III. CHOOSING A GLASS

Transcription

1 III. CHOOSING A GLASS 1 Roof and façade glazings Stages in choosing a glass Size of panes Acoustic performance Thermal performance Solar and light performance aspect Spandrel panels Safety Protection against fire Multiple functions Technical validation Feasibility Case study: tertiary building and conservatory Decoration and furnishings Factors influencing the choice of glass Summary tables Case studies: office partition and cupboard door 166

2 118 This chapter aims to help designers and architects choose the right glass by guiding them through various key stages. There are two major types of applications for glass products: > vision glass and spandrel panels for façades, roofs, etc. > decorative applications, interior design and furnishings. 1 ROOF AND FAÇADE GLAZINGS 119

3 STAGES IN CHOOSING A GLASS Introduction When choosing a glass, several factors should be taken into account such as thermal insulation, solar control, light transmission, colour, sound insulation, safety, harmony with spandrels where appropriate and so forth. It is therefore important to investigate these various aspects. Depending on the type of building (residential, tertiary), not all of them will be relevant. A case study detailing the various stages involved in choosing a glass is given at the end of this chapter Deciding on the structure (thickness) of the glass A mechanical calculation should be used to determine the minimum structure required to ensure that the glass is stable in view of its dimensions and the loads to which it will be exposed Determining the level of sound insulation Acoustic performance levels also have a direct impact on the structure of the glass: the higher the level of acoustic performance required, the greater the mass of the glass. At a certain level of performance and higher, Stratobel laminated glass or Stratophone acoustic laminated glass must also be used. The requirements in terms of structure and sound insulation are interrelated and should be considered in parallel Deciding on aspect (appearance and colour), levels of reflection and transmission, solar factor and thermal insulation The aspect is generally a decisive factor when choosing the appropriate type of glass (coloured glass, coated glass, etc.). In residential buildings, the general trend is towards neutralcoloured solutions. In tertiary buildings, a wide range of shades, reflection and performance levels are available. Samples, mock-ups or indeed the Glass Shuttle (mobile demonstration facility used by AGC on site in selective countries) can help to give an accurate idea of how products will look before making a final decision. In curtain-wall façades, it is important to choose a spandrel which either blends or contrasts with the vision glazing. Depending on the type of coated glass used, calculating the risk of breakage due to thermal shocks will determine whether glass providing enhanced thermal insulation (thermally toughened or heat-strengthened glass) is necessary Safety Safety considerations (risk of injury, protection of persons against falling, protection against burglary, firearms, explosions and fire, etc.) should also be taken into account in certain situations. In such cases, thermally toughened or, more often, laminated glass should be used. 121

4 Miscellaneous > Multiple functions Various functions (thermal insulation, solar control, safety, sound insulation, decoration) can be combined in a single glass by carefully choosing the components. > Feasibility You should check that the glass is available in the required thicknesses and sizes as well as the weight of the components. > Handling It is important to remember that the glass will need to be handled and positioned on site and that if it is too heavy, this will be difficult. You should also assess how accessible the glass will be if it needs to be replaced or repaired at a later date. 1.2 SIZE OF PANES (WIND, SNOW, etc) The architect/designer and the façade designer should determine the correct thickness for the glass or for the double- or triple-glazing units; this will depend, among other things, on the location of the building, the size of the units and how they are installed. The thicknesses should be adapted to fit the relevant size and stress levels (in accordance with local regulations) to prevent the glass from excessive deflections and to protect it from the risk of mechanical breakage associated with such deflections and, in the long term, problems with water penetration and condensation in insulating units. It is important to determine the minimum thicknesses required during the initial study phase for a façade in order to: > select the final structure of the glazing (coated glass available, sound structure, etc.) in view of these minimum thicknesses > reduce the size of the sealed units where necessary if they are too thick and use thinner ones. Information required to calculate the thickness of sealed units In all cases: > position of the sealed unit in the façade or roof > dimensions of the building > installation of the sealed unit (rebate, pressure gasket, structural sealant, etc.) > size of the sealed unit > type of glass. Plus: > Either: wind pressure to be used in the calculation > Or data required to calculate the wind pressure, i.e.: benchmark standard the building s surroundings (by the sea, in a rural area, in a town, etc.) whether there is internal partitioning the height of the building for roof glazings: the slope of the roof proximity to a tall building or hill

