Description
The designer of the envelope for an industrial building has to contend with a large number of determining factors that are often considered to be constraints from the outset. It is frequently assumed that these apparent constraints can lead only to very specific façade types and that they leave hardly any room for creative approaches.
However, the variety of projects realized particularly in the last two decades proves the contrary. It is precisely the variety of the determining factors that can lead to a great variety of façades, and this opens up creative latitude for their architectural design. However, even with very constraining general conditions, sophisticatedly designed building envelopes can be created through carefully planned details. Also, today’s society has developed a new conception of what constitutes a productive work environment – for example, one with natural lighting through generous arrays of glass – and this has had an effect on the building envelope for industrial buildings.
Newly emerging sectors of industry such as the production of computer chips give rise to new façades. These have to be extremely flexible and changeable in order to adapt to rapid development and thus general conditions in the grip of change. Very sophisticated glass façades are being planned for industrial buildings these days, for representative purposes to enhance the corporate image, but also for the purpose of energy conservation.
The architecture of industrial buildings is often a concomitant of industrial construction. In this connection, “industrial construction” means a high degree of prefabrication and pre-elementation of the individual components. As the use of production facilities can change over time, the façade elements should be developed as modules. They can then be easily exchanged without significantly disrupting production on the rest of the shop floor. A modular construction method can generate a high degree of flexibility that in premises rented to third parties allows tenants’ requirements to be taken into account.
Building with prefabricated elements
The requirement of great heights and large span widths can lead to structural elements dominating the ensemble. The envelope, whether it be the roof or the façade, then becomes subordinate and turns into the infilling of the supporting structure. The modular grid is thereby rigidly pre-determined. Yet through their positioning and the choice of a particular façade, the supporting members can be emphasized and be rendered clearly legible – or they can be toned down.
The façade and the roof serve not only to close off space, but also to take account of the needs of the people working there. The relation to the outside world is established through the apportioning of glazed surfaces. If homogeneous and diffuse natural lighting is required, light-diffusing glazing like etched or cast glass can be used. For transparent areas, efficient solar protection is necessary. It should be possible for individuals to regulate the amount of sun coming in; in large buildings, the task of reducing the amount of heat coming in is less important due to the ratio between room content and glazed areas. In the glazed areas, openable elements for the supply of fresh air can be integrated. Their minimum sizes should be determined by the necessary values for air supply and smoke extraction. This calculation gives size, quantity and distribution of the openings.
The requirements with regard to the internal temperatures that in Germany, for example, are set by the ENEV, lead to heavily insulated structures in the envelope. In this context, problems that arise from thermal building physics such as the avoidance of thermal bridges and condensate are to be taken into consideration. Careful, accurate planning of the finishing details is therefore especially important.
In contrast with the situation in housing, sound protection measures are not to be applied from outside to the inside, but instead, from inside to outside. The environment must be protected from the noise of the production plant. Low frequencies call for heavy components. High frequencies can be guarded against by clever combinations of different surfaces. Interior façades should be as smooth as possible so that dust cannot settle and the walls are easy to clean.
Primary load-bearing elements
As a rule, the roof construction is selected in correspondence with the requirements of the production facilities underneath. Usually the roof consists in large part of a closed flat roof. Trapezoidal sheets function as simple roof cladding and provide the supporting structure at the same time. The height of the beading can be chosen to correspond to the statics requirement. The systems are developed in accordance with the modular design principle. For each crimped sheet, there are matching insulation boards, edge connection endplates, etc., available. There are systems with a high degree of of prefabrication; elements are prefabricated as coffers, including roof cladding, insulation and supporting structure, with connecting elements along the lines of the tongue and groove principle on the edges. They can be put together very quickly in any given size.
As much light as possible should be brought into the premises via the roof. As a horizontal roof surface cannot easily be made of glass slabs for many structural reasons, tilted and perpendicular surfaces are formed that can be glazed. A typical example of this is the saw-tooth roof. The horizontal roof surface is folded, so that the above-mentioned tilted or perpendicular surfaces are formed. The statics of supports that span great widths can be well accommodated through the building height that thus results. Following the same principle, skylight turret levels can be built on the roof as separate volumes. The vertical areas can be glazed for weather-protection.
Vertically glazed saw-tooth roof
Strip-shape roof glazing
Where a great deal of light is required, as is the case with greenhouses, almost the entire roof surface will be developed transparently. This is not necessarily done with a classic roof form such as the pitched roof; rounded and even organic forms are now possible too. The materials for transparent roof surfaces are not limited to glass alone. Synthetic materials and foilscan also be used. In order to implement foils in conjunction with controlled temperature rooms, two layers of them are fused to form inflated cushions, the air with which they are filled being specially conditioned. They thereby attain noteworthy stability. They can be made in almost any shape.
