Glass 1x1



Absorption and thus weakening of energy rays as they pass through matter. Absorption is the third determining quantity, in addition to transmission and reflection, in the passage of rays through glass.

Transmission + Reflection + Absorption = 100 %

The radiation energy is converted into heat energy by absorption. This leads to an increase in temperature of the absorbing pane of glass.

Alarm Glass

TSG or LSG combined with various security systems such as alarm wire or alarm strip burnt into a sheet of TSG. Alarm TSG is a single-pane security glass with a burnt-in conducting strip that is interrupted when the pane is destroyed, thus triggering an alarm. The TSG alarm pane must be positioned facing the side exposed to attack.

Annual Primary Energy Requirement

The introduction of the new verification quantity "annual primary energy requirement" in the current German EnEV allows the planner to design the building shell of a new building in accordance with his creative ideas. He is free to choose the individual building materials for the different subsections and is no longer bound by the U-value specifications.

Verification of the annual primary energy requirement is carried out in accordance with the currently valid EnEV. The exact window sizes must be taken into account for the producing of the energy balance.

Anti-Vandal Glazing

The A class of anti-vandal glass defined in part A of DIN EN 356 is divided into five groups with increasing protective effectiveness. The testing procedure assumes a heavy missile, which is simulated with a 4110 g metal ball with a diameter of 10 cm in free fall. The ball is dropped onto each test piece (110 cm x 90 cm) three times from the same height.

There are four dropping heights, depending on the load type, which define the resistance class. In the group P1A the glass unit must withstand the ball dropping three times from a height of 1.5 m, in group P2A from 3.0 m, in group P3A from 6.0 m, in group P4A the dropping height is 9.0 m, and for group P5A the test piece must withstand this dropping height nine times.

Attack-Resistant Glazing

Divided into the groups:

test standard
PxA = anti-vandal glazing DIN EN 356 A
PxB = penetration-resistant glazing DIN EN 356 B
BR  = bullet-resistant glazing DIN EN 1063
D    = explosion-resistant glazing DIN 52290



Also known as the "shading coefficient", represents the average transmittance of solar energy, based on the solar heat gain coefficient of a 4 mm-thick pane. This is necessary for calculating the cooling load of a building.

Break-In-Resistant Glazing

In Germany, the VdS (Association of Property Insurers) tests break-in-resistant glazing for its penetration-resistant effectiveness for the setting of premiums for the protected properties. The products that it recognises are accepted into an index. The different break-in-resistant glasses are divided up into five protection classes with increasing protective effectiveness:

  • EH 01
  • EH 02
  • EH 1
  • EH 2
  • EH 3

The protection class that is required by a particular property in the specific case depends on the respective circumstances and must be agreed with the insurance company.

Bullet-Resistant Glazing

The testing of bullet-resistant glazing in accordance with DIN EN 1063 requires the test piece to be shot three times, in which the shots are to be placed at fixed distances from each other. There are nine protection classes of BR1-BR7 and SG1 and SG2. A distinction is also made between: "shatter-proof" (SF) and "splintering" (SA).

Because all bullet-resistant glazing consists of multi-pane, asymmetrically structured LSG, the BR and SG types inevitably have improved break-in protection.


Chemical Resistance

Glass is generally sufficiently chemically stable and resistant to acids (except hydrofluoric acids), and to bases, to a limited degree.

Chemically Toughened Glass

Stress state similar to thermally toughened glass, but the fracture structure does not meet the necessary safety requirements.

Cleaning of Glass Surfaces

Glass surfaces must be cleaned regularly, although, of course, the frequency of this depends on the level of dirt. The best method is to use lots of clear water and simple soft cloths or sponges. Conventional cleaner sprays may also be used. Alkaline washing solutions and acids and agents containing fluoride, however, should not be used. Grease and sealing material residue are to be removed with conventional, non-aggressive solvents (ethyl alcohol, isopropanol), rinsing afterwards with lots of water. All types of cleaning with abrasive, i.e. scouring or scratching materials (fine steel wool, glass scraper, razor blades at a shallow angle to the glass or similar) is only permitted for removing dirt from distinct points. The use of such tools to clean whole surfaces, such as in so-called “scraping-off”, is not suitable for glass.

These rules apply to all types of base and special glass.

Colour Reproduction Index Ra

The colour reproduction characteristics of glazing are calculated using the general colour reproduction index Ra in accordance with DIN 6169. The scale for Ra goes up to 100. The optimum possible Ra value for glazing is 99.

The Ra,D value states the colour recognition in daylight, firstly in the room and secondly looking through the glazing. In a similar way, the Ra,R value states the colour reproduction of the glass on the viewing side.

Condensation on the Outside Surfaces of Panes

Condensation can form on the outside glass surfaces if the glass surface is colder than the air next to it, (e.g. misted car windows).