5 ACOUSTIC PERFORMANCE Acoustic performance levels are expressed using the index R w (C; C tr ), expressed in decibels (db), as follows: > R w is used to categorise products and compare them to each other; the Rw value is not normally used to assess the sound insulation level of a particular element > for noise containing predominantly high- and medium-range frequencies, the sound insulation level of a product is determined using the index R w + C (= R A ) > for noise containing predominantly low- and medium-range frequencies, the sound insulation level of a product is determined using the index R w + C tr (= R A,tr ). Acoustic performance levels (R w values) of double-glazed units may vary between 29 db and approximately 51 db. A double glazed has an acoustic value of 29 db. To enhance the level of acoustic performance of a particular unit, its mass must be increased or a laminated glass used and/or the spacer in the sealed unit made bigger. The following double-glazed solutions are available in ascending order of acoustic performance: > dissymmetrical double glazing: to increase the mass of the glasses by using two glasses of different thicknesses > double glazing incorporating one or two Stratobel laminated glasses > double glazing incorporating one or two Stratophone acoustic laminated glasses. The diagram below details the anticipated performance levels using Planibel, Stratobel and Stratophone in monolithic glazing and in double glazing. For more accurate figures for a particular type of double glazing, see the chapter on Thermobel Phonibel. Acoustic performances of glass products R w (db) db 15 mm 12 mm 10 mm 8 mm 4 mm 3 mm 29 db 39 db db 43 db 88.2 ST 66.2 ST 55.2 ST 44.2 ST 33.2 ST 36 db 39 db db 43 db 35 db 40 db Planibel Stratobel Stratophone Planibel Stratobel Stratophone Float Laminated Laminated Standard Double Double glass glass with glass with double glazing with glazing with PVB acoustic PVB glazing laminated laminated PVB acoustic PVB Monolithic glass Double glazings 51 db 66.2 ST ST ST ST ST At equivalent levels of acoustic performance, Stratophone glazings are thinner than Stratobel ones. In practice, this means, for example, that to achieve a performance level (R w ) of 36 db, either a laminated Stratobel 66.2 or a laminated Stratophone 33.2 ST glass may be used. Equally, at equivalent levels of performance: > Double glazing with laminated acoustic PVB is thinner than double glazing with laminated PVB > Double glazing with laminated PVB is thinner than dissymmetrical double glazing. These performance levels pertain only to standard-size glazings measuring 1.23 m x 1.58 m. To determine the performance levels of frames and façades, it is recommended that a specialist be consulted or reference made to the tests conducted on the full elements made by joiners and/or façade designers. 125

6 THERMAL PERFORMANCE In most countries, insulation regulations require double glazing or even Low-E high-performance double glazing providing enhanced thermal insulation to be used. > Residential applications Double glazing is generally used, including: either a Planibel Top N+ coating providing enhanced thermal insulation or a dual function Planibel Energy N coating providing enhanced thermal insulation and solar control. These two products are perfectly neutral which means that they are perfect for use in this type of building. Toughenable versions Top NT and Energy NT are also available. > Tertiary buildings Double glazed units with solar-control coatings are generally used: coated Stopray glasses providing a U g value of 1.1 W/(m².K) coated Sunergy glasses providing a U g value of 1.8 W/(m².K) coated Stopsol glasses do not affect thermal insulation and, like uncoated double glazing, provide a U g value of 2.8 W/(m².K) coated Sunergy or Stopsol glasses, assembled in doubleglazed units with a coated Top N+ glass, which also provide a U g value of 1.1 W/(m².K). The table below shows the range of available U g values for double- and triple glazed units with an argon space 15 or 16 mm wide (90%). Glazing U g value (W/m²K) Single Planibel glazing, 6 mm 5.7 Double glazing Air 100% Spacer 16 mm (1) Argon 90% Spacer 16 mm (1) Planibel + Planibel Stopsol + Planibel Sunergy + Planibel Planibel + Planibel G Planibel + Planibel Top N+ / Planibel Top NT Planibel Energy N / Energy NT + Planibel Stopray + Planibel Stopsol + Top N Sunergy + Top N Triple glazing 4-gas-4-gas-4 with two Top N+ coatings Ar or Kr, 6-15 mm 0.5 to 1.0 (1) Identical values for 15 or 16 mm spacer. To achieve a U g value of less than 1.0 W/m².K, triple glazing should be used with at least one Top N+ coating and argon. As with sound insulation, the end performance also depends on the quality of the frame and whether or not it is completely airtight. Most national insulation regulations express performance levels in terms of the complete window (U w value) rather than of the glazing alone (U g value). 127

7 SOLAR AND LIGHT PERFORMANCE ASPECT The following key factors should be taken into account in the case of solar control glazings (as well as the U g value): > solar factor (SF or g) > level of light transmission (LT) > level of external light reflection (LR) > colour. Details of annual energy usage, inside temperature and, where appropriate, the level of air conditioning in the building will determine the maximum permissible solar factor for any given façade, i.e. the solar gains passing through the façade. The level of light inside the building, visual comfort (likelihood of glare) and the type of lighting will all depend on the LT level. Light reflection (transparency or mirror effect) and colour are aesthetic criteria. The details above are all interrelated and choosing certain values for one criterion may restrict the choice available in others. The levels of solar and light performance are achieved through the use of coloured or coated glasses; the latter achieve higher levels of performance. AGC uses two coating technologies: > Pyrolytic coatings: Stopsol and Sunergy > Magnetron coatings: Stopray, Stopray T, Planibel Energy N and Planibel Energy NT. In some special cases silk-screen printed glasses, coated laminated glasses or glasses with coloured interlayers can also provide a degree of solar control. Depending on the type of coating, the thicknesses available will vary. The main features of these coatings are detailed in the table below. Stopsol Sunergy Stopray / Stopray T Energy N Energy NT Use in single glazing Yes (# 1 or 2) Yes (# 2) No No Use in double glazing Yes (# 1 or 2) Yes (# 2) Yes (# 2) Yes (# 2) External light reflection Poor (# 2) to high (# 1) Poor Poor to high Poor Solar factor Poor to high Poor to average Poor to high Average Selectivity Poor Average High High Toughened Toughened Toughened (T) Toughened (NT) Processing options Bent Bent Bent (T) Bent (NT) Laminated Laminated Laminated * Laminated * Thermal insulation Poor Average High High * Coating must not come into contact with the PVB. To choose the correct product, the designer should consider the following criteria: > level of reflection and colour required > level of thermal insulation required; it may be necessary to combine the solar-control coating with a Top N+ -type Low-E coating to achieve a performance level of U g = 1.1 W/(m².K) (see 1.4 above) > desired solar factor > desired level of light transmission (depending on what is possible in view of the solar factor required; the LT level can never physically be more than double the SF) > type of product used (glass with pyrolytic or Magnetron coatings); this is more of a direct consideration during processing rather during the design stage. Depending on these various details, the table on the following pages will help you to choose the most appropriate product. The table includes most of the glasses available in the AGC range; the values indicated apply to single glazing and double glazing. The three tables detail respectively the solutions for thermal insulation alone, for solar control alone and finally for solar control and enhanced thermal insulation com- 129

