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1. Basic Types of Glass ..................................................201.1 History ....................................................................................20

1.2 Float glass ...............................................................................201.2.1 Colouring .................................................................................221.2.2 Properties ................................................................................23

Density | Elasticity module | Emissivity | Compressive strength | Tensile

bending strength | Resistance to alternating temperature | Transfor-

mation area | Softening temperature | Length expansion coefficient |

Specific heat capacity | Heat transmittance coefficient (U value) | Acid

resistance | Alkali resistance | Water resistance | Fresh, aggressive

alkaline substances

1.3 Coatingsonfloatglass ..........................................................261.3.1 Pyrolytic method .....................................................................261.3.2 magnetron process .................................................................26

magnetron-Sputter-Coater

Lotte Plaza, moscowSunGuard HP Royal Blue 41/29mosproekt 2, Kolsnitsins Arch. Bureau

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Basic Types of Glass

1.1 History The history of glass production dates back to about 5000 BC. Glass beads discovered in an-cient Egypt and early Roman sites bear witness to a long tradition of drawing and moulding tech-niques used in glass production. For centuries, however, individual craftsmanship dominated manu-facturing processes that ranged from using blowpipes and cylinder blow-moulding techniques to the crown-glass method. These man-ual production methods resulted in small quantities and small win-dowpanes, which were almost exclusively used in stained glass windows in churches.

Demand for glass during the sev-enteenth century rose because in addition to master church builders using glass in church windows, builders of castles and stately townhouses were now

discovering how to use glass to enclose spaces as well. French glassmakers first developed a glass rolling process that pro-duced 1.20 x 2 m glass panels, a size that until then had seemed impossible. Glass production did not become industrialized until the twentieth century when 12 x 2.50 m sheets of glass later be-gan to be mass produced on a large scale using the Lubbers and Fourcault methods of glass pro-duction, advancing to the more recent technologies developed by Libbey-Owens-and Pittsburgh.

All of these methods had one dis-tinct disadvantage: manufactured glass panels had to be ground and polished on both sides to ob-tain distortion-free and optically perfect mirror glass, a process that was extremely time-consum-ing and expensive.

1.2 F loat glassIndustrial glass which today would be glass used in the au-tomotive and construction in-dustries was originally manu-factured using a system known as float glass. This floating process, which reached its peak in 1959, revolutionised glass pro-duction methods. Until this float process was developed, glass panes were produced by drawing or moulding molten glass, and then polishing it.

This new method lets the glass float, that is, the molten glass spreads out evenly over the sur-face of a liquid tin bath. Due to the inherent surface tension of

the liquid tin, and the fact that glass is only half as dense as tin, the molten glass does not sink into the tin bath, but rather floats on the surface, thereby evenly moulding itself to the surface shape of the liquid tin. This meth-od creates absolute plane paral-lelism, which guarantees freedom from distortion and crystal clear transparency. Reducing the tem-perature in the tin bath from ap-prox. 1000 C to approx. 600 C turns a viscous mass of molten glass into a solid glass sheet that can be lifted right off of the sur-face of the tin bath at the end of the floating process.

Tin is ideal for shape forming be-cause it remains liquid through-out the entire shape-forming process and does not evaporate, thanks to its low vapour pressure. In order to prevent the tin from oxidizing, the floating process takes place in a protective gas atmosphere of nitrogen with a hydrogen additive.

The molten process precedes form shaping by floating glass in a tin bath. This process be-gins with an exact proportion of the raw materials that is based on about 60 % quartz, 20 % soda and sulphate, and 20 % limestone and dolomite. These materials are crushed in huge agitators and processed into a mixture. A blend comprising ap-prox. 80 % of this mixture and 20 % of recycled scrap glass is fed into the furnace and melted

at about 1600 C. The result is a chalk-natron-silicate glass that is in accordance with EN 572-2.

After gassing the molten mixture, which is referred to as refining, the molten glass is fed into the conditioning basin and left to cool to approx. 1200 C before flowing over a refractory spout into the float bath. This mixture is constantly fed, or floated onto the tin surface, a method that can be likened to a tub that overflows due to constant water intake. An infinite glass ribbon of about 3.50 m width is lifted off the surface at the end of the float bath.

At this point, the glass ribbon is approx. 600 C and is cooled down to room temperature using a very precise procedure in the roller cooling channel to ensure that no permanent stress remains in the glass. This operation is ex-tremely important for problem-free processing. The glass ribbon is still approx. 50 C at the end of the 250 m-long cooling line and a laser inspects the glass to detect faults such as inclu-sions, bubbles and cords. Faults are automatically registered and scrapped when blanks are later pre-cut.

Batch house

melting Forming Cooling Controling, cutting, stacking

app. 1.600 C

app. 1.200 C app. 600 C

app. 1.100 C app. 50 C

F loating process (schematic representation)

View of the melting process

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Basic Types of Glass

Pre-cuts are usually 6 metres or less, with the glass being cut per-pendicular to the endless ribbon. Both edges of the ribbon are also trimmed, generally produc-ing float glass panes of 3.21 m x 6 m, which are then immediately processed or stored on frames for further processing. Longer plates of 7 or 8 m are also produced.

An average float glass line is about 600 m long and has a ca-pacity of approx. 70,000 m with a thickness of 4 mm.

1.2.1 Colouring

The normal float glass has a slightly greenish tint. This colour-ing can mainly be seen along the edge of the glass and is caused by the naturally existing ferric ox-ide in the raw materials. By select-ing extremely ferric oxide-poor raw materials, or by undergoing a chemical bleaching process, the melt can be turned into an abso-lutely colour-neutral, extra white glass. GUARDIAN produces this type of glass, called GUARDIAN UltraClear. Interiors and spe-cialty solar products are the wid-est areas of application.

GUARDIAN also offers GUAR-DIAN ExtraClear, a third float glass alternative that distin-guishes itself from the competi-tion because of its reduced iron-content. In terms of colour and spectral properties, this glass falls between the UltraClear white float and the standard Clear float. Due to its interesting com-bination of properties, Float ExtraClear is used as the base material for ClimaGuard thermal insulating and SunGuard solar control coatings, which improves the selectivity as well as the col-

Tran

smis

sion

[%]

Wavelength [nm]

Clear float glass ExtraClear UltraClear

1.2.2 Properties

most of todays glass production is float glass, with thicknesses usually ranging from 2 25 mm and a standard size of 3.21 x 6 m

that is used for further process-ing. The glass has the following physical properties:

1.2.2.1 Density

The thickness of the material is determined by the proportion of mass to volume and is stated us-ing the notation r. Float glass

has a factor of r = 2,500 kg/m. That means that the mass for a square metre of float glass with a thickness of 1 mm is 2.5 kg.

1.2.2.2 Elasticity module

The elastic module is a material characteristic that describes the correlation between the tension and expansion when deforming a solid compound that possesses linearly elastic properties and the

formula symbol E. The more a material resists deformation, the higher the value of the E-module. Float glass has a value of E = 7 x 1010 Pa and is defined in EN 572-1.

our neutrality, irrespective of the particular coatings, especially for glass used in facades.

In addition to these three ver-sions of float glass, tinted glass can be produced using coloured mass. Chemical additives in the mixture allow green-, grey-, blue-, reddish- and bronze-coloured glass to be produced during

certain production floating line periods. Changing glass colour in the vat naturally means a con-siderable amount of work and increased cost due to scrap and loss in productivity. Thus, it is only produced for special campaigns.

1.2.2.3 Emissivity

Emissivity (e) measures the ability of a surface to reflect absorbed heat as radiation. A precisely de-fined black compound is used as the basis for this ratio. The

normal emissivity found for float glass is e = 0.89, which means 89 % of the absorbed heat is re-radiated ( chapter 3.3)

Colouring

1.2.2.4 Compressive strength

As the term implies, this indicator demonstrates the resistance of a material to compressive stress. Glass is extremely resilient to pressure, as demonstrated by its

700 - 900 MPa. Flat glass with-stands a 10 times higher com-pressive power in comparison with the maximum compressive load.

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Basic Types of Glass

1.2.2.5 Tensile bending strength

The tensile bending strength of glass is not a specific material pa-rameter, but rather an indicated value which, like all brittle mate-rials, is affected by the composi-tion of the surface being sub-jected to tensile stress. Surface infractions reduce this indicated value, which is why the value of the flexural strength can only be defined using a statistically reli-able value for the probability of fracture.

This definition states that the fracture probability of a bending stress of 45 MPa for float glass (EN 572-1) as per the German building regulations list may be maximum 5 % on average, based on a likelihood of 95 % as deter-mined by statistical calculation methods.

s = 45 MPa as per rating with the double ring method of EN 1288-2.