The formation of condensation on the external surfaces of the insulation glass panes is determined by the Ug-value, the air moisture, the airflow and the inside and outside temperature.

The formation of condensation on the pane surface facing the room is encouraged by the prevention of air circulation, e.g. by deep jambs, curtains, flowerpots, flower boxes, venetian blinds or unfavourable arrangement of radiators etc.

Condensation can form temporarily on the weather-side glass surface of insulation glass with high heat insulation if the outside moisture (relative air moisture outside) is high and the air temperature is higher than the temperature of the pane surface.

Conservatory Glass

Special glass for conservatories and/or glass extensions and porches for the passive utilisation of solar energy. Ensures a high level of heat insulation when combined with insulation glass.

Construction Glass

The use of glass as a material has a 5,000-year-old tradition. The importance of glass as a construction material was recognised very early. Glass soon became synonymous with light, protection and comfort. It is now used e.g. for glazing windows, doors, conservatories and façades with special heat, sun and noise-insulating properties in new buildings and in renovation work.


DB (A)

Sound pressure, which is measured according to frequency according to the weighting curve A (DIN 45633).

DB, Decibels

Physical measurement of the sound reduction index.

Dew Point Temperature

The dew point temperature is the air temperature at which the relative air moisture reaches the value of 100%. If the air temperature sinks with no change in the moisture content, condensation water occurs. Dew point temperatures can occur at different places:

Dew Point Temperature in Space Between Insulation Glass Panes
A new insulation glass unit should have a temperature in the glazing cavity of < -60° C. This temperature, which is determined in accordance with DIN 52 345, is an essential quality feature and ensures a long life span for the insulation glass.

Dew Point Temperature on the Room-Side Pane Surface
Condensation can form on the pane surface on the room-facing pane surface if warm air suddenly cools down on a cold pane surface or if relatively cold air has added moisture (e.g. wet rooms).
The tendency towards condensation can be substantially reduced by the use of insulation glass, such as e.g. UNIGLAS® | TOP, as the surface temperature of the pane is increased on the room side by the improved Ug-value. By using the UNIGLAS® | TS Thermo Spacer (stainless steel or thermix spacers) the risk of condensation at the edges is substantially reduced yet further.

Dew Point Temperature of the Outside Pane Surface
In individual cases, condensation may form on the outside pane surfaces, even of laminated insulation glass. It occurs early in the morning when the outside air has a high moisture content.
This is caused by the fact that the outer panes of insulation glass cool down greatly due to the high heat insulation.
This condensation disappears again quickly with the first rays of sun.
One should always bear in mind that the formation of condensation, on the room-side as well as on the outside, is due to physical and climatic reasons.


Deutsches Institut für Bautechnik (German Institute for Construction Technology), Berlin


Deutsches Institut für Normwesen (German Institute for Standards)


Edge Seal

With UNIGLAS®, the edge seal always consists of a two-stage sealing system:

A butyl band, extruded on both sides of the metallic spacer profile and sealed all the way around, as primary sealing material. It blocks water vapour and the diffusion of gas and thereby has the primary protecting the unit from the penetration of air moisture and the escaping of gas.
A secondary sealing material, which is applied snugly on the profile back between the two pane edges, i.e. at least 3 mm without bubbles.

This secondary has to perform two tasks:

  • The permanent joining of the two panes, with the sealing material forming a chemical bond with the glass surfaces at the edge of the pane.
  • Air and/or gas-tight sealing of the unit, i.e. the sealing material seals the space between the panes hermetically.

The emittance ε states the ratio of the quantity of energy emitted from a body to the quantity of energy that is emitted from a black body under the same temperature conditions.

Non-laminated glass has a normal emittance of 0.837. In the case of laminated glass surfaces, the normal emittance εn is calculated from the reflectance Rn which is measured with an infra-red spectrometer.

The effective emittance, which is necessary for the calculation of the U-value, is calculated from this normal emittance in accordance with DIN EN 673.

EN - European Norms

The exclusive right of sale for all DIN and EN norms is held by:
Beuth Verlag GmbH
10772 Berlin

Tel.: +49 (0)30 26 01 - 22 60
Fax: +49 (0)30 26 01 - 12 60

Energieeinsparverordung EnEV (German Energy Saving Ordinance

For new buildings, the EnEV limits the annual primary energy requirement Qp in kWh per m² of living space and year and the transferral heat loss H'T. For old buildings, there are U-value requirement for construction elements. Alternatively, calculations in the reference building process can be carried out as with new buildings.

In residential construction, verification is to be handled either in accordance with DIN 4108-6 in combination with DIN 4701-10, or - as an alternative option - in accordance with DIN V 18599, as already stipulated for commercial building. The verification is handled in accordance with a reference building process. In this, a building of the same size facing in the same direction is calculated with the U, g and LT values specified in the EnEV. The planned property must not exceed the H'T and QP values calculated in this way.