8 130 bined. Other performance levels may be achieved by varying the thickness of the glass, primarily in the case of coloured glasses. Details of such performance levels are available in the Glass Configurator on the site. Note: thermal shock (see document on available to download) Breakage due to thermal shock occurs if there is too much of a temperature difference between two areas of the same annealed glass. If the temperature of the glass rises, the glass expands; this does not present any difficulty if the temperature increase is uniform across the entire sheet of glass. However, if part of the glass remains cold, it will prevent the warm part from expanding freely. This gives rise to tensile stress which may exceed the mechanical resistance of the glass. If there is a risk of this happening the glass should be thermally toughened or heat-strengthened. To assess the risk of thermal shock and whether heat treatment is required, a sheet entitled Risk of Thermal Shock giving details of the information needed to make the relevant calculation (type of glazing and frame, location of the building, blinds, shadows, etc.) is available on the site and should be completed before any calculation is made by the specifier or the technical research department. Look (1) Double glazing FS TL RL U g (2) neutral Clear Ar 90% -4 (2) neutral G neutral Top NT neutral Top N (1) Neutral: used to describe a clear glass to which a coating has been applied. (2) Identical values for 15 or 16 mm spacer. Solar control Base glass Look (1) Double glazing (2) SF LT LR U g CLEAR GREY GREEN BRONZE AZUR DARK BLUE PRIVA- BLUE Shiny silver Stopsol Supersilver clear # Slightly blueish silver Stopsol Supersilver clear # Clear metallic Stopsol Classic clear # Amber silver Stopsol Classic clear # Grey Planibel grey Metallic steel Stopsol Supersilver grey # Silvered steel Stopsol Supersilver grey # Silvered Stopsol Classic grey # Metallic grey Stopsol Classic grey # Green Planibel green Shiny green Stopsol Supersilver green # Silver steel Stopsol Supersilver green # Metallic green Stopsol Classic green # Silvered Stopsol Classic green # Bronze Planibel bronze Metallic bronze Stopsol Classic bronze # Yellowish silver Stopsol Classic bronze # Light blue Planibel Azur Dark Blue Planibel Dark Blue Shiny blue Stopsol Supersilver Dark Blue # Silver blue Stopsol Supersilver Dark Blue # Dark Blue Planibel PrivaBlue Deep blue Stopsol Silverlight PrivaBlue # Silver blue Stopsol Silverlight PrivaBlue # (1) General appearance of the glass (neutral, green, bronze, etc. to be checked against samples. (2) Identical values for 15 or 16 mm spacer. Other factors: apart from the solar and thermal performance levels detailed in this table, the level of acoustic and safety performance of the chosen product can easily be enhanced by including 1 or 2 laminated panes of Stratobel safety glass and/or Stratophone acoustic laminated safety-security glass in the sealed unit. Note: the performance levels detailed opposite apply to glasses 6 mm thick. By varying the thickness of the glass, other performance levels may be achieved. 131

