Author: amit Dhaneya
Smart Glass Market Growth in India & Major Coaters Offerings.
By amit Dhaneya
Smart Glass Market Growth will be driven by rising Global Energy Consumptions
By 2020 Global demand for High performance glass is set to rise as with the current trend & scenario with rising Environmental Issues in the Country. On one hand we want to build smart cities but on other hand existing Metros have very poor Air Quality.
Optimal Energy Savings is driving the smart glass market in the Commercial sector with few developers realizing the need of the country to save energy consumption for the occupied premises & save the Country's Environment.
Despite high Energy cost the energy supply demand Gap is increasing. Switching to smart Glass for Government Building, Commercial Complex, and Residential Buildings, Schools, Hotels & even Shop fronts will optimize the consumptions.
Today's smart glass helps a developer to achive more Light in & block the heat to largest extent.
Benefits of Smart Glass
Less Heat coming inside thereby increasing efficiency of the Building.
Saves Money on day to day Electricity consumptions.
More Light Entering helping in daylight planning.
Very Less Payback period against the initial capital investments.
Blocks UV rays thereby not fading the interiors like Curtains, Paints & furniture of the occupants.
Increases efficiency of the Façade on long term basis.
Current Options in Efficient Glass Category
The current range available in the country for Energy Efficient Glasses from Manufacturers like Asahi are Brook Series with Blue, green & clear option with better Light transmittance & low Solar factors.
Saint Goban provides Coolite Series, Evo series, Nano Series & various other combinations of advanced products.
Pilkington offers glasses which are imported from its various manufacturing locations across North America, Europe, Middle East, South America. Pilkington Eclipse Advantage, Solar E & Solar E plus are effective in Single & double forms.
Currently Guardian being 4th Aggressive player offering SunGuard Solar Series, High performance series & high selective series from their respective plants across the globe.
With this various options available which can be easily Tempered, Double Glazed, laminated from processors across India.
One has to know that using a Energy Efficient Glass on their project, One not only reduced the consumption of Electricity but also is part of global Environment Policy as an Individual participant to save Earth.
For any further assistance mail us at
Whatsapp on 09324789080 your Requirement we can help you build a efficient façade.
Source – AIS, Saint gobain , Pilkington & Guardian Catalogue.
Posetd on: Dec 19, 2015
Nearly Zero Energy Buildings
NzeB- Have you heard about this?
Nearly Zero Energy Buildings is the target of European Building Policy, where by end of year 2020, all the new constructions should be consuming as minimum energy & could use more renewable sources.
How to achieve "Nearly Zero Energy Building"
Two major factors will help you achieve
Adaptive Facade on buildings.
Onsite demand with renewable energy generations.
Adaptive Facade on Buildings
Adaptive façade is an intelligent façade which differs from normal façade as it has various variable devices that helps to act as climate moderator.
By using this façade we provide a building an ability to accept or reject energy from external environment & in turn reduce the excess energy required to keep a comfort zone internally.
How an Adaptive Façade help in creating a nearly Zero Energy Building.
Selection of appropriate design based on building typology & Climatic location.
An ideal adaptive façade is the one which is able to minimize the total energy consumption of indoor space by means of adapting thermo-optical properties to varying outdoor/ indoor environmental studies like Solar Radiation, Air temperature, Wind velocity, Internal Loads & various factors effecting the façade.
Extensive research being done & a 365 days energy absorption through the façade is studied on micro level basis to reduce the net heat gain / or to increase the heat gain based on climatic location.
This study also studies the micro consumption of energy room wise in order to assess performance of the façade.
Evaluation of adaptive façade is performed by means of minimizing energy consumption of building.
There are adaptive ceramic frittings which moveable graphical pattern that can modulate its transparency to control light, heat gain & aesthetic looks into the façade.
Total Energy Consumption = E heating + E cooling + E lighting.
Onsite Demand with renewable Energy generations
Onsite supply can be boosted with use of optimal Solar PV module, where in our last article we covered a recent invention of glass highly effecient than conventional solar module. These methods would boost energy productions without effecting fossil fuels & thus minimizing Co2 emissions & other green house gases effecting the earths global warming.
Conclusions-
With energy crisis across globe & an intent to reduce carbon emissions a lot focus is driven on saving energy as it is always said in simple words
" A unit Saved is Unit Earned"
Source-
www.studiocomi.com
www.powerhouseeurope.eu
Posetd on: Oct 16, 2015
Researchers in Japan have created an unbreakable new glass that is reportedly as strong as steel. This breakthrough could see the new material revolutionise the use of glass in buildings, cars and technology, and it should be available within five years.
The glass, whose composition is 54Al2O5-46Ta2O5, underwent strength, hardness and elasticity tests including Young's modulus and Vickers methods. The tests revealed that the glass was twice as strong as typical glass and evidently rivalled that of steel and iron.
For more read Article Source
http://www.ibtimes.co.uk/unbreakable-glass-thats-strong-steel-created-by-scientists-japan-1526816
Posetd on: Nov 4, 2015
Source: http://www.ibtimes.co.uk
SUSTAINABLE FACADES
One could have observed an absurd climatic change in the country where sudden rains, unbearable heat & lot of climatic issues arising. With the modernization of building facades lot of glass buildings coming up there is a need for Sustainable Façade.
The modern façade becomes Sustainable in regards to the thermal & functional performance not compromising on the aesthetics.
For any building two important aspects come to the developer
Investment on the construction of facade.
It is preferable for any building façade to be durable on the long run & usage of recyclable materials needs is increased. Fortunately most of the façade materials like Aluminium, Glass, ACP, Solid cladding has reusability properties, and one can recycle & reuse them.
Operating cost of the facade.
People have a tendency that as they are not the occupants of the buildings any low quality materials can be used & somehow the façade needs to be completed.
This is a wrong approach as in today's scenario Operating cost is very high in terms of Electricity bills of HVAC, Lighting & various mechanical utilities used in a building. So it must be very crucial for the designer to save energy as & where possible. For example Glass is major transmitter of heat inside the building, hence Glass can be designed to suit the climatic conditions.
Core Aspect of an intelligent façade:
Façade are responsible for the comfort of the occupant within the building & at the same time consumption of Energy. One needs to incorporate various strategies to achieve Low Energy consumption in a building.
Various important Aspects of Effective Design:
Maximizing Day Lighting Strategies.
Blocking Heat in South & South West Area using Louvers & Blinds.
Insulating the Spandrels to block the heating of RCC structures.
Generating Electricity by using Photovoltaic cells.
Utilization of Pressure Differentials.
Classification of Intelligent Facades:
Single Skin Façade.
Double Skin Façade.
Combined Façade
Single Skin Façade:
To achieve a certain level of Solar Control in Single Skin façade following things to be done
Use Effective Solar Control Glass with Low Solar Factor & Low U values.
Use of better Gaskets (EPDM) to thermally break the heat transfer of conduction.
Pressure Equalized facades helps in proper Air Circulations inside the chambers to drive water & heat away trapped inside.
Use of perforated Panels in high heat areas to have optimized day lighting & blocking unwanted heat.
Various Internal Shading strategies can be adopted to block the Glare & incoming heat.
Double Skin Façade:
The term double skin facade refers to an arrangements with a glass in front of the actual building a facade. Solar control devices are placed in the cavity between these two skins, which protects them from the influences of weather and air pollution.
Solar shading helps achieve optimized temperature inside.
Re-radiation from the solar radiation is emitted in the central cavity.
Better Sound Control by creating a cavity in between two facades.
