Glossary – our knowledge from A to Z

This is a body-tinted, light-permeable glass. Mostly supplied in the form of small slabs with an irregular surface.

A special type of true antique glass. It has a very streaky surface with incisions, scratches and air bubbles. (Danzig is the German name for the Polish city of Gdańsk.)

Sound pressure weighted according to frequency in line with weighting curve A (DIN 45633). This curve takes into account the fact that the perceived loudness depends on the frequency (pitch). Also used as a unit of measurement for sound level. Corresponds roughly to the phon value at 1000 Hz.

Delivery duty paid: the seller is responsible for making the goods available to the buyer at a named destination and also responsible for all import customs formalities and duty and for final delivery of the goods to the buyer at the destination.

Delivery duty unpaid: the seller is responsible for making the goods available to the buyer at a named destination but not cleared for import. The seller is also responsible for all costs involved in delivering the goods to the destination. The seller’s risk does not end until the goods reach the destination.

The effective weight acting on a building component due to the total mass of the building materials and any stored materials.

As even tiny impurities in the raw materials can cause undesirable discolouration of the glass, the glass can be either chemically or physically decolourised.

Ornamental fittings made up of straps, strips and rosettes that look like metal fittings held in place by rivets. These are decorative items without any technical function.

A deflection limit guarantees the serviceability of a design. Loads acting on toughened glasses can cause very large deformations. These must be kept within reasonable limits. The deflection limit can also apply to the supporting construction in order to guarantee the durability of insulating glass, for instance.

The process of removing the glass from its frame or supporting construction, a process that can be made easier, for example, by using glazing beads that are merely clipped in place.

This specifies the percentage of visible light that is reflected from the surface of a pane of glass.

The layer-by-layer breakdown in a laminated material composite, e.g. a PVB sheet becoming detached from the surface of the glass. In glass construction the main reason for delamination is incompatibility between the plasticisers in silicones and PVB sheets.

Concrete with a density of 2.8–4.5 kg/dm³. Dense concrete is a mix of cement, aggregates and water.

This is the mass of a body related to its volume.

The ratio of the mass of a body to its volume. This is specified, for example, in g/cm3 or kg/l. Considered as a descriptive term, it describes whether the body, for its weight, is as “light as a feather” or as “heavy as lead”.

The removal of mill scale (caused by rolling or annealing). Descaling can be carried out by mechanical, chemical or electrochemical means.

A test that generally results in the destruction of the material. It is used to identify internal or external irregularities or to estimate mechanical or metallurgical properties by means of mechanical effects.

This is the national standardisation organisation for Germany and represents German interests in European and international standardisation work. The task of the organisation is to define standardisation efficiently, and to prepare standards as a service for industry, state and society.

The temperature at which water vapour in the air condenses on a building component. In its roof and façade designs, seele makes sure that the dew point lies in a layer that is ventilated by the outside air so that any condensation that might form dries out again and does not cause any damage.

The external temperature at which condensation forms on the inside face of a window pane can be determined from this diagram depending on the relative humidity of the air and the U-value of the glazing.

The temperature at which water vapour changes to liquid form in the form of fine droplets. The higher the humidity of the air, the higher is the dew point temperature.

Deutsche Gesellschaft für nachhaltiges Bauen (German Sustainable Building Council). The task of the DGNB is to determine and promote measures and solutions for designing, constructing and using buildings in order to realise the aims of sustainable building. The DGNB awards a certificate for buildings certified as sustainable.

Deutsche Gesellschaft für Qualität e.V. (German Society for Quality)

Double glazing unit, i.e. insulating glass.

Deutsches Institut für Bautechnik (German Institute of Building Technology). The DIBt is the only German approval body for construction products and forms of construction.

A glass product with a coating of thin layers of metal oxides with different light refraction characteristics which form a system of interference layers so that light is split into its spectral colours. These coloured effects vary depending on the sunlight, viewing angle and background.

This type of elevating platform is characterised by its good operation on different terrains, especially loose, unstable surfaces. All-wheel drive and the option of using outriggers to compensate for uneven ground make such lifts ideal for outdoor uses.

This is a special epicyclic or planetary gear, e.g. between the driven wheels of a vehicle. As the wheels on one axle travel different distances when traversing a curve, this difference may not become excessive in the case of rigidly coupled wheels.

The process of mixing together two substances with different chemical properties. In construction this term is used for an exchange process, especially for water vapour being exchanged between the air and the surface of a wall or a porous material.

German standard currently in preparation that will cover the use of glass in building. It is intended to bring together and replace the existing regulations (TRLV, TRAV, TRPV) and add further new ones. But the standardisation work cannot keep pace with the rapid developments in glass design, which is why Individual Approvals are necessary again and again.

This German standard regulates the estimation of costs in construction, especially for building and civil engineering works. It defines the procedure for estimating costs and is divided into five stages: cost framework, cost estimate, cost calculation, cost quotation and cost determination. The corresponding standard in Austria is ÖNORM B 1801-1.