1.2.2.6 Resistance to alternating temperature

Resistance of float glass to tem-perature differences along glass panes is 40 K (Kelvin). This means that a temperature difference of up to 40 K over the glass pane has no effect. higher differences can cause dangerous stress in the glass cross section, which may result in glass breakage. heat-ing devices should therefore be

kept at least 30 cm away from glazing. If this distance cannot be maintained, installing one pane safety glass is recommended ( chapter 7.1). The same applies if the glazing is massive, perma-nent and partially shaded, due, for example, to static building elements or to nearby plantings.

1.2.2.8 Softening temperature

The softening point for float glass is approx. 600 C.

1.2.2.9 Lengthexpansioncoefficient

This value indicates the minimum change in float glass when tem-perature is increased, which is extremely important for joining to other materials:

90 x 10-6 K-1 according to ISO 7991 at 20 - 300 C

This value gives the expansion of a glass edge of 1 m when tem-perature increases by 1 K.

1.2.2.10 Specificheatcapacity

This value determines the heat increase needed to heat 1 kg of float glass by 1 K:

C = 800 J kg-1 K-1

1.2.2.12 Acid resistance

1.2.2.11 Heattransmittancecoefficient(Uvalue)

Chart: Class 1 acc. to DIN 12116

This value is calculated in accord-ance with DIN 4108-4 to EN 673.

1.2.2.13 Alkali resistance

Chart: Class 1-2 acc. to ISO 695

1.2.2.14 Water resistance

Chart: hydrolytic class 3-5 acc. to

1.2.2.15 Fresh, aggressive alkaline substances

For example, this includes sub-stances washed out of cement that must be completely hard-ened, and when they come into contact with the glass, attack the silica acid structure that is part of the glass structure. This causes a change of the surface as contact points get rougher. This effect oc-

curs when the liquid alkaline sub-stances dry and is completed af-ter the cement has fully solidified. For this reason, alkaline leaching substances must not come into contact with glass at all, or all points of contact have to be re-moved immediately by rinsing them off with clean water.

ISO 7191.2.2.7 Transformation area

The mechanical properties for float glass vary within a defined temperature range. This range is between 520 - 550 C and

must not be compared with the pretempering and form shap-ing temperature, which is about 100 C warmer.

The value of float glass with a thickness of 4 mm 5.8 W/mK.

100

nm

Pyrolytic method (online)

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Basic Types of Glass

Cross-section of a magnetron coating line

Entrance chamber

Coating

Lock valve Turbomolecular pump

Top layerProtection layer

Functional layerProtection layer

Bottom layer

Glass substrate

Glass substrate Sputter cathode

Buffer chamber

Buffer chamber

Exit chamber

Sputtering chamber

1.3.2 Magnetron process

The magnetron process has many appellations, even one which dates back to the beginning when this process was termed softcoating, as oppose to hard-coating. Today, this definition is misleading, since there are now extremely resistant magnetron-

sputter films that are always com-posed of ultra thin, individual lay-ers of film.

No other technology is able to coat glass so perfectly smoothly with such outstanding optical and thermal properties.

The material (i.e. the target, which is a metal plate) that is going to be deposited on the glass surface is mounted on an electrode that has a high electrical potential. Electrode and target are electri-cally isolated from the wall of the vacuum chamber. The strong electrical field (fast electrons) ion-ize the sputter gas argon. The accelerated argon ions are able

to break off material from the target by colliding with it, which then comes into contact with the glass, where it is deposited onto the surface.

metals and alloys are spattered with or without additional reac-tive gases (O2 or N2). Now it is possible to deposit metals, metal oxides and metal nitrides.

1.3.2.1 Typical assembly of a Magnetron-Sputter-Coater

1.3 CoatingsonfloatglassIndustrial coatings for float glass are produced in huge quantities, primarily in 2 techniques. One is the chemical pyrolysis process, also called hardcoating; the sec-ond is a physical process called vacuum deposition process or magnetron-sputtering.

Depending on the coating used, materials in both methods cre-ate a neutral and coloured ap-

pearance, whereby the coloured effects are less obvious when viewing the glass head-on and are easier to note when looking at reflections on the glass sur-face. These two technologies are base-glass oriented and not to be mistaken for surface coating ap-plied through spraying, rolling or imprinting processes ( chapter 8.2).

1.3.1 Pyrolytic method

This type of float glass coating process occurs online during the glass production on the float line. At this point, the glass surface is still several hundred degrees Celsius when metal oxides are sprayed onto it. These oxides are permanently baked onto the surface, and are very hard (hard-coatings) and resistant, but their properties are very limited due to their simple structure.

To meet the higher demands that are generally required to-day, multi-layer glass systems are

used. They are produced offline under vacuum in the magnetron-sputter process.

GUARDIAN therefore focuses solely on the coating technology described below.

Layer srack of high performace coated glass

Bottom and top layer:

influence, reflectance, trans-mittance and colour of the coating

silicone nitride top layer gives a very high mechanical durabil-ity

Functional layer:

e.G. silver, chromium

responsible for the reflection of long wave and short wave radiation

strong influence on U-value and Shading Coefficient/Solar Factor

Protection layer:

protection of the functional layer against mechanical and chemical influences

Glass substrate app. 800 C metal oxide layer

metal oxides

Floating Cooling

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2 Light, Energy and Heat ...........................................302.1 Light .........................................................................................30

2.2 Solar energy ............................................................................31

2.3 Heat..........................................................................................32

2.4 UV radiation ............................................................................33

2.5 Photovoltaics ..........................................................................33

Dream house, moscowSunGuard hP Light Blue 62/52murray OLaoire Architects

00.0003 - 0.0025

103 10-2 10-5 10-6 10-8 10-10 10-12

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Light, Energy and Heat

The physical definitions of light, energy and heat describe de-fined areas of the electromag-netic spectrum.

The area relevant to architectural glass in connection with light and solar energy falls within a 300 - 2,500 nm (0.0003 mm - 0.0025 mm) wavelength.

In this spectrum there is the UV radiation between 300 and 380 mm (300 nm = 0.0000003 m), the visible light between 380 and 780 mm and the near IR between 780 and 2,500 mm. Heat means long wave radiation which is in the far IR wavelength areas of approx. 5,000 and 50,000 nm (0.005 mm - 0.05 mm).

Longer wavelengths are radar-, micro- and radio waves, shorter ones are x-ray- and gamma radia-tion.

Wavelength [mm]

Wavelength [m]Range building glass

Radio

microwave

Infrared visible light

Ultraviolet

X-rayhard gamma radiation

The small area of the solar spec-trum that can be seen by the hu-man eye is called (visible) light.

If the unbroken (visible) light hits the human eye, it is perceived as white light. It is, however, com-posed of a light spectrum where the various wavelengths each representing a defined energy flow into each other:

2.1 Light

When light hits an object, the object absorbs part of the en-ergy spectrum. Glass, however, transmits light, reflecting the rest of the energy. Depending on the nature of the object, certain wavelengths are reflected and others absorbed. The eye per-ceives the reflected color as be-ing the colour of the object.

Color Wavelength [nm]

violet 380 - 420

blue 420 - 490

green 490 - 575

yellow 575 - 585

orange 585 - 650

red 650 - 780

Artificial lighting can cause colour misinterpretation due to missing wavelength ranges. A well-known example is low-pressure sodium vapour lamps. Since they lack the blue, green and red wavelengths, everything appears in monochro-matic yellow tones.

2.2 Solar energyThe radiation emitted by the sun that strikes the earth is called so-lar energy. This wavelength range has been defined through inter-national standardisation (EN 410) as ranging from 300 to 2.500 nm and includes the UV, visible light and near infrared light categories.

The worldwide accredited global radiation distribution curve (acc. to C.I.E., Publication No. 20) shows the intensity of the total solar radiation in its respective wave ranges. Fifty-two percent of these wavelengths are visible and forty-eight percent are invisible.

Wave spectrum

Total radiation 100 %

heat 41 %

visible 55 %

UV 4 %

Rela

tive

radi

atio

n in

tens

ity [%

]

Rela

tive

sens

itivi

ty o

f the

nak

ed e

ye [%

]

Wavelength [nm] ClimaGuard Premium Conventional insulating glass Sensitivity of the naked eye Solar spectrum

Global radiation distribution curve (C.I.E., Publication No. 20)

ClimaGuard Premium

conv. Insula-ting glass

Visible radiation 75 % 79 %

Heat radiation 30 % 66 %

Total radiation 54 % 73 %

Permeability of ClimaGuard Premium and conv. Insulating glass, based on the intensity distribu-tion of the solar spectrum. Energy distribution acc. to DIN EN 410 (Air mass 1.0)

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Light, Energy and Heat

The shorter the wave length, the more energy is transported. That means that there is a consider-able quantity of energy in the visible portion of the radiation. Therefore, light and energy can-not be separated from each oth-er. This is a critical aspect in using and improving architectural glass.