The verification of the annual primary energy requirement is always carried out with an energy balance, in accordance with EnEV. In this process, gains of solar energy, as are only possible with the transparent material glass, are taken into account. This can be ascertained either through direct evaluation of the solar gains or with simple calculations.

It is already now known that a further tightening of the Energy Saving Ordinance is intended in 2012. By using high-quality heat insulation glass such as UNIGLAS® | TOP with Ug values of up to 0.4 W/m²K, planners and builders will certainly also be able to fulfil these further-tightened conditions.


The EnEV represents the continuation of the Heat Insulation Ordinance (WSVO) in its 1982 and 1995 edition.  The EnEV combines the previously separate Heat Insulation Ordinance and Heating Appliances Ordinance of 1994.

Previously, the WSVO '95 related to the annual heating energy requirement. A new feature is the taking-into-account of the annual heating energy requirement and the primary energy requirement. The annual heating energy requirement additionally includes, among other things, the costs of heating up water and heat losses of the heating system. The primary energy requirement finally also takes into account the special characteristics of the primary energy source used, e.g. losses in electricity production at the power station or in the transportation and processing of crude oil and losses in conveying to the buildings.

Environmental Protection

A drastic reduction of heating energy consumption is urgently necessary in the interests of climate protection, environmental protection and the saving of our resources. That is why the field of construction plays a central role in the CO2 reduction programme of the government of the Federal Republic of Germany.

Every saving on energy renders an active contribution to protecting the environment.

As a rule of thumb, it can be assumed that, in glazing, the reduction of the Ug-value by 0.1 W/m²K leads to a saving of 1.2 l of heating oil per m² and heating period.

Because half of the buildings already have energy improvements in accordance with the Heat Insulation Ordinance of 1982, the reduction in energy consumption thereby achieved can be estimated at around 73 billion kWh per year. This is still equivalent to a quantity of 7.3 billion litres of heating oil.


Fire-Resistant Glass

is a flat glass, suitable for producing fire protection systems of the fire protection classes F and G, which fulfil all requirements made of separating walls of the corresponding fire protection classes in accordance with DIN 4102, parts 2 and 5.

Float Glass

The modern float glass manufacturing process has now replaced practically all earlier production processes for flat glass. The word “float”, when understood as meaning something like "floating on top” or "drifting”, characterises the actual principle of this procedure.

In the float procedure, an endless strip of glass from the melting tank moves on a bath of liquid tin. Floating on the surface of the molten metal, it spreads out and is kept at a sufficiently high temperature for an adequate length of time. Due to the surface tension of the glass melt and the plane surface of the tin bath, an absolutely plane-parallel glass strip forms naturally.

In the cooling channel and on the subsequent conveying path the glass cools down to room temperature so that it can be cut into plates.



The g-value is the solar heat gain coefficient of glazing for solar radiation in the wavelength range from 300 nm to 2,500 nm. The quantity is important in climate-technical calculations and is expressed as a percentage. The g-value is determined in accordance with DIN EN 410.

The g-value is composed of the direct solar energy transmission and secondary heat emission inward as a result of long-wave radiation and convection.

Gas Filling

Modern special-function insulation glass is furnished with various gas fillings in order to improve heat and noise insulation performance. Usually, this is argon, krypton or mixtures of the two. Krypton also improves sound insulation.
It is thus possible for modern UNIGLAS® insulation glass to achieve Ug values of up to 0.4 W/m²K or sound insulation values of up to Rw = 52 dB.

Glass - Definition

Glass is an inorganic product of fusion. It solidifies largely without crystallising. Glass is a "tough (undercooled) liquid".

Glass Edges

Open glass edges in laminated safety glass:
The polyvinyl butyral films (PVB films) used in laminated safety glass are hygroscopic. At weathered edges and/or at all points at which air moisture and water vapour come into contact with the films, the water absorption of the film can cause detaching and visible drooping of the film or minimal de-lamination, which are made visible by small blisters.

Greenhouse Effect

Around 50 % of the infamous greenhouse effect is due to CO2. Due to globally increasing CO2 emissions, the concentration in the atmosphere is inevitably increasing. This is leading to a global increase in the temperature. The consequences may be the rising of the sea level and a shifting of the climate zones. 97 % of CO2 emissions in Germany occur due to the burning of fossil fuels, such as coal and brown coal, crude oil and petroleum gas.

The targets set for climate protection only have a chance of being achieved, however, if the right additional energy and environmental policy measures are taken quickly.

Heating energy consumption values of less than 50 kWh/m²a are already realisable with the heat insulation technologies already available on the market, especially for windows and glazing. This means a reduction of more than 80 % compared with the average consumption.

