Structural Glazing Works – Glass (Commercial & Residential Projects)

Glazing

1. Structural Glazing Works – Glass (Commercial & Residential Projects) S.Sudha Velan B.E (Civil)

2. Glass is a Combination of sand, soda ash, limestone, dolomite and some other minor ingredients.

3.   Architectural Selection The key selection criteria when considering the choice of glass in an architectural projects are: Climate Control (heat gain, heat loss and insulation). Fading Control Sound Control Risk Control (safety, security, fire and surface protection)

4. Glass Selection Guide Heat Loss   Single monolithic glass provides poor insulation. Laminated glass does not improve insulation. Low E-glass improves insulation.. Insulating Glass Units (DGU) provide the best insulation. Larger air space (up to 16mm) provides better insulation. Argon gas fill is better than air for insulation (12mm optimum). Argon and Low E can be combined for higher performance. Insulation is measured by the U Value. The lower the number the better. Insulation can be measured by the R Value. The higher the number the better. Internal blinds and drapes may help reduce heat loss but only if installed correctly.

5. Condensation Select the   insulation to help reduce Condensation. Single glass provides poor condensation control without air conditioning and dehumidification. Single Low E glass can increase condensation Condensation can reduce the performance of Low E glass. Insulating Glass Units provide the best comfort and condensation control. The better the insulation the less cold zones near windows. The better the insulation the more comfortable the environment. The better the insulation the less condensation will occur. Low E glass and Argon gas further reduce condensation .

6. Conduction  – is a type of heat transfer that occurs within a solid material. When a solid receives a source of heat, that solid in effect will absorb the heat . .

7. Convection   – while heat transfer through conduction occurs within a solid material, convection describes the transfer of heat energy in a liquid or gas.

8. Comfort One of the key benefits of using double glazing as insulation is the increase in comfort. If you sit by single glazing when it is cold outside you can feel the cold and this is known as the “Discomfort Zone”. By using insulating glass the discomfort zones can be reduced even when it is -10ºC outside

9. Daylight – Glare &  Colour Daylight is the primary source of life and essential to our existence. Natural light enables us to orientate ourselves while glass enables us to control and manipulate light to our advantage.

10. Visual Comfort Most people spend much of their day in buildings and the quality of light in their surroundings has considerable influence on their efficiency, state of mind, health and safety. The important principles are: Position work areas close to windows. Facilitate visibility out of the building. Avoid direct sunlight in work areas and the associated problems of glare. Distribute light evenly avoiding areas of strong contrast which can result in problems associated with glare.

11. Fading As solar radiation enters the room it is absorbed by the exposed furnishings or other material causing the temperature to rise. This continual heating of the fabric by the visible light and infra-red radiation, combined with the most damaging effects of the UV light rays, deteriorate and break down the structure of the furnishings, and other materials, eventually leading to the dis-colouration that is associated with fading

12. Key Points on Fading UV light is the most damaging radiation. Visible light and Infra-red heat are contributors. Glazing which absorbs or reflects solar radiation will help to reduce fading. Fading can never be completely prevented. Northern faces of buildings will receive greater exposure to solar radiation. Very large glazed areas will permit greater exposure to solar radiation. Glazing can be selected to significantly reduce the rate of fading. Laminated glass with PVB interlayer absorbs up to 99% of UV light. Tinted or reflective PVB laminated glass gives better fading reduction. Tinted or reflective glass will reduce solar heat and visible light and reduce fading. Drapes or curtains can help to reduce furniture exposure to damaging solar radiation. Building design can help to reduce direct solar transmission onto glazing.

13. Sound Control Glass Glazing and windows play a critical role in the sound insulation of a building, and are frequently highlighted as the most vulnerable element in a building’s ability to resist noise intrusion Sound reduction will increase with increased glass thickness, due to the increased mass involved. Sound reduction will increase with the use of all laminated glass due to the vibration dampening effect of the plastic interlayer sandwiched between the plies of glass. Multi laminates combine the increased mass effect of solid glass with the dampening effect of plastic inter layers can provide even superior sound reduction. Sound reduction can be improved by using different glass thicknesses and types in double glass / glazing combinations. This minimizes sympathetic vibrations which occur when glass of the same thickness resonates in unison and transmits sound.

