated steel roofing products have been found to have high wind resistance and have been tested to withstand strong winds.

Surface treatment has an effect on long term appearance of metallic coating on steel. A good surface treatment practice ensures brighter and uniform luster (surface) for much longer. The resultant bright finish also ensures higher Heat reflectivity/Thermal efficiency of the surface thereby much lower level of heat transmission inside and consequently reduced electricity bills.

During the summer, it makes buildings cooler by efficiently reflecting away sunlight and reducing the amount of heat transmitted into the building. Likewise, it makes buildings warmer in the winter by reflecting inside heat from the underside of the roof back into the building. This good thermal reflectivity translates into energy savings by reducing cooling costs in the summer and heating costs in the winter. This saving continues for long with retained brightness over a long period.

Metallic coated steel is also the most fire safe material. It is classified as a noncombustible material with a Class “A” rating - the highest given rating. In the event of lightning, coated steel roof will not catch fire and combust like wood. Instead, it will disperse the electrical charge over a larger surface area and reduce the impact.

55% Aluminium–Zinc Alloy Metallic Coated Steel

55% Aluminium–Zinc alloy metallic coated steel
55% Aluminium-Zinc alloy (Zn-Al) metallic coating contains both Zinc and Aluminium. It provides both sacrificial and barrier protection to steel. Typical Zn-Al as per Australian Standard AS1397 has metallic coating AZ150, i.e. Aluminium (55%) – Zinc coating of minimum 150 grams per square meter (GSM) total of both surfaces. AZ150 corresponds to coating thickness equivalent to Zinc coating thickness with coating mass of 275 GSM. For same coating thickness, Zn-Al metallic coating provides upto four times longer life than that of typical zinc coating to steel in near neutral conditions, which is typical of most environments.

55% Aluminium–Zinc Alloy Metallic Coated Steel

In the initial stages of exposure, the corrosion starts at the Zinc rich area. The corrosion product and Aluminium form an adherent protective layer at the Zinc rich areas, which tends to control the corrosion to a lower rate and is capable of providing sacrificial protection. After long exposure, when the Zinc rich areas have either been removed or shifted by corrosion product formation, the Aluminium-rich areas corrode, also at low rate and provide continued protection to the steel base for long. Also the coating is adherent and ductile enough to compliment flexibility of steel for various designing. Zn-Al coating has small, tight spangle (1 to 2 mm), spread evenly across the surface of the sheet. It has an aesthetically pleasing uniform finish. For these reasons, Zn-Al coated steel has now become more popular for building construction.

55% Aluminium–Zinc Alloy Metallic Coated Steel

Conclusion
With metallic coating life of the steel increases. The increase in life depends on the coating type, coating thickness and the environment the coating is subjected to. Zn-Al metallic coating provides upto four times of life compared to typical zinc coating to steel in near neutral condition. The good thermal reflectivity of metallic coated sheets translates into energy savings. Although the initial cost of metallic coated steel systems may be a bit higher, operational costs are lower over the life of building. Coated steel in different profiles (including tile profiles-much lighter then clay tile option) are widely used almost universally to cover large buildings for their high strength to weight ratio, low cost, durability, attractiveness and environment friendliness. Incorporating this green building material into building makes even more sense when we take a long-term view of life cycle costs.
MGS Architecture March-April 2009

No comments yet, Be the first one to comment on this.

×

Terms & Condition

By checking this, you agree with the following:
  1. To accept full responsibility for the comment that you submit.
  2. To use this function only for lawful purposes.
  3. Not to post defamatory, abusive, offensive, racist, sexist, threatening, vulgar, obscene, hateful or otherwise inappropriate comments, or to post comments which will constitute a criminal offense or give rise to civil liability.
  4. Not to post or make available any material which is protected by copyright, trade mark or other proprietary right without the express permission of the owner of the copyright, trade mark or any other proprietary right.
  5. To evaluate for yourself the accuracy of any opinion, advice or other content.
Bartec BV Coupler: Reliable Rebar Splicing for Structural Integrity

Bartec BV Coupler: Reliable Rebar Splicing for Structural Integrity

Bartec BV Coupler – a rebar splicing solution - is designed to ensure structural integrity of buildings even under extreme conditions. It provides a robust and reliable connection for concrete reinforcement bars. Its key features

Read more ...

HomeSure TileEx Tile Adhesives The Power of 4 Aces

HomeSure TileEx Tile Adhesives The Power of 4 Aces

Based on extensive R&D, HomeSure has pioneered tile adhesives that are superior in quality and performance, offering the power of 4 Aces: Application, Adhesion, Aqua-Safe, and Accessibility. Kaushal Mehta, Managing Director, Walplast Products Pvt. Ltd.

Read more ...

ICrete - A Revolutionary Material for Making Concrete Better

ICrete - A Revolutionary Material for Making Concrete Better

ICrete is a powder additive for concrete that can improve the properties of concrete in many ways. Invented by Dr. Ramkumar after 20 years of research, the primary objective of design of Icrete is to make concrete more economical when incorporated into

Read more ...

FAIRMATE Introduces Mould Release VR to Enhance Construction Efficiency

FAIRMATE Introduces Mould Release VR to Enhance Construction Efficiency

From timber’s enduring strength to steel’s structural integrity, and from the flexibility of plywood to the adaptability of plastic-faced materials, our newly developed FAIRMATE Mould Release VR integrates with various formwork types, catering to diverse

Read more ...

