By: Architectural Institute of Japan (AIJ)
Reported by: Sheau-Chyng Wong (M2)
Chapter 2 / The Vision and How to Make and Use (part 2)
Chapter 2-3, comprising five sub-chapters, focuses on “how to economize the resources”.
Industrial Science Professor Yashiro introduces the concept of ‘building life-span’ by first explaining ‘design life’; ‘design life’ represents a ‘target value’ of “time-period during which it is possible to maintain performance and utility of the building’ while ‘life-span’ is its ‘actual value’. The “short life-span syndrome” in Japan has resulted in various problems, in particular: 1) the difficulty of future generations maintaining the lifestyle of the current generation due to depletion of non-renewable resources; 2) generation of massive amount of construction waste; 3) burden of housing loan being passed on to the next generation; and, 4) impediment of the maturing process of town-scaping. The causes of such “short life-span syndrome” are believed to have stemmed from socio-economic factors; to cope with these issues, three solutions are proposed: 1) provide incentives through laws and housing loans to encourage renovation and discourage demolition and rebuilding; 2) restrain the increase of floor area; and, 3) upgrade the functionality of existing buildings.
Due to the difficulties in predicting the changes in the needs and conditions of a building (e.g., technological advancements, housing standards’ upgrades, and resident lifestyles), it is necessary that buildings and houses are designed with sufficient flexibilities for future renovations. Such awareness is reflected in a concept called “adaptable building”, which possess the “capacity to change” in five aspects: span between structural elements, amount of indoor bearing walls, flatness of structural elements, floor height and separation of wiring/piping from the structure. To illustrate further, Professor Yashiro introduces a building concept known as “SI Building” or “Open Building”, which emphasizes independent decision-making by stakeholders; residents are given full control in creating an identifiable space (‘infill’) for themselves while the ‘skeleton’ external to the dwelling space is taken care by other parties or local community.
In developed countries, half of the total annual resource consumption is due to construction, and therefore the efficiency of resource use in construction directly impacts the overall efficiency of resource use in a country. Resource efficiency can be expressed as:
resource efficiency = quantities of benefits and services / quantities of resource use,
implying that resource use is acceptable if a sufficient level of benefits and services could be yielded. For this, Weisz_cker et al recommended ‘Factor 4’, while Schmidt-Bleek proposed ‘Factor 10’ as the target efficiency.
In the subsequent sub-chapter, refurbishment technologies are presented by Nohara. Towards the realization of a ‘recycling-based society, refurbishment technology is essential for the extension of life-span of old buildings, but they are often faced with architectural and economic constraints. One particular example of architectural constraint is the limitations in floor height, shaft area etc. of skyscrapers built economically in the 1960’s; refurbishment of such type of buildings may require reduction in the weight and size of new products.
According to Professor Yashiro, the term ‘eco-material’ may have grown so popular that its technical meaning has become obscure. Technically, an ‘eco-material’ must be assessed against the following criteria: renewability and remaining reserves of the raw material, reusability, use of industrial byproducts or recycled materials as raw material, reduction of environmental impacts during manufacturing, reduction of environmental impacts during disposal or destruction, reduction of impact on ecosystem and health during manufacturing, and enhancement of comfort, texture and amenity enjoyed through the five senses.
Reporter’s Own Thoughts
Our lab recently watched a video about the history and development of the waste management and recycling system in Japan, which is one of the most unique among developed countries. Recycling household waste has apparently become a routine practice for all Japanese since the enactment of the Basic Law for Establishing a Recycling-based Society. However, until the discipline of recycling is extended into the building practice and accepted as a norm for the society, Japan’s vision to become a true ‘recycling-based society’ will not be realized.
 Basic Law for Establishing a Recycling-based Society was enacted in June 2000. It consists of six related laws, including Waste Disposal Law, Law for the Promotion of Effective Utilization of Resources, Construction Material Recycling Law, and Law on Promoting Green Purchasing.