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- Herausgeber: John Wiley & Sons
- Kategorie: Geisteswissenschaft
- Sprache: Englisch
With the improved efficiency of heating, cooling and lighting in buildings crucial to the low carbon targets of all current governments, Building Science: Concepts and Applications provides a timely and much-needed addition to the existing literature on architectural and environmental design education. Taking a logical and didactic approach, the author introduces the reader to the underlying concepts and principles of the thermal, lighting, and acoustic determinants of building design in four integrated sections. The first section explores the thermal building environment and the principles of thermal comfort, translating these principles into conceptual building design solutions. The author examines the heat flow characteristics of the building envelope and explains steady state design methods that form the basis of most building codes. He discusses the sun as a natural heat source and describes the principles of active and passive solar building design solutions. The second section introduces the scientific principles of light, color, and vision, stressing the importance of daylight in building design, presenting the Daylight Factor design concept and methodology, and discussing glare conditions and their avoidance. It also addresses artificial lighting, delving into the prominent role that electricity plays in the production of light by artificial means and comparing the efficacy and characteristics of the various commercially available light sources in terms of the energy to light conversion ratio, life span, available intensity range, color rendition properties, and cost. The third section deals with the various aspects of sound that impact the design of the built environment, discussing the nature of sound as a physical force that sets any medium through which it travels into vibration and laying the foundations for the treatment of sound as an important means of communication as well as a disruptive disturbance. The final section discusses the foundational concepts of ecological design as a basis for addressing sustainability issues in building design solutions. These issues include the embedded energy of construction materials, waste management, preservation of freshwater and management of graywater, adoption of passive solar principles, energy saving measures applicable to mechanical building services, and the end-of-lifecycle deconstruction and recycling of building materials and components. * Covers the fundamental building science topics of heat, energy, light and sound * Takes a logical and didactic approach, tracing the historical roots of building science * Includes summaries of new technologies in solar energy and photovoltaic systems * Features a section on the principles of sustainable architecture * Website with answers to MC questions testing students' learning