Important properties that are critical for characterizing the na-ture of architectural glass such as solar energy transmission, re-flection and absorption and the total energy transmittance, can be derived from the solar energy in the global radiation wave-length range of (300 - 2,500 nm) and their interactions with glass ( chapter 5.4).

2.3 Heatheat and heat radiation are a wavelength range that is not part of the solar spectrum. heat radia-tion has far longer wavelengths and is in the far infrared range. In the European standard EN 673, this range is defined as being be-tween 5,000 and 50,000 nm.

Its interaction with heat defines the insulation characteristics of architectural glass, which are in-fluenced by heat radiation, heat conduction and convection. The Ug value the coefficient of the heat conductivity is the funda-mental characteristic for judging the glass construction mate-rials heat insulation capability ( chapter 3.5).

2.4 UV radiationThe wave range between 315 and 380 nm are known as the UV-A rays. If the intensity is too great, this radiation has not only a more or less destructive impact on the skin but also for many oth-er elements (paintings, sealing material etc.).

Normal insulating glass with 2 panes reduces this radiation by more than 50 %, and when com-bined with laminated safety glass, the radiation is almost complete-ly filtered out ( chapter 7.4).

2.5 PhotovoltaicsAnother interesting range of the light spectrum falls between ap-prox. 500 and 1,000 nm, where certain semiconductors are able to generate electric current out of solar radiation. The most popular forms are various silicon crystals that are to be found packed be-tween panes of glass, in numer-ous faade balustrades and on roofs.

Developments in recent years continue to expand this techno-logy through other n-semicon-ductors like indium sulphide, which are mounted directly onto base glass on a large scale us-ing the magnetron process. GUARDIAN offers a wide range of these types of coatings for float glass, including special, light-deflecting and transmission-optimizing ornamental glass.

Tran

smis

sion

, QE

[%]

Wavelength [nm]

EcoGuard

QE c-Si

Clear float glass

EcoGuard pattern offers a significantaly higher energy transmission than normal clear glass over the wavelength range critical to photovoltaic modules

EcoGuard pattern transmission vs. clear glass

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3. Insulated Glass terminology ................................363.1 General ....................................................................................36

3.2 Production ...............................................................................36

3.3 Thermo-technical function .....................................................38

3.4 Edge Seal ................................................................................393.4.1 Stainless steel ..........................................................................393.4.2 Metal / plastic combination ...................................................393.4.3 Thermoplastic systems (TPS) .................................................40

3.5 Uvalueheattransmittancecoefficient .............................403.5.1 Ug value ....................................................................................40

Ug value for inclined glass surfaces

3.5.2 Uf value ....................................................................................413.5.3 Y value .....................................................................................413.5.4 Uw value ...................................................................................42

3.6 Dew point and condensation ................................................433.6.1 In the interspace between the panes ...................................433.6.2 On the interior surface of the pane .......................................433.6.3 On the outer pane surface of the insulating glass ...............44

3.7 Solar factor (g value) ..............................................................45

3.8 bfactor(shadingcoefficient) ................................................45

3.9 Solar energy gains ..................................................................45

3.10 Selectivityclassificationfigure ..............................................46

3.11 Colour rendering index..........................................................46

3.12 Interference phenomena .......................................................46

3.13 Insulating glass effect ............................................................47

North Galaxy, BrusselsSunGuard Solar Light Blue 52Jaspers-Eyers & Partner Architectsmontois Partners ArchitectsArt & Build Architect

GUARDIAN GlassTime

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Insulated Glass terminology

A series of factors and physical regularities define the character-istics of insulating glass as it is

used in heat and solar protection applications.

3.1 General To achieve thermal insulation properties, several float glass panes must be combined with at least one low-e-coating on an insulating glass unit.

Two or more panes of the same size are aligned with each other at a defined distance and glued together. The resulting hermet-ically sealed interspace will be filled with especially high thermal insulating inert gas. No vacuum is generated, as laymen often as-sume.

The width of the pane interspace depends on the inert gas that is used. Argon is used most often, krypton more rarely. To reach its optimum thermal insulation ef-

ficiency, argon needs an inter-space of 15 - 18 mm; krypton needs only 10 - 12 mm for better insulating results. The interspace is usually filled to 90 % capac-ity. Krypton is many times more expensive than argon since it is more rare.

The spacer that permanently separates the panes has some influence on the insulating per-formance, and thus on the dew-point at the edge of the glazing ( chapter 3.6). For the past sev-eral decades, aluminium spacers have been the industry standard. Today, they are being replaced by systems that have lower heat conductivity.

3.2 ProductionThe insulating panes are glued together using the dual-barrier system, in which a spacer is used to keep the two panes separated, and a continuous string of butyl adhesive is applied around the edges of the spacer to keep both panes of glass glued together. The space that is created is filled with a desiccant that keeps the interspace permanently dry.

Glass pane

primary seal (inside)secondary seal (outside)

Spacer

Desiccant (molecular sieve)

Invisible thermal insulating coating

Insulating glass structure

During the gluing process, it is important that the coated side of the pane of float glass faces the interspace and that the adhe-sive is applied to this side. Some types of coatings have to be me-chanically removed first before the adhesive can be properly ap-plied. Removing the coating first before the adhesive is applied increases the bonding strength and protection against corro-sion. The functional layer is now hermetically sealed and perma-nently protected. The butyl adhe-sive sealant, also called the inner sealant level, prevents the water vapour from forming and the in-ert gas from escaping. After the two panes of glass are bonded together, a gas-pressure press is used to withdraw some of the air from between the panes and

replace it with a defined amount of inert gas. Finally the insulating pane receives its second sealant and adhesive level by filling in the hollow between the installed spacers and the outer edges of the panes. The material most-of-ten used is polysulfide or polyu-rethane.

Instead of these adhesive materi-als, a UV-resistant silicone is used in special installations that have exposed insulating glass edges. The insulating panes that have a UV-resistant edge seal are filled often with air, since the gas diffu-sion density is lower for silicone. however, to a lesser extent, us-ing this silicone also reduces the insulating glazings U value ( chapter 3.5).

17 C

17 C

10,4 C

12 C

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Insulated Glass terminology

Invisible thermal insulating coating

heat radiation (2/3 of heat transmission in conventional double insulating glass)

heat conduction (together 1/3 of heat transmission in conventional double insulating glass)

Convection

1. heat transmission based on radiation can be almost eliminated by a coating (up to 98 %)

2. Filling insulation glass with argon reduces conduction

3. Convection can be reduced by optimization of the gas space

Heat loss in a double insulating glass

The result is an extreme differ-ence in temperature between the inner pane and a massive loss of heat during the cold seasons due to the heat transfer from the inner pane to the outer pane.

Typically one side on todays insu-lation glass is coated with a low-e film. These coating with emissivi-ties up to 0.02 (2%) or even less are capable of reflecting 98% and more of the incoming long-wave-

3.3 Thermo-technical functionThree factors define heat trans-mission: heat radiation, heat con-ductivity and convective flow.

The electromagnetic long-wave thermal radiation that every en-tity emits due to its temperature transfers thermal energy without transmitting the entity or medium itself.

Heat conductivity is the heat flow within a medium because of temperature discrepancy. In this case, the energy always flows in the direction of the lower tem-perature.

Convectiveflow is a flow of gas particles in the interspace that is due to the difference in tempera-ture between the inner and outer panes of insulating glass. The particles drop on the colder sur-face and rise on the warmer one. Consequently, the gas circulates, thus creating a heat flow from warm to cold.

Insulating glass consisting of just two uncoated panes of float glass where air fills the interspace loses about 2/3 of the heat that room would otherwise have due to the radiation loss between the two panes, and loses 1/3 due to heat conductivity and heat convection to the outside air.

heat radiation, so that radiation loss is completely eliminated.

This is an improvement of approx. 66 % as compared with traditional insulating glass. heat conductiv-ity and convective flow are not affected by low-e-coating. This heat conductivity can, however, be reduced by using an inert gas like argon. Inert gases have sig-nificantly lower heat conductiv-

ity than air, thereby reducing the heat flowing through the insulat-ing glass system. Depending on the fill gas, the convective flow in the insulating glass requires a minimum amount of space when there is a defined pane distance, for example, for air: approx. 16 mm; for argon: 15 - 18 mm; and 10 - 12 mm for krypton.

3.4 Edge SealConclusions made so far refer to the centre area that is between the panes without any influences from the insulating glass edges.

