Mitchell's Introduction to Building

Roger Greeno

• Publisher: Routledge
• Year: 2014
• ISBN:
  9781317902805
• Edition: 5
• Topic: Technology & Engineering
• Subtopic: Construction & Architectural Engineering
• Index: Technology & Engineering

Introduction to Building provides a comprehensive introduction to various aspects of development and associated building procedures, from initial planning and design through procurement of building work, contractual arrangements and construction techniques.

Now in its Fifth Edition, this popular text continues to present an authoritative overview of the many design and practical considerations associated with the creation and maintenance of modern buildings, including repair of existing buildings and traditional construction procedures. Topics covered include the functional requirements of a building: appearance, durability, dimensional suitability, strength and stability, weather exclusion, sound control, thermal comfort, fire protection, lighting and ventilating, sanitation and drainage, security, cost, sustainability, building processes, the building team, communication and construction methods.

Part A
An analysis of a building in terms of what it is expected to do: its function and performance

1
The requirements of a building

CI/SfB (E)/(Y)

1.1 Materials and technical ability

When a building is constructed two main physical resources are involved. These are materials necessary to form the various parts, and technical ability to assemble the parts into an enclosure (Fig. 1.1). Initially, the materials employed were those which could most easily be obtained from the accessible areas of the surface of the earth. The technical ability was mostly simple, having evolved from the convenient methods of economically working the rudimentary characteristics of these available materials. The gradual widening in means of communication and corresponding developments in attitudes led to an increased range of these resources becoming available.

The current uses of particular construction methods no longer need to rely on locally available materials or traditional technical ability. Continued investigation has resulted in the enormous range of materials now becoming available which may be used singly, in combination with one another, or even to form new materials. Technological developments are interrelated with this range and use of materials, and enable virtually anything to be constructed.

Nevertheless, there are certain considerations which have always exerted some control on the indiscriminate use of resources. These controls remain, and now that the range of resources is wider, and attitudes towards the function of a building are more complicated, the selection of appropriate construction method becomes much more difficult. For this reason, it is first necessary to understand precisely what is required of a building before selecting an appropriate method of construction.

1.2 Functional requirements

Figure 1.1 Construction method.

Elaborate shelters have been, and still are, made by most species of insects, reptiles and animals capable of using the readily available materials (earth, stones, branches and leaves, etc.) with the aid of the inherent manipulative skills (technology) of their arms, legs, wings, claws, beaks and jaws. Early humans also required shelter which provided security for them, their possessions and activities. However, they developed their inherent manipulative skills by inventing tools which led to less indigenous construction methods and also ways of changing the natural state of materials so that they could be used to greater advantage. Each innovation devised usually resulted in shelters, which, although initially providing a good standard of comfort and convenience, eventually became sub-standard accommodation as requirements became more elaborate. But, regardless of technical developments, the provision of a physically comfortable shelter was not the only or even the principal reason for building. From early times, a building was also required to give an established place of social and religious identity: it must indicate culture, status and mood, while creating the humanised space in which to learn, experience and carry out normal daily functions in comfort.

Sir Henry Wooten, a fifteenth-century humanist who adapted the writings of Vitruvius for his book, The Elements of Architecture (1624), wrote that a good building must satisfy three conditions:

• Commodity: comfortable environment conditions
• Firmness: stability and safety
• Delight: aesthetic and psychological appeal

These functional requirements are implicit in the provision of a shelter which is also a building fit for human habitation. A well-constructed building reflects contemporary attitudes towards environmental control, structural concepts and aesthetic excellence. And the materials and technical ability used throughout history have normally provided the means of achieving these particular ends.

1.3 Performance requirements

A modern building is expected to be a life-support machine (Fig. 1.2). It is required to provide the facilities necessary for human metabolism such as clean air and water, the removal of waste produce, optimum thermal and humidity control, privacy, security and visual/acoustic comfort. It is also required to be a source of self-generating energy for appliances, and provide means for communication with computer, television, telephones and postal services. In addition, a building must be safe from collapse, fire, storm and vermin; resistant to the physical forces of snow, rain, wind and earthquakes, etc.; and capable of adaptation to various functions, external landscaping or internal furniture arrangements. It must also be easily, economically, quickly and well constructed; and allow easy maintenance, alterations and extension as well as having a sustainable form of construction which can be adapted to changing trends and legislative requirements. All this must be accomplished in the context of providing a building which has character and aesthetic appeal.

Criteria of this nature form today’s interpretation of the basic functional requirements for a building quoted earlier. In order for them to be conveniently considered, it is necessary to divide a building into the various related duties to be fulfilled and establish the precise performance requirements for each. When these duties are incorporated into a building where the functional requirements have been clearly defined, the selection of a suitable construction method (materials and technology) can be achieved by using the criteria given by the performance requirements under the following headings:

• Appearance
• Durability
• Dimensional suitability
• Strength and stability
• Weather exclusion
• Sound control
• Thermal comfort and efficiency
• Fire protection
• Lighting and ventilation
• Sanitation and drainage
• Security
• Cost
• Sustainability

Performance requirements cannot be placed in order of importance because any one of them may be more critical than another for a particular element of a building. Priority is normally dictated by the precise function and location of a specific building.

The use of these interrelated performance requirements in establishing a building design was instigated many years ago by the then Building Research Station (now Building Research Establishment, see page 156). Although firm principles have now been established, critical factors arise which result in fundamental changes in attitudes towards construction methods. In recent years, one such influence concerns the availability of energy resources for the production of building materials, and for the heating and lighting of buildings.

During the formation of the earth some 5 billion years ago, only a relatively small amount of hydrocarbon atoms were incorporated and these now form our fossil fuels of gas, oil and coal. These fuels have been continuously used in one form or another during the development of humankind and the rate of consumption has increased rapidly over the last 70 years. As a result of this situation, even if the world population were stabilised, the requirements for fuel were static, and the poorer countries remained undeveloped, there would be only another 40 years of gas

Figure 1.2 Performance requirements for a building.

supply, 25–30 years of oil, and 200–300 years of coal obtainable through easy access. Of the net energy consumed, about 50 per cent is subject to decisions by those involved in the design and construction of buildings (Fig. 1.3).

Figure 1.3 Energy consumed by the building industry during the late 20th century. See section 14.5 for comparison with recent data.

Converting our diminishing fuel resources into heat energy creates other problems and responsibilities for control and regulation of the combustion products. The byproducts of combustion and the noxious gases produced contribute to the greenhouse effect and depletion of the ozone layer in the atmosphere. Flue gases from boilers and electricity generating plant produce a blend of pollutants of which carbon dioxide is the most prominent, comprising about 80 per cent of the total. Means for assessing these carbon emissions and for limiting their impact by the creation of sustainable and energy-efficient buildings in the United Kingdom are addressed by the Building Regulations, Approved Document L: Conservation of fuel and power. See Chapters 8 and 14 for more information on this topic.

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