9 132 Solar control and thermal insulation Base glass CLEAR GREY GREEN Look (1) Insulating glazing 6-12 Ar 90% -4 (2) FS TL RL U g Neutral Sunergy Clear # Neutral Sunergy Clear #2 + Top N Neutral Thermobel Energy NT Neutral Thermobel Energy N Neutral Stopray Vision-50 T Neutral Stopray Vision Neutral Stopray Galaxy on Clearvision Green neutral Stopray Elite Neutral Stopray Safir Shiny silver Stopsol Supersilver clear #1 + Top N Slightly blueish silver Stopsol Supersilver clear #2 + Top N Clear metallic Stopsol Classic clear #2 + Top N Amber silver Stopsol Classic clear #1 + Top N Grey Planibel grey + Top N Metallic steel Stopsol Supersilver grey #2 + Top N Silver Stopray Silver Dark grey Stopray Titanium 37 T Silver Stopsol Supersilver grey #1 + Top N Metallic grey Stopsol Classic grey #2 + Top N Silvered Stopsol Classic grey #1 + Top N Green Planibel green + Top N Green Sunergy green # Green Stopray Lime 61 T Shiny green Stopsol Supersilver green #2 + Top N Green Sunergy green #2 + Top N Silver steel Stopsol Supersilver green #1 + Top N Metallic green Stopsol Classic green #2 + Top N Silvered Stopsol Classic green #1 + Top N Base glass BRONZE AZUR DARK BLUE PRIVABLUE Look (1) Insulating glazing 6-12 Ar 90% -4 (2) FS TL RL U g Bronze Planibel bronze + Top N Metallic bronze Stopsol Classic bronze #2 + Top N Amber silver Stopsol Classic bronze #1 + Top N Light blue Planibel Azur + Top N Light blue Sunergy Azur # Light blue Sunergy Azur #2 + Top N Dark Blue Planibel Dark Blue + Top N Shiny blue Stopsol Supersilver Dark Blue #2 + Top N Silvered blue Stopsol Supersilver Dark Blue #1 + Top N Dark Blue Stopray Indigo 48 T Deep blue Sunergy Dark Blue # Deep blue Sunergy Dark Blue #2 + Top N Dark Blue Planibel PrivaBlue + Top N Dark Blue Stopsol Silverlight PrivaBlue #2 + Top N Silvered blue Stopsol Silverlight PrivaBlue #1 + Top N (1) General appearance of the glass (neutral, green, bronze, etc. to be checked against samples. (2) Identical values for 15 or 16 mm spacer. Other factors: apart from the solar and thermal performance levels detailed in this table, the level of acoustic and safety performance of the chosen product can easily be enhanced by including 1 or 2 laminated panes of Stratobel safety glass and/or Stratophone acoustic laminated safety-security glass in the sealed unit. Note: the performance levels detailed opposite apply to glasses 6 mm thick. By varying the thickness of the glass, other performance levels may be achieved. 133

10 SPANDRELS Spandrels hide the opaque sections and structure of façades. In conjunction with vision glazing, they can be used to create all-glass façades. Depending on the products and colours used, either complete harmony or contrasting effects can be achieved. Different functions can be combined within spandrels such as thermal or sound insulation and protection against fire (Arvahcolor). The following types of spandrels are available: > enamelled single glass: clear or coloured glass or glass with a pyrolytic coating with an enamel coating and then thermally toughened or heat-strengthened > double glazing comprising the same glass as vision glass on the outside and a Blackpearl glass on the inside; the coating on the Blackpearl glass should be in position 4 > a shadow box: a spandrel comprising a vision glazing combined with an opaque background (metal sheet, etc.) to achieve a partially opaque effect in harmony with the building. Vision glazing and spandrels should always be the same thickness. Except in the case of a preliminary thermal study, spandrels should always be heat-strengthened or thermally toughened. In the case of spandrels made of double glazing positioned in front of a structure made out of concrete or other insulating material a thermal study should be conducted to assess the glazing s durability. Type of spandrels to be used for different types of vision glazing Vision glazing Spandrel* Planibel Bronze Planibel bronze + Blackpearl Green Planibel green + Blackpearl Grey Planibel grey + Blackpearl Azur Planibel Azur + Blackpearl Dark Blue Planibel Dark Blue + Blackpearl PrivaBlue Planibel PrivaBlue + Blackpearl Thermobel Thermobel Thermobel Top N+ (#3) Thermobel Top NT (#3) Themobel Energy N (#2) Planibel Energy N + Blackpearl Themobel Energy NT (#2) Planibel Energy NT + Blackpearl Stopsol Classic clear (#1) Classic clear #1 + Blackpearl Classic clear (#2) Classic clear #2 + Blackpearl Classic bronze (#1) Classic bronze #1 + Blackpearl Classic bronze (#2) Classic bronze #2 + Blackpearl Classic green (#1) Classic green #1 + Blackpearl Classic green (#2) Classic green #2 + Blackpearl Classic grey (#1) Classic grey #1 + Blackpearl Classic grey (#2) Classic grey #2 + Blackpearl Supersilver clear (#1) Supersilver clear #1 + Blackpearl Supersilver clear (#2) Supersilver clear #2 + Blackpearl Supersilver green (#1) Supersilver green #1 + Blackpearl Supersilver green (#2) Supersilver green #2 + Blackpearl Supersilver grey (#1) Supersilver grey #1 + Blackpearl Supersilver grey (#2) Supersilver grey #2 + Blackpearl Supersilver Dark Blue (#1) Supersilver Dark Blue #1 + Blackpearl Supersilver Dark Blue (#2) Supersilver Dark Blue #2 + Blackpearl Silverlight PrivaBlue (#1) Silverlight PrivaBlue #1 + Blackpearl Silverlight PrivaBlue (#2) Silverlight PrivaBlue #2 + Blackpearl * For monolithic solutions, enamelled spandrels can be used. 135