Until very recently, the major-ity of insulating glass has been produced using aluminium spac-ers. Increased requirements have created thermo-technically improved alternatives that are

gaining ground in insulating glass production.

Inside20 C

Inside20 C

Outside0 C

Outside0 C

Aluminum spacer

Stainless steel spacer

3.4.1 Stainless steel

Extremely thin stainless steel profiles possessing consider-ably reduced heat conductivity as compared with aluminium are the most frequent alternative. They are similar to aluminium, how-ever, in terms of their mechanical stability and diffusion capability.

3.4.2 Metal / plastic combination

Another option is plastic spacers that offer excellent thermal insu-lation capability but do not have a sufficient gas diffusion density to guarantee the life cycle for in-sulating glass.

Therefore, combinations of plas-tic have been developed that have gas-impermeable stainless steel or aluminium foils.

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Insulated Glass terminology

3.5 UvalueheattransmittancecoefficientThis value states the heat loss through a component. It indicates how much heat passes through 1 m of component when there is a temperature difference of 1 K between the two adjacent sides for example, between a room and an outside wall. The smaller this value is, the better the heat insulation.

Please note that the European U values are different from the American values. This must be taken into consideration when making international compari-sons.

3.5.1 Ug value

The Ug value is the heat transfer coefficient for glazing. It can be determined or calculated accord-ing to defined standards. Four factors determine this value: the emissivity of the coating, which is determined and published by the producer of the float glass, the

distance of the panes,filling type and the fill rate when using inert gases.

(To find the rated value for real-life usage, you have to con-sider national aggregates DIN 41408-4 applies for Germany)

3.5.1.1 Ug value for inclined glass surfaces

The Ug value that is most often defined and published refers to glazing that is vertically (90) in-stalled. Installation with inclina-tion changes the convection in the interspace and decreases the Ug value. The bigger the glass surface inclination, the faster the circulation in the interspace and the bigger the heat flow from the inner to the outer pane. This can reduce the Ug value by up to 0.6 W/mK for double insulating glass. Mounting

positionMounting angle

Ug [W/m2K]

Vertical 90 1,1Inclined 45 1,5Overhead 0 1,7

Effect of the mounting position of the glazing Ug value

3.4.3 Thermoplastic systems (TPS)

A hot extruded, special plastic substance, which is placed be-tween two panes during produc-tion and which guarantees the required mechanical strength as well as gas diffusion density after cooling down replaces the con-ventional metal. The desiccant is part of this substance.

There is a wide range of dis-posable alternatives today that provide important reductions of the Y value, the unit of the heat transport in the boundary zone, when they are directly compared with each other ( chapter 3.5.3).

3.5.2 Uf value

The Uf value is the heat conduc-tivity coefficient of the frame, the nominal value of which can be determined by three different ways:

measuring according to EN ISO 12412-2,

calculating acc. to EN ISO 10077-2,

using the EN ISO 10077-1 definition, appendix D.

The nominal value plus the na-tional aggregates determine the rated value for the real-life usage.

3.5.3 Y value

The Y value (Psi value) is the line-ar thermal bridge loss coefficient for a component. Regarding win-dows, it describes the interaction of insulating glass, dimensions, spacer and frame material, and

defines the components thermal bridges. The insulating glass itself has no Y value, this applies only to the construction element into which it is integrated.

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Insulated Glass terminology

3.6 Dew point and condensationThere is always humidity in the air. Warmer air can hold more wa-ter than cooler air. Once the air cools down, the relative humidity increases, yet the water vapour volume remains the same. The dew point temperature is the

temperature when the relative air moisture reaches 100 % and wa-ter vapour condenses.

This can occur at different places on the insulating glass:

3.6.1 In the interspace between the panes

This rarely occurs with todays in-sulating glass, since they are her-metically sealed and filled with dried gases.

3.6.2 On the interior surface of the pane

Appears on poorly insulated win-dows or those with single glazing. Warm air cools suddenly near win-dows and transfers humidity to the cold inside pane the temperature in winter is often below the dew point of the ambient air. The inside pane for modern insulating glass stays warm longer so that conden-sation very seldom occurs.

If the relative air humidity is very high, for example due to cooking, washing or proximity to a swim-ming pool, panes may condensate more often. One way to correct this is to exchange the air by means of short and direct ventilation.

The outside temperature, at which the glazing on the inner side condensate (= forming of condensation water = dew point), can be determined by the dew point diagram.

Recorded examples: room temperature 20 C room humidity 50 % outdoor temperature 9 C

Reached dew points: Ug = 5,8 W/mK 9 C Ug = 3,0 W/mK -8 C Ug = 1,4 W/mK -40 C Ug = 1,1 W/mK -48 C

3.5.4 Uw value

Insulating glass is normally used in windows. The Uw value de-scribes the heat conductivity of the construction element win-dow. Based on the Ug value, it can be determined using three different methods:

reading in the EN ISO 10077-1, Tab. F1

measuring acc. To EN ISO 12567-1

calculating acc. to EN ISO 10077-1 as per the following formula

Uw = Af Uf + Ag Ug + S(lg Y)

Af + Ag

Uw: Thermal transmittance from the window

Uf: Thermal transmittance from the frame (assessment value!)

Ug: Thermal transmittance from the glazing (rated value!)

Af: Frame surfaceAg: Glass surfacelg: Periphery for the glazingY: Linear thermal transmittance from

the glass edge

The heat loss in the edge zone is more important than in the mid-dle of the glazing, which is why thermally improved spacers are becoming increasingly important. Like Ug and Uf, the Uw values are nominal values, which only be-come rated values after having added the national supplements.

100

80

1,11,41,61,8

30

20

109

0

-10-20-8

-30-40-48-50

3,0

5,8

30

20

10

-10

0

60

60

50

20

Ug

[W/m

2 K]

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Insulated Glass terminology

3.7 Solar factor (g value)The total energy transmittance degree (solar factor or g value) defines the permeability of insu-lating glass versus solar radiation. Solar protection glass minimize the g value due to appropriate choice of glass and coatings.

The g value of transparent heat insulating glass is preferably high in order to optimize the energy balance of the component glass by passive solar gains.

3.8 bfactor(shadingcoefficient)The non-dimensional value serves as calculation for the cooling load of a building and is also called shading coefficient. It describes the proportion of the g value of a respective glazing versus a 3 mm float glass with a g value of 87 %.

Acc. to EN 410 (2011):

b = gEN 410

0,87

3.9 Solar energy gainsThermal insulation glazing allows a large proportion of solar ra-diation into the interior of the building. Furniture and fixtures, walls and floors absorb the short-wave solar radiation and convert it into long-wave heat radiation. This heat radiation cannot leave the room due to the thermal in-sulation quality of the glazing, and the heat warms up the air in the room. These real solar gains support traditional heating. De-pending on the orientation of the

windows, these gains are differ-ent, less when the windows face east and west, and more when the glazing faces southward. This energy is free of charge and helps to save on heating costs during the cold season. In the summer months, however, it may cause the building to heat up to an uncomfortable degree. This is called the greenhouse effect. Therefore, the demands on summer heat protection must be taken into consideration ( chapter 5.5).

3.6.3 On the outer pane surface of the insulating glass

This effect appears with the ad-vent of modern insulated glass, and is particularly noticeable during the early morning hours, when the moisture content in the outside air has sharply increased during the night.

The excellent insulating quality of these glass surfaces prohibit heat transfer to the outside, so that the outer pane remains extremely cold. When the suns rays start to heat the outside air faster then

the temperature of the pane, it may lead to condensation, de-pending on the orientation of the building and the environment. This is not a defect, but the proof of an excellent thermal insulation of the insulating glass.

GUARDIAN offers special coat-ings that allow a clear view through the glazing even during the morning hours ( chapter 4.4).

Outdoor temperature [C]

Rela

tive

hum

idity

[%]

Out

door

tem

pera

ture

[C

]

Room

tem

pera

ture

[C

]

Dew point diagram

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Insulated Glass terminology

Under extreme weather condi-tions, unavoidable distortions may show up despite the plane-parallel glazing. It can also occur due to extreme changes in air pressure, and influencing factors include the size and geometry of the pane of glass, the width of the interspace, and the structure of the pane of glass itself. With triple

insulation glazing, the medium pane remains nearly rigid, which is the reason why the impact on both outer panes is stronger than on double insulating glass. These deformations disappear without effect once the air pressure nor-malizes and represent no defect, but rather are an indication of the edge seal density.

3.13 Insulating glass effect Part of each insulating glass is at least one hermetically enclosed space, i.e. the interspace. Since this space is filled with air or gas,

the panes react like membranes that bulge in and out in reaction to varying air pressure in the sur-rounding air.