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Table of Contents
Cover
Title Page
Copyright Page
Foreword
1 Technical Underpinnings in Mathematics and Physics
1.1 Linear equations
1.2 Some statistical methods
1.3 Foundational concepts in physics
Endnotes
2 Principles of Thermal Comfort
2.1 Heat transfer between body and environment
2.2 Some physiological considerations
2.3 More about individual differences
2.4 Measurement of the thermal environment
2.5 Selecting the appropriate index
2.6 Thermal comfort factors
3 Thermal Control by Building Design
3.1 How important is the thermal environment?
3.2 Thermal building design strategies
3.3 Importance of sunshading devices
3.4 Radiation through roofs
3.5 Sun position and orientation
3.6 Solar design steps
3.7 Achieving air movement naturally
3.8 Removal of heat by ventilation
4 Heat Flow and Thermal Insulation
4.1 The need for energy conservation
4.2 How is heat transferred?
4.3 Steady-state heat-transfer assumptions
4.4 The nature of thermal conductivity
4.5 Building heat-flow calculations
4.6 Energy conservation standards
4.7 Insulation and insulating materials
4.8 The cause and nature of condensation
4.9 Heat-flow calculation example
5 Solar Energy: The Beckoning Opportunity
5.1 Opportunities and limitations
5.2 Two types of solar collection system
5.3 Flat-plate solar collectors
5.4 Solar heat-storage systems
5.5 Sizing a solar hot-water service
5.6 The degree–day concept
5.7 Sizing a solar space-heating system
5.8 Integrating building structure and heat storage
5.9 Passive solar systems
Endnotes
6 Light, Color, and Vision
6.1 Some historical background
6.2 Light speed and color
6.3 What is light?
6.4 Light viewed as mechanical waves
6.5 Measurement units of light
6.6 Light reflection, absorption, and transmission
6.7 The visual field and adaptation level
6.8 Perceptional constancy
6.9 The nature of glare
Endnotes
7 Daylight Design Principles
7.1 Variability of daylight
7.2 Quality of daylight and color
7.3 How much daylight is available?
7.4 Measurement of daylight
7.5 Model analysis
7.6 The daylight factor concept
7.7 Glare from daylight
8 Artificial Lighting
8.1 Definition of terms
8.2 Creation of light artificially
8.3 Functions of the luminaire
8.4 Light fixtures
8.5 The lumen method of lighting design
8.6 The room cavity ratio
8.7 The PSALI concept
9 The Nature of Sound
9.1 What is sound?
9.2 Objective units of sound measurement
9.3 Addition, deletion, and reduction of sound pressure levels
9.4 The concept of octave bands
9.5 Subjective units of sound measurement
9.6 How do we hear sound?
9.7 Hearing conservation in the environment
9.8 Sound-measurement instruments
10 Room Acoustics
10.1 Reflection and diffraction of sound
10.2 Absorption of sound
10.3 Speech communication
10.4 Halls for speech and music
11 Noise Control and Insulation
11.1 Noise control by legislation
11.2 Airborne and solid-borne sound
11.3 Airborne noise insulation
11.4 Solid-borne noise insulation
11.5 Noise insulation in practice
11.6 Common noise sources
12 Sustainable Architecture Concepts and Principles
12.1 Human resistance to change
12.2 Discernible trends
12.3 Fundamental concepts and definition of terms
12.4 Assessment of high-performance buildings
12.5 Energy design strategies
12.6 Water conservation strategies
12.7 Closed-loop building materials
References and Further Reading
Keyword Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Sample of the heights of persons (in inches).
Table 1.2 Frequency distribution table.
Table 1.3 Expanded frequency distribution table.
Table 1.4 The normal probability integral A(z).
Chapter 8
Table 8.1 Typical coefficient of utilization table.
Chapter 9
Table 9.1 Perception of SPL changes.
Table 9.2 Deletion of sound sources.
Table 9.3 Maximum background noise levels (i.e., SIL) for reliable speech communi...
Chapter 10
Table 10.1 Maximum background noise levels (i.e., SIL) for reliable speech commu...
Table 10.2 Maximum background noise levels (i.e., SIL) for reliable speech commu...
Table 10.3 Maximum background noise levels for various occupancies recommended b...
Table 10.4 Average and extreme noise levels generated in typical school spaces.
Table 10.5 Suggested maximum SIL values for open-plan schools employing masking...
Table 10.6 Framework for rating concert halls (according to Beranek, 1962).
Table 10.7 Measured reverberation times (sec) of the Sydney Opera House.
Chapter 11
Table 11.1 Reduction in transmission loss (TL) of an assembly of two components.
Table 11.2 Reduced increase in STC value of glass of different thicknesses.
Table 11.4 Vehicular traffic noise (expected 80% of the time).
Chapter 12
Table 12.1 Comparison of embodied energy and thermal insulation effectiveness....
Table 12.2 EPAct water usage standards for plumbing fixtures.
Table 12.3 Embodied energy in volume and mass.
List of Illustrations
Chapter 1
Figure 1.1 Statistical sampling.
Figure 1.2 Histogram (or bar chart).
Figure 1.3 Distribution curve.
Figure 1.4 The normal distribution curve.
Figure 1.5 Various distributions.
Figure 1.6 Standard deviations.
Figure 1.7 Two different normal distributions.
Figure 1.8 Standard normal distribution.
Figure 1.9 Normal distribution table formats.
Figure 1.11 Black body curve for 5000K.
Figure 1.12 The black-body radiation spectrum at increasing temperatures w...
Chapter 2
Figure 2.1 The human heat engine.
Figure 2.2 Environmental adjustment.
Figure 2.3 Vaso-motor control mechanism.
Figure 2.4 Human comfort and discomfort.
Figure 2.5 Proportional heat exchange.
Figure 2.6 Thermal comfort control factors.
Figure 2.7 Objective comfort temperatures.
Figure 2.8 Impacts on thermal comfort.
Figure 2.9 Hooke’s law applied to the thermal environment.
Figure 2.10 Thermal stress and strain relationships.
Figure 2.11 The thermal comfort parameters.
Figure 2.12 Very common thermal indices.
Figure 2.13 Less common thermal indices.
Figure 2.14 Groups of thermal indices.
Figure 2.15 Index selection rules.
Figure 2.16 Typical metabolic rates.
Chapter 3
Figure 3.1 Accident rates in British coal mines during the 1940s.
Figure 3.2 Limits of barely acceptable thermal conditions.
Figure 3.3 Heat flow through a heavyweight building envelope (idealized) i...
