Glossary – our knowledge from A to Z

A large hot-rolled steel section with wide or very wide flanges.

Such a test specimen is used to assess the curing, adhesion and strength of an adhesive used in a structural glazing façade, for instance. The test should be carried out at least once for every combination of catalyst and base used. A new test is required every time a new container is opened.

A miniscule crack in a glass surface that is hardly perceivable and only becomes visible in a glancing light.

This is used to attach loads to reinforced concrete components. The channel is placed in the formwork prior to concreting and then cast in permanently. Such channels must be planned at an early stage so that they are delivered to the building site in good time. The channel has a C-shaped cross-section and anchors on the back to secure it in the concrete.

At the end of the 19th century the American chemist Charles Martin Hall and the French scientist Paul Héroult both independently developed a method of electrolysis for producing aluminium. In this method aluminium is obtained from aluminium oxide by means of an electrolytic smelting process. Carl Josef Bayer improved the method.

A small-size specimen of a coating, section, glass, hardware or other item for the client and/or architect. Produced in a handy size, usually A4 or A3. Such samples are usually required for approvals.

The handrail to a balustrade finishes off the top of the infill panel and is primarily fitted for safety reasons. Adjacent to a stair a handrail must be at least 900 mm above a line joining the nosings of the treads and there must be a clear distance of 40 mm between the handrail and any wall behind so that it is possible to grip the handrail properly.

Chemically resistant and thermally stable apparatus glass with a high glass transition temperature and a coefficient of thermal expansion < 6 x 106 1/K.

This is a test method for assessing the strength of glazing when subjected to the impact of a body with a relatively low mass (normally a steel ball) but high velocity. This test can be carried out, for example, on overhead glazing in order to simulate the impact of a falling object such as a tool.

Hard coating is a method of coating that is carried out directly during the manufacture of float glass, with the coating substance being applied and fired while the surface of the glass is still fluid. The ensuing hard surface is resistant to the effects of chemicals and abrasion.

This process involves heating a material to the hardening temperature (also known as austenising) followed by cooling at such a speed that a considerable increase in hardness occurs, either superficial or radical, due to martensite formation. Hardening of steels is a very common heat treatment method.

A heat treatment method comprising hardening, quenching and subsequent reheating (tempering). Water, oil or air can be used as the quenching medium following hardening.

This process increases the mechanical resistance of the steel through the specific alteration and modification of its microstructure. It can be achieved by way of heating with subsequent rapid cooling. If a metal is plastically deformed, dislocations spread throughout the workpiece.

A material’s resistance to deformation. The hardness of a material enables us to surmise its strength. Various hardness test methods can be used to determine the hardness of a material.

A European standard (EN) that has been drawn up on behalf of the European Commission and the EFTA secretariat in order to support the essential requirements of a European directive.

Designation for a German wide-flange I-beam with parallel flanges.

This is a form of energy produced through the conversion of other forms of energy. When a hot and a cooler body come into contact, the quantity of energy that flows from the former to the latter is known as heat. This increases the internal energy of the cooler body. Mechanical work too – not only heat – can increase the internal energy of a body.

This is a term from thermodynamics and designates the capacity of a body to store energy in the form of heat. It is generally represented by the symbol C. By definition, C specifies the quantity of heat Q (in joules).

This is the exchange of thermal energy between neighbouring particles or layers of a building component. Heat conduction depends on the thermal conductivity. The lower the thermal conductivity, the better is the insulating effect.

This is the thermal energy (measured in watts) that passes through a certain area of a certain material with a certain thickness.

This is the energy required to transform a material specimen from the solid state to the liquid state. In doing so, the bonding forces between the molecules or atoms are overcome without increasing their kinetic energy and hence their temperature.

There are three forms of heat transfer: conduction, convection and radiation.

Glass ceramics with a slightly yellowish colouring. Normally used in stoves or as a spark guard in front of an open fireplace. This type of glass can normally resist temperatures up to 700°C.

An additional thermal treatment for toughened safety glass following the toughening process itself. The aim of this test is to reduce the risk of spontaneous failure of the glass due to nickel sulphide inclusions.

This is a monolithic safety glass with a very high quality. Following the toughening process, the toughened safety glass is subjected to a special heat-soak test, which involves storing the glass for at least four hours at a temperature of 290°C.

This is a type of glass that has been subjected to a thermal treatment. The bending strength of heat-strengthened glass lies between that of float glass and toughened safety glass.

As a rule, a heated façade comprises hollow sections that in addition to carrying the loads are also filled with water, not unlike a standard radiator, as a heat transfer fluid. The advantages of a heated façade are the even emissions of thermal energy and the decrease in the zones of cold air adjacent to the façade.

A further development of laminated safety glass. It is heated by virtually invisible electrical wires. Depending on requirements, two or more panes of float glass are bonded together with PVB sheets.

Individual or combined plates of any steel grade rolled on a four-high mill – the opposite of continuously rolled steel strip.