Outside

Wind force/pressure

Deformation Deformation

Excess pressure

Low pressure

Inside

Insulating glass effect

3.12 Interference phenomena When several parallel float glass panes exist, very specific light-ing conditions can cause optical phenomena to appear on the surface of the glass. These can be rainbow-like spots, stripes or rings that change their position when you press on the glazing, also referred to as Newton rings.

These so-called interferences are of a physical nature and are

caused by light refraction and spectral overlap. They rarely oc-cur when looking through the glazing, but in reflection from outside. These interferences are no reason for complaint but rath-er are a proof of quality regarding the absolute plane parallelism of the installed float glass.

3.11 Colour rendering index Colour rendering is not only relevant for the physiological feeling of the observer but also for the aesthetical and psycho-logical aspects. Sunlight that falls through an object or is reflected by it will be changed depend-ing on the nature of the object ( chapter 2.1).

The colour rendering index (Ra value) describes how much an objects colour changes when it is observed through glazing. It de-fines the spectral quality of glass in transmission, and the value can range from 0 to 100. The higher the colour rendering index is, the more natural the reflected col-

ours appear. A Ra value of 100 means that the colour of the ob-ject observed through the glazing is identical to the original colour.

A Ra value of 100 means that the colour of the object observed through the glazing is identical to the original colour.

A colour rendering index of > 90 is rated as very good and > 80 as good. Architectural glass based on clear float glass generally have an Ra value > 90, and mass-coloured glass usually have an Ra value between 60 and 90.

The colour rendering index is determined according to EN 410.

3.10SelectivityclassificationfigureSolar control glass works to mini-mize solar heat gain while maxi-mizing the amount if light trans-ferral into the building. The S classification number represents the proportion of the total energy (g value) and light transmittance (tv) for a glazing. The higher this value, the better and more effi-cient the ratio is.

S = light transmittance tV

g value

The latest generation of GUARDIANs solar control glass already exceed a ratio of 2:1, which has long been considered the maximum value.

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4. Translucent thermal insulation ...........................504.1 Economy ..................................................................................50

4.2 Ecology ....................................................................................51

4.3 Comfort ...................................................................................51

4.4 GUARDIAN product range for thermal insulation .............52

Sddeutscher Verlag, MunichSunGuard Solar Neutral 67Gewers Khn + Khn Architects

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Translucent thermal insulation

Saving energy is a hot topic worldwide The thermal insulation of building envelopes is an im-portant part of contemporary ar-chitecture. Yet advances in glass transparency of the last three dec-ades must not be pushed back

in favour of energy savings ar-chitectural achievement. Trans-parent insulation was therefore developed and designed to offer not only unique economic and environmental benefits, but to guarantee also both comfort and convenience.

4.1 Economy

Technological advances of the last three decades have pro-duced systems and equipment that can coat high-tech insulating glass with razor-thin, neutral coat-ings using low-cost processes. This has optimized the e emis-sivity capability for thermal insu-lation as low as 0.02 and even below, whereas for normal float glass, e is 0.89.

From an economical perspective, however, this development and its application in new buildings is only the first step. The next step must be to integrate this new glass technology into the millions of square meters of glazed areas of windows and faades. This is nearly automatic for new build-ings today. however, existing buildings represent a much larger opportunity, and there is a lot of advocacy work to be done so that the ecological, economic and cli-mate goals can be achieved.

In times of steadily increasing heating energy costs, this eco-nomical benefit presents a per-suasive argument. Just making a simple change, such as glazing offers a rather short amortization period and also offers the occu-pants remarkable improvements in convenience and comfort ( chapter 5.3).

The following formula offers one possibility for estimating the en-ergy savings potential provided when replacing outdated glass with modern thermal insulation:

E = (Ua - Un) F G 1,19 24

h W=

l

hP

E Savings Ua U value of your existing glazing Un U value of your future glazing F Glazing area in m G heating degree day number

according to VDI 4710 1,19 Conversion of kilograms to liters:

1 liter = 1.19 kg fuel oil h heat value of fuel:

light fuel oil at approx. 11,800 W Heating system efficiency:

oil heater at about 0.85I LiterhP heating season

4.2 EcologyEvery liter of fuel oil or cubic meter of natural gas that can be saved through using advanced glazing reduces CO2 emissions and provides an ecological ben-efit. Fossil fuel resources are also saved by reducing their con-sumption and in addition, glass is one hundred percent recyclable because it is made from natural raw materials. Due to its natural ingredients and superior ener-gy-balancing properties, glass should not be overlooked or dismissed as a viable material in globally recognized certification programs for building sustain-

able and environmentally friendly buildings.

Leadership in Energy and En-vironmental Design (LEED) is a leading system in this field. Other systems, for example, are DGNB or Breeam. Buildings follow-ing these systems use resources more efficiently than convention-al techniques because they take all phases within the life cycle of a building into account starting with design and construction to renovation, and eventually dem-olition and proper clean-up.

4.3 ComfortApart from its economic and eco-logical aspects, one important goal of building with glass is the tangible improvement in living and working environments. Tint-ed float glass installed in insulat-

ed glass ( chapter 3.2) increases the glazings room-side surface temperature, thus drastically minimizing unpleasant drafts in an area where glazing is present.

Outside air temperature [C] Type of glass

0 -5 -11 -14

Single-pane glass, Ug = 5,8 W/m2K +6 +2 -2 -4

2-pane insulated glass, Ug = 3,0 W/m2K +12 +11 +8 +7

2-pane coated insulating glass, Ug = 1,1 W/m2K +17 +16 +15 +15

3-pane coated insulating glass, Ug = 0,7 W/m2K +18 +18 +17 +17

Surface temperature at 20 C room temperature [C]

modern glass increases this tem-perature to a near room-temper-ature level and significantly im-proves the comfort level of ones home. The decisive factor in com-fort is the temperature difference between ambient air and the ad-jacent wall and window surfaces.

Most people find a room to be particularly comfortable when the temperature differences between wall (glass) and room air is not more than 5 C and between foot to head height is not more than 3 C.

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Translucent thermal insulation

12

10

0

14

20

16

30

18

40

20

50

22

60

24

70

26

80

28

90

30

100

12

12

14

14

16

16

18

18

20

20

22

22

24

24

26

26

28

28

30

30

Surf

ace

tem

pera

ture

[C

]Re

lativ

e hu

mid

ity [%

]

Room temperature [C]

Room temperature [C]

Uncomfortable, hot

Uncomfortable, cold

U = 0,3 W/m2K highly insulated wall

Outdoor temperature -10 C

Ug = 1,1 W/m2K heat insulation glass

mugginess limit

Comfort Less comfort Uncomfortable dry Uncomfortable moist

Ug = 3,0 W/m2K Double-insulating glass

Optimal curve

Comfort chart according to Bedford and Liese

Comfort as a function of room temperature and humidity

The diagram above shows the range where ambient air feels most comfortable. humidity should always be viewed as de-pendent on room temperature. When the air temperature is

cooler, then the humidity should be higher for the space to feel comfortable. When the room temperature is higher, the humid-ity should be lower.

4.4 GUARDIAN product range for thermal insulation

Guardian provides a broad range of state-of-the-art thermal insu-lation glass normally coated on Float ExtraClear.

ClimaGuard Solar (where appropriate based on climate and / or construction norms)

A product optimised for the change of seasons. Possesses excellent thermal insulation during cold weather and ex-cellent solar protection for the summer months.

ClimaGuard Neutral 70 (where appropriate based on climate and / or construction norms)

This durable product features low processing requirements. It was developed mainly for markets where not only ease in handling but also heat and solar protection are critical. ClimaGuard Neutral 70 can be heat treated and bent.

ClimaGuard Dry

ClimaGuard Dry is a coating, especially designed for surface #1 (outer side) which perma-nently minimizes condensation on the outer surface. The pho-to-spectrometrical values are scarcely affected (exact values see chapter 10).

The coating must be heat trea-ted in order to get activated and can be combined with any heat treatable ClimaGuard coating and as SunGuard Dry with any SunGuard solar con-trol coating on the same glass pane.

Please see chapter 10 for de-tails on all products and their rel-evant values.

Following are our options regard-ing thermal insulating glass:

ClimaGuard Premium

Todays standard product in modern glazing.

This insulating glass offers excellent thermal insulation at best light efficiency. That means that a standard insu-lating glass filled with argon has a Ug value of 1.1 W/mK at high light and solar energy permeability. GUARDIAN also offers Premium T, a heat treat-able version of ClimaGuard Premium.

ClimaGuard 1.0

With an Ug-value of 1.0 W/mK for an Argon filled double insu-lated glass ClimaGuard 1.0 of-fers the physical maximum but without using the expensive Krypton gas filling.