Figure 3.4 Design strategies for a
hot-dry
climate.
Figure 3.5 Design strategies for an (idealized)
hot-humid
climate.
Figure 3.6 Design strategies for an (idealized)
cold
climate.
Figure 3.7 The “greenhouse” effect.
Figure 3.8 Sunshading design considerations.
Figure 3.9 Horizontal sunshading devices.
Figure 3.10 Vertical sunshading devices.
Figure 3.11 Internal shading devices.
Figure 3.12 Transmission spectrum of various types of window glass.
Figure 3.13 Sun variables and assumptions.
Figure 3.14 Radiation spectrum and seasons.
Figure 3.15 Equinox and solstice.
Figure 3.16 Algebraic sun path solution.
Figure 3.17 The Burnett sun path chart.
Figure 3.18 The UK Heliodon.
Figure 3.19 The Australian Solarscope.
Figure 3.20 Pleijel’s sundial.
Figure 3.21 Impact of wind on buildings.
Figure 3.22 Effect of external vegetation.
Figure 3.23 Impact of door location on air-flow patterns.
Figure 3.24 Impact of door vertical room location on air-flow patterns.
Figure 3.25 Ventilation rate formula.
Figure 3.26 Ventilation rate calculation.
Chapter 4
Figure 4.1 Heat transfer by conduction.
Figure 4.2 Heat transfer by convection.
Figure 4.3 Heat transfer by radiation.
Figure 4.4 Reflectivity and emissivity.
Figure 4.5 Heat-transfer parameters.
Figure 4.6 Steady-state assumptions.
Figure 4.7 Steady-state heat transfer through the building envelope.
Figure 4.8 Calculation of the thermal transmittance or U-value of a Constr...
Figure 4.9 Influences on the thermal conductivity of materials.
Figure 4.10 Thermal resistance of common building materials.
Figure 4.11 The heat exchange between a building and its external environm...
Figure 4.12 Steps for estimating the heat gain or loss through the buildin...
Figure 4.13 Calculation procedure for the air infiltration component.
Figure 4.14 Calculation procedure for the perimeter (footings) component....
Figure 4.15 Thickness as a measure of the efficiency of thermal insulation...
Figure 4.16 Return on investment of thermal insulation in a typical home....
Figure 4.17 Causes of condensation.
Figure 4.18 Types of condensation.
Figure 4.19 Section and floor plan of a portion of a classroom building.
Chapter 5
Figure 5.1 Solar energy promises.
Figure 5.2 Solar energy reality.
Figure 5.3 Availability of solar energy.
Figure 5.4 Active or passive systems?
Figure 5.5 Water and air collectors.
Figure 5.6 Typical collector efficiencies.
Figure 5.7 Comparison of water and air collectors and efficiency factors....
Figure 5.8 Heat storage potential of common building materials.
Figure 5.9 Solar water system components.
Figure 5.10 Solar air system components.
Figure 5.11 Sizing a solar hot-water system.
Figure 5.12 The degree–day concept.
Figure 5.13 Sizing a solar heating system.
Figure 5.14 Sizing the heat-storage facility.
Figure 5.15 Optimum collector slopes.
Figure 5.16 Rules of thumb.
Figure 5.17 System diagram of the sand-column concept.
Figure 5.18 Typical passive solar systems.
Figure 5.19 The direct gain system.
Figure 5.20 Solar heat gain through glass.
Figure 5.21 The Trombe wall system.
Figure 5.22 The Sunspace system.
Figure 5.23 The roof pond system.
Chapter 6
Figure 6.1 A second prism has no effect on the color of any one of the spe...
Figure 6.2 A second inverted prism will recombine the spectrum into white ...
Figure 6.3 Diffraction of light around an object.
Figure 6.4 Polarization of light.
Figure 6.5 Young’s double-slit experiment.
Figure 6.6 Explanation of Young’s experiment.
Figure 6.7 Properties of light waves.
Figure 6.8 Comparative measures of wavelength size.
Figure 6.9 Spectral colors of light.
Figure 6.10 The full spectrum of electromagnetic radiation.
Figure 6.11 Section through the human eye.
Figure 6.12 The standard luminosity curve.
Figure 6.13 Light flux.
Figure 6.14 Luminous intensity.
Figure 6.15 Illumination or illuminance.
