Building science is the collection of scientific knowledge and experience that focuses on the analysis and control of the physical phenomena affecting buildings and architecture. It traditionally includes areas such as building materials, building envelope, heating, ventilation and air conditioning systems, natural and electrical lighting, acoustic, indoor air quality, passive strategies, fire protection, and renewable energies in buildings. In Europe, building physics and applied physics are terms used for the knowledge domain that overlaps with building science. The practical purpose of building science is to provide predictive capability to optimize the building performance of new and existing buildings, understand or prevent building failures, and guide the design of new techniques and technologies.
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Overview
Building science is the architecture-engineering-construction technology discipline that concerns itself with the 'mainly detail-design' of buildings in response to naturally occurring physical phenomenon such as:
- the weather (sun, wind, rain, temperature, humidity), and related issues:e.g. freeze/thaw cycles, dew point/frost point, snow load & drift prediction, lightning patterns etc.
- subterranean conditions including (potential for seismic or other soil + ground-water activity, frost penetration etc.).
under the constraints of
- characteristics of materials,(e.g.response to UV, freeze-thaw, rot, mold, Galvanic corrosion between dissimilar metals, and properties such as permeability of materials to water and water vapor, swelling, shrinkage, compatibility, etc.).
- physics, chemistry and biology such as capillary-action, absorption, condensation ("will condensation occur at a good or bad place within the wall?"), gravity, thermal migration/transfer (conductivity, radiation and convection), vapor pressure dynamics, chemical reactions (incl. combustion process), adhesion/cohesion, friction, ductility, elasticity, and also the physiology of fungus/mold.
- human physiology (comfort, sensory reaction e.g.radiance perception, sweat function, chemical sensitivity etc.).
- energy consumption, environmental control-ability, building maintenance considerations, longevity/sustainability, and occupant (physical) comfort/health.
The building science of a project refers to strategies implemented in the general and specific arrangement of building materials and component-assemblies.
The practical outcome of building science knowledge is reflected in the design of the architectural details of the building enclosure (see building envelope), and ultimately in the long-term performance of the building's 'skin'. The scope can be, and is, much wider than this on most projects; after all, engineering is applied science mixed with experience and judgement. When architects talk of "building science", they usually mean the 'science' issues that traditional engineering disciplines traditionally avoided, albeit there are emerging disciplines of 'building scientists', 'envelope consultants', and 'building engineers'.
Many aspects of building science are the responsibility of the architect (in Canada, many architectural firms employ an architectural technologist for this purpose), often in collaboration with the engineering disciplines that have evolved to handle 'non-building envelope' building science concerns: Civil engineering, Structural engineering, Earthquake engineering, Geotechnical engineering, Mechanical engineering, Electrical engineering, Acoustic engineering, & fire code engineering. Even the interior designer will inevitably generate a few building science issues.
Building Science Degree Video
Earthquake/seismic design
All kinds of structures are projected according to two strain conditions: static and dynamic. The static ones are tied to the structure's dead loads added to the so-called live loads (of people, furniture, etc.), the dynamic ones are tied to the natural, abnormal, and artificial movements (earthquake and loads wind) the structure can sustain during its life cycle. The parameters which characterize structure dynamics are tied to the geometry of the building and to the physical and mechanic properties of its composition. The parameters are:
- The fundamental frequency of vibration (f) and the respective oscillation period (T=1/f) (see oscillation frequency);
- The equivalent dumping coefficient (neq);
- The mode shape (the way in which the structure buckles);
The first parameter varies according to the structure stiffness; very tall and then very flexible buildings as skyscrapers (low oscillation frequencies) oscillate slowly with respect to lower and squat buildings, and according to the building mass. The second parameter takes into account all the dissipation phenomena tied to the viscosity of materials and to friction phenomena. The mode shape describes the way of deformation which the structure is subjected to during the seismic event, and highlights whether or not the structures presents a good seismic behavior.
Reducing the effect of earthquakes on buildings
By monitoring the response of structures subject to earthquakes and by applying new knowledge and technologies, scientists and engineers continuously develop design and repair techniques on buildings, so that their ability to control the earthquake effects will grow. In order to reduce the destructive effects of earthquakes both on new-built buildings and especially on older ones, there exist some seismic adjustment techniques, with the aim of reducing the strain effects that earthquake causes. These techniques can be divided into two different categories:
Base isolation: it is aimed to untie the ground-foundation system, so that the structure can be seen as it is "floating" on the ground during the seismic event, thus reducing the strains.
Dissipation systems: there exist various types of dissipation systems, but they all have in common the effect of increasing the previously seen viscous dissipation coefficient of the structure. The better known base isolation technique consists of inserting some special equipment (isolator (building design)) in the proximity of foundations. This equipment offers a high stiffness for vertical loads so that the structure is not subject to sinking, while offering a low stiffness for horizontal ones, which are peculiar of seismic events. This way all seismic effects are absorbed by the equipment, whereas the structure is subject to low oscillations and consequently to low strains.