ClimaGuard nrG

modern buildings are con-structed following low-energy and passive-house standards, and require high-tech glaz-ing in triple pane construction with Ug values 0.8 W/mK with maximum transparency in terms of light and solar en-ergy (g value up to 62 %). GUARDIAN also offers Cli-maGuard nrG T, a heat treat-able version.

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5. Transparent solar protection ...............................565.1 Economy ..................................................................................56

5.2 Ecology ....................................................................................56

5.3 Comfort ...................................................................................56

5.4 Energyflowthroughglass .....................................................57

5.5 Sun protection in summer .....................................................58

5.6 Sun protection using glass ....................................................59

5.7 Solar control glass as design component ............................60

5.8 SunGuard sun protection glass ...........................................60

Dexia, BrusselsSunGuard High Selective SN 62/34Jaspers-Eyers & Partner Architects

RoutTe

qinqout

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Transparent solar protection

modern architecture today rep-resents spaciousness and trans-parency. Steadily growing glass elements for the outer building merge the outside with the inte-rior. This is reflected worldwide in office and administration build-ings from the last two decades, but also in private housing that includes atriums, gables and win-ter garden glazing using increas-

ingly large glass components. This style of construction only became feasible with the advent of solar protection glass. These types of glass reduce the green-house effect that mainly occurs in summer due to that fact that rooms can heat up to the point that they become unpleasant to be in.

5.1 Economy Large window and faade sur-faces allow a great deal of light deep into a buildings interior, thereby avoiding excessive use of artificial lightning. Despite this large amount of light that can penetrate deep into a buildings interior, one very important bene-fit of using sun protection glass is

the immense number of options now available for minimizing the amount of heat energy that pen-etrates a building, limiting the extreme costs of air-conditioning, since it costs much more to cool the interior of a building than to heat it.

5.2 Ecology Wherever energy is saved whether by reducing the amount of cooling power use or reducing the phases of artificial light of course saves on the environment. ln this context, it is a logical con-

sequence to certify these types of sun protection glass products acc. to e.g. LEED, Breeam, DGNB, or other worldwide-approved cer-tification systems for sustainable constructions. ( chapter 4.2).

5.3 ComfortSuper-cooled interiors and over-heated rooms are both uncom-fortable to be in, and when rooms are overheated, it can be due to too much incoming solar energy ( chapter 4.3). The floor, walls and furniture absorb solar energy and reflect it as long-wave heat radiation. For this reason, all ef-forts must be made to keep this energy outside the interior rooms to achieve an acceptable room climate without air condition-

ing. This was previously achieved by constructing buildings using opaque building components that only had small openings in the walls.

Todays architecture which strives to create living and work-ing areas that are close to nature and are open and spacious has shifted away from this opaque way of construction towards transparency. Therefore it is es-

sential to master the essential parameters of the sun protection using glass to create a functional and comfortable interior while

also meeting other requirements, such as structural-physical guide-lines while also achieving energy efficiency.

5.4 EnergyflowthroughglassAn interaction occurs whenever solar radiation strikes a window: one part of this radiation is re-flected back into the environ-ment, another part is allowed to pass through unhindered, and the rest is absorbed.

The sum of all three parts is always 100 %:

transmission + reflection + absorption = 100 %

secundary heat coefficient inside (re-radiated)

secundary heat coefficient outside (re-radiated)

Transmission AbsorptionReflection

Solar factor

direct enegy transmission

direct energy reflection outside

Sun Energy = Te + Rout + qout + qin

Solar performance of glass

hT

hV

Qs

Qs QsQwQc Qi

Qh

hT

hT

Representation of the energy demand

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Transparent solar protection

5.5 Sun protection in summermodern insulated glass lets the short-wave solar radiation pass through without hindrance, but the majority of the short-wave heat radiation is reflected. This results in solar heat gain in the cold seasons. ln summer, howev-er, this solar radiation can result in overheating. Therefore, specific requirements need to be met to prevent this overheating that can result from these larger glass sur-faces, starting with the solar input factor S, which must be deter-mined as follows:

S = Sj (AWj gtotal)

AG

AW: glazed area in m2AG: total area of the room behind the

glazinggtotal: Total energy penetration degree of

the glazing incl. solar protection, calculated according to equation (*) resp. acc. to EN 13363-1 or adjusted to EN 410 resp. warranted manufac-turer details.

*gtotal =

g

FC

g: total solar energy transfer of glazing acc. to EN 410

FC: reducing coefficient for solar protec-tion equipment acc. tabel 8

hT Transmission heat losshV Ventilation heat lossQw Energy demand for hot waterQh heating demandQc Cooling demand

Qs Solar heat gainsQi Internal heat gains

(e.g. people, electrical equipment)

In addition to other energy sourc-es (see figure above), the position and size of the glazing are critical. In general, windows or faades with large areas of glazing that

face the east, west, and especial-ly the south, must be equipped with suitable sun protection glaz-ing.

5.6 Sun protection using glassEarly production of sun-protec-tive glass was based on glass that was coloured en masse. Com-pared with clear glass, coloured glass increases solar radiation absorption but it also has a sig-nificant effect on the transmitted visible light. As monolitic glass it reducees the transfer of energy to approx. 60 %, and in insulat-ing glass, combined with a nor-mal pane of clear float glass, it reduces the solar energy transmi-sion to approx. 50 % when the coloured glass thickness is 6 mm. The thicker the glass, the higher the energy absoption and the lower the transmision. Green-, grey- and bronze-coloured glass is used most often. Due to their own inherent colouring, they can significantly change the way interior colours are perceived. Advances in glass coating tech-nology have produced a much broader range of colours that are also a lot more neutral in terms of the effect they have on interior colours.

Todays sun protection glazing is based on coated glass rather than on coloured glass, and is produced using the magnetron-sputter-process ( chapter 1.3.1).The multitude of coating varieties can be used for special applica-tions. GUARDIAN is focusing on this technology and developing new glass for a large variety of requirements.

Besides actual solar protection, which is constantly being refined, a great deal of research and de-velopment effort is being put into optimizing regarding warehous-ing, processing and resistance to mechanical influences. Another essential requirement regarding coating is to offer versions for all products that can be laminated, tempered and bent. Only with these parameters can the large spectrum of modern architecture be met in all aspects.

Sun protection coatings are nor-mally on the outer pane and oriented towards the interspace (insulating glass position #2). A 6 mm thick outer pane is standard. A thinner counter-pane works against optical distortion caused by the insulating glass effect ( chapter 3.1.3). lf the inter-space is bigger than 16 mm due to fixtures in the interspace or for sound-damping purposes; this effect has to be considered in the design. Static requirements often need thicker glass.

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Transparent solar protection

5.7 Solar control glass as design componentThe trend today is toward design-oriented faades, which entail new designs in solar control glass.

Glass with low outside reflection can be produced, depending on the coating that is used. Glass faades can be built to neutral-ize the visible borders between inside and outside, yet remain energy efficient.

On the other hand, there are mirroring or colour-reflecting coatings that allow for some architectural license, including

realizing unconventional design concepts. Colour-coordinated balustrades, for example, enlarge the range of solar control glass ( chapter 8.2).

Such creative and additive glass designing is generally project-related and feasible once the physical construction rules have been taken into consideration. Digital or screen print techniques are available, as well as glass-like laminated glass. Please refer to chapter 8.3 for more informa-tion.

5.8 SunGuard sun protection glassNo matter what the architecture or the requirements on building physics are, the broad range of SunGuard glass offers the best transparent solution.

SunGuard High Selective

This product line, which is based on ExtraClear float glass, represents a unique combination of transparency, thermal insulation and sun protection. The focus is on the high selectivity the ratio of light-to-solar energy transmis-sion. Another important fea-ture is its neutral appearance with low reflection. All prod-ucts of this product line are also available in a heat treat-able version as SN-hT.

SunGuard high Selective glass, in a double insulating glass unit, can achieve Ug val-ues of up to 1.0 WmK with light transmission values be-tween 40 and 70 %.

SNX, the latest development of the SunGuard high Selec-tive series, has a spectral selec-tivity above 2 (for exact values chapter 10).

SunGuard HP

A product line of selective coatings with a broad variety of colours and reflection grades. All of this glass can be tem-pered, bent and can imprinted using a ceramic process.

Thanks to the consistency of the coating, many SunGuard hP types are compatible with several series of insulating glass sealants and structural silicones. many of this coatings can be used facing the PVB in-terlayer inside laminated glass.