14. Types of Glass Float glass Shatterproof glass Laminated glass Extra clean glass Chromatic glass Tinted glass Toughened glass Heat Strengthed Glass (HS) Glass blocks Glass wool Insulated glazed units

15. Float Glass Float glass manufactured from sodium silicate and calcium silicate so, it is also called as soda-lime glass. It is clear and flat, so it causes glare. Thickness of the float glass is available from 2mm to 20mm, and its weight range from 6 to 36 kg/m 2 . The application of float glass includes shop fronts, public places, etc

16.  visible light transmittance (VLT). CLEAR FLOAT   EXTRA CLEAR FLOAT                 (LOW IRON)

17. Shatterproof Glass Shatterproof glass is used for windows, skylights, floors, etc. Some type of plastic polyvinyl butyral is added in its making process. So, it cannot form sharp-edged pieces when it breaks.

18. Laminated Glass Laminated glass is the combination of layers of ordinary glass. So, it has more weight than a normal glass. It has more thickness and is UV proof and soundproof. These are used for aquariums, spider glazing area ,bridges, etc.

19. Polyvinyl butyral  ( PVB ) film that bonds with glass under heat and pressure to form laminated safety glass. The   interlayer  sandwiched between the layers of glass is responsible for the enhanced performance properties of laminated glass.

20. Benefits and applications of Laminated glass Security Laminated glass offers greater protection for people and property by providing an effective barrier from attack. Although the glass will break if hit with a hammer, brick or similar object, the interlayer can resist penetration, ensuring any attempt to enter a premises will be slow and noisy. Fading Control PVB laminated glass products absorb the sun’s UV radiation while allowing important visible light to pass through. It therefore helps protect curtains, furnishings and carpets from fading caused by the damaging effects of short-wave ultra-violet radiation.

21. Sound Control Laminated glass is very effective in reducing the transmission of noise through glazing. Climate Control Laminated glass can have a tinted interlayer or be made with tinted or reflective glass to reduce glare and heat gain in a building. Colour and Light Laminated glass can be made with a wide range of coloured PVB interlayer to provide special lighting effects. Visible Distortion Due to the controlled nature of the laminating process, façades glazed with annealed laminated glass avoid the risk of visible distortions that are sometimes created by the heat treatment processes, providing significantly sharper visual transmission and reflections.

22. Extra Clean Glass Extra clean glass has two unique properties, photo catalytic and hydrophilic. Because of these properties, it acts as stain proof and gives a beautiful appearance.

23. Chromatic Glass Chromatic glass is used in ICU’s, meeting rooms etc. it can control the transparent efficiency of glass and protects the interior from daylight. The chromatic glass may be photo - chromic which has light sensitive lamination, thermos-chromatic which has heat sensitive lamination and electro-chromic which has electric lamination over it.

24. Tinted Glass Tinted glass is nothing but colored glass. A color producing ingredients is mixed to the normal glass mix to produce colored glass which does not affect other properties of glass. Different color-producing ingredients are tabulated below: Different Types of Ions Used to Produce Various Colors in Glasses Iron oxide - Green Sulphur - Blue Manganese dioxide - Black Cobalt - Blue Chromium - Dark green Titanium - Yellowish brown Uranium - Yellow

25. Toughened Glass

26. Types of Toughened Glass Clear toughened glass Laminated toughened glass Reflective toughened glass Tinted toughened glass  Frosted toughened glass Advantages of Toughened Glass Toughened glass is about  to 6 times stronger than normal float glass. Moreover, the process of tempering does not affect any other property of the glass. Hence, with the same visible light transmission as normal float glass comes simply greater strength Toughened glass is able to withstand massive differences in temperature (of up to 250°C) whereas normal float glass can handle only up to 40°C Tempering of glass renders it difficult to break and even when it does due to whatsoever reasons, it will fall apart into very small, blunt, cube-like pieces that do not cause fatal injuries.