Widely used in high rises to have less effect of wind & cavity helps as natural ventilation zones.
Very Expensive in terms of cost, so very few building used.
Combined Facades
This is combination of single & double skin facades by providing a baffle panel in the vision area helping in reducing noise levels in the building.
Baffle panel is an additional panel in front of a window in a perforated or conventional panel.
Baffle Panel blocks lot of sound comes from the primary façade.
Baffle panel helps in solar screening.
Baffle panel needs to be openable for cleaning, & ventilation.
Because of reduction energy resources and increasing cost in the world every day, energy conservation in buildings primarily focused on building systems. After 2010, targeting the energy crisis, which can produce its own energy, ventilation, heating and cooling that provides "intelligent facades" came up.
No doubt in the short run these facades are expensive but in Long run they pay you back in terms of Cost, Better Environment & Sustainability.
For Further any info do mail us at info@glazingshopee.com
Source : www.pinterest.com
www.battlemacarthy.com
Posetd on: Nov 30, 2015
Source: http://www.glazingshopee.com
Glazing & Windows Estimator Version 1
In Facade Budgeting & Softwares, Softwares
1st Version Glazing & Windows Estimator Software
Glazingshopee.com is investing time & resources to help Contractors, developers & end users by unveiling its 1st version of façade Estimation software very soon.
We are meeting leading Extrusions companies to share their database of Standard systems available in the market help us create a library of sections & systems for easy estimation.
Now just put the Size of the Window & Quantity & get the perfect estimate.
27mm Series, 32mm Series & 37mm Series will have library built in for fast calculations.
Library of Glass with Single Glass, Double Glass & various process options shall be available just to select & optimize the time efficiently.
Hardware library with standard market hardware, other leading system hardware supplying company's library also shall be integrated to have exact cost.
It will save time & be efficient to handle big projects.
Even the contractor will be able to create customizations of his system.
Speed & Accuracy minimum errors in deriving the project costing.
Consistency of performance & can create the library of cost versus sizes.
Help small contractor increase his speed & delivery of Tender submissions.
This software shall be launched by End of November 2015.
For any query write to :info@glazingshopee.com
WINWALL
In Façade testing, Facade Testing & Materials Testing
Winwall Technology India Private Limited (WTIPL) is a state of the art façade testing facility that conducts tests and certifies facades, doors, windows and skylight for design verification and performance requirement to meet ASTM & AS/NZS and /or any international standards.
WTIPL has established its first façade testing facility and is a joint venture between WinwallTechnology PteLtd. (WTPL), a leading façade testing company in Singapore and Abhinava Aluminium Private Limited, a well-known anodizing company in South India.
Winwall Technology Pte.Ltd.,Singapore (WTPL) was established in the year 1992 and is one of the leading façade testing facilities in Asia. WTPL has successfully carried out over 1000+ projects in Asia. It is accredited by the Singapore Accreditation Council (SAC) under Singapore Laboratory Accreditations Scheme (SINGLAS) which is mutually recognized by many other countries. Since its establishment, WTPL has been serving the building and construction industry with a highly commendable level of quality testing services for twenty years. We have acquired invaluable experience and earned commendations from clients for our service excellence, not only for quality testing services, but above all, a comprehensive solution provider.
Throughout the years, we have devoted ourselves to learning about our clients' practices. Harnessing the knowledge of the products and our modern facility, we are proud to be one of the largest facilities in the region providing facade test and solutions beyond the minimum regulatory requirements adopted by countries in the Asia Pacific region. History has proven that all products tested by us and used in renowned skyscrapers in the region have withstood the harsh weathering conditions and protected the safety of the building users and general public.
With abnormal climate changes especially over the last decade, awareness for the safety of the buildings has escalated and testing requirements made more stringent. Architects, building developers, contractors, specifiers including manufacturers of cladding materials have taken great efforts in considering all probable scenarios which might endanger the general public from problems attributed to design defects of building envelopes such as curtain walls, windows & door systems and poor workmanship during installation of such systems.
Our comprehensive testing solutions have by far assisted our clients in eliminating probable defects such as glass breakage, water leakage, excessive deformation of structural components and air leakage or damages to hardware and accessories. This ensures timely completion of building projects and most importantly, safety of users of buildings and the general public, preventing any legal implication due to product defects or professional negligence. Hence, there has been an increasing demand for performance tests by owners, specifiers and manufacturers to obtain a credible degree of assurance.
Performance Testing:
AIR PERMEABILITY
Different pressures are applied incrementally up to specified pressures. Air infiltration or exfiltration measured by air flow meters are available.
WATER PENETRATION
Consists of Static, Dynamic and Cyclic tests, Water is delivered at rates of up to 10 litre per minute per meter square through a matrix of spray nozzles 700mm centre to centre. Differential pressures are applied incrementally to specified static, dynamic or cyclic pressures.
Other Performance Testing:
Air infiltration and exfiltration (ASTM E331 and AS/NZS 4284)
Static water penetration (ASTM E283 and AS/NZS 4284)
Dynamic water penetration (AAMA 501.1) (within 60 days)
Lateral movement (Seismic test) (AAMA 501.4 and AS/NZS 4284)
On-Site Testing (AAMA 501.2, AAMA 501.3, ASTM E1105 and ASTM E783)
Cyclic water penetration (ASTM E547 and AS/NZS 4284)
Structural performance (ASTM E330 and AS/NZS 4284)
Proof Load (ASTM E330 and AS/NZS 4284)
Building Maintenance unit load (BMU) (AS/NZS 4284)
Testing Services:
Testing of :-
Exterior windows & Doors
Storefronts & Sloped Glazing Systems
Building Facades
Field or On-site testing
Third party witness
S RAIL
In Education, Louvers & Railings, Railings
S RAILS (balustrade and handrails)
Shivam products as a manufacturing unit, specialises in balustrade and handrails system has emerged as the fastest growing company under the brand name of S RAILS.
Stainless steel is the architect's material of choices for a wide range of high profile developments from luxury residential apartments, bungalows, shopping malls, hotels etc.
Functionally practical and aesthetically pleasing stainless steel hand railing coupled with complementary glass and co-rail systems is a hallmark of today's contemporary and minimalist designs. With its emphasis on simplicity, elegance and crucially low maintenance, the S RAIL range can accommodate all your requirements.
The benefits of S RAIL hands railing systems are its versatility, modular nature and comprehensive range. In addition the entire system is designed with the ease of assembly and installation in mind.
Company has state of the art plant having bending machines, metal finishing shop, fitting and assembly section along with dye casting facilities, well planned machine shop, abrasive grinding-polishing facilities etc.
S RAIL products are unique, economical, longer lasting, versatile and affordable. S RAILis a customer focused company having well established network of dealers and distributors giving services from installation to after sales.
S RAIL :
Shivam products
Rajkot; Gujarat
www.s-rail.in
infosrail@gmail.com
AUM INDUSTRIES
In Louvers & Railings, Railings
Aum industries (A range of aluminium railing system)
Aum industries take the privilege of introducing this cost effective, maintenance free and elegant railing system in India.
Factory is based in Rajkot Gujarat and gives onsite fittings and aftersales service efficiently. The new advance supporting glass system based on aluminium profiles is ideal system for glazed railings for balconies, stairs and building enclosures with high architectural standards.
system base is covered by aluminium side covers which allow replacement of the glass without damaging the system and the floor.
The system is certified for its highly resistance, maintenance free, cost effective and sound engineering design by international institutes. The concept of aluminium railing is new in India but it is used extensively worldwide.