In a double-glazed insulating glass unit SunGuard hP pro-vides Ug values between 1.5 and 1.1 WmK without addi-tional thermal insulation glass

as counter pane and tL-values between 60 and 30 % and g-values between approx. 50 - 20 %, depending on the in-tensity of colouring and reflec-tion grade (technical detailed values chapter 10).

SunGuard Solar

Providing the highest flex-ibility for use and processing, SunGuard Solar is our series of pure solar control caotings The whole range of conceiv-able processing such as lami-

nating, tempering, bending or imprinting is possible with Sun-Guard Solar glass. They toler-ate nearly all glazing materials and sealants.

ln double-insulating glass the SunGuard Solar series pro-vides with a counter pane of ClimaGuard Premium a Ug value of 1.1 WmK with tL-val-ues of approx. 10 to 60 % and g-values of < 10 up to approx. 50 % (further values chapter 10).

KIA European headquarters, FrankfurtSunGuard high Selective SN 51/28Yutake Omehara ArchitectJochen holzwarth Architect

662 63

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6. Transparent noise protection ..............................646.1 Human aspects .......................................................................64

6.2 Sound wave characteristics ...................................................646.2.1 Limits ........................................................................................646.2.2 Detection .................................................................................65

6.3 Sound ratings for buildings ...................................................666.3.1 medium noise reduction factor .............................................666.3.2 Correction factors ...................................................................67

6.4 Influencefactorsandproductionvarieties ..........................686.4.1 Weight of the pane .................................................................686.4.2 Insulating structure / Interspace ............................................686.4.3 Decoupled single panes ........................................................70

6.5 GUARDIAN sound protection glass .....................................71

Raiffeisen International Die Welle, ViennaSunGuard Solar Royal Blue 20hans hollein Architect

0 20 40 60 80 100 120 140 160 180

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Transparent noise protection

6.1 Human aspectsIn the past several decades, our environment has become much louder due to mobility and in-dustrialization. This development has become a severe problem for many people. Permanent noise represents two key dangers: Once a persons sense of hearing is damaged, it can start to dimin-ish unnoticed over time, which

can lead to worsening tinnitus and anblyacousia. hearing loss may also contribute to mental ill-nesses that can start with insom-nia, inability to concentrate (due to the tinnitus), all of which can further lead to allergies, circula-tion diseases, high blood pres-sure, even to an increased risk of heart attack.

6.2 Sound wave characteristicsNoise is a mixture of different sound waves that arise in solid compounds, liquids or gases (air).

Airborne sound Structure-borne sound

6.2.1 Limits

Depending on the way they are transmitted, the waves are called airborne or structure-borne noise.

Sound is normally transported by both through the air and through solid objects. The intensity of the variability in pressure is called sound pressure, and can be ex-

tremely variable, from the ticking of a clock to the crack of a gun-shot, and is measured in decibels (dB).

Sound level dB(A)

Auditory threshold

Soft music Car

hammer outSpeech Truck

hearing impairment (Long-term ex.) Pain threshold

Jet

Firecrackers

Gunshot

Decibel meter

Sound source Distance app. [m] Sound level dB(A)

Rustling leaf 1 10

Clock ticking 1 20

Soft music 1 40

Normal speech 1 50 - 60

Car 7 80

Heavy truck 7 90

Jackhammer 7 90 - 100

Police siren 10 110

Jet 20 120 - 130

Hammer out 5 150

F irecrackers 0 170

Gunshot 0 180

Noise source and sound level

Frequency is the number of waves or vibrations per second, and is measured in hertz (hz). Sound or noise is composed of

many waves of different frequen-cies. Deep tones are low frequen-cies and high tones are high fre-quencies.

Soun

d pr

essu

re [d

B]

Soun

d pr

essu

re [d

B]

Time [s] Time [s]

Bass (low-pitched) tones Treble (high-pitched) tones

6.2.2 Detection

The mix of these frequencies in a sound can be represented as a frequency spectrum. The fre-quency spectrum of sounds that the human ear can hear falls be-tween 20 and 20,000 hz. Only the highest frequency range i.e. kHz to 4 is relevant to protecting against structural noise; humans ability to perceive frequencies in this range drops off mark-edly in either direction from this point. Sound insulation ratings, therefore, mainly take the range between 100 and 5000 hz into account. The rating represents the fact that the human ear per-

ceives high frequencies more readily than low frequencies into account and states it in terms of dB(A). A means adjusted. De-fining sound reduction does not follow a linear path, but rather is a logarithmic function. Two sources of sound that are each 80 dB, for example, do not add up to 160 dB, but only to 83 dB. Thus, the human ear registers a difference of 10 dB as doubling, or cut-ting, the volume in half.

Generally, the following rating applies based on logarithmic as-sessments:

125 250

0

10

20

30

40

50

60

500 1000 2000 4000

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Insulation Noise reduction

10 dB 50 %

20 dB 75 %

30 dB 87.5 %

40 dB 94.25 %

Since a large percentage of to-days installed soundproof glass insulation is rated for 40 dB, this type of glass only lets about 6% of external noise inside.

6.3 Sound ratings for buildingsA building component (e.g. glass) with a noise-reduction capacity rating of 40 dB will reduce the 70 dB of outside noise to 30 dB on the inside of the building, which is a noticeable reduction that is one sixteenth the outdoor noise level.

When working with buildings, it is not possible to consider the building itself in terms of noise level. One must take the entire periphery around the building into account to get the total dB possible for sound reduction.

6.3.1 Medium noise reduction factor (Rw)

The noise for solid objects is de-fined acc. to EN 20 140, EN ISO 717 and EN ISO 140, and is stat-ed as Rw in dB.

This is done by measuring and comparing a reference curve. Rw represents an average sound insulation over the relevant fre-quencies.

Road noise Noise level outdoors = 69 dB (A)

Standard insulation (4/16/4) Rw,P = 30 dB

Interior sound level in standard insulating glass Noise level indoors = 43 dB (A)

Acoustic insulating glass (44.1/14/6) Rw,P = 43 dB

Interior sound levels in acoustic insulating glass Noise level indoors = 30 dB (A)

Gain in sound insulation between the standard insulating and acoustic insulating glass.

Frequency [hz]

One

-thi

rd o

ctav

e no

ise

leve

l [dB

]

Comparisonsoundproofingbetweenstandardinsulatingandacousticinsulation

here, the reference curve is moved vertically as long as the centre part of the underflow is not more than 2 dB. Exceed-ing the curve is not considered.

cially in Germany, DIN 4109 has to be considered. It follows the following nomenclature:

Rw = assessed noise reduc-tion extent in dB with no noise transfer over the adjacent components (just the net glass value, for example)

Rw = weighted sound reduc-tion index in dB with sound transmission via adjacent structural com-ponents (for example windows)

6.3.2 Correction factors (C, Ctr)

This correlation can be used to compare and calculate individual acoustic components to arrive at the total sound level. however, real-life application has shown that, depending on the noise

source for these Rw mean values, there are certain correction fac-tors that must be taken into con-sideration, which are also defined in the EN.

Source of the noise Spectrum adaptation value

Normal frequency noise levels such as talking, listening to music, radio and TV

CChildren playing

Railcars moving at a average and high speeds*

Highwaytraffictravellingatover80km/hr*

Airplanes using jet propulsion from a short distance

Production plants, which emit predominantly medium-to high-frequency noise

Spectrum 1

Inner city street noise

Ctr

The sound made by railcars moving at a slow speed

Prop planes

Airplanes using jet propulsion from a great distance

Disco music

Manufacturing companies with predominantly low-frequency noise radiation

Spectrum 2

Spectrum adaptation value

The value of the ordinates of the moved reference curve at 5,000 hz complies then with the average assessed noise reduction value of Rw. Additionally, espe-

Rw, res = resulting sound reduc-tion index in db of the entire structural com-ponent (e.g. entire wall incl. Windows consisting of frames with glass and structural connections)

Rw,P = weighted sound reduc-tion index in dB, deter-mined on the test station

Rw,R = weighted sound reduc-tion index in dB, calcula-tion value

Rw,B = weighted sound reduc-tion index in dB, values measured on the con-struction

20

20

30

40

241612

50

60

20

2

4 5 6 7 8 9 10 15 20 30

4 6 8 10 12

30

35

40

45

50

Rw of double insulated glass

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* In several EU countries, there are com-putational methods for the fixation of octave-width sound levels for road and

rail traffic noise. These can be used for comparison with the spectra of 1 and 2.

These correction factors, i.e. spectrum adaptation values C and Ctr, reduce the sound reduc-tion index Rw of the component if the noise sources acc. to the EN list are causative. This means that a component with the values Rw

(C,Ctr) = 40 (-2,-8) has an average insulating capacity of 40 dB, es-pecially for noise sources at high-er pitches. however, the noise re-duction is 2 dB lower, and mainly for those with lower frequencies, the reduction is even 8 dB lower.