Sheet steel with a thickness of 3 mm and more. Heavy sheet steel can be supplied in practically all unalloyed and alloyed steel grades.

A very common mineral from the mineral class of the oxides (and hydroxides) and a modified form of iron (III) oxide with the chemical formula Fe2O3.

In insulating glass units the cavity between the panes is maintained by a peripheral, sealed spacer, the hermetic edge seal. The edge seal generally consists of a spacer profile made from aluminium, stainless steel or plastic which is bonded to the glass with a polyisobutylene adhesive.

A type of steel that exhibits good mechanical properties (creep limit, creep strength, relaxation resistance) at temperatures up to about 540°C when subjected to long-term loading. (For higher thermal stresses: elevated-temperature steel, heat-resistant steel.) Typical applications: seamless steel pipes, boiler pipes.

Panes of float glass have been finished with light-permeable, heat-reflecting coatings for many years. The high-vacuum sputtering method is now firmly established worldwide. The coatings consist of several layers of metals and metal oxides ranging in thickness from 0.1 to 0.01 nm.

A point at which the continuity of a building component is interrupted. Not all internal forces can be transferred across a hinge. We distinguish hinges according to their internal forces. Hinges are found at the nodes of building components or structures.

An imaginary line to DIN 18268 which fixes the position of a door hinge. It is measured from the upper frame rebate. Only after the hinge reference lines have been determined exactly for the upper and lower hinges is it possible to assemble door leaf, door hinges and door frame.

This type of joint cannot accommodate any bending forces. The cross-sectional area of the pin in a fork joint must be such that it can carry the loads without shearing. A hinge gives a beam a minimal rotational capacity.

An incorrect term for a side-hung door. The door swings open in one direction only. The door leaf fits flush with the frame upon closing. Multiple locking to all sides is possible to improve security.

A sloping linear intersection between two roof surfaces that slope downwards from this line.

A hipped roof has sloping surfaces on the gable sides as well as the eaves sides.

Glass is not a human invention, but rather a copy of a natural product. Natural glass is produced, for example, during volcanic eruptions, meteorite impacts and lightning strikes. Astronauts found natural glass on the Moon! Experts assume that minerals on the Moon were melted to form “glass spherules” during meteorite impacts.

The German Honorarordnung für Architekten und Ingenieure (HOAI, Official Scale of Fees for Services by Architects & Engineers). The latest edition was published on 30 April 2009.

Hollow sections can also be rolled sections. There are three forms: square, rectangular and circular. One further distinguishing feature is whether the sections are seamless or welded. Hollow sections are frequently used for architectural reasons because they present a more harmonious appearance than open cross-sections.

The entire surface at the edge has been finely ground. Honed edge surfaces have a matt appearance. Untreated areas and chips are not permissible.

This law established by Robert Hooke describes the material constant E (elastic modulus, modulus of elasticity) that is defined by the ratio of the stress in a body to the relative change in its length.

Like horticultural sheet glass but with a lightly textured surface (rolled glass with good light-scattering properties).

A low-quality glass used for greenhouses and frames for horticultural purposes.

A production line for hot-rolled wide strip material. We distinguish between three forms: continuous hot-rolled strips (five or six roughing stands and six finishing stands) and semi-continuous hot-rolled strips.

Flat products with a rectangular cross-section and a width much greater than their thickness, manufactured from unalloyed or alloyed semi-finished steel products. The strip is wound up into a coil immediately after passing through the finishing roll, or rather after pickling or continuous annealing, in such a way that the side surfaces of the coil are approximately in one plane.

An optically effective property of glass with a relatively high selective absorptance and non-diffuse light transmission. The view through appears coloured (coloured glass) but focused. See: obscured glass.

German abbreviation for high-strength connection (Hochfestverbindung). A standardised bolted connection in which additional fittings to prevent loosening are not required. The bolt is secured by introducing an appropriate preload. HV connections must always consist of bolt, nut and washers from one supplier.

High Strength Bolt

This describes the flow behaviour of fluids. Hydraulic elements are included in façades for controlling sunshades or for opening roof windows. Hydraulic systems can be used to generate enormous forces. Hydraulic jacks are used for prestressing cable structures.

Such a coating increases the fire resistance of fire-resistant glazing.

Hydrogen can damage steel through hydrogen embrittlement. It can infiltrate the steel during production and also during surface treatments. Tempering measures can remove the hydrogen.

A change in the ductility of metals, more specifically their brittleness, through the infiltration and inclusion of hydrogen in their metallic structure. Hydrogen embrittlement is a form of corrosion, the results of which are similar to material fatigue.

Such a surface is based on the wetting behaviour of fluids (water) on the treated surface. On a hydrophilic surface the water spreads out to form a film of constant thickness that runs off the surface and leaves behind no significant amounts of dry residue (hydrophilic = attracts water).

Such a surface is based on the wetting behaviour of fluids (water) on the treated surface. A hydrophobic surface repels the water; pearl-like droplets form which can roll off and take particles of dust and dirt with them (hydrophobic = repels water).