Perfect aesthetic results
Unlimited crystal clear view
Easy to clean and durable
It is ideal solution for balconies, stairs and building enclosures for high architectural standards. It offers impressive and functional results with no view limit.
Aum industries:
Rajkot, Gujarat.
91+ 2827293302
www.sgrip.in
infosgrip@gmail.com
RAILINGS MATERIAL SELECTION PRECAUTIONS
Precautions to be taken in a SS Railing Materials Selection
How to choose the perfect SS grade for Site Conditions
All that looks mirror finish & matt finish is not the perfect grade of SS for the right railing systems for your site. Following information below Is must if you need your railing system to look good after few years of installation.
SS widely used in railings because it has properties to fight against corrosions, as its construction is Fe(Iron) + C (carbon) +Ch( Chromium).
It is the chromium when it comes in contact with oxygen it forms a passive layer which has the ability to repair itself.
Corrosion begins only when this passive layer is missing or damaged. Hence to have better resistance properties Chromium is added with Molybdenum, nickel & nitrogen to have least corrosion.
SS 316, SS 304, SS 202 & other grades have major differences in terms of factors to fight corrosions. Below table will show you which is better
1 SS 316 16% to 18 % Chromium, 10% Nickel, 2% Molybdenum. Molybdenum helps resistance towards chlorides.
i.e. ( Sea Water & other Salts)
2 SS 304 16% to 18% Chromium, 8 to 10% Nickel.
3 SS 202 16% to 18% Chromium, 0.5% to 4% Nickel
From the above table one can clearly make out SS 316 is the best no doubt expensive but it solves the purpose as it have non corrosive properties with presence of Molybdenum.
Rest all forms of SS will corrode over period of time.
Also note not only chemical construction of any metal is responsible for corrosion, but also mechanical properties such as stressed in a materials drive to corrode faster.
Thermal stresses & ageing of materials also are reasons to corrode.
From the above comparison it is clear & evident Low grade SS is not helpful in the long run & one daily the railing will corrode.
SS Pipes 316 Finished
SS Corroded Pipe ( either 304, 202)
Try to maximize use of better SS & bind your supplier to chemical tests & mechanical tests in any laboratory before risking the applications. Evident that to save some cost we are functionally compromising on quality of end product.
HOW TO SELECT THE PERFECT RAILING GLASS
Similarly Glass constitutes important part of Railing systems. Very few glass processors & raw materials suppliers provide the right materials.
Ideally Laminated Glass is the right Application for any railing applications considering the safety of the occupants.
If you are using a tempered glass in railings the risk of breaking is 8 / 1000 due to Nis breakage & stress at the holes. So please don't use stand alone tempered glass, use a safety film from Garware, 3m & other suppliers.
Laminated Glass is the right product but due to cost constraints people use tempered glass. As railings are widely used in balconies safety of the occupant is most important aspect.
Two sheet of Annealed, Heat strengthened , Toughened glass joined with PVB, Sentry, Saflex DG interlayer are processed in autoclave to become single integrated glass.
Precautions on has to take while selecting a right Laminated Glass
In the whole process of Lamination the interlayer & Process constitutes equal responsibility for end quality.
Open edge application is aesthetically good as per Architects but in terms of performance in long run interlayer must not ingress water.
PVB is widely , but is very poor as it absorbs water & moisture from the edges, eventually failure is very high after some time.Images of Poor PVB Application with open Edge & Water, Moisture Ingression
How to Prevent Failures
Kindly involve interlayer manufacturer or hire a consultant so that you get the right product for right application.
Get the structural Analysis of the Glass done from Consultant / Interlayer Suppliers, as it is they who know their materials properties.
Structural Analysis of system is must.
With more failures & water entering open edge applications one has to know how to seal the edges & have right sealants approved in writing from Interlayer suppliers.
Recently new interlayer materials have come like Sentry Layer, Saflex DG & other but before going away with them please consult rightly if they are the right
SS Materials & Glass constitues 75% of railing cost in terms of materials, hence ensure before going with any vendor these 2 components are perfect, else failure is imminent.
Also alternate Aluminium systems in railings are emerging to prevent problem of corrosion.
if you are looking for designs write to
Mob : 08652446321
How is Self Cleaning Property on Glass, ACP Achieved.
In cleaning, Education, Lighting & Cleaning Solutions
How is Self cleaning Properties on Glass, ACP & other materials Achieved
Self Cleaning Materials becoming the new trend in the façade industries. Now a days we hear lot about transparent liquid which when applied to the surface, like glass, acp, aluminium sheets and various external façade materials, makes the Self cleaning. This nature also known as" Lotus effect" where water on the leaves of Lotus plant rolled down. These leaves had a combination of surface roughness & water repellent wax crystals givng it super hydrophobic properties.
Many companies like 3m, Alcoa, Active, BASF, Corning, Ford, Nippon, and PPG are investing into research of the long term technology where any material would have self cleaning properties.
The growing interest in self cleaning coatings technologies is due to their high potential in reducing maintenance cost of the window & façade.
Two type of Self Cleaning Properties
These have high water angles above 90 degrees. Self cleaning has water angles of more than 150 degrees know as super hydrophobic. Nature also has "Lotus Effect" where water droplets can be seen on Lotus leaf due to its hydrophobic properties. These surfaces are highly water repellent & water roll down into spherical droplets carrying the dust also.
A super hydrophobic surface is obtained if hydrophobic surface is roughened on a micro or nano scale. Thus efficiency of self cleaning coating is dependent on roughness & chemical composition on the surface & dust particle adhesion to water droplet.
These self cleaning coatings are based on photcatalysis, i.e. when exposed to Light they are able to break down impurities. Titanium Dioxide is well know hydrophilic self cleaning coating due to its physical & chemical properties. It is non toxic, chemically inert when there is no light present, inexpensive, easy to handle.
The strong oxidation power & super hydrophilic properties of Tio2 makes it good material used for outdoor. Just see illustration how Tio2 drives the dust away.
. 1. When UV light shines on Tio2 electrons negative charges releases.
Electorns interact with water (H2O) breaking them to hydroxyl(OH) which are reactive.
These agile hydroxyl radicals attack the hefty organic (carbon-based) molecules from which most dirt is made, breaking apart their chemical bonds and turning them into smaller, harmless substances such as carbon dioxide and water. This is an example of oxidation.
The hydroxyl radicals also make the glass hydrophilic (water-loving). When it rains, water molecules spread evenly across it and wipe it clean like a kind of automatic squeegee!
Ultra Violet Light + TiO2 can be used in following areas
Self Cleaning Window looks neat for Life time.
Less maintenance of Window & Façade cleaning.
Less Water Consumption for cleaning.
15 to 20% More Cost of the Glass.
Reliability of TiO2 systems on Sunlight & Rains.
Cleaning with abrasive materials might damage the coatings.
Inside cleaning has to be done manually.
To Know more write to us
Source Image- explainthatstuff.com
U.P. Twiga
In Anchoring & Facade Insulation, Education, Glass Wool
U.P.Twiga Fiberglass Limited
An ISO 9001:2008 , 14001 Company
Twiga, a technical licensee of Isover Saint Gobain, is the leading manufacturer of fiberlass wool insulation in India with a 30 year track record of supplying domestic and export customers with world-class products for thermal and acoustic insulation. The hallmark of Twiga products are their superior fire properties and their extremely cost-effective nature. Twiga Insul, the premierinsulation brand in India is also now present in South East Asian countries like Sri Lanka, Hong Kong, Singapore, Vietnam and many other Asian and African countries.