6.4 InfluencefactorsandproductionvarietiesThe following parameters affect noise reduction via glazing.

6.4.1 Weight of the pane

It generally follows that the thick-er the pane per surface unit is, the greater the noise reduction.

Therefore, insulation efficiency increases as glass thickness rises.

Soun

d in

sula

tion

valu

e R w

[dB

]

R w [d

B]

Inte

rspa

ce [m

m]

Gla

ss th

ickn

ess

Glass thickness [mm]

Total glass thickness [mm]

Insulating performance as a function of the glass thickness

6.4.2 Insulating structure / Interspace

Double or triple insulating glass is a mass-spring-mass system: both outer panes (masses) are separated from each other by the air or gas that fills the interspace. The interspace muffles the vibra-tions from the outer pane before they reach the inner, second pane, with the rule being the bigger the interspace, the more effective the

noise reduction. But this is only possible to a limited degree, since this process not only reduces ther-mal insulation ( chapter 3.3) but also increases the climates impact on the unit. If you moderately increase the interspace with an asymmetrical insulating structure, the glazing will provide excellent noise reducing values.

Interspace

Variation of the insulating glass interspace

Asymmetrical insulating glass construction

Valid insulating glass constructions

125

125

250

250

0

0

10

10

20

20

30

30

40

40

50

50

60

60

500

500

1000

1000

2000

2000

4000

4000

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6.4.3 Decoupled single panes

The noise-reducing effect of thicker, heavier glass may be fur-ther optimized by using a flexi-ble interlayer (PVB) to connect two single panes of glass. With

this solution, the thickness and space weight remain the same; the pane, however gets softer and thus increases its insulating capacity in terms of sound waves.

PVB film

Glass

Time [s]

reduced vibrationLamiGlass Sound Control

Standard PVB filmAm

plit

ude

[V]

Glass

Special noise-protection films are also used in addition to the usual commercial PVB films that have been utilized to produce lami-

Decoupling of single panes

8 mm float glass

LamiGlass Sound Control consisting of 2 x 4 mm glass and acoustic PVB interlayer

Insulating glass consist-ing of 2 x 4 mm glass

LamiGlass Sound Control 44.2 Rw = 37 dB

LamiGlass Standard 44.2 Rw = 34 dB

Frequency [hz]

Frequency [hz]

Soun

d re

duct

ion

leve

l R [d

B]

Soun

d in

sula

ting

valu

e R w

[dB

]

Comparisonsoundproofing

Comparison between LamiGlass Standard and LamiGlass Sound Controlnated safety glass for many years. In addition to the safety aspect, they furthermore increase noise protection.

6.5 GUARDIAN sound protection glassThe GUARDIAN base line of products uses two different ver-sions for manufacturing noise control products. The first version is for manufacturing laminated

safety glass products that pro-vide improved sound insulation because they are made using the proven polyvinyl butyral (PVB) ( chapter 7.4).

Another improvement to the products is that standard films have been replaced with sound-optimized versions. Depend-ing on the structural require-

ments of the building, you can choose between different types of glass since a wide range of functional glass is manufactured ( chapter 10).

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7. Transparent safety .......................................................747.1 Fully tempered glass ..............................................................747.1.1 Production ...............................................................................747.1.2 Building physical characteristics ............................................767.1.3 Resistance to impact and shock ............................................767.1.4 Tensile bending strength........................................................767.1.5 Resistance to ball-impacts .....................................................767.1.6 Heat influence .........................................................................767.1.7 Anisotropies (strain pattern) ...................................................777.1.8 Optical quality .........................................................................777.1.9 Moisture film on tempered glass...........................................777.1.10 Identification............................................................................77

7.2 Heat-soaked and tempered glass ........................................77

7.3 Partially tempered glass (heat strengthened glass) ...........797.3.1 Production ...............................................................................797.3.2 Tensile bending strength........................................................807.3.3 Heat influence .........................................................................80

7.4 Laminated safety glass ..........................................................807.4.1 Production ...............................................................................817.4.2 Building physical characteristics ............................................827.4.3 Impact resistance ....................................................................82

7.5 Safety with and through glass ..............................................827.5.1 Active safety.............................................................................82

Impact Resistance (ball drop) acc. to EN 356 | Impact Resistance (axe)

acc. to EN 356 | Bullet resistance acc. to EN 1063 | Explosion resistance

acc. to EN 13 541

7.5.2 Passive safety ..........................................................................85Protection against injury | Glazing for protecting people against falling

out | Overhead glazing | Post - glass breakage performance / residual

strength

7.6 Recommendations for certain glass implementations .......887.6.1 Vertical glazing without protection against crashing...........887.6.2 Horizontal / overhead glazing ...............................................907.6.3 Fall protection glazing ............................................................917.6.4 Glazing in buildings used for special purposes ...................937.6.5 Glazing for interior works without fall protection ................957.6.6 Special safety glasses .............................................................967.6.7 Structural glass construction ..................................................97

International house of music, moskowSunGuard hP Light Blue 62/52Architects Yuriy P. Gnedovski + Vladlen D. Krasilnikov

> 600 C

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A component must be reliable if it is going to be safe to use. Glass manufacturers recognized this fact more than 100 years go, and apply this principle to automo-tive glass manufacturing today. A wide range of safety glass is avail-

able that is used either individu-ally or in combination with other types of glass in building con-struction. The three main types of glass are tempered safety glass, laminated safety glass and heat-strengthened glass.

7.1 Fully tempered glassTransparent insulation was therefore designed to offer unique economic and environ-mental benefits, while providing both comfort and convenience. In this process, the basic glass is thermally treated (tempered), which gives it three outstanding characteristics: it has a four to five times greater tensile strength than annealed glass of the same thickness and can therefore han-dle much higher suction or blunt impact forces. Tempering also makes glass more resistant to severe, short-term fluctuations in hot and cold temperatures, as well as more able to handle large differences in temperature within the pane of glass itself.

however, should failure occur due to overloading, then the glass will fracture into a blunt-edged mass of loosely connect-ed pieces that pose a lesser risk of injury than the sharp-edged shards produced by shattered conventional glass.

Fracture tempered glass

7.1.1 Production

The only glass panes that reach the tempering unit are those cut from basic glass. These glasses are precisely measured, the edges have already been worked, and drilled holes and boundary cuts have already been made.

These panes are heated to ap-prox. 600 C using controlled and even heating, are then next rapidly cooled using cold air, and finally quenched by quickly be-ing brought back to room tem-perature.

Applying the glass heating Quench Cooling Lift off, stacking

Manufacturing process of tempered glass (schematic representation)

This quenching or, stated in professional terms, blowing off, makes the glass surface cool down faster that the centre of the glass, which creates a durable tensile strength in the glass. The tensile stress increases from glass surface, which is under compres-sion stress, to the core of the glass section.

Tension

Tension

Tension

Compression

Compression1

Compression2

Compression

No load applied

Compressive strength

Nominal tensile strength Slight bending pressure applied

Increased bending pressure applied

Tensile strength distribution

Tension dynamic

Tension dynamic visible

This tension structure gives the glass its outstanding features, and also explains why all machin-ing must be carried out on the glass in advance. If drilling, for ex-ample, is carried out on the glass after it has been tempered, the entire glass will shatter. The rea-son is that the drilling procedure breaks up, or interrupts, the ten-sion structure, which causes the glass to break apart. The tension zones are visible under polarized light and can be viewed at cer-tain angles as coloured, optical effects.

100 mm

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7.1.2 Building physical characteristics

Thermal conductivity, light and energy permeability, thermal ex-pansion, compressive strength and elastic modulus remain iden-tical in the basic glass, as do the

weight, the sound insulation char-acteristics as well as the chemical properties. Other parameters, however, will vary tremendously.

7.1.3 Resistance to impact and shock

Fully tempered glass is resistant to shocks from soft, deformable objects like the human body, and is in acc. with EN 12 600 (the

pendulum impact test for glass in buildings). The respective field of application determines the re-quired glass thickness.

7.1.4 Tensile bending strength

Fully tempered glass can be made out of various basic types of glass and is additionally coated with ceramic colours. The tensile bending strength must therefore be classified as per the design:

Tempered glass made from float glass s = 120 mPa

Tempered glass made from ornamental glass s = 90 mPa

Tempered glass made from enamelled plane glass, whereby the enamelled side is under tensile stress s = 75 MPa

7.1.5 Resistance to ball-impacts

At 6 mm thick, fully tempered glass glass is especially suitable for use in large surface glass applications in gyms and sports halls as is typi-cal in countries such