11 136 Stopray Elite 67/37 Safir 61/32 Vision-50 Vision-50 T Vision glazing Galaxy 40/21 on Clearvision Silver 43/25 Lime 61 T Titanium 37 T Indigo 48 T Elite + Blackpearl Safir + Blackpearl Vision-50 + Blackpearl Spandrel* Vision-50 T + Blackpearl Galaxy on Clearvision + Blackpearl Silver + Blackpearl Lime 61 T + Blackpearl Titanium 37 T + Blackpearl Indigo 48 T + Blackpearl The recommendations for harmonising colours for each product are given for information only. They are based on a range of tests designed to identify the best possible solution without the latter necessarily being a perfect match (harmony). It is not uncommon for an architect to seek to achieve a degree of contrast between vision glazings and spandrels rather than complete harmony. Some combinations of glass may give rise to more or less marked differences in colour or reflection. Such differences are due to the nature of the glasses used, the angle of vision, surroundings, weather conditions, light intensity at a particular time etc. For all these reasons, AGC advises clients to build prototypes for each project and to view them on site during the construction phase to confirm their choice. AGC cannot be held responsible for any differences in harmony, colour or reflection in a façade. 1.7 SAFETY The level of safety afforded by various glasses is defined according to a range of tests used to categorise their safety performance (impact, burglary, bullet-proof, explosion-proof); depending on the applications, thermally toughened or laminated glasses can be used to meet these requirements (see table). Standards Toughened glass Laminated glass Stratobel Stratophone Impact resistance and accident prevention EN Protection against defenestration EN Burglar-proof EN 356 Bullet-proof EN 1063 Explosion-proof EN In terms of safety, Stratobel and Stratophone perform to the same level. In terms of sound insulation, Stratophone glasses perform better than Stratobel glasses. Depending on the local situation and regulations, you should assess whether laminated double glazing should be used and adapt it if necessary (for instance, double glazing with a single laminated glass only provides protection against shocks and injury on the laminated side of the glass). Below are some examples as applied in most countries: > for roof glazings, laminated glass is essential to protect persons beneath the glass opening from injury from loose splinters, particularly if external objects fall onto it > for windows which extend to the floor, there is the risk that a person may fall in the event of a shock or if the glass breaks; only laminated glass provides adequate protection against defenestration > for shop windows, depending on the value and size of the goods to be protected, a laminated glass should be used, the composition of which should be adapted to provide protection against burglary and theft. 137

12 138 Note: the performance of the joinery and hardware should be equivalent to that of the glazing to achieve an acceptable overall performance level. Classification standards also exist for joinery and will help you choose the correct solution. 1.8 PROTECTION AGAINST FIRE Different performance levels (E, EW, EI) can be achieved using different glazings. The table below gives an overview of the AGC range. E EW EI Performance Polished wired glass Pyrobel/Pyrobelite 139

13 MULTIPLE FUNCTIONS Introduction The various functions available (thermal insulation, solar control, sound insulation, safety and security) above can be combined with each other by adapting the composition of the glass. The following functions are detailed in the tables: > Thermal insulation + enhanced thermal insulation > Sound insulation > Safety > Solar control > Enhanced thermal insulation + solar control > Enhanced thermal insulation + sound insulation > Enhanced thermal insulation + safety > Enhanced sound insulation + safety > Sound insulation + solar control > Solar control + safety > Sound insulation + solar control + safety > Decoration Glazing symbols Glazing symbols Single glazing Single glazing thicker than above Double glazing Laminated glass with acoustic PVB or PVB Coated glass Thermally toughened glass Examples Double glazing comprising a coated glass and a laminated glass with PVB Dissymmetrical double glazing in which the thinner glass has a coating in # Interpreting the tables On the following pages, various tables show the appropriate glass to be used depending on the performance level(s) required. These tables show: > Desired performance levels higher than those of standard double glazing on a blue background with a tick () > Additional performance levels achieved: in some cases, the glass obtained also enhances other functions which were not necessarily desired (for example, a laminated glass with PVB always enhances acoustic performance even when used to provide safety); these are shown by a tick () > In some cases, enhanced thermal insulation can be obtained by assembling the glass with a Top N+ or Top NT coating in position 3. This is indicated with a * in the enhanced thermal insulation column. Note: the tables have been simplified and do not include all information, in particular the thickness of the glass Applications thermal insulation and enhanced thermal insulation A distinction is drawn between: > Standard thermal insulation, i.e. a U g value of approximately 3.0 W/(m².K). Solution: standard double glazing with two clear or coloured glasses (without a low-emissivity coating). 141

14 142 > Enhanced thermal insulation, i.e. a U g value of between 1.0 and 2.0 W/(m².K). Solution: double glazing with a low-emissivity coating compulsory in some countries and strongly recommended in terms of energy performance. U g values below 1.0 W/(m²K) can be achieved using triple glazing. Most countries now have regulations on thermal insulation which require double glazing to be used which provides enhanced thermal insulation. In all the cases below, a low-emissivity coating may be included in the double glazing to enhance the thermal insulation provided. Standard thermal insulation Solution Standard DGU Enhanced thermal insulation Solution Top N+ Enhanced thermal insulation Enhanced thermal insulation Safety Sound Solar Safety Sound Solar Other functions are possible by altering the glass components see below. Sound insulation The acoustic performance of symmetrical double glazing is lower than that of single glazing with a total equivalent thickness. To limit noise pollution, acoustic double glazing should be used. Solutions in ascending order of efficiency: > double glazing with two glasses of different thicknesses > double glazing with one or two laminated glasses with a PVB interlayer (this glass is designed for safety purposes but also provides enhanced sound insulation) > double glazing with one or two laminated glasses with an acoustic PVB interlayer > Composition being equal, it is always advisable to widen the spacer within the double glazing assembly. Sound insulation Solutions Disymmetrical DGU Stratobel Stratophone Enhanced thermal insulation Safety Sound Solar * * * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. Safety There are several levels of safety and different glass products meet the individual requirements at each of these levels: > Safety of individuals against injury (no risk of defenestration) Solution: thermally toughened or laminated glass with PVB. A double-glazing unit comprising a thermally toughened glass and an annealed glass provides no protection against the risk of injury if both panes of glass break at the same time. For safety reasons, when a thermally toughened glass is used in double glazed unit, the other glass should also be thermally toughened or laminated. To prevent accidents, the safety glass should be positioned on the side on which shocks are likely to occur. Where such shocks 143