Ventilation of production facilities takes place ideally at the topmost point, which is to say via the roof. The openings should be relatively weatherproof, in order to provide fresh air even when it is raining. For this reason, louvers too should be set into the slanted surfaces mentioned above. The size of the louvers is mostly determined not by the demand for fresh air but rather by the diameter needed for smoke extraction.
Domed skylights combine lighting and ventilation via the roof. Completely industrially prefabricated, insulated, box-like frames are set into the roof and caulked in. They are covered with a dome-shaped plexiglass cap that lets light in. Motor-powered mechanisms can open the domes so that they also function as smoke vents.
Technical requirements for the closed parts of the façade of industrial buildings are limited for the most part to heat and sound insulation. The large surface areas make it possible to use simple, prefabricated wall elements. As with roofs, the span widths between the main girders can be bridged with transversally mounted trapezoidal sheets. A damp course and external wall cladding with ventilation behind it provide for the necessary heat insulation. The outer envelope can take any form desired. A wide range of options, from wood to shingles and stone to corrugated metal or sheet-iron waffle panels is possible, depending on the desired effect and the budget available. Prefabricated modules can be adjoined at will.
Wall construction consisting of concrete sandwich elements and waffle metal made of ventilated trapezoidal sheet metal
Transparent areas in the walls let daylight into the interior. They create a relation to the outside world. Conversely, the enterprise’s effect on the outside world can be intensified by offering views onto the shop floor. A very easy way of putting up transparent walls is to use profiled glass, what is called industrial glass. As the name indicates, this glass is often implemented in the construction of industrial buildings because it is inexpensive. Its U-shape means that it functions well as a self-supporting element. The U-values can be optimized by the use of coatings and/or layering. Heat insulation glazing meets the higher demands that we are familiar with in office buildings and domestic construction. The heat-insulating characteristics can be varied by the use of coatings. Through special superstructures, a great range of characteristics can be integrated in this functional layer. The safety characteristics of the glazing can be increased from burglary-proof to explosion resistance. The addition of soft plastic films or cast resin layers can improve sound insulation.
Post-and-beam structure with ventilated metal-and-glass façade
The glazing is set into thermally separated profiles. These constructions can be set directly onto the supporting steel profiles. The form is restricted solely by the necessary planar overlay of the plate level. Thus the envelope’s supporting structure can be designed relatively freely within the limits imposed by the statics requirements. If the glazing extends over large areas, the admission of solar energy should be limited. This can be done by using high-quality solar protection coatings or solar protection devices, for example, stationary lamella or broad, overhanging eaves.
Most production premises have long since acquired computers. The building envelope must therefore meet the requirements for workplaces with computer monitors, such as the amount of daylight desired conflicts with the avoidance of dazzle. The glazing of greenhouses or uninsulated structures represents other special cases. Because there is no need for thermal insulation, very light-weight and highly transparent structures are possible.
The openings in industrial buildings are designed primarily on the basis of the size of the goods to be transported. The desired speed of opening determines the choice of particular gateway types. In most industrial companies, trucks are used for delivery and dispatch. Loading and unloading takes place at loading ramps or in the building. In such cases, the speed with which the gates open is not important, and roller shutters or rolling gates can be used. If forklifts are used for transport on the premises, then the more rapid sectional gates are often used. If there is a constant flow of traffic through the building envelope, rapid operation gates will be used. These consist of foils that can very quickly unwind or be wound up. As these gates offer only weather protection, but very little heat protection or burglary resistance, they are combined with an insulated rolling gate or roller shutter, for closing at night. Special structures are necessary for oversize openings, for example for dirigibles or airplanes.
Wall made of profiled glass with casement
Very different branches of industry require very different envelopes. The pharmaceutical industry and computer chip production facilities require dust-free rooms. In these cases, the façade has to satisfy the most stringent and exacting requirements with regard to sealing joints. In order to avoid dirt and dust settling, profiled surfaces are slanted or tilted. For the same reason, joints, and interior corners should be reduced to a minimum. Caulking material has to possess fungicidal qualities.
The implementation of textiles in building is gaining in importance. They are used primarily for weather protection, being far less important for thermal separation or protection against burglary.
Fully glazed folding gate
Industrial façades are no longer just functional façades. The design of the envelope has an enormous influence on the workplace ambience. Workers’ motivation and productivity can be significantly increased this way. The design of the envelope of an industrial building can have great influence on the public. Façades may serve as gigantic billboards. Large areas of glass guarantee a view into the production processes. Potential customers can take part in production visually, if they are not shown around on the factory floor. With the current trend toward bringing production plants back into the city, the functional and design expectations for industrial façades will increase.
Examples have shown that industrial façades can have a sophisticated design. Courage and strength are necessary in order to achieve detachment from the apparent constraints and to plan the envelopes of industrial buildings with new creative approaches. This is the challenge that face property developers, architects and engineers equally.
Originally published in: Jürgen Adam, Katharina Hausmann, Frank Jüttner, Industrial Buildings: A Design Manual, Birkhäuser, 2004.