A window glazed with UNIGLAS® | TOP 1.1 (Ug-value 1.1 W/m²K), with a life cycle of almost 30 years, means a reduction of around 1.2 t CO2 per m².


Hard Glass

Chemically and thermally resistant laboratory glass with high softening temperatures, a coefficient of linear thermal expansion under 6 - 10-6 K-1; not to be confused with toughened safety glass.


In each case, in testing resistance against the penetration of a harder body of two different materials, only one material scratches the other. A diamond scratches a sapphire, but not the reverse. A range of scratch resistance is the Mohs scale of hardness in ten levels from talc = 1 to diamond = 10. Window glass has the equivalent hardness of 5.5.

Heat Insulation Glass

see also Insulation Glass.

Heat-Soak Test

Due to unavoidable inclusion of nickel sulphide in a pane of glass, the volume of nickel sulphide is raised by increases in temperature. This disturbs the internal stress balance of the pane of toughened safety glass. This change in volume causes spontaneous cracking, which can lead to the destruction of the pane.

In order to be able to largely avoid spontaneous cracking in installed glazing, TSG panes can be subjected to the HS test. For this, the panes are subjected to a heat-soak test for a holding time of 2 to 4 hours at an average oven temperature of 290°C.

According to DIN EN 14179, TSG panes must be subjected to a heat-soak test when the TSG is to be used as rear ventilated siding for an external wall. In this procedure, any possible spontaneous cracking is deliberately brought about by heating the pane up to 290°C for a holding time of 2 hours.

In Germany, the heat-soak test is regulated by the building authorities in addition to the standardisation. The heat-soak for a TSG-H must take place in a calibrated and externally monitored oven. The holding time is extended to 4 hours.

Heat-Strengthened Glass (HSG)

Due to heat-strengthening, the glass receives a higher mechanical resistance to pressure and impact than a technically cooled glass (normal float glass). The temperature-resistance is also much higher than that of normal glass.


Insulation Glass

Insulation glass has been around for about 60 years. The oldest patent on this subject is even from the year 1865.

The official definition of the term insulation glass is set out in DIN EN 1279:

Multi-pane insulation glass is a glazing unit, manufactured from one or more panes of glass (window glass, mirror glass, cast glass, flat glass), which are separated from each other by one or more spaces between the panes, filled with air and/or gas. The panes are joined at the edges by organic sealing compounds, soldering or heat sealing, so that they are gas or moisture-tight.

There is no vacuum in the enclosed space between the panes, as is often incorrectly assumed, but instead dried air or special gas. A vacuum is impossible for static reasons.

Insulation Glass Effect

The edge seal of insulation glass encloses a volume of air/gas, the state of which is essentially determined by the barometric air pressure, the height of the production site above sea-level and the air temperature at the time and place of manufacture. The installation of insulation glass at different heights, with changes in temperature and fluctuations of the barometric air pressure (high and low pressure) inevitably causes concave and convex bending of the individual panes and thereby optical distortions.

Multiple reflections can also occur to varying degrees on surfaces of insulation glass.

These reflections can be more noticeable if e.g. the background of the glazing is dark or if the panes are laminated.

This phenomenon is inherent in all insulation glass units, due to the laws of physics. (An insulation glass unit acts like a big barometer capsule.)

Interference Phenomena

In certain light conditions, the optimal plane parallelism of panes of float glass can lead to physically-caused optical phenomena.

These become noticeable as rainbow-coloured patches, strips and rings, which alter their position with pressure on the pane.

Interferences are purely physically-caused refraction and superimposition phenomena. They only occur in cases in which two or more panes of float glass are arranged one behind the other.

These interferences are thus phenomena that are to be regarded as the manifestation of excellent float glass quality.


Kelvin (K)

The Kelvin is the unit of thermodynamic temperature above absolute zero (-273.15°C) and also the unit for temperature difference. The temperature difference of 1 degree Kelvin corresponds to 1 degree Celsius.


Laminated Insulation Glass

Colour-neutral insulation glass was introduced onto the market at the beginning of the 80s. In order to combine the transparency of the glass with the outstanding emission characteristics of noble metals, thin layers of metal are applied to the glass.

Laminated insulation glass is understood as referring to a pane of float glass provided with a wafer-thin (approx. 10 µm thick) functional layer. Due to the very thin coating of metal, the material can be permeated by the sun but the emittance of the glass surface is reduced.

Genuinely neutral heat function layers with low emittances (εn = 0.01) can be manufactured, which ensure a Ug value of 1.0 W/m²K in standard construction with argon filling.

An extensive range of products can be produced from the base glass coated in this way. These types of heat-insulating glass are marketed under the product names of UNIGLAS® | TOP. Combinations with sound-insulation (UNIGLAS® | PHON) or security properties are also possible.

Laminated Safety Glass LSG

In the manufacturing of LSG from polyvinyl butyral (PVB), two or more panes of glass lying one over the other are joined firmly to each other using one or more highly-elastic films.