Stabilizing Buildings Through Injection Grouting with Assess Build Chem's Resin Grouts

Stabilizing Buildings Through Injection Grouting with Assess Build Chem's Resin Grouts

Injection Grouting with Assess Build Chem’s range of Resin Grouts are designed to enhance a building’s stability and durability. These polyurethane and acrylic gels have revolutionized the field of injection grouting by offering superior performance and

Read more ...

Reinventing Building Strength: Thermax Construction Chemicals at the Forefront of India's Structural Transformation

Reinventing Building Strength: Thermax Construction Chemicals at the Forefront of India's Structural Transformation

In the dynamic landscape of modern Indian infrastructure, the cornerstone of advancement resides within our edifices. With urban landscapes evolving and population surging, the demand for robust and secure structures takes center stage. However, the aging

Read more ...

ALUCOBOND Launches a Series of Colours and Surfaces

ALUCOBOND Launches a Series of Colours and Surfaces

ALUCOBOND, a flagship brand of Swiss major 3A Composites (a global manufacturer of high–quality Aluminium Composite Materials), has launched a unique and classic range of colours and surfaces to boost its premier portfolio. The three new offerings – Colourscapes

Read more ...

Rock Fall Protection Nettings

Rock Fall Protection Nettings

It is important to understand the suitability and effectiveness of Rock Fall Protection systems and how they can provide optimal protection. Namrata Bichewar, Regional Manager (Maharashtra), Gabion Technology India. Rockfall constitutes one of

Read more ...

Getzner India isolates vibrations at IECC - India's largest convention centre in New Delhi

Getzner India isolates vibrations at IECC - India's largest convention centre in New Delhi

Getzner’s Acoustic Floor Mats and anti-vibration mountings for walls and ceilings used at India’s iconic Exhibition and Convention Centre IECC are protecting visitors from vibrations and structure-borne noise. The IECC will host the G-20 Summit in 2023, with

Read more ...

Innovative Materials for Construction Industry

Innovative Materials for Construction Industry

The beginning of civilization as we know it, started with a series of material innovations; the Bronze Age and the Iron Age set us on the path to where we are now. Skyscrapers would have never reached such heights without developments in steel

Read more ...

Liberty: Why One Needs ESD Footwear in Electrical Environments

Liberty: Why One Needs ESD Footwear in Electrical Environments

Wearing static dissipative footwear (ESD) is the best way to protect feet against hazards when working in electrical environments. The footwear is designed with a high level of resistance to protect them from electric shocks. ESD work shoes reduce the amount

Read more ...

Magtech Magnetic: Looking for Business Opportunities in India

Magtech Magnetic: Looking for Business Opportunities in India

From researching, manufacturing to marketing, and from producing magnetic units to finished products, Taiwan-based Magtech Magnetic Products Corp (MMPC) is positioned as one of the most reputed and reliable partners in the magnetic field

Read more ...

Da Jie: Keen to Expand Footprint in India

Da Jie: Keen to Expand Footprint in India

Da Jie Electricity Machinery Industrial Co. Ltd has lined up strategic business plans for the Indian market where it aims to provide high quality, efficient, and cost-effective products through its channel partners

Read more ...

Portable Multipurpose Reusable Living Units (PMRLU) for Onsite Workers

Portable Multipurpose Reusable Living Units (PMRLU) for Onsite Workers

Mumbai-based Habitat n Skins is offering modular and factory assembled housing units for site workers and captive staff at construction sites. The PMRLU is the ideal solution for project developers / contractors looking

Read more ...

Air to Water Generation is a Reality

Air to Water Generation is a Reality

Air-to-Water Generation (AWG) technology is real; in fact, we have devoted our life and work - separating moisture, and drinking water, from air – and are set to enter Indian markets – both consumer and institutional

Read more ...

Liberty Safety Shoes: Wear More, Store Less

Liberty Safety Shoes: Wear More, Store Less

Ageing of safety shoes is an entirely normal process. To benefit from all the positive properties of a safety shoe, one must be aware of the limited product life of shoes. Ageing happens because the PU sole material is subject to

Read more ...

Liberty: Importance of Safety Shoes at Workplace

Liberty: Importance of Safety Shoes at Workplace

More and more countries are embracing the mandatory safety shoes standards in order to guarantee protection at the workplace and are creating awareness on the importance of wearing safety shoes at work. Liberty’s Warrior brand of boots

Read more ...

Liberty 'Warrior' Construction Shoes for Safety, Comfort & Durability

Liberty 'Warrior' Construction Shoes for Safety, Comfort & Durability

For a construction worker, the most important safety equipment is probably “a good pair of working shoes”. This, in fact, is a necessity as he is on his feet for long hours of the day and even at night, and quite often in dangerous site conditions such

Read more ...

Liberty Warrior: Customer's Safety & Satisfaction is the Key

Liberty Warrior: Customer's Safety & Satisfaction is the Key

The Warrior brand from the house of Liberty is an acclaimed name in the construction industry for safety shoes. Designed to ensure utmost safety against extreme odds and to facilitate comfort during work, the Warrior work

Read more ...

To get latest updates on whatsapp, Save +91 93545 87773 and send us a 'Saved' message
Click Here to Subscribe to Our eNewsletter.