Glossary – our knowledge from A to Z

A steel section with only one flange. We distinguish between long-stalk and wide-flange T-sections, which can have either square or rounded corners.

A connector that can be used in a detachable connection.

This is a term used in business accounting. It shows the difference between the actual and the budgeted costs. The anticipated profit from a project is calculated from this.

This type of drawing provides information about the form, construction and function of workpieces, subassemblies and systems. We categorise technical drawings as follows according to their content and purpose: sketches, part drawings, subassembly drawings and general drawings.

Coloured glasses achieve their colour effects only after additional heat treatment – the glass is annealed. Minute particles form in the glass. The colour effect is due to the absorption or scattering of specific wavelengths of light.

A type of glass in which heat treatment is used to generate mechanical stresses in the material and hence increase its ultimate strength with respect to mechanical or thermal stresses.

This is the reheating of a workpiece after hardening to temperatures below Ac1 (lower critical temperature), holding at this temperature and subsequent cooling. We distinguish between two types of tempering: relieving at approx. 150°C in order to compensate for the stresses that ensue during hardening but without reducing the hardness; tempering at 400–650°C as part of the hardening and tempering process.

This is a design principle for stabilising systems based on a balance between tension and compression forces.

The is the maximum tensile stress a material can accommodate while being subjected to bending. The microstructure of the material is irreversibly damaged if the bending stress induced in an element is greater than its tensile bending strength. This can lead to a structural failure.

Material parameter that characterises the tensile force a unit area can accommodate up to failure. Normal unit of measurement: N/mm². The tensile strength is determined by means of standardised tests on standardised specimens.

A term from structural analysis. This is the stress in a component caused by a tensile force. In a reinforced concrete component, tensile and compressive stresses occur at different places. Tensile stresses preferably occur in the bottom in the span(s) and in the top over the support(s).

A standardised method of assessing the tensile strength and other parameters of a material. The result of a tensile test is shown on a stress-strain diagram.

This is a cold-rolled flat product for cold-working applications. It is made of soft unalloyed steel with a coating of terne metal.

The name given to fired, unglazed clay items such as vessels, sculptures and ceramic products for the building industry. A warm, earthy colouring is also sometimes referred to by this name. Firing once at a relatively low temperature (900–1000 °C) means that the production is not particularly complicated.

All the components that do not contribute to the load-carrying capacity of the secondary structure but are still required to carry certain loads. These include, for example, the glazing to façade elements and windows.

Test certificates for materials or forms of construction are required when these are called for in the specification or individual approvals are necessary. seele employs many innovative designs and so such certificates are part and parcel of our work.

This is a model made for testing purposes.

This offers many advantages and permits interesting combinations with other materials (timber, glass, concrete and steel). Furthermore, these textile solutions from seele are very popular because of their superior lightness, good durability and recycling properties.

The science of the stability of loadbearing constructions. The methods of calculation and modelling derived from the theory of structures are the tools of the structural engineer.

A necessary constructional measure to avoid a thermal bridge. One typical example can be found in the aluminium frame to a window, where a plastic spacer is used to avoid the transmission of heat from the inner to the outer frame sections.

A thermal bridge (often erroneously called a cold bridge) is an area in a component of a building through which heat flows more quickly outwards or inwards than is the case in the other areas of the component.

This specifies how much thermal energy is transported through a material in the form of heat by means of conduction.

The coefficient of thermal expansion specifies the change in length of a solid body subjected to a temperature change of 1 K in relation to the total length L0.

Components change their form and volume when subjected to temperature changes. If this fact is not taken into account in the design and construction of a structure, this can result in damage. The magnitude of the change in volume is determined by the coefficient of thermal expansion.

All measures that reduce the heat transfer between interior and exterior or between rooms at different temperatures.

General term for “soft” thermal insulation materials such as glass wool, sheep’s wool, rock wool, hemp or mineral wool. These products are generally available in the form of batts, fleece, blankets or as loose fill. The latter is used for filling voids and cavities.