The dissipation systems (dissipator (building design)) are made by a series of devices inserted on the inside of the building frame using different techniques, with the aim of slowing down the structure oscillation and dispelling seismic energy.
Topics in Building Science
Indoor Environmental Quality (IEQ)
Indoor environmental quality (IEQ) refers to the quality of a building's environment in relation to the health and wellbeing of those who occupy space within it. IEQ is determined by many factors, including lighting, air quality, and damp conditions. Workers are often concerned that they have symptoms or health conditions from exposures to contaminants in the buildings where they work. One reason for this concern is that their symptoms often get better when they are not in the building. While research has shown that some respiratory symptoms and illnesses can be associated with damp buildings, it is still unclear what measurements of indoor contaminants show that workers are at risk for disease. In most instances where a worker and his or her physician suspect that the building environment is causing a specific health condition, the information available from medical tests and tests of the environment is not sufficient to establish which contaminants are responsible. Despite uncertainty about what to measure and how to interpret what is measured, research shows that building-related symptoms are associated with building characteristics, including dampness, cleanliness, and ventilation characteristics. Indoor environments are highly complex and building occupants may be exposed to a variety of contaminants (in the form of gases and particles) from office machines, cleaning products, construction activities, carpets and furnishings, perfumes, cigarette smoke, water-damaged building materials, microbial growth (fungal, mold, and bacterial), insects, and outdoor pollutants. Other factors such as indoor temperatures, relative humidity, and ventilation levels can also affect how individuals respond to the indoor environment. Understanding the sources of indoor environmental contaminants and controlling them can often help prevent or resolve building-related worker symptoms. Practical guidance for improving and maintaining the indoor environment is available.[1]
Building indoor environment covers the environmental aspects in the design, analysis, and operation of energy-efficient, healthy, and comfortable buildings. Fields of specialization include architecture, HVAC design, thermal comfort, indoor air quality (IAQ), lighting, acoustics, and control systems.
HVAC Systems
The mechanical systems, usually a sub-set of the broader Building Services, used to control the temperature, humidity, pressure and other select aspects of the indoor environment are often described as the Heating, Ventilating, and Air-Conditioning (HVAC) systems. These systems have grown in complexity and importance (often consuming around 20% of the total budget in commercial buildings) as occupants demand tighter control of conditions, buildings become larger, and enclosures and passive measures became less important as a means of providing comfort.
Enclosure (Envelope) Systems
The building enclosure is the part of the building that separates the indoors from the outdoors. This includes the wall, roof, windows, slabs on grade, and joints between all of these. As part of its function, the enclosure must control (not necessarily block or stop) the flow of heat, air, vapor, solar radiation, insects, noise, etc. The comfort, productivity, and even health of building occupants in areas near the building enclosure (i.e., perimeter zones) are affected by outdoor influences such as noise, temperature, and solar radiation, and by their ability to control these influences.
High Performance Facades Case Studies [2]
Building Sustainability
Environmental design Part of building science is the attempt to design buildings with consideration for the future and the resources and realities of tomorrow.
A push towards Zero-energy building also known as Net-Zero Energy Building has been present in the Building Science field. The qualifications for Net Zero Energy Building Certification can be found on the Living Building Challenge website.
Certification
There are no professional architecture or engineering certifications for building science. It is currently a specialization within these broad areas of practice. In the US contractors certified by the Building Performance Institute, an independent organization, advertise that they operate businesses as Building Scientists. This is questionable due to their lack of scientific background and credentials. This is true in Canada for most of the Certified Energy Advisors. However, many of these trades and technologists require and receive some training in very specific areas of building science (e.g., air tightness, or thermal insulation).
List of principal building science journals
Building and Environment: This international journal publishes original research papers and review articles related to building science and human interaction with the built environment. [3]
Building Research and Information: This journal focuses on buildings, building stocks and their supporting systems. Unique to BRI is a holistic and transdisciplinary approach to buildings, which acknowledges the complexity of the built environment and other systems over their life. Published articles utilize conceptual and evidence-based approaches which reflect the complexity and linkages between culture, environment, economy, society, organizations, quality of life, health, well-being, design and engineering of the built environment. [4]
Building Simulation: This international journal publishes original, high quality, peer-reviewed research papers and review articles dealing with modeling and simulation of buildings including their systems. The goal is to promote the field of building science and technology to such a level that modeling will eventually be used in every aspect of building construction as a routine instead of an exception. Of particular interest are papers that reflect recent developments and applications of modeling tools and their impact on advances of building science and technology. Impact Factor: 0.631 [5]
Energy and Buildings: This international journal is devoted to investigations of energy use and efficiency in buildings. [6]
Source of the article : Wikipedia
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