OVERVIEW

Approximately two thirds of man’s impact on nature is directly or indirectly related to the construction industry. Thus the most important challenge of modern construc-
tion business is to develop solutions that will lead to a better balance between man and nature. Environmental issues in town planning and construction can be seen not as a burden but as an opportunity.

Urban and city planning has the key role in sustainable development. Current planning practices tend to separate living, working and business areas even if the benefits of a dense and multi-functional urban area are obvious. Integrating living, leisure and working will result in better life.

Designing sustainable buildings and cities requires greater integration of different functions and techniques than does a standard design. A simple summing up of qualities does not necessarily bring good results; it takes a thorough consideration of inter-relationships. Sustainable building solutions are built on whole building practices, utilizing the latest technology together with natural ventilation and daylight.

Over a building’s lifetime, change is inevitable. Increasing changes in user demands require buildings and installations to be flexible enough to cope in both new construction and adaptive re-use projects. Efficient use of space and prolonging the life span of the built environment are impor-
tant measures with which the environmen-
tal performance can be improved.

MAXIMIZING DAYLIGHT

Daylight is the healthiest form of light and is important to the physiological and psychological wellbeing of people. Daylight solutions help reduce the need for artificial light and save electricity. Natural light helps increase employee satisfaction, productivity and may increase overall sales in retail environments. Daylighting helps create a visually stimulating and productive environment for building occupants, while reducing as much as one-third of total building energy costs.

Daylighting design is not so much how to provide enough daylight to an occupied space, but how to do so without any un-
desirable side effects. It involves more than just adding windows or skylights to a space. It is the careful balancing of heat gain and loss, glare control, and variations in daylight availability. Applications need to adopt the latest glass technologies and utilize computerized controlled systems. Roof lights require protection against direct sunlight during the summer and heat loss during the winter.

New types of glass have improved the possibilities for designing well-functioning buildings with glass as the major material for the envelope. Glazing can easily and inexpensively be altered to increase both thermal and optical performance.

EMPLOYING NATURAL VENTILATION AND CLIMATE CONTROL

Natural ventilation has become an increasingly attractive method for reducing energy use and maintaining a healthy, comfortable, and productive indoor environment. In favourable climates and building types natural ventilation can save 10%-30% of total energy consumption. When correctly designed additional mechanical cooling is not required.

Natural ventilation systems rely on pressure differences to move fresh air through buildings. Pressure differences can be caused by wind or the stack effect created by temperature differences or variations in humidity. It is useful to think of a natural ventilation system as a circuit, with equal consideration given to supply and exhaust. Openings between rooms such as transom windows, louvers, grills, or open plans and internal courtyards are techniques to complete the airflow circuit through a building.

Natural ventilation implies a holistic building concept, and may be achieved by various architectural solutions –more recently by using a computer controlled double skin facade. Wind and stack pressure drive the air flow up through the void created by the double skin facade. The flow rate is determined by a number of factors including wind speed and the height of the top of the facade void, or in still conditions, the temperature generated inside the void.

Natural ventilation can be used as an alternative to, or together with mechanical ventilation. Hybrid ventilation takes advantage of natural ventilation forces, using mechanical forces only when natural forces are not sufficient.

SUSTAINABLE MATERIALS AND STRUCTURES

A building that is sustainable must, by nature, be constructed using sustainable materials. Structural and material selections are based on overall sustaina-
bility, while emphasizing the specific conditions of each design in terms of material and structural life spans, environmental impact, availability and recycling.

A life cycle analysis of building products, from the gathering of raw materials to their ultimate disposal, provides a better understanding of the long-term costs of materials. These costs are paid not only by the client, but also by the owner, the occupants, and the environment. Each step, from gathering raw materials, manufac-
turing, distribution, installation and maintenance, to ultimate reuse or disposal, is examined for its environmental impact.

Key design factors in terms of ecological and financial efficiency involve functionality, flexibility and efficiency in spatial design, while material and structural selections are based on durability and ease of maintenance.