Figure 6.16 Luminance.
Figure 6.17 Perception of luminance as brightness by the human eye.
Figure 6.18 Comparison of metric and American units of measurement.
Figure 6.19 Reflectance factor (RF).
Figure 6.20 Reflectance of common materials.
Figure 6.21 Transmittance of light.
Figure 6.22 Impact of light reflectance.
Figure 6.23 Brightness differences.
Figure 6.24 Components of the visual field.
Figure 6.25 The apparent brightness scale.
Figure 6.26 Typical illumination levels.
Figure 6.27 Simultaneous contrast effect.
Figure 6.28 Spatial configuration effect.
Figure 6.29 Anchoring within a framework.
Figure 6.30 The T-junction illusion.
Figure 6.31 Direct glare and reflected glare.
Figure 6.32 Glare mitigation approaches.
Figure 6.33 The constant glare curve.
Figure 6.34 The glare index.
Chapter 7
Figure 7.1 Variability of daylight.
Figure 7.2 Daylight penetration constraints.
Figure 7.3 The Munsell Color Atlas.
Figure 7.4 The CIE Color Notation.
Figure 7.5 Colorimeter.
Figure 7.6 CIE Chromacity Diagram.
Figure 7.7 Idealized sky conditions.
Figure 7.8 CIE Standard Overcast Sky.
Figure 7.9 Photometer.
Figure 7.10 Photoelectric light meter.
Figure 7.11 Artificial sky dome.
Figure 7.12 Mirror-box artificial sky.
Figure 7.13 The Daylight factor concept.
Figure 7.14 Daylight factor components.
Figure 7.15 BRS Sky Factor table parameters.
Figure 7.16 BRS Sky Factor table excerpt.
Figure 7.17 Case (1) – reference point at windowsill level.
Figure 7.18 Case (2) – reference point above windowsill level.
Figure 7.19 Case (3) – reference point below windowsill level.
Figure 7.20 Case (4) – reference point not on center line of window.
Figure 7.21 Externally reflected component.
Figure 7.22 Internally reflected component.
Figure 7.23 Daylight factor adjustments.
Figure 7.24 Roof lighting variations.
Chapter 8
Figure 8.1 Lighting design approach.
Figure 8.2 Efficiency of light sources.
Figure 8.3 Units of electric power and energy.
Figure 8.4 Electricity relationships.
Figure 8.5 Color temperature and efficacy.
Figure 8.6 Lamp, luminaire, and ballast.
Figure 8.7 Black-body radiation spectrum.
Figure 8.8 Artificial light sources.
Figure 8.9 Average lifespan of lamps.
Figure 8.10 The incandescent (filament) lamp.
Figure 8.11 The halogen regenerative cycle.
Figure 8.12 Luminaire considerations.
Figure 8.13 Discharge lamp principles.
Figure 8.14 High-intensity discharge lamps.
Figure 8.15 The metal-halide lamp.
Figure 8.16 The low-pressure sodium lamp.
Figure 8.17 The high-pressure sodium lamp.
Figure 8.18 Comparison of mercury vapor, metal-halide, and high-pressure s...
Figure 8.19 The fluorescent lamp.
Figure 8.20 Color-rendition properties of fluorescent lamps.
Figure 8.21 Comparison of incandescent and fluorescent lamps.
Figure 8.22 Other potential light sources.
Figure 8.23 Polar diagrams.
Figure 8.24 Shielding the eyes.
Figure 8.25 Direct and semi-direct luminaires.
Figure 8.26 Diffuse and direct-indirect luminaires.
Figure 8.27 Semi-indirect and indirect luminaires.
Figure 8.28 Comparative analysis of luminaires.
Figure 8.29 Coves, coffers, and luminous ceilings.
Figure 8.30 Valences, cornices, and luminous wall panels.
Figure 8.31 Coefficient of utilization (CU).
Figure 8.32 Room index (RI).
Figure 8.33 Calculation of the average illumination level (E Lm/SF or Fc)....
Figure 8.34 Looking up the CU value for the example shown in Figure 8.33....
Figure 8.35 Number of lamps required for a given illumination level.
Figure 8.36 Looking up the CU value for the example shown in Figure 8.35....
Chapter 9
Figure 9.1 Sound as wave motion.
Figure 9.2 Propagation of sound.