Laminated safety glass is a splinter-binding glass. This means that when a pane of LSG breaks the fragments stick to the film. This way, almost no sharp-edged glass shards are released. The risk of injury is minimised.

A fundamental distinction is made between laminated glass with a casting resin filling and laminated glass with intermediate layers of film. In addition, the casting resin or viscoplastic film makes the whole glass element more difficult to penetrate, so that active security is also substantially increased (break-in to bullet-resistant, depending on structure).


Low-E glasses are laminated heat insulation glasses. The structure of these function layers, their technical values and their visual characteristics can vary depending on the type of coating; these are divided into "hard coatings" and "soft coatings".

Hard Coatings refers to pyrolytically applied layers of tin-oxide with or without an under-layer based upon silicon oxide.

Soft Coatings are sputtered coatings that sometimes consist of five layers placed one on top of the other.

Low-Energy Houses

In order to fully exploit the potential for protection of the environment in building heating, the heat insulation of the building must be drastically improved, beyond the extent demanded by the new EnEV.

The term low-energy houses refers to buildings that – relating to heated living space and/or usable area – have an energy consumption of less than 50 kWh/m²a.

UNIGLAS® offers especially suitable products for low-energy houses under the name UNIGLAS® | TOP.


Multi-Pane Insulation Glass

Glazing unit; manufactured from two or several panes of glass that are separated by one or more air and/or gas-filled spaces in between. The panes are joined at the edges with organic sealing compounds, so that they are gas and moisture-tight. Multi-pane insulation glass provides a high level of heat insulation and/or sound insulation, depending on the construction.

Multifunction Glass

By using various basic products and different special gas fillings, it is now possible to manufacture individually suitable, property-specific multi-function glazing. It is in the nature of these glasses that there cannot be a “standard multifunction glass”, as after all the range comprises such various basic functions as

  • heat protection
  • sun protection
  • security
  • sound protection
  • break-in protection
  • design etc.

For example, UNIGLAS® offers a multifunction glass under the name UNIGLAS® | PHON 28/37 1.1 A3 that offers substantially improved sound protection as well as a high level of heat insulation and in addition safety characteristics in accordance with safety class P4A.

Muntin Insulation Glass

Different muntin systems in attractive colours, various widths and designs are available to builders and planners for a wide variety of applications, such as e.g. the renovation of old buildings or the external construction of cottages.

The harmony of the external overall impression of a house or building depends here not only on the window itself, but instead primarily on its division and framing.

Visibly Installed Muntins
In the case of visibly installed muntins, a powder-coated aluminium muntin is built into the space between panes, looking like a genuine, hand-made muntin.

Covered Muntins
In appearance, this muntin system corresponds to a genuine muntin window made by hand in the conventional way. The insulation glass element fills the entire window sash. Only later are the wood, aluminium or plastic muntin strips made by the window manufacturer firmly attached to the pane surface and sealed on both sides.


Natural Colour

All of the materials used in the manufacture of glass products have their own natural colour due to their raw materials, which can become more obvious with increasing thickness. Laminated glass is used in order to meet the legal requirements regarding saving energy. Laminated glasses also have their own natural colour. This natural colour can be noticeable when looking at or through the glass, to varying degrees. Variations in the colour impression may occur due to the iron oxide content of the glass, the lamination process, the coating or changes in the glass thickness and the pane structure, and cannot be prevented.

Noise Control Glass

see also Sound Protection Glass and/or Sound Protection Insulation Glass.


Ornamental Glass

Cast glass manufactured in a machine-rolling process. It can be produced colourless or coloured, with or without embedded wire netting, with a structured surface on one or both sides. It is light-permeable but only transparent to a reduced degree.

Overhead Glazing

At present, there are no specific standards for overhead glazing in Germany. The federal states have introduced the "Technische Regeln für die Verwendung von linienförmig gelagerten Überkopfverglasungen" (technical provisions for linearly supported overhead glazing), issued by the DIBT, as a temporary measure through the building authorities. If these rules are adhered to in the planning and realisation of overhead glazing, approval in individual cases may no longer be necessary.


A series of oxides of calcium, magnesium, aluminium and zinc, used as admixtures in the glass melt, lend the glass physical and chemical characteristics.


P-Value (Ψ)

Rating of the glass edge zone

The new Ψ-value (PSI) takes into account the increased passage of heat through the edge seal of the insulation glass and the glazing rebate area of the window frame.

The Ψ-values are here dependent on the choice of the spacer material, depth of the glass rebate, profile geometry and frame material used.

UNIGLAS® has long since recognised this situation and offers the UNIGLAS® | TS Thermo-Spacer as a thermally improved edge seal system.