15 144 are likely to occur on either side of the glass, double glazed units comprising two safety glasses (laminated or thermally toughened) should be used. > Safety of individuals against injury (risk of defenestration) Solution: only laminated glass may be used. > Roof glazings / glass roofs Solution: laminated glass must be used. It is placed on the inside to protect individuals from injury due to flying pieces of glass. > Protection against vandalism and burglary in shops, isolated dwellings or homes located in unsafe districts Solution: laminated glass. The relevant type of laminated glass according to the desired level of safety should be selected on a case-by-case basis. > Protection against firearms, explosions and fires Solution: laminated glass. Special cases should be assessed individually. Safety Solutions DGU (with 2 toughened glasses) DGU (with Stratobel/ DGU (with Stratobel/ Enhanced thermal insulation * Safety Sound Solar * * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. Solar control Solution: solar control glass (coated and/or coloured glasses). The solar-control glass is positioned on the outside of the double glazed unit; the solar-control coatings are applied in either position 1 (pyrolytic) or 2 (pyrolytic or Magnetron). Solar control Solutions Energy N Stopray Stopsol Sunergy Enhanced thermal insulation Safety Sound Solar * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. 145

16 146 enhanced thermal insulation + solar control Solution: some solar-control coatings are dual-function and combine low-emissivity (enhanced thermal insulation). If this is not the case, a Top N+ coating may be applied in position 3. Thermal insulation + solar control Solutions Energy N Stopray Stopsol and Top N+ Sunergy or Sunergy and Top N+ Enhanced thermal insulation Safety Sound Solar Other functions are possible by altering the glass components see below. enhanced thermal insulation + sound insulation Solution: enhanced thermal insulation may be achieved in an acoustic glazing by using a Top N+ / Top NT coating in position 3. Thermal insulation + sound insulation Solutions Top N+ in dissymmetrical DGU Top N+ and one or two Stratobel Top N+ and one or two Stratophone Enhanced thermal insulation Safety Sound Solar Other functions are possible by altering the glass components see below. 147

17 148 enhanced thermal insulation + safety Solution: enhanced thermal insulation may be achieved in a safety glass by using a Top N+ / Top NT coating in position 3. Thermal insulation + safety Solutions Top N+ (with 2 toughened glasses) Top N+ Top N+ Enhanced thermal insulation Safety Sound Solar Other functions are possible by altering the glass components see below. Sound insulation + safety Solution: double glazing comprising one (or two) laminated glass(es) with PVB or acoustic PVB. Sound insulation + safety Solutions One or two Stratobel One or two Stratophone Enhanced thermal insulation Safety Sound Solar * * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. 149

18 150 Sound insulation + solar control Solution: dissymmetrical double glazing or double glazing comprising one (or two) laminated glass(es) with PVB or acoustic PVB. The external component of the double glazed unit includes a coated solar control glass. Sound insulation + solar control Solutions Energy N Stopray Stopsol Sunergy Energy N Stopray Stopsol Sunergy Enhanced thermal insulation Safety Sound Solar * * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. Solar control + safety Solution: double glazing comprising one (or two) laminated glass(es) with PVB or acoustic PVB. The external component of the double glazed unit includes a coated solar-control glass. Solar control + safety Solutions Energy N Stopray Stopsol Sunergy Enhanced thermal insulation Safety Sound Solar * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. 151

19 152 Sound insulation + solar control + safety Solution: double glazing comprising one (or two) laminated glass(es) with PVB or acoustic PVB. The external component of the double glazed unit includes a coated solar-control glass. Sound insulation + solar control + safety Solutions Energy N Stopray Stopsol Sunergy Enhanced thermal insulation Safety Sound Solar * * Enhanced thermal insulation may be achieved by using a Top N+ / Top NT coating in position 3. Other functions are possible by altering the glass components see below. decoration For façade applications or interior design, many different decorative glasses can also be incorporated into the double glazed unit. Solutions: > Patterned glasses (depending on design) > Matt-finish glasses (depending on assembly) > Coloured glasses > Painted glasses > Enamelled or silk-screen printed glasses > Decorative laminated glasses > Built-in Georgian bars > Built-in blinds > Inclusion of various decorative features TECHNICAL VALIDATION Once all the specifications of the glass have been determined, they must then undergo technical validation: > The size of the glass, the loads to be considered and installation will all determine which thicknesses are required > Thermal shock: a thermal shock investigation is recommended > Temperature and behaviour of insulating glazing: checks must be conducted to ensure that the permissible temperatures for the glass components and putty-mastic are not exceeded > An appropriate sealant should be chosen for the relevant application > etc. 153