Twiga, an ISO 9001 and ISO 14001 certified company has manufacturing facilities at Sikandrabad (Near Delhi) and Ambernath (Near Mumbai). The Ambernath facility is OHSAS 18001 certified.
Twiga Insul being a Green Building product are made of inorganic fibers with a thermosetting resin binder. Products are either flexible blanket or semi -rigid and rigid boards with wide range densities, thicknesses and facings. Twiga Insul is a high performing insulation with high energy efficiency and acoustic properties.
Product Range:
Fiberglass wool insulation long and short blankets, bats, boards with and without aluminium polypropylene, glass cloth and tissue laminations
HVAC prefabricated duct boards and acoustic boards
Preformed chilled water and hot water pipe-sections
Insulated and un-insulated flexible ducts
Fiberglass tissue.
Application areas for Twiga Insul:
Drywall partition
Pre engineered buildings and light gauge/pre fabricated structures (e.g low cost housing
Other segments include cold storage, bus-body, metro rail cars, long distance rail coaches and many other processes/niche segments.
So under steady state condition, normal Brick wall of 230 mm thickn
Approvals and enlistments:
GRIHA/SVAGRIHA (National green building rating system –India)
Indian Green Building Council
FM Approved for metal building and HVAC
Central Public Works Departments (India)
Engineers India Limited…and many more
Twiga Glass Wool spandrel Insulations are available with factory-applied Aluminum Foil – FSK, Black Glass Tissue – BGT, Black Glass Cloth & with other various suitable options as required.
The other salient features of Twiga Fiberglass Wool products are: –
Twiga Insulators saves energy and reduce heat transfer, lowering operating costs.
Twiga Insul is chemically inert & is rot proof & odorless
Twiga Insul is non combustible in accordance with BS 476 ,part 4 , ISO 1182
Twiga insul is light weight & resilient. Easy to handle , fabricate & install at site.
Complies to environmental, health and safety criteria as per the green assessment requirement laid by Singapore Green Building Council
It has NIL shot content in accordance to IS 3144 / BS 2972. It does not corrode the material on which it is applied.
Resin bonded fiberglass wool material is free from impurities. Conforms to IS 8183
The moisture content and water absorption is less than 2% in accordance to IS 3144 / BS 2972.
Delivers Higher Thermal Resistance R value along with acoustic insulation.
Twiga Insul can contribute to earning Leed points
Why to Insulate: To minimize the Heat Gain in the building.
Case I = so under steady state condition, Normal Brick wall Construction – 230 mm thick without using any insulation.
The Total Heat Transmittance will be U = 1 / ΣR , where as R = R1+R2+R3+R4
R1 = Thermal Resistance of Air Film onExterior Surface = 0.04 M2.K / W
R2 = Thermal Resistance of Gypsum Plaster 13 mm = 0.079 M2.K / W
R3 = Thermal Resistance of 230 MM Brick wall = 0.284 M2.K / W
R4 = Thermal Resistance of Air Film on Interior Surface = 0.13 M2.K / W
So ,Σ R = 0.04 + 0.079 +0.284+0.13 = 0.533 M2.K / W.
U = 1 / 0.533 = 1.8 W / M2.K
ess, when subjected to 1 degree Celsius temperature differential, will transmit heat of 1.8 Watt per sqm area from hot face to cold face.
In CLADDING MATERIAL, Education, Zinc, Copper, GRC Panels, roofing materials
To preserve the views from a historic residence, the architectcovered the roof with a skin of zinc.
In the middle of Mahabaleshwar surrounded by the green envelope of trees, stands thisPrivate House, distinguished by the green roof that gives it a contemporary feel.
The new roof of this classic residence is inseparable from the building which is several years old. It is austere and powerful and its stone walls are equally impressive. The old building was restored: The architect gave it back its double-sloped roofing(The original roof was damaged).
A zinc roof, which is visible from all around, now forms a frame for the rectangular spread out home. Zinc with a contemporary design creates a striking contrast with the original historic building. The layout of Zinc and the overhang of the roof protects the ground floor patio.
The architect chose Zinc as the roofing material due to its longevity, environmental suitability and aesthetics. Zinc also requires little or no maintenance. The roof that blends so well with the original brick walls of the house also appears in total symbiosis with nature.
ETFE The New Facade Material Weighing Just 350 gms/Sqmtr.
In CLADDING MATERIAL, ETFE Material
ETFE –
Ethylene Tetrafluoroethylene (ETFE) the new material earlier developed for aeronautic insulation around 1930's is now eveolving as the new Architectural material for façade.
ETFE was widely used in 2008 summer olympics for building facades.
Material Advantages in Façade.
Ethylene Tetrafluoroethlene
Weight 350 gms/sqmtr.
Thickness one layer 200 microns.
Fire Resistant Class B1
Good light transmitance.
Life minimum 20 years without loosing transperency & maximum upto 40 years.
Non stick in nature.
Self Cleaning as no dust adheres to.
Can be used in Multiple layers & air blown from inside.
High level heat retention.
ETFE panels are prefabricated & pneumatically pre stressed ETFE obtains their integrity from air inflation system. Air inflated needs controlled moisture or no dust particles within the gap.
Source : cenews.com
Source : http://www.thearchitect.lk
Transmits more sound in the room.
When used in multiple layers steady air pressure maintaining is challenging.
Not recommended for small projects as it becomes expensive.
Source – cenews.com
http://www.thearchitect.lk
Aludecor Firewall The mighty fire fighter
In Aluminium composite Panel cladding, CLADDING MATERIAL, Education
Safety has always been a major concern in the building industry. With skyscrapers dotting the contemporary cityscape, fire-related risks are on the rise continuously. Aludecor, a leading manufacturer of Aluminium Composite Panels (ACP) and colour coated coils, has truly acted as a responsible corporate citizen in contributing to minimizing the quantum of loss in incidents of fire. Its revolutionary fire-retardant product Firewall has already won praises galore.
In recent years, fire has indeed been one of the most alarming threats to urban life across India. In November 2012, Hyderabad experienced one of the worst fire accidents ever when a high-rise in the city centre caught fire, killing 6 people including new-born babies. A sizeable crew of fire fighters fought for two hours to bring the flames under control. There are a plenty of such examples across India. Fire casualties have taken too many lives in our country, and it calls for serious action. Lack of safety measures for the building in the planning and design stage, non-conformation to the norms laid down by the National Building Code and wrong selection of building materials have proved to be the real causes behind such mishaps, time and again. Many projects, which had overlooked the usage of fire-retardant ACP, faced drastic consequences. Leading architects, facade consultants and Project Management Consultants have unanimously advocated the use of quality materials which are fire-retardant and have proper international certifications. They also feel that due to lack of awareness, majority of the builders in India have been compromising on fire safety norms to keep costs in check. It is an ominous sign.
Since ACPs are widely used in high-rises today, Aludeor has launched its fire-retardant variant Firewall which has been tested as per the guidelines of ASTM E119-12 and the result says that the fire resistance performance of Firewall is 120 minutes. Also its reaction to fire performance is in accordance with EN 13501-1 and the classification is B-s1, d0 which clearly indicates negligent or zero smoke emission levels and zero flaming droplets in an event of fire. Time is extremely crucial in case of fire disasters. The usage of Aludecor Firewall gives occupants sufficient time to evacuate the building. In incidents of fire, people are most vulnerable to the smoke generated, as smoke kills faster than fire. Therefore, simply put, Aluedecor Firewall resists fire for 2 hours, prevents fire propagation, suppresses smoke and produces zero flaming droplets or particles. Every Aludecor ACP can be fire rated and fall under the Firewall brand.