27. Heat Strengthed Glass (HS)

28. High Performance Glass High Performance Glass is one which reduces the ingress of heat and at the same time allows higher penetration of daylight . Benefits of Using High Performance Glass : It can result in energy savings to the tune of 35-40% as compared to conventional glass It provides access to day lighting which can enhance occupant comfort and productivity High performance glazing is one which can contribute to optimizing energy efficiency and at the same time enhance light penetration. High performance glazing has low U-value, low Shading Coefficient and High VLT (Visual Light Transmittance) and is the ideal choice for today's energy stressed buildings.

29. Types of High-Performance Glass Low-E Glass Low-E or low-Emissivity glass has exceptional thermal insulation capabilities. This surface stands to guard against ultraviolet (UV) radiations.

30. Low E- Coating Low Emissivity (low  -E  or low thermal emissivity) Low-E coatings have been developed to minimize the amount of ultraviolet and infrared light that can pass through glass without compromising the amount of visible light that is transmitted. Two types of Low-E glass: hard coat and soft coat Hard coat Low-E glass is manufactured by pouring a thin layer of molten tin onto a sheet of glass while the glass is still slightly molten.

31. Solar Control Glass Much like low-E glass, this type also comes with a special oxide coating responsible for exchanging less amount of solar glare from outside to inside.

32.  Glass Blocks Glass block or glass bricks are manufactured from two different halves and they are pressed and annealed together while melting process of glass. These are used as architectural purpose in the construction of walls, skylights etc. They provide aesthetic appearance when light is passed through it.

33. Self Cleaning Glass Self cleaning glass is clear float glass with a pyrolitic coating which works in two stages. Firstly the coating reacts with UV light rays to generate a photocatalytic process that loosens and breaks down organic dirt particles on the surface of the glass. Secondly, when rain lands on the glass, the water is attracted to the surface by the hydrophilic properties, causing it to sheet evenly across the glass, washing away the loose dirt and drying without spotting. 

34. Glass Wool Glass wool is made of fibers of glass and acts as an insulating filler. It is fire-resistant glass.

35. Edge Working

36. Notches, Cutouts, Slots & Holes

37. Bevelling With straight line and shaped bevelling a beautiful and decorative touch can be added to mirrors, table tops, glass door panels and furniture glass

38.   MITRES Straightline machines produce mitred edges with either ground or polished edges for glass silicone butt joints at set angles. 22.5° and 45° mitres are available as standard.

39. Sandblasting Sandblasting float glass with a combination of high pressure sand and air creates a frosted glass panel which is permanent. Toughened and laminated glass can only have surface sandblasting, not deep bite sandblasting

40. Acid Etching Acid etched glass is a durable finish created when a glass surface has been etched with hydrofluoric acid to create a fine translucent frosted or patterned finish

41. Types of Glass Construction Monolithic Glass  – Monolithic glass is the most basic of glass forms. It is simply a single piece of glass constructed using one glass thickness.  Laminated Glass  – Laminated glass is constructed by combining two panes of glass fused together with a middle layer of Polyvinyl Butylenes Film (PVB). PVB acts like a bonding agent to hold broken glass together.

42. Insulated Glazed Units Insulated glazed glass units contains a glass is separated into two or three layers by air or vacuum. They cannot allow heat through it because of air between the layers and acts as good insulators.

43. Reflective Coated Glass Special coatings can be applied to a float glass surface to make it reflective to short wave radiation from the sun and/or long wave radiation from heat inside or outside the building. Pyrolytic Coatings A coating applied on line at high temperature during the float manufacturing process. Also known as on line or hard coatings. Sputtered Coatings A coating applied off line in special equipment, also known as off line, vacuum, or soft coatings.

44. Pyrolytic Reflective A pyrolytic coating is a metal oxide coating applied on line during the float manufacturing process. The coating is fused into the glass surface at high temperature making it extremely hard and durable.