20 FEASIBILITY 1.12 CASE STUDIES The following feasibility restrictions should be adhered to when selecting components: > the maximum possible sizes for a sheet of glass are 6 m by 3.21 m; most products designed for use in façades are available in these sizes > depending on the factories and products, the maximum permissible sizes for processing vary considerably > not all products can be processed in all ways: please contact us for details; the glass is heavy: 2.5 kg per mm² and per mm thickness; the weight of glasses should be verified so that they can be handled in the factory and on site > not all coloured and coated glasses are available in all thicknesses; the 6-mm and 8-mm thicknesses are the most flexible. Below are two practical examples of the stages involved in choosing a glazing based on the comments above Tertiary building For an office building located in a town (wind pressure of 1,000 Pa), an architect wants to install glazing with the following properties: > panes of glass measuring 2.5 m x 1.5 m > high level of light reflection (mirror effect) and silvered look > solar factor < 30 % > highest possible level of light transmission > U g = 1.1 W/(m².K) > Acoustic requirements: R w (C; C tr ) of at least 35 (-1; -4) db. The case can be solved as follows: > A mechanical calculation (Belgian standard) shows that the minimum acceptable thickness corresponds to a double glazed unit: 8 + 8, or > In terms of sound insulation, an double glazed unit cannot achieve an R w level of 35 db; a composition equivalent to 38 (1; -4) db or an Stratobel equivalent to 41 (-2; -4) db is needed; since there are no safety requirements, a composition is satisfactory > The solar-performance table for various glasses (page ) shows that two products meet these requirements: Stopray Silver 43/25 Stopsol Supersilver grey position 1 and Top N+. If safety (defenestration) or theft prevention are issues, simply substitute at least one of the components in the double glazed unit with a laminated glass. Finally, the risk of thermal shock should be calculated. 155

21 Conservatory The size of the glazed surfaces in conservatories make it extremely important to choose a form of thermal insulation which will limit losses as much as possible; we would generally advise the use of products with a U g value of 1.1 W/(m².K). For glazed areas of roofs, to avoid overheating and glare in the summer when the sun is high it is a good idea to use a highperformance solar-control glass, for example Stopray Silver (combined with a laminated glass for safety). For vertical partitions, depending on the direction and the level of sunlight, either double glazing with a Top N+ coating to provide thermal insulation or double glazing with an Energy N coating to limit heat gain should be used. 2 DECORATION AND FURNISHINGS 157

22 FACTORS INFLUENCING THE CHOICE OF GLAZING When choosing a decorative glass, several factors should be noted Appearance > Transparent solutions provide the greatest possible transparency (passage of light); objects and people are clearly visible through the glass > Translucent solutions, while enabling you to see objects behind the glass, at the same time provide a degree of privacy; the shapes of objects and people can be made out through the glass Depending on the products used, the level of light transmission in a translucent glass may be just as high as that of clear glass > Opaque solutions hide the surfaces they cover or objects positioned behind the glass; objects and people cannot be seen through the glass > The diagram below shows (left to right) the effects of transparent, translucent and opaque glasses. Transparency, translucence and opacity Transparency Translucence Opacity Colour or graphics All solutions are available - neutral, coloured, metallic or patterned Type of application This will determine the type of glass used from the point of view of particular functions required in terms of the safety, appearance or installation of the product (bonding, thicknesses or specific sizes, etc.): > ground: floor plates, stairs, pedestrian bridges > balustrades > walls: wall cladding > partitions > furniture: in horizontal applications such as tables, consol tables and shelves or in vertical applications such as decoration for furniture > doors: doors with glass such as furniture doors, sliding or non-sliding wardrobe doors, entry doors to buildings > two-way mirrors > frames > others Safety Some products are available in a safety version: > thermally toughened glass > laminated glass > glass with a Safe film > fire-resistant glass. Some applications such as floors or balustrades, for example, automatically require laminated glass to be used for safety reasons. For other applications such as furniture, wall cladding, etc., most countries have national regulations requiring safety glass to be used in certain situations. 159

23 Installation Decorative products may be installed by laminating, gluing, mechanical fixing, pressure gaskets and other methods. Some products are subject to installation restrictions: for example, you should check that a silicone used to glue Lacobel glass is compatible. Some products are restricted to interior use while others can be used both indoors and out. For more details, please see the detailed installation brochures for these products Existing functions In the tables below, a distinction is drawn between: > existing safety or sound-insulation functions afforded by the standard product > additional functions which may be added to the product through further processing. The desired functions are dependent on the application required and the specific rules to be observed. 2.2 SUMMARY TABLES The following tables will help you to choose a glass according firstly to its look (three tables for transparent, translucent and opaque solutions), and thereafter according to colour and graphics, type of application and functions. 161

