The Effect of life-cycle analysis on the design of mass housing projects

Abstract

ABSTRACT In each society there are various social, cultural, ethnical, geographical and built environment conditions, which affect the way of living and put forward different needs and various solutions in architectural products. The most important one might be the 'house', which is supposed to fulfil physical and psychological needs of the inhabitant and be suitable for* his/her lifestyle and economical conditions. Housing is not only a technical concern. It has a significant role in the development of any society and is of utmost importance for social, economic and cultural progress. Its social, financial and qualitative aspects have to be considered by generating a comprehensive approach. A luxurious and comfortable building may sometimes house a badly managed enterprise that shows very poor performance. There are two main causes to this situation: the lack of a systematic approach to the subject during the design stage, and the absence of a defined party that should be responsible for its implementation. Decisions that are given at the first stages of a construction project, that is the design stage, have important effects on the quality of life through the whole life cycle. Today, in construction sector researches on relations between design decisions and the lifecycle cost and quality gain more and more importance. Recent trends to minimize facility obsolescence, meet the economic, non-monetary aspects such as social and cultural; and achieve environmental sustainability have forced the design decision makers to generate different design alternatives and examine them in greater detail. There are different target groups for various mass housing projects. But in any case owners want buildings with the lowest possible initial project cost, as well as minimized annual energy consumption, maintenance cost, replacement cost, and staffing cost, together with the longest serviceable building life attainable within the other parameters, the highest possible quality, the best appearance. Life cycle analysis is a comparatively new way to study all these parameters and try to achieve a feasible alternative. Life cycle cost analysis, which is the economic evaluation part of the analysis, can be described as the `spine` of the life cycle analysis. Accordingto the broadest meaning; Life cycle costing is a mathematical method used to form or support a decision and is usually employed when deliberating on a selection of options. But for design professionals, life cycle costing can be described as an economic assessment of design alternatives, considering all the significant costs of ownership over an economic life expressed in equivalent amount of money. The life cycle cost of a building is defined as all costs that emerge throughout its entire life cycle- from construction, through operating and maintenance, to disposal. The maintenance costs are defined as the cost of keeping the building in good repair and working condition. Operating costs are defined as the costs associated with operating the building itself. Running costs are the sum of maintenance and operating costs. Although the LCC approach should be used in the early stages of the project, so that the maximum performance could be achieved, life cycle costing applications can be made through the all stages of the project. In performing an LCCA, the design professional deals with costs of several types that are expected to be incurred at various times during the analysis period. The analysis may be conducted at anytime during the design phase, so these costs may range in preciseness from actual costs or more exact estimates become known. All the costs for each design alternative that is chosen through various management procedures have to be examined by using certain economic analysis techniques such as present worth method or annualized method and then a sensitivity analysis have to be applied to obtain more accurate solutions. The non-monetary benefits are also evaluated with a special matrix system to achieve the optimum alternative for the specific mass housing project. The general belief is that life cycle costing will enable the selection of the most economic solution for the whole life of a project. If the forecasts are unreliable because of an absence of appropriate data or if estimates are misleading because they rely upon the myth of being able to forecast the future then the reliability of the technique declines. But in any case the philosophy of whole cost appraisal is certainly preferable to the narrow initial cost estimating approach. As experience grows in these areas, more efficient performance from the facilities can be expected.