45. Slip Resistant Glass Floor Treatment In some situations floors and stair treads require slip resistance and TempaGrip can be combined with patterns to produce a stunning visual effect on the upper glass surface. In some designs a sacrificial top toughened glass layer can be provided to protect more expensive multi-ply laminate and allow for economic replacement. Some special clear non slip floor coatings are available depending on the glass combinations and special non slip adhesive tapes and films can be also be used.

46. Glazing Properties Requirement Light transmission – 40 -50 % Visible light reflectance (Out) – 15-20 % Visible light reflectance (In ) – 8-16% UV -13% Solar transmission – 20% Solar factor – 0.4 for SGU & 0.35 for DGU Shading co-efficient – 0.33 U-Value – – 5.5 for SGU & 2.5 for DGU

47. Glazing Photometric Properties & Characteristics Solar factor : the ratio between the thermal energy coming from the sun and entering the environment and the energy arriving on the external surface of the glass; Solar transmission factor : the portion of solar radiation transmitted directly from the glass;

48. Shading Coefficient (SC)   It's the ratio of solar heat gain passing through a glazing system to the solar heat gain that occurs under the same conditions if the window were made of clear, un-shaded window glass. A lower shading coefficient number indicates better solar shading performance

49.   U-Value   – is a measurement of heat transfer due to outdoor/indoor temperature differences. It's the amount of heat passing through one square foot of glass in one hour for each 1 degree Fahrenheit temperature difference between the indoor and outdoor air. Some of the ways U-values can be improved are: Use double- or triple-glazed IGUs Use a noble gas, such as argon, in the cavity Use low-e coatings

50. Visible Light Transmission (VLT)  – is simply the measurable amount of solar visible light (daylight) that travels through a glazing system.

51. Visible Light Reflectance (VLR)  – is the measurable amount of visible light that is reflected out by a glazing system. A glazing system with a high VLR means that most of the daylight is not passing through the window.

52. Ultraviolet (UV) Rays UV solar energy is very powerful and dangerous to the human skin and other earthly materials such as furniture, wood floors, leather seats, etc. This section will provide a synopsis of the various forms of UV rays, along with what happens when UV rays strike a glazing system. 1. UV-A Rays:  UV-A rays have the longest energy wavelength and have the ability to penetrate the skin. These rays are considered one of the primary causes of skin aging. 2. UV-B Rays:  A percentage of UV-B rays are filtered out by the earth's atmosphere and ozone layers. These rays often cause sunburn when the skin is overexposed. 3. UV-C Rays:  The earth's atmosphere and ozone layers filter out all UV-C radiation below 290 nanometers.

53. Causes of Fading

54. General Notes Sound performance - 28 to 30 db reduction from outside to inside intensity for 6mm+12mm+6 mm DGU. Laminated glass increases sound insulation. Series of Glass of Saint Gobain make KT – Vision SKN - Vision KS - Vision ST – Spandrel Glass Wastage - It is mandatory for Consultants to design glass wastage within 5 %. Glass Deflection - Short Span/90 or Long span/175 to be considered or should be < or = 15mm, Spider Glazing – span/180. Per capita consumption of glass in India - 0.54 kg per capita. Unit weight of glass -2500 Kg/Cum

55. Glass Breakage (Failures) Thermal stress occurs when there is an uneven distribution of heat (solar radiation and/or interior heat) on a glass surface. If glass is heated uniformly, the whole panel will expand. If uneven heat distribution exists, the glass expands in different spots causing excessive stress. Thermal stress fractures normally occur on the glass edge where the stress exceeds the strength of the glass. 

56. Tinted Glass The amount of Total Solar Absorptance (TSA) is a major factor in understanding thermal stress. The TSA is higher for tinted or coated glass, since more heat is absorbed (30% to 75%), resulting in a greater chance of thermal stress fractures. Glass Thickness The thickness of the glass can also determine whether thermal stress may occur Window Size The size of the window can also contribute to thermal stress Exterior Shading Glass temperature imbalances can be caused by exterior shading of sunlight. Interior Shading Window blinds, drapes and other window treatments trap heat if placed too close to a glass window. This can cause glass temperature imbalances as well.