The substantially better Ψ-value:            W/m²K
(e.g. in a conventional wood or plastic window)
Conventional aluminium spacers     =     0.07-0.08
UNIGLAS® | TS Thermo-Spacer      =     0.04-0.05

This substantially increases the surface temperatures in this critical area and has a positive effect on the thermal characteristics of the window element.

Passive House

The special thing about a passive house is that the heat requirement is reduced so much by the extremely high quality of the building shell and utilities management, that – in addition to highly efficient heat recovery by means of a convenient ventilation system – the "free" amounts of energy from

  • received solar energy,
  • body heat of the people in the house and
  • heat given off by machines

are enough to keep the building pleasantly warm. The slight remaining heating requirement can be covered by slight post-heating of supply air or by stored solar heat.

The following, essential features of a passive house are sufficient for achieving the passive house standard:

  • Passive houses are "super-insulated" with extremely low heat transmission coefficient for all external elements (roof, wall, cellar roof and/or floor section). The insulation thicknesses are between 25 and 40 cm and are free of thermal bridges and airtight.
  • Triple glazing with two coatings ensure passive gains in solar energy which exceed heat loss even in the winter months.
  • Comfort ventilation with heat recovery recovers 80% of the heat from the used air and at the same time always ensures fresh air throughout the house.

In comparison to normal houses, which not infrequently require up to 400 kWh thermal heat per square metre of living space, or even modern low-energy houses with a requirement of less than 70 kWh/(m²a), the additional thermal heat requirement for a passive house comes to a maximum of 15 kWh/(m²a). Because the installation of a conventional heating system is not necessary in a passive house, the higher building costs incurred for the special heat insulation, ventilation system and use of solar heat are partially balanced out. The initial additional investment also pays for itself over the years due to the savings on heating costs. At the same time, pollution is reduced.

The passive house is a consistent further development of the low-energy house and offers cheap, environmentally-friendly and comfortable housing.

Penetration-Resistant Glazing

Glazing is divided into three protection classes against penetration in accordance with part B of DIN EN 356: P6B up to P8B with an increasing degree of security. The suitability test is carried out with a mechanically-guided 2 kg axe. In this test, the number of blows is ascertained that is necessary to break a 400 mm x 400 mm opening in the test piece (110 cm x 90 cm).

DIN EN 356 part B requires a minimum of 30 to 50 blows before this opening is achieved for glazing in the group P6B, 51 to 70 blows are required for the group P7B and over 70 blows for the group P8B.

Penetration-resistant glazing is offered by UNIGLAS® under the brand name UNIGLAS® | SAFE.


Photovoltaic is the direct conversion of sunlight into electrical energy by means of solar cells.
The conversion effect is based upon the photoelectric effect already discovered by Alexander Bequerel in 1839.
The term photoelectric effect refers to the releasing of positive and negative charge carriers in a solid body by light irradiation.
If the sun shines on the cell, a direct current voltage builds up between the facing and reverse side. So-called contact fingers collect this energy and convey the electricity out of the cell.

Quality Tested by UNIGLAS® and Certified

Modules tested and externally monitored:

  • ISPRA certificate and TÜV
  • Safety P4A (A3) DIN EN 356
  • Module made of TSG 6mm in accordance with DIN 1249
  • Cable compatibility test with different sealing materials for the edge seals of insulation glasses.

Insulation Glass Tested and Externally Monitored:

  • System test in accordance with DIN EN 1279 part 2 and part 3
  • TSG in accordance with EN 12150 with heat-insulating layer of noble metal
  • Safety P4A (A3) DIN EN 356
  • Fogging test of the insulation glass unit

UNIGLAS® offers you a complete service. Starting with the planning and calculation to the installation and/or commissioning. Our trained solar technicians will provide you with comprehensive information.

Polyisobutylene (Butyl)

Permanently elastic sealing material with which the spacer of an insulation glass unit is covered so that no water vapour can penetrate.

Polysulfide (Thiokol)

Permanently elastic sealing material with which the hollow space above the spacer in an insulation glass unit is sealed.

Polyvinyl Butyral (PVB)

Viscoplastic and highly tear-resistant film that joins two or more panes of glass together to form a laminated safety glass unit.

Pressure Compensation

During production, insulation glass is sealed at the respective prevailing air pressure. The air pressure of the surroundings alters at different heights and/or with different weather conditions. Then, for example, the external air pressure is lower than the one in the space between the panes of the insulation glazing. This leads to the bulging of the panes and to overstraining of the insulation glass element. Pressure compensation measures can be necessary if insulation glass is to be installed at and/or transported to locations more than 600 m higher than the place of manufacture.



The needs of the consumer, the harmonisation of the European internal market and the high requirements in Switzerland, Austria and Germany are increasingly focussing on product quality.