This is the capacity of a building material, primarily glass, to withstand larger temperature fluctuations within the body of the material without any damage. The thermal shock resistance of toughened safety glass is particularly notable. Non-toughened glasses exhibit a low thermal shock resistance.

Float glass is heated to 620–650°C and subsequently cooled very quickly by way of convection from the surface. The rapid cooling process leads to the surfaces of the glass contracting to a greater extent than the inner core. The result of this is that a compressive stress is generated at these surfaces, a tensile stress within the body of the glass.

The thermal transmittance is the measure for the physical magnitude of a heat flow in building components when different temperatures prevail on the two sides. It specifies the quantity of energy that passes through a surface of 1 m² in 1 s when the difference between the temperatures on the two sides is 1 K. The unit of thermal transmittance is W/m²K. The lower the value, the better the insulating effect.

This is a method measuring the heat lost from a building. The method is based on the fact that every body emits heat depending on its temperature. Using a thermographic image (thermogram) of a façade, for example, it is easy to see that the doors and windows are the weak spots.

Thermoplastics are meltable, high-polymer materials that change to a plastic state upon the application of heat. They can be easily moulded when in this state, and the shape is retained upon cooling. This process can be repeated. Thermoplastics are mostly viscoplastic.

See: thermosetting plastic.

Once they have cured, thermosetting plastics can no longer be deformed. They are particularly resistant to heat and chemicals and cannot be deformed plastically. As there is intensive cross-linking between the molecular chains, thermosetting plastics are hard to brittle at normal temperatures.

Sheet or plate glass with a thickness of up to 1.8 mm.

Method of manufacture for photovoltaic modules which allows them to be used in façades. The elements are so thin that they possess semi-transparent properties. Consequently, it is possible to use façade surfaces for generating electricity.

Thiokol® is a trade name for sealants made from polysulphides. Thiokol® is not UV-resistant and therefore the edge seal must be shielded from the light.

Bar with helical, thread-like ribs for use in conventional reinforced concrete or prestressed concrete.

A tie is often used in an arch construction when the supports cannot or should not resist the enormous thrust forces. The tie connects the two outer arch supports in tension.

A member that carries exclusively axial tensile forces, e.g. the diagonals in trusses or bracing. If it can be guaranteed that a certain building component will carry only tensile forces, a more slender section with a low bending stiffness can be chosen and this results in a more delicate appearance.

Tungsten inert gas welding is a process that makes use of inert gases. The electric arc is generated by a non-consumable tungsten electrode. Torch and electrode are usually guided manually. The main applications are high-alloy steels and aluminium materials, but unalloyed engineering steels can also be welded using this method.

A side-hung window that by means of a special mechanism can also be tilted inwards like a hopper window.

This damage monitoring system is used by the seele group primarily during the transport of sensitive products. If shipped goods fitted with these labels are tilted during transport, the indicator field turns red. In the event of damage during transport, it is therefore easier to find out how and where the damage occurred.

This is a framework of timber posts and rails with infill panels generally of loam or masonry.

In the production of float glass the glass floats on a bath of molten tin. During this process, tin ions diffuse into the surface of the glass and these can be made visible in black light.

A surface treatment in which a coating of tin is applied to (usually) metallic workpieces to protect them against corrosion. Tin-plating is used mainly on workpieces that come into contact with foodstuffs.

Up to 0.5 mm thick sheet or strip steel with a coating of tin applied by electrocoating. It is primarily used for packagings.

In corrosion-resistant steels, titanium is an alloying element that reduces the susceptibility to intergranular corrosion. This effect is achieved through the finely distributed carbides that are formed by titanium. In addition, titanium has denitrifying and deoxidising effects and also bonds sulphur.

Float glass coated with titanium oxide has a dual action, combining two properties in order to achieve a self-cleaning effect. Coating the outside with titanium dioxide reduces the surface tension (hydrophilic) and prevents the formation of droplets.

There is no such thing as absolute accuracy, i.e. the realisation of a given dimension is always associated with deviations. With quality control production, this actual size must lie within permissible deviations. The difference between the upper and lower limits of size is the tolerance.