Figure 9.3 Wavelength and velocity of sound.
Figure 9.4 Types of sound vibration.
Figure 9.5 The logarithmic scale.
Figure 9.6 Sound pressure level (SPL).
Figure 9.7 Range of sound pressures and equivalent sound pressure levels (...
Figure 9.8 Range of sound intensities and equivalent sound intensity level...
Figure 9.9 Addition of two SPLs.
Figure 9.10 Addition of multiple SPLs.
Figure 9.11 Reduction of sound in the environment.
Figure 9.12 Comparison of point, line, and area sound sources.
Figure 9.13 The concept of octave bands.
Figure 9.14 Center frequency of an octave.
Figure 9.15 Human speech.
Figure 9.16 Pitch and frequency.
Figure 9.17 Subjective loudness (phon).
Figure 9.18 Subjective loudness (phon).
Figure 9.19 The anatomy of the ear and the biological hearing mechanism.
Figure 9.20 Mechanical simulation of the human hearing mechanism.
Figure 9.21 Physical hearing damage.
Figure 9.22 Subjective considerations.
Figure 9.23 Sound-level meter components.
Figure 9.24 The weighting networks.
Figure 9.25 Typical sound-level meters.
Figure 9.26 The condenser microphone.
Chapter 10
Figure 10.1 Reflection of sound.
Figure 10.2 Reflection on irregular surfaces.
Figure 10.3 Acoustical shadows.
Figure 10.4 Diffraction around openings.
Figure 10.5 Absorption coefficients.
Figure 10.6 Absorption of a wall surface.
Figure 10.7 Porous absorbers in theory.
Figure 10.8 Porous absorbers in practice.
Figure 10.9 Mechanical action of a panel absorber.
Figure 10.10 Volume absorber or Helmholtz resonator.
Figure 10.11 Different configurations of a concrete block absorption unit....
Figure 10.12 Role of resonance in a volume absorber.
Figure 10.13 The relationship between SIL and LL (acording to Beranek).
Figure 10.14 Masking effect of a pure tone.
Figure 10.15 Masking effect of a narrow band.
Figure 10.16 Window-fan masking unit (after Carr and Wilkinson).
Figure 10.17 Noise conditions before and after installation of window fan ...
Figure 10.18 Conceptual layout of an open-plan school.
Figure 10.19 Sound absorption in air.
Figure 10.20 Absorption due to audience (according to Beranek, 1966).
Figure 10.21 Auditorium size limits.
Figure 10.22 The Haas effect.
Figure 10.23 Impact of absorption on reverberation in a hall.
Figure 10.24 Reverberation time calculation example.
Figure 10.25 Impact of absorption on reverberation time.
Figure 10.26 Reverberation times for different kinds of hall.
Figure 10.27 Sydney Opera House.
Figure 10.28 Sectional view of the main concert hall (Sydney Opera House)....
Chapter 11
Figure 11.1 Legislated maximum noise levels.
Figure 11.2 Transmission of airborne and solid-borne noise through a build...
Figure 11.3 The sound-board effect created by placing a tuning fork on a t...
Figure 11.4 Effect of thickness on a single-leaf panel.
Figure 11.5 Effect of frequency on a single-leaf panel.
Figure 11.6 Effect of mass on a single-leaf panel.
Figure 11.7 The impact of stiffness on the TL value of a single-leaf panel...
Figure 11.8 The impact of openings on the TL value of any sound barrier.
Figure 11.9 Sound insulation impact of a well-fitted door.
Figure 11.10 Sound insulation impact of a poorly fitted door.
Figure 11.11 Impact of resonance.
Figure 11.12 The coincidence effect.
Figure 11.13 Sound transmission class.
Figure 11.14 Impact insulation class.
Figure 11.15 Impact of resilient floor coverings on structure-borne noise ...
Figure 11.16 Discontinuous construction at the floor level of buildings.
Figure 11.17 Concrete floating floor on concrete structural floor construc...
Figure 11.18 Wood floating floor on concrete or wood floor structure.
Figure 11.19 Alternative stud wall construction methods.
Figure 11.20 Proper sealing of electric power outlet boxes in walls.
Figure 11.21 Common sound insulation problem between adjacent office space...
Figure 11.22 Common sound insulation problem between adjacent apartments....
Figure 11.23 Small air-conditioning units.