57. Glass Protection (Protect) Glass damage on building sites is a common problem in the construction industry. It is normally caused by splatter from concrete, paint, welding or grinding, impact scratches or scratches from trying to clean off paint, plaster and other contaminates. Protect is an 80 micron UV resistant film that has been fully researched and tested by a major international film manufacturer and is specifically designed for use on glass.

58. Quick tips about tempered & heat-strengthened glass Fabrication first.  Because of the high internal stresses caused by heat-strengthening or tempering glass, all fabrication, including cutting, hole-drilling, notching or edge treatment, must be performed before glass is heat-treated. Rate of cooling determines strength.  During heat treatment, annealed (untreated) glass are heated to approximately 1,200 degrees F, then “quenched” in cold air. Cooled rapidly, glass tempers. Slower cooling produces heat-strengthened glass.  Tempered is stronger.  Tempered glass has a minimum surface compression of 10,000 pounds-per-square-inch (psi) and minimum edge compression of 9,700 psi. That makes it about four times stronger than annealed glass.

59. Tempered glass is safety glass.  When broken by impact, fully tempered glass shatters into tiny particles, reducing the potential for serious injury by flying shards of glass. Heat-strengthened glass is not a safety glass.  Though heat-strengthened glass may meet requirements for wind, snow and thermal loads, it is not considered a safety glazing. Heat-strengthened glass does not shatter when broken, but fractures into larger, sharper pieces that can become projectiles in a tornado, hurricane, explosion or fire. Avoiding fall-out.  Because it does not shatter, heat-strengthened glass tends to remain in the framing system after it is damaged, which makes it a better choice for applications where glass fall-out is a concern. Lamination for consideration.  Laminated inter layers, required for overhead glazing, can be used with annealed, heat-strengthened or tempered glass to combine several safety advantages into a single glazing solution, including less risk of spontaneous breakage and glass fall-out, and increased resistance to wind loads, snow loads and thermal stress. 

60. Distorted views.  Heat-treatment can generate subtle roller waves in glass, which are more likely to occur in tempered glass than in heat-strengthened glass. Edge quality is critical.  Poor edge quality – or edge damage during fabrication, delivery or installation – makes glass more likely to break, which can offset or negate any benefit associated with heat-strengthening or tempering.

61. Approved List of Materials & Suppliers Clear Float Glass – Saint Gobain /Asahi/ Modi flat glass /Sun-guard Guardian/ Pilkington Soft Coated Low –E Reflective glass- Saint Gobain Glass Processors – Asahi / Glass tech/ Sejal / Fuso/Saint Gobain / Sezal / Prakash /Guardian/PPG/SYP/ Balaji-Banglore Fiber Glass wool – Twiga fibreglass / Lloyds insulations Rock wool - Vetrotex /Lloyds insulations /Rockwool India/ Twiga / KNAUF / Roxul Rockwool Glass Laminate -Dupont (Kuraray) / Saflex Automatic Sliding Door- Dorma / Kaba / Geze / Savio / Alualpha / Giesse / G-U

62. Basic Cost of Glass 6mm KS series –Rs.1100/ Sqm (Vision panel) 6mm ST series –Rs.900 / Sqm (Spandrel ) Heat Strengthening Process – Rs.300/ sqm 6 mm clear toughened glass - Rs.800/ Sqm Automatic sliding entrance door (12 mm clear toughened glass) –Rs.40000 / Sqm Spider glazing 8+1.52 PVB inter layer +8 mm laminated glass & fin 10+1.52 PVB inter layer +10 mm laminated glass –Rs.9500/ Sqm Increment cost of glass thickness of each 1mm - Rs 130/ Sqm

63. Saint Gobin Cool Light - ST136 Graphite Blue Glass Facade View

64. IGBC Rating Energy - 2 points Local and regional material - 2 points Recycled content - 2 points Daylight - 1 point Views - 1 point

65. Thanks & Regards S.Sudha Velan