For the members of UNIGLAS®, quality is not just the fulfilment of the agreed and promised quality requirements, but also the meeting of our own, sometimes substantially higher quality standards. In addition to pure product quality, requirements such as particularly exact adherence to promised delivery times and complete delivery have become more and more important. The members of UNIGLAS® make every effort to satisfy customers and partners.


Rated Sound Reduction Index

The rated sound insulation index Rw, in accordance with DIN 52210 and/or DIN EN ISO 717, is used when calculating the sound insulation of glazing. It is calculated by measuring and comparing with the reference curve and is expressed in decibels.

Based on the logarithmic standard, an improvement in sound insulation of 10 dB halves the noise pollution.


Describes the amount of radiation that is reflected when striking the glass (see Absorption and Transmittance).


Security Glass

Particularly break-in-resistant glass and/or insulation glass for windows and doors, which provides additional protection with other glass combinations.

See also Laminated Safety Glass (LSG) and Break-In-Resistant Glazing

Selectivity Coefficient S

The selectivity coefficient S identifies the ratio of transmittance to the solar heat gain coefficient (g).

The coefficient S rates sun protection glasses in relation to a (desired) high transmittance in proportion to the respective low total thermal conductivity been striven for.

A high selectivity coefficient expresses a favourable ratio.
S ~ 2 here identifies the limits of what is physically feasible with neutral glazing products.


Silver-coating allows the manufacturing of colour-neutral insulation glasses. Colour neutral insulation glass was introduced onto the market at the start of the 80s. Silver-coated insulation glass is now regarded as the state of the art.

The coating system consists of metal oxides and silver. Using this, absolutely neutral heat function layers with low emittance (εn = 0,01) can be manufactured, which guarantee a Ug-value of 1.0 W/m²K in accordance with the DIN in the standard insulation glass structure with argon filling (UNIGLAS® | TOP 1,0).

With special gas fillings and triple glazing, Ug-values up to 0.4 W/m²K in accordance with DIN are possible (UNIGLAS® | TOP 0,4).

Solar Energy Utilisation

Glass is the only construction material that allows the use of free solar energy. The new EnEV also takes this into account with the introduction of the so-called solar gains.

Because, however, no or only insufficient amounts of solar radiation occur in particular when the need would be greatest, which is to say in the evening, in the transition period and in the winter months, the heat insulation of the glazing element (U-value) continues to be extremely important.

A low U-value means that the expensive-to-produce heat energy stays in the room.

Sound Protection

Sound protection largely depends on the whole element, i.e. window frame, sealing of joins, contact with the structure, sound insulation pane.

Sound Protection Insulation Glass

The members of UNIGLAS® market sound protection insulation glasses under the brand name UNIGLAS® | PHON. Because the requirements of the EnEV normally also require improved heat insulation as well as increased sound reduction, however, the modern UNIGLAS® | PHON types also have low Ug-values at the same time.

The sound-absorbing properties of insulation glass are achieved primarily by means of three characteristic features:

  • larger space between panes,
  • asymmetric glazing structure and
  • if necessary, use of special panes of laminated glass.

The members of UNIGLAS® offer a wide range of products, individually adapted to the appropriate requirements. Sound insulation values thus vary from Rw = 36 dB up to Rw  = 54 dB. The corresponding Ug-values according to DIN range from 1.2 W/m²K down to 0.4 W/m²K. UNIGLAS® possesses test certificates from recognised testing institutes for all UNIGLAS® | PHON types.

Sound-Reduction Index Rw

The rated sound reduction index Rw is used for assessing the sonic properties of glazing, in accordance with DIN 52210 and/or DIN EN ISO 717, and is determined by measurements and comparison with the reference curve. It is expressed in decibels.

Based on the logarithmic scale, an improvement of 10 dB in the sound reduction causes the noise pollution to be halved.

Space Between Panes

The space between two panes of float glass separated from each other. The space between panes is filled with air or with noble gases such as e.g. argon or krypton, depending on the Ug-value.


UNIGLAS® insulation glass products generally consist of two panes of float glass separated from each other by a dried and hermetically sealed space between the panes. For this purpose, the two panes are kept the desired distance from each other by means of a spacer. The spacers can be made of aluminium, galvanised steel, stainless steel or plastic (s. also "warm edge").

Sun Protection Insulation Glass

Large glass areas normally lead to high air-conditioning costs in the summer. The cooling costs can be up to four times as much as the heating costs in winter. This is why sun-protection glazing is used in the architecture of large buildings, where air-conditioning systems are used and also in large-area glazing in private apartment construction.

The product range of UNIGLAS® in the field of sun protection is marketed under the brand name UNIGLAS® | SUN. Types designed with deliberate use of colour are also possible, as well as neutral products for façade constructions facing in or out.

The members of UNIGLAS® also offer sun protection glazing that simultaneously combine high transmittance and a low energy transmission (g-value).