Figure 11.24 Built-up air handling units.
Figure 11.25 Duct break-in and break-out noise.
Figure 11.26 Active noise control.
Figure 11.27 Industrial noise sources.
Figure 11.28 Residential noise sources.
Figure 11.29 Parameters considered in the calculation of the noise reducti...
Figure 11.30 Impact on noise reduction of the height and distance from bui...
Chapter 12
Figure 12.1 Situated in our environment.
Figure 12.2 Many fundamental changes .
Figure 12.3 Volume versus mass.
Guide
Cover
Table of Contents
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Building Science
Concepts and Application
Jens Pohl
Professor of Architecture
College of Architecture and Environmental Design
California Polytechnic State University (Cal Poly)
San Luis Obispo, California
This edition first published 2011© 2011 John Wiley Ltd
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Library of Congress Cataloging-in-Publication Data
Pohl, Jens. Building Science : Concepts and Application / Jens Pohl, Professor of Architecture, College of Architecture and Environmental Design, California Polytechnic State University (Cal Poly), San Luis Obispo, California. – First. pages cm Includes bibliographical references and index. ISBN 978-0-470-65573-3 (pbk. : alk. paper) 1. Buildings–Environmental engineering. I. Title. TH6021.P64 2011 720'.47–dc22 2010042179
A catalogue record for this book is available from the British Library.
This book is published in the following electronic format Wiley Online Library [9781444392333]
Foreword
The design of buildings and the broader field of environmental design are often described as an art and a science. Design is an art because of both the complexity of the problem-solving and decision-making processes involved, and the innate desire of the designer to produce a solution that is unique and at the same time pleasing to our human senses. In the first instance, the complexity of the design process itself is not necessarily due to the complexity of any single issue or factor that must be considered – although some of these certainly demand indepth subject-matter knowledge – but rather the many interrelationships among those factors.
For example, placing a window into the external wall of a building for the primary purpose of providing daylight may well have farreaching implications on other areas of the overall design solution. The same window will also allow heat to either enter or escape from the building and in this way impact the thermal balance of the building interior. If located near an external noise source such as a freeway, the presence of the window may adversely affect speech communication within the space that is served by the window. In addition, the existence of the window may impact the building structure and it may also have privacy and security implications.
Clearly, the designer is faced with a very complex situation where a change in any one factor of the overall solution can impact a host of other factors and possibly unravel the current solution altogether. But why is dealing with such complexity considered an art rather than a science? The answer is perhaps surprising to the reader. While true and tried methods exist for solving most of these factors in isolation, there are really no such methods available for producing an optimum overall solution that satisfies all of the individual factors. Instead, the designer typically utilizes a rather time consuming, iterative process that commences with the solution of the individual design factors more or less in isolation. These individual solutions are then tested in terms of their impact on each other, usually requiring major adjustments to be made based on progressively more clearly defined constraints. This is a cyclic process that has so far defied rigorous scientific explanation. However, we do have knowledge of at least some of the characteristics of this human design activity (Pohl, 2008).
Even though the designer may assign weight-ings to the multiple issues and factors that appear to impact the design solution, the relative importance of these issues and their relationships to each other often changes dynamically during the design process. So also do the boundaries of the problem space and the goals and objectives of the desired outcome. In other words, under these circumstances decision making is an altogether dynamic process in which both the rules that govern the process and the required properties of the end result are subject to continuous review, refinement, and amendment.
Observation of designers in action has drawn attention to the important role played by experience gained in past similar situations, knowledge acquired in the general course of design practice, and expertise contributed by persons who have detailed specialist knowledge in particular problem areas. The dominant emphasis on experience is confirmation of another fundamental aspect of the decision-making activity. Designers seldom start from first principles. In most cases, the designer builds on existing solutions from previous design situations that are in some way related to the problem under consideration. From this viewpoint, the decision-making activity involves the modification, refinement, enhancement, and combination of existing solutions into a new hybrid solution that satisfies the requirements of the given design problem. In other words, building and environmental design can be described as a process in which relevant elements of past prototype solution models are progressively and collectively molded into a new solution model. Very seldom are new prototype solutions created that do not lean heavily on past prototypes.