Also known as sponge iron. The reduction of iron ore in the solid state produces a sponge-like product with a large pore volume which contains small amounts of oxygen and slag. Direct reduced iron is further processed in an electric arc furnace or can be used in powder metallurgy.

A glass defect that results from impurities in the raw materials. Even the tiniest impurities can lead to undesirable colour casts. The glass can be decolourised in order to overcome discolouration. We distinguish here between chemical and physical decolourisation.

This is the clear internal distance between the flanges of a steel I-section. German HEA, HEB and HEM sections with the same section number have the same distance between flanges, which results in advantages for design and construction.

A dome is a hemispherical or similarly shaped roof over a building or part thereof. The glazed dome on top of Germany’s parliament building in Berlin, the “Reichstag”, is one prominent example.

A door is boundary component between rooms or between interior and exterior which still permits the passage of persons or goods. Doors can be locked to prevent the entry of unauthorised persons. Doors also perform other functions such as thermal and sound insulation and can also be designed to prevent the spread of fire or smoke or the passage of radiation.

A device for closing a door slowly, in some cases also locking it again. Special types of door closer enable the door to be held open at a certain position and also ensure that double-leaf doors close in the right sequence.

At an opening angle of about 70–120°, a valve reduces the closing speed in order to give disabled persons or those with bulky loads enough time to pass through the door. From about 70° onwards, the door returns to the preset closing speed.

A module in an automatic door mechanism for ensuring that the meeting stiles of a double door close in the right sequence. This prevents jamming of the door leaves.

A piece of door hardware used for opening and/or unlocking a door.

This is a piece of door hardware used for opening and/or unlocking a door.

A horizontal or vertical rigid bar fitted to a door. Length, diameter, fixings and surface finish can be adjusted to suit the customer’s specification.

A rooftop structure that projects above a sloping roof surface and is usually finished with the same roof covering as the rest of the roof. Dormers permit the inclusion of vertical windows for rooms in the roof space.

A type of edge working with two different chamfer angles along the edge of the glass.

In this type of double door the two side-hung leaves close against one another in the middle (there is no central mullion). Such double doors for traffic in both directions are frequently designed for right-hand traffic, with one leaf opening inwards, the other outwards.

Also known as double-skin façade. This is an additional transparent single-glazed glass envelope erected in front of an existing façade. The new outer leaf protects the building behind against wind, weather and overheating in the summer.

An old designation for glass 4 mm thick.

An interim development between single glazing and insulating glass. The volume of air trapped between the two single-glazed windows functions as an additional layer of thermal insulation.

A façade with inner and outer leaves. The cavity between the two provides protection against the weather and solar radiation and ensures ventilation; if wide enough it can also be used for maintenance and as an escape route. Also referred to as a double-skin façade.

An adhesive tape with adhesive on both sides which is used in assembly and erection.

This is a double-leaf façade open to the outside. The sunshade in the cavity is protected by the outer leaf. Opening lights in the inner leaf enable the interior to be naturally ventilated.

This is a horizontal loadbearing member that projects below a suspended floor and transfers the loads to columns, walls or other loadbearing elements.

A presentation and visualisation of a project in the form of graphics, drawings and models which is used for checking and if necessary improving the quality, functions, etc., but also for detecting possible flaws in the design.

This is the collection and non-pressurised removal of rainwater, surface water or groundwater.

A grease, oil, soap or coating used to improve the surface properties of a workpiece and prevent tool wear.

A type of glass produced according to an industrial method employing electrical melting and mechanical, vertical drawing. Drawn glasses are fire-polished on both sides during the production process.

This is a standard process in the working of glass. A hole is drilled, or rather ground, in the glass with the help of special carbide-tipped drills or diamond-tipped crown drills. There is always a wasted disc of glass in the case of large diameters.

It is possible to drill a hole of any diameter in glass, but the usual diameters are 4–6 mm. Drilled holes can be ground and polished internally for special applications. Minimum spacings and edge distances must be adhered to for safety and security glasses.

The ability of a window or façade construction to resist the infiltration of rainwater. DIN EN 12208 provides a resistance classification.

The sealing of windows and façades by means of preformed elastic gaskets to prevent the passage of air and water.

Dry lining techniques do not use any building materials that contain water, e.g. concrete, plaster, for constructing components. Therefore, no drying times are necessary. All dry lining trades can follow each other in direct succession.

Effective and permanent sealing of insulating glass by providing a primary polyisobutylene seal and a secondary seal of polysulphide, polyurethane or silicone.

The capacity of a material to deform under load and dissipate stress peaks through yielding. Glass is not a ductile material. Local stress peaks, e.g. around drilled holes, are relevant for the design of the entire piece of glass.

Existing conventional flat roofs can be refurbished by improving the waterproofing and adding a second layer of thermal insulation made from extruded polystyrene (inverted roof) to the existing roof finishes.

The duopitch roof is the most common roof form in cold and temperate climate zones. It consists of two surfaces that slope downwards either side of the highest, horizontal edge, the ridge. Also known as gable roof.

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