In case of FR ACPs, the core material which is sandwiched between the two layers of aluminium plays a pivotal role. The core material used in a normal ACP, comprising LDPE, is highly inflammable. It can produce smoke and molten droplets. In order to make the LDPE core fire-retardant, either Magnesium Hydroxide (or Aluminium Tri Hydroxide) should be added to it. Magnesium Hydroxide or Mg(OH)2 is used as a functional additive to enable flame and smoke resistive performance of many polymer compounds, particularly in non-halogen, low-smoke applications. Mg(OH)2 has a dual functionality of flame retardation and smoke suppression when heated to its decomposition temperature of about 340°C. At this temperature, Mg(OH)2 gives off bound water amounting to about 31% of its weight. This endothermic decomposition reduces the heat generated by fire while the released water also suppresses smoke and dilutes potential fuel supply. MgO formed as a result of the Mg(OH)2decomposition acts as a charring layer that helps insulate potential fuel from heat and oxygen. The relatively higher thermal stability of Mg(OH)2 makes it more desirable for use in polypropylene and other engineering thermoplastics which often require the compounding and processing temperatures of well above 200°C.
Firewall is already making its presence felt in the real estate segment. As fire safety awareness spreads in society and decision-makers show greater interest in paying that extra bit for the premium product, the future of Firewall gets to look brighter than ever before.
For any queries about FR-grade ACP, please contact our technical team atinfo@aludecor.com
Sustainable Construction – New Technologies & Materials – (GLASS)
In Glass & Glass Processing, Studies on façade glass
Glass today, has become an integral part of modern day architecture. Using glass in a building instantly adds a touch of modernity to the living space. It not only gives the designers the choice of finish & a manifestation to their design aspirations, but also a wonderful chance to participate with the outside world. Glass, in fact, is the only building material which can not only give see-through properties but also the desired structural strength to be used in facades.
Glass ensures that the building gets ample natural light – making interiors look brighter and livelier reducing the need for artificial lighting and saving energy, or in other words, reducing the electricity bill. Ample light inside the home makes spaces look more spacious and roomy, an important factor to consider given today's shrinking living spaces in urban areas.
These Energy Efficient Glasses provide the benefit of reducing the heat gain in buildings due to its excellent energy saving properties without compromising on the natural light coming inside the building or the brilliant aesthetics that add value to the façade. And in winter, they ensure solar gain. So that no matter what the season, people inside stay comfortable at all times. Using energy-efficient glass also helps in ensuring that the interiors – and the occupants of the home – feel more comfortable. Ideal for solar and thermal insulating parameters, these glasses combine aesthetics with environmental sensibility and conform to all International and National Green Standards, making it the natural choice as a Green Building solution. Performance parameters of glasses like Visual Light Transmission, Solar Factor, U-Value and Internal Reflection make buildings more efficient and ecologically viable.
Energy efficient glasses, when used properly can reduce the total energy consumption by anywhere between 8~10% of the total energy consumed & hence the accrued benefits of using these glasses keep growing over the years. Furthermore, it is not just the recurring savings but also the reduction in the capex because of the lower energy loads required for conditioning the building. Typically the heat gained/lost through Glazing in a normal building in India is anywhere between 40~50% and using the right type of glass can bring down the energy consumption by 30~40% (only Glazing). The incremental cost for the high performance glazing can be recovered in a time span of 3~4 years.
Illustration (Cost Benefit Analysis):
The above mentioned rates are assumptions used for energy and payback calculations only.
However the market rate will differ and include taxes and wastage charges.
HP refers to High Performance Glass
Post the detailed Building Analysis on Energy Performance and comparing with a base case, it is very clear that HP 4is performing best with a payback period of 7.4 months and 67 % energy saving.
Until a few years back energy efficiency was neither a practice nor a fad in the country. However with the launch of the Energy Conservation Building Codes (ECBC), concurrently accompanied by the gain in popularity of the Green Building practices, users alike, builders & architects started looking at ways to reduce energy consumption in buildings.
So no matter which perspective you look at it from – aesthetics, modernity, elegance, adding a sense of space to interiors and of course, monetary savings – making homes energy efficient with glass makes perfect sense.
Source Asahi India
Quality control of toughened glass
In Education, Glass & Glass Processing, Processing glass sudies
Toughened or tempered glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the inner surfaces into tension. Such stresses cause the glass, when broken; to crumble into small granular chunks instead of splintering into jagged shards as plate glass (i.e. annealed glass) creates. The granular chunks are less likely to cause injury.
Properties: Toughened glass is physically and thermally stronger than regular glass. The greater contraction of the inner layer during manufacturing induces compressive stresses in the surface of the glass balanced by tensile stresses in the body of the glass.
In such glasses, the surface compressive stress exceed 100 megapascals (15,000 psi), for as greater the surface stress, the smaller the glass particles will be when broken.
It is this compressive stress that gives the toughened glass increased strength. This is because any surface flaws tend to be pressed closed by the retained compressive forces, while the core layer remains relatively free of the defects which could cause a crack to begin.
As per the nature of the glass, any cutting or grinding must be done prior to tempering because Cutting, grinding, and sharp impacts after tempering will cause the glass to fracture.
Now here we will be discussing the issues related to optical defect:
roller waves
The surface of tempered glass does exhibit distortion or surface waves caused by contact with flattening rollers. This Optical issue of waviness is a significant problem in manufacturing high-end façade projects.
The strain pattern resulting from tempering can be observed with polarized light or by using a pair of polarizing sun glasses.
There are three main reasons causing the roller wave effect:
High exit temperature of glass from furnace:
While tempering the glass, heat treatment requires uniform heating of the glass to 621 +/- 3 deg C, while holding the glass in a flat state.
The glass softens and is prone to cause internal bending as it approaches the critical temperature closer to 650 ˚C. So hotter the glass that exits the furnace, the worse is the quality.
The colder the glass, the better is the quality. However, the risk of breakage increases. Sometimes, overheating is needed to compensate for bad edge work or hole finishing.
Corrections: Although the furnace is designed to control thermodynamic conditions, variations are difficult to eliminate.
So for perfection precisely enough heat is added to relieve stress without making the glass too soft. But in reality, such as glass type, glass thickness, coatings, furnace temperature, atmospheric temperature, ambient humidity etc. define the final outcome.
Key rule is:
"Decrease the furnace temperature and increase the heating time."
Any roll eccentricity imparts deformation to the glass.
The leading and trailing edges of each lite form a cantilever as the glass leaves a roll. The glass sags under this load. Overheating causes sag between the rollers. Uneven heating and inconsistent loading exacerbate the problems due to hot spots in the furnace.
Large roller pitch:
There are differences in roller settings in tempering furnaces. When the distance between consecutive rollers is longer, the glass travels a longer distance unsupported. Longer roller pitch results in a larger peak-to-valley roller wave value, thus creating a visually more noticeable distortion.
Roller shape accuracy along the whole roller length also plays an important role in roller wave quality.
This problem is mechanical, related to the roller pitch of a furnace and should be taken care while opting for new tempering line. Later it is extremely challenging to change it.
For better quality results the total indicated run out (TIR) of rollers is checked and measured and high-quality rollers should be used in the process. They have a direct impact on the quality.