Finally, there is a distinctly irrational aspect to design. Donald Schön refers to a “… reflective conversation with the situation …” (Schön,
1983
). He argues that designers frequently make value judgments for which they cannot rationally account. Yet, these intuitive judgments often result in conclusions that lead to superior solutions. It would appear that such intuitive capabilities are based on a conceptual understanding of the situation that allows the designer to make knowledge associations at a highly abstract level.
Based on these characteristics, the design activity can be categorized as an information-intensive process that depends for its success largely on the availability of information resources and, in particular, the experience, reasoning capabilities, and intuition capacity of the designer. The appropriate blending of these skills is as much an art as a science.
Much of the science of design falls under the rubric of building science, which includes climatic and thermal design determinants, day-lighting and artificial lighting, and acoustics. The field of building science is built on solid rational foundations that are based on scientific concepts and principles. This does not mean, however, that an in-depth knowledge of science and mathematics is necessarily required for the application of consistent building science principles during the design process. In most cases an understanding of the higher-level technical notions involved is sufficient for the designer to make the necessary decisions during the early design stages, when the conceptual design solution is formulated. However, it is most important that those decisions are sound, so that they can be translated into detailed solutions during later design stages by consultants with specialized expertise.
Accordingly, the purpose of this book is to describe and explain the underlying concepts and principles of the thermal, lighting, and acoustic determinants of building design, without delving into the detailed methods that are applied by engineers and other technical consultants to design and implement actual system solutions. Nevertheless, there are some fundamental mathematical methods and scientific concepts that are a prerequisite for a full understanding of even those largely qualitative descriptions and explanations. For this reason Chapter 1 is dedicated to brief explanations of mathematical methods, such as the principal rules that govern the solution of equations, the notion of logarithms, and elementary statistical methods, as well as some basic scientific concepts such as the notion of stress and strain, the difference between objective and subjective measurements, temperature scales and other units of measurement that are used in building science, and the idealized notion of a black body in physics. Readers who have an engineering or science background may well wish to pass over this chapter.
Exploration of the thermal building environment is divided into four chapters. Chapter 2 deals with the principles of thermal comfort, and Chapter 3 translates these principles into conceptual building design solutions. Chapter 4 examines the heat-flow characteristics of the building envelope and explains steady-state design methods that form the basis of most building codes, with examples. Chapter 5 explores the sun as a natural heat source and describes the principles of active and passive solar building design solutions.
The treatment of light is divided into three chapters. Chapter 6 introduces the scientific principles of light, color, and vision. In particular, it provides an historical account of the difficulties that were encountered by physicists in formulating a scientifically plausible and con sistent explanation of the nature of light. Chapter 7 stresses the importance of daylight in building design, presents the Daylight Factor design concept and methodology, and concludes with a discussion of glare conditions and their avoidance. Artificial lighting is the subject of Chapter 8. This chapter delves into the prominent role that electricity plays in the production of light by artificial means and compares the efficacy and characteristics of the various commercially available light sources in terms of the energy-to-light conversion ratio, lifespan, available intensity range, color rendition properties, and cost.
The various aspects of sound that impact the design of the built environment are also divided into three chapters. Chapter 9 discusses the nature of sound as a physical force that sets any medium through which it travels into vibration. This chapter lays the foundations for the treatment of sound as an important means of communication and source of pleasure in Chapter 10, and as a disruptive disturbance that must be controlled in Chapter 11.
Chapters 2 to 11 are largely historical, because they deal with the concepts and principles of building science that were mostly established during the emergence of this field of architecture in the post-World War II period of the 1950s and 1960s. Based on existing scientific premises in physics and other sciences, these foundations have gradually become an increasingly important component of the education and training of architects. However, it can be argued that except for some innovations in artificial light sources, relatively minor mechanical system improvements, and alternative energy explorations, little was added to this body of knowledge during the concluding years of the twentieth century.
There are strong indications that this will change quite dramatically during the twenty-first century, owing to an increased awareness of the human impact on the ecology of planet Earth. Clearly, the sustainability movement will have a major impact on the design and construction of the built environment during the coming decades. For this reason the final section of this book, Chapter 12, provides an introduction to ecological design concepts and describes both the objectives that are being established and the approaches that are emerging for meeting sustainability targets in building design and construction during the twenty-first century.
Multiple choice questions and answers for all chapters except Chapters 1 and 12 can be found on the website
www.wiley.com/go/pohlbuildingscience.