24 Transparent glasses Applications Use Safety Sound Acoustic PVB laminating Fire-resistant Thermally toughened Laminating, safety Safe Film Interior Exterior Framing Two-way mirrors Doors (2) Furniture (2) Partitions (2) Walls (2) Balustrade (1) Flooring (1) Product Description Neutral or coloured Clear base glasses available as antibacterial glass Planibel Clear, Clearvision and Linea Azzurra Planibel Coloured Body-tinted base glasses Stratobel Laminated safety glasses with PVB interlayer(s) Stratobel Color Standard Laminated safety glasses with glass or Stratobel Color Rainbow decorative interlayer Stratophone Laminated acoustic safety-security glazing Balustra All-glass balustrade system Pyrobel / Pyrobelite Laminated, fire-resistant glasses Intrinsic function. Additional function through processing. (1) These products may only be used in laminated glass. (2) In most countries, regulations require the use of safety glass (toughened, laminated, with a Safe film) for certain applications. Applications Use Safety Sound Acoustic PVB laminating Fire-resistant Thermally toughened Laminating, safety Safe Film Interior Exterior Framing Two-way mirrors Doors (2) Furniture (2) Partitions (2) Walls (2) Balustrade (1) Flooring (1) Product Description Neutral or coloured Blackpearl Hard-coated glasses Glamatt Matobel Anti-glare glasses for framing Polished wired glass Patterned glasses Graphics Stratobel Design Laminated safety glasses with glass or decorative interlayer Imagin wired Patterned wired glasses Imagin Patterned glasses (3) (3) (3) Intrinsic function. Additional function through processing. (1) These products may only be used in laminated glass. (2) In most countries, regulations require the use of safety glass (toughened, laminated, with a Safe film) for certain applications. (3) Processing may be possible depending on pattern. 163

25 Translucent glasses Applications Use Safety Sound Acoustic PVB laminating Fire-resistant Thermally toughened Laminating, safety Safe Film Interior Exterior Doors (2) Furniture (2) Partitions (2) Walls (2) Balustrade (1) Flooring (1) Product Description Graphics Imagin Patterned glasses (3) (3) (3) Neutral or coloured opalescent Lacomat Painted, matt-finish glasses Matelux Acid-etched glasses available as antislip glass Matelux Stopsol Acid-etched coated glass Sandblasted glsass Sandblasted glass Stratobel Color Standard Stratobel Color Rainbow Laminated safety glass with glass or decorative interlayer Intrinsic function. Additional function through processing. (1) These products may only be used in a safety version. (2) In most countries, regulations require the use of safety glass (toughened, laminated, with a Safe film) for certain applications. (3) Processing may be possible depending on the pattern Opaque glasses Applications Use Safety Sound Acoustic PVB laminating Fire-resistant Thermally toughened Laminating, safety Safe Film Interior Exterior Doors (2) Furniture (2) Partitions (2) Walls (2) Balustrade (1) Flooring (1) Product Description Coloured or metallic Stratobel Color Laminated safety glasses with PVB interlayer(s) Lacobel Painted glasses available as antibacterial glass Matelac Silver Silvered, acid-etched glasses Matelac Painted, acid-etched glasses White Stratobel Color Pure White Laminated safety glasses with PVB Lacobel Painted glasses Matelac Acid-etched painted glass Reflective Mirox New Generation Ecological Copper- free and lead-free environmentally friendly Mirox 3G Ecological mirror -ROHS -available as antibacterial glass Sanilam Easycut Laminated double sided safety mirrors Intrinsic function. Additional function through processing. (1) These products may only be used in a safety version. (2) In most countries, regulations require the use of safety glass (toughened, laminated, with a Safe film) for certain applications. 165

26 CASE STUDIES Office partition For an office in a town, an interior designer wants to install glass with the following features: > translucent, matt-finish look > sound insulation: R w (C; C tr ) at least 35 (-2; -5) db > safety: minimum of 1B1 according to standard EN > glazings 2.5 m high and 1 m wide in a glazing rebate only on the lower and upper sides. Stages: > Given the large sizes of the glass and installation on two supported sides only, a mechanical calculation (wind pressure inside the building of 450 Pa) shows that the glass used must be at least 88.2 mm thick > The 1B1 safety requirement for the partition requires a laminated Stratobel product with two PVB films > To meet the sound-insulation requirement of 35 (-2; -5) db, no less than a 55.1 Stratobel or 33.1 Stratophone glass should be used > Deciding on aesthetic options: the following options are available according to the table on Translucent Glasses : Lacomat, Matelux, sandblasted glass, standard Stratobel Colour with matt PVB and Imagin Satinbel or Screen patterned glass > Since Lacomat cannot be laminated, this option can be ruled out. Care should be taken to check that the Imagin patterns can be laminated (see Imagin): both Satinbel and Screen can be laminated > There are therefore five different looks which may suit the designer s requirements and s/he can look at samples to help make a decision Cupboard door For a new range of cupboards, a designer wants to incorporate glass with the following features: > red opaque appearance > safety: 2B2 according to standard EN > glass measuring 2.44 m x 0.9 m. Stages: > Deciding on aesthetic options: the following options are available according to the table on Opaque Glasses : Lacobel, Matelac > There are two possible looks: Lacobel (shiny) and Matelac (satin-finish). The designer can look at samples to help make a decision > Deciding on the technical solution: to achieve a performance level of 2B2, Lacobel or Matelac must be made safe with a Safe film. A thickness of 4 mm is possible. 167