Better accuracy with high-quality rollers, improves the overall flatness of the roller bed and thus prevents roller "vibrations" and level differences, which can greatly affect the overall roller wave values.
The oscillation speed is too low.
Lower oscillation movement in the end of the heating cycle increases the time that the glass is without roller support, and thus causes optical distortion. A faster oscillation speed has the better result to improve roller wave effects.
Since glass as a material changes during the heating, it's good to have dynamic control of the oscillation speed. New control systems can control the conveying process more accurately and at different speeds. Such system makes it possible to set different oscillation speeds for the various heating cycle stages to improve roller wave defect.
: Pay attention to pre-processing quality :
Accurate cutting, grinding and drilling processes will allow colder glasses to exit the furnace and improve the roller wave quality. It is to be assured that pre-processing is not a bottleneck for the tempered glass quality and yield.
The need for higher quality, distortion-free, heat-treated glass is creating both challenges and opportunities for the glass industry. While furnace technologies are advancing to meet more stringent requirements, improved measurement of roll distortion is required for process control of the furnace.
A new machine-vision technology has been developed and is now available to accurately measure roll distortion. The LiteSentry Roll Wave Distortion Measurement system, measures the peak-to-valley optical distortion on-line as glass exits the furnace. This system provides the tool necessary to improve and maintain the quality of heat-treated glass, thereby opening new markets for tempered and laminated glass.
(The float glass process can be used to provide low-distortion sheets with very flat and parallel surfaces.)
Quality Issues & Solutions in a Laminated Glass
In Glass & Glass Processing, Processing glass sudies
Day by day usage of Laminated Glass is increasing in the façade & Railing systems.Laminated glass is glass which is manufactured using multiple panes of glass and a flexible interlayer which is bonded in between the panes of glass. The interlayer could be
PVB, Sentry layer, Saflex DG& many other interlayer's'.
Multiple panes panes mostly are Heat Strengthened or Tempered needs a high level of accuracy during processing in order to deliver a Perfect product.
Quality Problems in a Laminated Glass
Excessive Moisture & Water Ingression
PVB is hygroscopic & absorbs moisture. If the panes are exposed to excessive moisture adjacent to the edge of the interlayer, the bond to the glass is reduced and Delamination can occur.
This is often poor detailing allowing moisture to collect or poor installation where measures intended to reduce moisture build up negated.
Compatibility of Edge Silicone Application
Very few silicone sealants have compatibility with PVB, Incorrect seals can lead to edges delaminating.
Vendors needs to address this issue as major silicone failures happen at edges gradually after 2nd or 3rd year of Installation.
If you are using laminated glass in Spider Glazing especially in fins where Fin acts as Structural members one has to ensure right thickness of PVB to be used & even tightening of the bolts also have to be done rightly else too much pressure on glass can lead to lamination failure.
Poor Quality of tempered Glass
Toughened or heat strengthened) glass exhibits distortion within the glass caused by the rollers during the manufacturing process. This distortion is commonly known as roller wave or edge dip. If the distortion within the glass plies is not 'matched' peak to peak and trough to trough then there can be stresses applied to the interlayer, particularly at the edges. Delamination could occur if the interlayer is unable to withstand the stresses applied by the glass plies.
Where Delamination Occurs
Occurs usually at the edge of glass.
Bolted Position of the Glass Fin in event of tightening issues.
Exposed edge Applications in railings.
Failure in compatibility of Structural & weather Silicones.
Mismatch of 2 glasses due to poor processing due to roller distortion
Solutions to get the Right Laminated Glass
Technical acceptable limits of roller wave distortion have to be specified to the vendor so that during pre process bonding is good.
Force of bonding should be uniformly applied equally over the glass & QC must check it continuously.
No tightening of at one particular locations before going into autoclave else those areas will not bond properly.
Quality Control during processing
Glass pane alignment plays important role.
Interlayer storage must be rightly done with correct moisture & humidity conditions.
Right water Ph values needs to be maintained during cleaning of the glass prior to lamination.
Pre autoclave process needs to be followed in accordance with Interlayer manufacturer's guidelines.
Quality Aspects during Installation
Don't apply any weather silicone or structural silicone. Get written approval from the interlayer vendors.
Ensure Panels are rightly ventilated & no particular area has moisture or water ingression.
Ensure no compressions beyond acceptable limits in Application processes.
Always discuss laminated glass applications with Interlayer manufacturers & Glass processors.
Randomly check production quality audits at factory.
Insist on Product warranty in writing from Interlayer & Processor based on your applications, so that in event of failures they too are equally responsible.
Get a complete application guide from the Interlayer manufacturers or visit their websites before concluding your sale.
Spontaneous Breakages
Spontaneous Breakages in Tempered Glass
Sharanjit Singh
GSC Glass Ltd
Sharanjit Singh is the Founder Chairman of GSC Glass Ltd., a technology driven company, leader and pioneer in glass processing. GSC has many firsts to its credit including the first architectural tempering, laminating, ceramic fritting, hardware, processing machines etc. It is also the first company to design and supply glass with design, systems and solutions for many European airports and rail stations, where quality and safety requirements are very high. He is an accomplished engineer and a third generation glass-man and regarded as one of the most knowledgeable person on glass in India. He has conducted many seminars and training workshops and has also written and compiled 'Architectural glass guide' for Federation of Safety Glass (FOSG), which is a comprehensive and complete book on the subject.
Spontaneous breakages: Most of us have come across a situation where a tempered (toughened) glass has broken without a provocation or any apparent reason. Non-tempered glasses do also break and sometimes, without any visible reason. Any non-tempered glass will normally break as a single crack or multiple cracks, which develop or propagate from origin either spontaneously or gently. Spontaneous breakage in tempered glass is however much more dramatic, as the whole pane of tempered glass breaks with a loud noise and high visibility as it breaks into thousands of small pieces.
Most of the times, a tempered glass will disintegrate and fall out of the fixing, but the cause of breakage can be assessed with reasonable fairness, if it stays in fixing. Breakages due to impact or wind loading are less likely to stay in frame. A tempered laminated glass will almost always stay in place after breakage and makes it easier to identify and analyze the cause. By simply looking at the point of origin of breakage and its pattern, the cause can be identified in most cases.
Causes of breakages: There can be several causes or reasons for spontaneous breakages in tempered glass like impact load, poor glazing, glass to glass contact, glass to metal contact, very hard setting blocks etc. Any of these can result in creating a concentrated point load on the edge or corner of the glass. In such cases, the point of origin of breakage will generally give a clue.
Improper or uneven tempering can also cause a post installation breakage. This will happen only if the stress differences on the same pane of glass are very large and this can be easily identified from such breakage. The breakage pattern will be highly non-uniform with some large islands of non-fragmented glass, enclosed or surrounded by much smaller fragments. (See Image-1)
Image 1: Breakage due to uneven tempering
Breakages due to Nickel Sulfide: While the causes mentioned in previous section, can be attributed to errors in designing, manufacturing or glazing, there is one cause, which cannot be attributed to any of these and cannot be fully eliminated or fully addressed. It is the breakage caused by Nickel sulfide inclusions. Looking at the broken glass will give an initial impression of glass being hit by a sharp object and the point of origin of breakage will be obvious. On closer examination, at the origin, there will be at least two fragments in the shape of wings of the butterfly. (see image-2) This is often called 'butterfly pattern' or 'double D Pattern'. The origin of breakage is generally away from the edge of glass.