A surcharge added to the price for delivery because of the road toll incurred by goods vehicles and higher energy costs. The amount of the surcharge depends on the weight of the glass.

This is the physical variable activated upon increasing or decreasing the speed of rotation of a rotating body. Torque is measured in newton-metres (Nm) and is the vector product of lever arm and force.

The moment of a force with respect to a reference point is the product of the absolute magnitude of the force and the distance of its line of action from the reference point.

This is a body’s resistance to twisting about its own axis. A measure of the torsional strength is the torsional stiffness, which specifies the resistance to deformation.

This value is defined as the sum of the direct transmission due to solar radiation plus the inward heat emissions due to radiation and convection. Double glazing made from clear glass has a g-value of approx. 0.8.

At the transition from one medium to another, not all of the incident light is refracted – part is reflected. The larger the angle of incidence, the greater is the proportion of reflected light. When the angle of incidence reaches the critical angle for total reflection, all the light is reflected. At the transition from air to glass, this critical angle is 42°.

We distinguish between toughened safety glass and heat-strengthened glass depending on the degree of toughening. Either a thermal or chemical process can be used for toughening. Toughening improves the safety properties and load-carrying capacity of the glass.

This is a type of glass that has been thermally (to DIN 12150-1) or chemically treated to achieve a better thermal shock resistance plus better bending, impact and shock resistance. (US: tempered glass)

The work stored due to deformation or another type of energy conversion up to rupture.

Electric cables can be laid on roof surfaces, in gutters or in downpipes. These prevent the accumulation of snow or formation of ice. Most systems on offer are self-regulating and adapt automatically to the ambient temperature.

A lightweight, compact form of elevating platform. Available with articulated or telescopic booms, with or without a so-called basket/bucket for persons, such plant can reach working heights of up to 30 m. When attached to a vehicle with a tow ball coupling, these platforms are easy and convenient to transport. Their low weight means that they are also suitable for surfaces with a low bearing capacity.

The softening point of a glass melt. The transition temperature of float glass is about 520°C.

The ability of a material to allow the passage of light but prevent a view through (cf. transparency and opacity).

This is the permeability of a medium with respect to wave forms, e.g. light. It specifies the ratio of the radiation passing through the medium to the radiation incident on the medium.

The ability of a material to allow the passage of light, to allow a view through. The opposite of opacity.

Technische Regeln für die Verwendung von absturzsichernden Verglasungen (Technical Rules for Glass in Safety Barriers). A mandatory German code of practice for vertical glazing elements that must act as a safety barriers to prevent falls. Balustrade infill panels, glass panels fixed at the base and storey-high glazing are among the types of construction covered.

A framework consisting exclusively of triangles. The advantage is that the framework is always statically determinate internally.

TRIP stands for transformation induced plasticity. This is a further development of dual-phase steel. TRIP steels can either have higher strengths (up to 850 N/mm²) with comparable elongation, or much higher elongation values with comparable strengths of approx. 600 N/mm².

Three panes of float glass and two intervening cavities, which can be filled with a noble gas (argon, xenon) to improve the U-value. The disadvantages of triple glazing are the high weight of the units and the lower light transmittance.

German Technical Rules for the use of Glazing on Linear Supports (Technische Regeln für die Verwendung linienförmig gelagerter Verglasungen)

German Technical Rules for the Design and Construction of Point-Supported Glazing (Technische Regeln für die Bemessung und Ausführung punktförmig gelagerter Verglasungen)

This is the density of the material part of a body in any state.

A special flat roof form in which the roof pitch is zero.

This is a timber or steel construction made up of several linear members joined together at their ends. This principle results in individual members being loaded exclusively in either tension or compression, and it is this that gives a trussed frame its high load-carrying capacity.

The welding equipment in this case consists of a power source, which in most cases can be switched between a.c. and d.c., and a welding torch connected to the power source by a hose.

Forces that act on a structure can occur in various forms such as point, knife-edge (linear) or uniformly distributed (in two or three dimensions) loads.