In all UNIGLAS® | SUN types, a low thermal transmittance value (Ug-value from 0.5 to a maximum of 1.2 W/m²K) ensures high heat insulation in winter.


Tenders (Texts of Tenders)

UNIGLAS® provides fully pre-formulated texts of tenders, for architects, planners and glass processors, as a special service. These can be accessed under “Services”.


The insulation glass of the 70s, without special characteristics.

see also Insulation Glass


Permanently elastic secondary sealing material; normally used to fill the empty space above the spacer of an insulation glass unit up to the edge of the pane.

Three-Litre Houses = Ultra-Low-Energy Houses

The term 3-litre houses is used to refer to buildings that have an annual primary energy requirement of a maximum of 34 kWh per m² of usable area for the heating of the building; this corresponds to the primary energy content of 3 litres of light heating oil. The calculation of the primary energy requirement must be carried out in accordance with the harmonised European standards and the respective current Energieeinsparverordnung (EnEV, German Energy Saving Ordinance). The calculation value includes the fuel requirement for heating purposes and the required operating energy. A single-family house built today along conventional lines has a heating energy requirement about 3 times as high, at approx. 80 kWh per m².


The transmittance states the visible portion of radiation directly let through, in the range of the wavelengths of visible light from 380 nm to 780 nm, based on the sensitivity to light of the human eye. The transmittance is stated as a percentage and is influenced by the thickness of the glass, among other things. Slight fluctuations are possible due to the varying iron oxide content of the glass. As a single pane, float glass has a transmittance of 90% in the visible range.

Normal, non-laminated insulation glass, consisting of two panes of float glass, possesses a transmittance of approx. 80%.

The latest heat insulation glass UNITOP from UNIGLAS® | TOP Premium possesses e.g. a transmittance of over 80%, which is like that of insulation glass without a function layer.

The reference quantity of 100% is an unglazed opening in a wall.


Property of the glass of allowing through rays over a wide wavelength range. It describes the amount of radiation allowed through upon striking the glass.

TSG Toughened Safety Glass

TSG is a thermally pre-stressed glass. The pre-stressing is achieved by heat treatment of the glass. The manufacturing process of TSG consists of the rapid and even heating of a pane of glass to above 600°C and subsequent swift cooling-off (chilling) by being blown with cold air. The characteristic stress distribution in toughened safety glass has the effect that the outer areas up to the core are under compression stress, but the actual core of the glass is under tensile stress. The two stresses must be in balance with each other, because only then can the stable stress state be achieved that ensures the safety characteristics of TSG.

TSG provides increased protection against injury, because in the event that it is destroyed, a close meshed lattice of small, mostly blunt-edged glass is produced and no sharp-edged glass shards.

In addition to this safety feature, TSG is distinguished by further advantages:

  • Increased bending tensile strength: calculation value 50 N/mm² compared with a calculation value of 30 N/mm² for float glass
  • Increased shock and impact strength in accordance with DIN EN 12600 (pendulum impact test)
  • Resistance to temperature differences over the pane area 150 K in TSG, 40 K in float glass.



Ü Symbol (Compliance Mark)

Since the 1st January 1996, the only building products, including glass, which may be used in Germany are those that are published in the construction regulations list of the German Institute for Construction Technology (DIBT) and conform to the rules contained in it. As proof of this, a compliance symbol (Ü symbol) in accordance with the Compliance Symbol Ordinance and/or a CE mark must be applied to either the construction product itself, the packaging or, if neither is possible, the delivery note. Compliance with the technical rules is tested in different ways, depending on the building product. Three compliance certificates are stipulated:

ÜH   = declaration of conformity of the manufacturer
ÜHP = declaration of conformity of the manufacturer after prior testing of the construction product by a recognised testing body
ÜZ   = certificate of compliance from a recognised certification body



The thermal transmission coefficient (U-value) states the quantity of heat that passes through 1 m² of a building element per unit of time, with a temperature difference between the air in the room and the air outside of 1 K. The smaller the U-value, the greater the heat insulation is. The unit of measurement is W/m²K. The test standard of the U-value for glazing (Ug) is DIN EN 674. The thermal resistance is measured with the hot plate method in accordance with DIN EN 674 in the centre of the pane.



Verein Deutscher Ingenieure (Association of German Engineers), Düsseldorf

Vehicle Glass

is the generic term for the group of types of glass used in vehicle construction, such as e.g. laminated safety glass or toughened safety glass.


Warm Edge

If a thermally improved spacer is used in the production of insulation glass, then one speaks of the "warm edge":

Advantages of the warm edge are:

  • reduction of the heating losses
  • increasing of the surface temperature and reduction of condensation formation
  • improvement of the room climate
  • saving energy – conserving resources


Window Glass

Glazing unit of two or more panes of glass, depending on application, for heat insulation, sun protection and sound insulation and protection against break-in in all kinds of windows.