Image 2: The origin of breakage, caused by Nickel sulfide inclusions
The phenomenon was first acknowledged in 1940 but the first documentation happened in 1961. Since then, there has been extensive research by many companies, institutes and scientists to identify, prevent and resolve the issue. Standards have evolved and many extensive publications have been made on the subject. There have been a number of case studies on manufacturing processes and on glazed building as well. The entire community of designers, specifiers, manufacturers, fabricators and glaziers etc are now broadly aware of the problem. The industry has come a long way and has made rapid strides in addressing the problem, but the problem still remains to be fully resolved.
To understand this phenomenon of spontaneous breakages due to nickel sulfide, we need to briefly understand the manufacturing process of float glass and its heat treatment namely tempering, heat strengthening and heat soak testing.
Annealed Glass: Float Glass or annealed flat glass is the most basic form of glass. This is made of five basic ingredients namely silica sand, soda ash, dolomite, limestone, and salt cake. These are heated in huge furnaces to 1400-1500 degrees C, and then made to float out on a pool of molten tin in controlled atmosphere. The large sheets are pulled onto a conveyor, and taken through an annealing tunnel called lehr, where it is cooled very slowly for an evenly controlled heat dissipation rate. If it is allowed to cool rapidly or in uneven manner, it will result into cracking while manufacturing or in service due to uneven stresses. The cooled glass is cut into large sheets, and then sent to other processing locations for finishing, such as cutting to size, strengthening, or insulating. A large glass furnace can easily produce from 500 to 800 tons of glass each day.
Heat Strengthened and Tempered Glass: Heat Strengthened and tempered glass are created through the same process. At a processing plant,large sheets of annealed glass are cut to the appropriate sizes and shapes. The edges are ground and any holes or cutouts required in the panels are created. It is then heated in a furnace to a temperature of 600-700 degrees C. This temperature is held until the glass softens slightly, at which time it is rapidly cooled through the use of air jets, a process called quenching. Quenching reduces the temperature of the surfaces of the glass quickly and significantly, but due to the low thermal conductivity of glass, the core of the panel remains at a much higher temperature. As this core cools, it induces compression in the already-cooled outer layers, and a balancing tension force is formed in the core of the panel. (See diagrams –3a and 3b)
The difference between heat-strengthened and tempered glass is the speed at which they are cooled, which results in different surface compression and therefore different overall glass strengths and properties, which are compared as under:
Diagram 3a: Process of Tempering
Diagram 3b: Stress Distribution in Tempered glass
NiS in the Glass Production Process: Some microscopic imperfections, known as inclusions, are inherent in the glass production process. Inclusions are microscopic particles that are incorporated into the structure of the glass in the initial melting process of silica sand and other ingredients. There are approximately 50 different types of dirt or other inclusions recognized, but almost all of them are completely harmless. Nickel sulfide is the only exception, and it is a problem in tempered glass only.
There is a reasonable consensus in the industry as to how NiS is formed, from the compounds that are initially introduced into the glass. Assuming that the nickel enters in the form of a nickel-alloy metal (like stainless steel), which is the most commonly accepted explanation for its origin, nickel sulfide forms in a three-step process. First, the nickel separates from the other materials in the alloy, then it bonds with sulfur in the high heat of the melting furnace, and finally is trapped in the glass as the glass cools to its sheet form. Major studies have been made in reducing the contamination of rawmaterials, and great care is taken to avoid the contact between the raw materials and any nickel-containing alloys but it is practically impossible to prevent some microscopic quantities finding the way into the melt, from other sources of Nickel.
Nickel sulfide, like many compounds, exists in different phases at different temperatures. There are two specific phases of NiS, known as the alpha-phase and the beta-phase. This would have no effect on glass whatsoever were it not for the fact that when the NiS changes from alpha-phase to beta-phase, it increases in volume by 2-4 per cent. At temperatures below 3800C, nickel sulfide is stable in the beta-phase form. Above this temperature, it is stable in the alpha-phase. Therefore, when glass is produced in the furnace, it is overwhelmingly likely that any NiS inclusions will be in the alpha-phase. In typical annealed glass, the slow cooling process provided by the annealing lehr, allows the NiS, ample time to transform to its beta-phase as the glass cools.
Image 4: NiS Particle causing Micro Image 5 – Nis Particle Photographed after
cracks spontaneous breakages
In the fast cooling process used in tempered glass, and also heat strengthened glass, there is insufficient time to complete the phase transition of NiS from alpha to beta. The inclusions therefore are trapped in the glass in their high temperature alpha-phase.
Once the glass cools past the phase change temperature, the NiS inclusion seeks to re-enter its lower energy beta-phase. For "trapped" inclusions, this process takes anywhere from months to years. This expansion creates localized tensile stresses that are estimated to be as high as 125,000 psi (860 MPa) at the glass-NiS Interaction surface. The magnitude of this stress drops off sharply away from the face of the inclusion, but is sufficient at the face to cause micro-cracking. (See image 4 and 5).
In compression zones, even this large of a stress is not a concern due to its extreme localization. However, in the core tension zone of the glass, these micro-cracks are propagated by stress concentrations at the tip of the crack until the structure of the glass is undermined completely and the tempered glass undergoes its characteristic shattering, which causes the seemingly spontaneous failure.
For simplified explanation, one can imagine tempered glass as akin to an inflated balloon, which can take substantial loads but when pricked or triggered by a sharp object, it will burst very easily. If there is a NiS particle sitting in the tensile zone or very close to it, the phase change from alpha to beta, can act as a trigger and cause the spontaneous breakage. Tempered glass with higher stresses, will have higher probability of NiS breakage as compared to tempered glass with lower stresses, just as a more pressurized balloon will need lesser provocative force to trigger its bursting. It has been observed that the incidences of NiS breakages are more in thicker tempered glasses (8mm-19mm) as compared to thinner glasses (4mm-6mm).
Heat strengthened glass has substantially lower stresses than tempered glass and therefore have very little possibility of NiS breakages.
Critical vs. Sub-Critical Inclusions: Research has created a theoretical equation that predicts the smallest diameter of a NiS inclusion that would cause failure as 50 microns (0.05mm) in diameter. Inclusions larger than this are typically referred to as "critical" inclusions, whereas smaller inclusions are classified as "sub-critical" inclusions. The relationship between stress and diameter of NiS inclusion has been scientifically proven and field studies have also examples of such small inclusions causing the spontaneous breakages.
It is important to note that sub-critical inclusions of size substantially lower than 0.05mm (say 0.02mm) are generally not capable of creating enough localized tensile stresses, to be able to break the glass, but these can cause a failure if the glass is placed under additional tensile stress due to bending or thermal loading. It has been shown that when glass undergoes deflections that are in excess of 75 per cent of the panel thickness, the stresses in the glass due to lateral loads change from a bending stress profile to a membrane stress profile. Under this condition, lateral loads may increase the tensile stresses at the center of the glass.
Breakage Frequency and Timeline: NiS breakage occurrences are not very significant if we consider the total volume of tempered glass produced globally or nationally, and the volume of glass broken due to NiS. There are many buildings with no report of NiS breakages. There are quite a few which have experienced an occasional failure, but there are some examples, which have repeated failures.
It has not been possible to put exact numbers on frequency and timeline since the results of various studies are all different in units. One study puts the number of NiS occurring as 1 in 500 glass panes. Another study by a prominent Indian float manufacturer puts the no. as 1 critical occurrence in 13 tons of glass. Many other studies have come out with different numbers and though the numbers do not match, it seems clear that failures due to NiS inclusions are incredibly rare. Buildings that have seen multiple instances of NiS failures often have huge expanses of glass, which automatically increases the odds of such a failure occurring. It is also possible for a particularly bad batch of float glass to be produced, which would have a higher failure rate.
Another aspect of nickel sulfide failure is the fact that these failures rarely occur upon installation or even within the first few months following installation. Even so, the overwhelming trend is that most panels break in the first 2 to 7 years, after which the number of breakages tapers off with what is commonly considered as logarithmic decay.
Preventive Measures: The industry is pursuing several courses of action in order to reduce the risks and costs associated with nickel sulfide in tempered glass. For the purposes of comparing various preventive or corrective methods, three criteria were selected which seem to be a fair evaluation of the effectiveness of a solution. In order to be a successful solution, the method must be cost-effective to implement, eliminate the costs of replacement of panels upon breakage, and prevent any injury to bystanders in a failure. So far, no solution has adequately fulfilled all three criteria, and thus the industry is still searching. However, a summary of preventative measures already in use or development in the industry is discussed here.
Image -Heat Soaking Oven
Controlling NiS in Annealed Glass: It might seem the simplest solution to nip the problem at its origin by ensuring that there is no nickel or its alloys entering the glass-melting furnace. Responsible float manufacturers are supposed to take every precaution to control this but it is very difficult to prevent it altogether and in spite of best efforts, small amounts of nickel will find its way through inclusions in raw materials itself or their handling/ storage equipment etc. There is a need for float manufacturers to further strengthen the quality procedures to include necessary steps for its prevention and to subject their quality procedures to internal and external quality audits.
Heat Soak Testing: Tempered glasses can be heat soaked by heating the glass panels for a third time to a temperature below the phase change temperature of NiS and maintaining it or soaking it at that elevated temperature for a set time. Maintaining an elevated temperature facilitates faster conversion of any particle of NiS, if present, from alpha-phase to beta-phase, and therefore the idea is that any panel, which has a possibility of failure from NiS, should fail in the HST oven rather than on the building. The process was introduced in 1982 and the first standard that evolved was DIN 18516. The most common standard, currently being followed is EN 14179. This standard requires glass to be heated to 290 100C and held at this temperature for 2 hours, which is a shorter duration than 8 hours for DIN 18516. The Ŧ reduction in time was based on recommendations from research, which indicated that less than 1 break in 10,000 panes of glass was expected to occur after 2 hours.
There are costs associated to HST which are the processing costs, cost of glass breakages due to NiS in HST oven, and damage by broken glass to the neighbouring panels in HST oven, potentially even causing them to break as well and propagating the problem.
Another issue is that the secondary heating of tempered glass relaxes surface compression slightly without a corresponding decrease in core tension, which reduces the strength of the glass, though marginally. This was more evident in the 8 hours soaking specified in DIN than in the 2 hours soaking as per EN. The designers should keep a small safety margin to account for the same.
In spite of all the issues with the process, it is still the only method the industry has, to eliminate a large portion of nickel sulfide inclusions in batches that are compatible with large-volume production. The success rate of HST is hard to define because of the difficulty of accurate data collection on resulting nickel sulfide failures, which are very rare occurrences. But it can be safely said that appropriately done HST, would eliminate 95 to 98.5 per cent of such glasses as could have caused a spontaneous breakage post installation.
Smart specification and selection: The most logical solution to the problem is by avoiding the use of tempered glass where there are other options like
Use heat-strengthened glass instead of tempered glass where technically feasible.
Heat strengthened laminated glass is the best option for most applications, except for point fixedglazing
Nickel Sulfide Breakage
In applications, where tempered glass cannot be avoided due to load considerations or code requirements, it is advised to get it HST.
Alternately one should be prepared for such occurrences and for replacing NiS broken glasses.
Annealed Laminated glass will have no occurrence of NiS breakage.
Other methods for detection: There are other methods such as laser-imaging and ultra-sound which are non destructive but these methods will need a scan of each panel of glass which will show up all inclusions and not only NiS and thereafter, it will separately need an assessment of each inclusion in each panel to decide which ones are fatal types of NiS and located in the risk zone. The exercise is prohibitively expensive and not feasible on production scales. A person must interpret the results of ultrasound and laser imaging, glass by glass and the margin of user error might be quite large when searching for such a small problem.
Conclusions: Spontaneous breakage due to NiS is not due to any manufacturing defect but is an inherent risk or problem associated with use of tempered glass. As of now, 100 per cent success in eliminating nickel sulfide from tempered glass cannot be guaranteed by any method. Therefore this is an issue which designers should be aware of, and take into account when deciding the use of tempered glass in their building and adopt smart specifications. Glass is a fragile material and no glass supplier can warranty breakages, as there can be numerous causes of breakages and NiS breakages is just one amongst many.
In Education, Glass & Glass Processing, Glass handling, transporting
Traditionally, the materials used to design and decorate homes have been wood, metal or cloth furnishings. Few people realize that delightfully beautiful effects can be achieved with glass. Available in a stupendous variety of styles, colors, designs and textures, glass has the potential to create stunning ambiences that have the power to transform living and elevate lifestyle.
It is a smart, adaptable and versatile material, offering itself to endless possibilities both in terms of design and functionality, across exterior and interior applications. All in all, glass stands in a league of its own. The inherent beauty of glass as a material, when combined with contemporary design sensibilities, makes for an irresistible combination, one that mesmerises and enthrals in equal measure. Delightfully beautiful effects can be achieved with glass.
Glass flooring and stair trends continue to be a popular design choice. Glass flooring can become an artistic showpiece. With recent innovation in glass and glass fittings, any design can be executed for glass stairways and floors. Glass floors enhance the visual appeal of living spaces, and add a touch of modernity. Glass floors and staircases help create illusion of space. A simple glass floor adds life to a room. It also brightens up the space.
Various applications include glass stair tread, ramps and footbridges. Glass flooring adds a design element. The visual appeal of glass tiles can be enhanced further with LED lighting. This is common feature in clubs, restaurants and hotels.
Safety is very important when glass is used for floorings. A commonly perceived notion is that glass compromises safety and security. However, continuous research and technology advances have made glass safer and more secure that it ever was. The range of specialized laminated glass from Asahi India Glass Ltd. ( AIS) includes – Value glass (heat-strengthened laminated glass with 1.14mm PVB interlayer), Security glass (Intrusion-resistant laminated glass with 1.52 mm PVB interlayer), Securityplus (Dupont Sentry Glass interlayer makes it 5 times stronger and 100 times stiffer than conventional laminating materials).
The first step while designing the glass floors is calculating the glass size and thickness depending on the loading or foot traffic on the application. Also, the support systems for the glass should be adequate to prevent distortion under load.
Designing surfaces to be walked on is different as issue related to impact resistance and slip and scratch resistance come into the picture. Many architects are concerned with maintenance and the potential of glass flooring scratching due to normal foot traffic and wear and tear. Anti-slip glass flooring and glass stair trend products are available in the market. Etched or printed surfaces help in improving grip. Imbedded textures provide an anti-skid surface that is scratch- proof and easily hides any smudges or streaks. Anti-scratch glass floorings reduce the opportunity and need for cleaning.
To maintain the aesthetic beauty of your glass flooring, it is important to keep the glass panel clean. A soft, clean, non-abrasive cloth and a mild detergent, or non-abrasive glass cleaning solution is suitable for cleaning. After cleaning, the water should be rinsed immediately. Abrasive cleaners, bleach, scouring powder or pads should not be used as they can scratch and damage glass flooring.
Source: Asahi India
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