Developing a multicriteria approach for the measurement of sustainable performance

In Australia, cost–benefit analysis (CBA) is one of the conventional tools used widely by the public and the private sectors in the appraisal of projects. It measures and compares the total costs and benefits of projects that are competing for scarce resources in monetary terms. Growing concerns that the values of environmental goods and services are often ignored or underestimated in the CBA approach have led to the overuse and depletion of environmental assets. A model of a sustainability index as an evaluation tool that combines economic, social and environmental criteria into an indexing algorithm is presented and described. The sustainability index uses monetary and non-monetary approaches to rank projects and facilities on their contribution to sustainability. This process enables the principle of trade-off to occur in the decision-making process and thereby allows environmental values to be considered when selecting a development option. This makes it possible to optimize financial return, maximize resource consumption and minimize detrimental effects to the natural and man-made world. A case study is used to demonstrate the model.     

Partnership in building energy performance contracting

Building energy performance contracting is a business strategy to assist building owners overcome the financial barriers for improving the energy performance of their buildings. In return for the investments made into the energy-saving measures, the energy service contractors would share with the building owners the energy cost saving. Although the contractual arrangement is meant to create a win-win situation, disappointments could arise due to mismatches between the expected and actual outcomes. From a micro-economics viewpoint, the key factors contributing to the failure of a building energy performance contract are reviewed. To solve the commonly encountered problems in building energy performance contracting, it is proposed the conventional performance contract is replaced with a partnership formed jointly by the building owner and the energy service contractor, with the latter assuming the role of the performance contractor. This would unite the goals of the two parties and cultivate genuine cooperation between them. The key features for this new contractual arrangement are described along with how this arrangement could resolve typical energy performance contracting problems.     

Integrating a performance-based approach into practice: a case study

Organizations in both the public and private sectors are increasingly focusing on performance and results, on outcomes rather than on outputs, or on the ends rather than the means to accomplish their mission(s). In the US, the federal government actually embedded this focus in the Government Performance and Results Act, 1993. Since then, US federal government agencies have been in the process of a major shift in their management procedures. The paper illustrates how the US Coast Guard (USCG) is implementing these procedures. USCG missions are clearly defined in 'legal authorities' by the US Congress. These missions in turn are also responding to external public and industry drivers and trends. The USCG is highly dependent on its logistical assets to support its operational units and accomplish its missions. Therefore, the Civil Engineering Program, which is that part of the organization responsible for the most stable and long-lasting assets, namely constructed assets, has been commissioned to create and implement a far-reaching Shore Facility Capital Asset Management system, including Regional Strategic Plans. The design of this integrated system is part of a Framework for Integrated Decision-Making for the USCG as a whole. It is performance based and results oriented. It includes metrics that will allow the USCG to measure objectively and transparently how it performs against the requirements of its missions and strategic goals. All parts of this integrated system are presented, with emphasis on the suitability metrics that most directly link assets to missions.     

Towards a knowledge-based assessment of conceptual cost estimates

Conceptual cost estimates are critical inputs for owners' decision-making in the early planning stages of construction projects. However, a recurrent problem associated with conceptual estimating is how to assess the quality of the estimates, i.e. the expected accuracy and reliability of cost figures given the uncertainty and risk that every project will face during its development. One of the approaches used to assess the quality of an estimate is the application of expertise and experience. This paper examines the problem of the quality of conceptual estimating, proposes a model of this problem based on existing knowledge and shows how the model was used to develop an assessment system. Through the use of expert knowledge, it is possible to get an appropriate initial assessment of the expected accuracy and reliability of an estimate which should be later complemented with historical and empirical information.     

Simple durability test for cement stabilized blocks

Compressed and cement-stabilized blocks are now recognized as important walling units for building low-cost dwellings in developing countries. Although the durability of their surfaces under in-service exposure conditions in the humid tropics has become a major matter of concern, it has received little formal research. Premature deterioration - as typified by surface erosion, mass loss, pitting, cracking and crazing - is common. A weather-resistant surface is required if a block is to remain durable for its service lifetime. However, current accelerated ageing tests to predict the overall performance of blocks under conditions causing surface deterioration (wetting, abrasion and drying) are inadequate. A new method is required that can be applied to blocks immediately after curing to evaluate the likely durability of their surfaces. The present paper explores the suitability of using the slake-durability test, originally developed for argillaceous rocks, to evaluate the durability of low-cost walling materials. During the test, surface erosion leading to mass loss of between 1 and 50% is recorded within only 10 minutes, representing an acceleration of in-service ageing by a factor of around 1 million. The test method proved reliable, controllable and repeatable. More importantly, the ranking of materials via their performance in this test correlated well with a ranking of their durability in service based on long professional field experience in Uganda. It is concluded that the slake-durability test not only is robust, but also provides a quick predictive surface and quality test for cement-stabilized blocks and other like materials.     

Durability and the factor method of ISO 15686-1

Interest in the service life of buildings and components and the future need for maintenance is growing, and the methodology for service life planning is starting to appear in standards. The standard ISO 15686 prescribes a factor methodology for deciding about the expected service life of a component with a prescribed probability of earlier failure. The methodology is based on extensive knowledge about materials and building technology, and examples of the use of this methodology on building components are of value for the discussion on service life planning. Results from a condition survey of timber windows are used to define the service life and effect of the factor method in the Standard. Wood is a very variable material, and for wooden windows maintenance plays a key role in the durability of the component. In this instance, condition assessment is, therefore, not sufficient to estimate the service life. Information about former maintenance and refurbishment is also needed. The results from a condition assessment and the house owner's answers to a questionnaire are combined to evaluate the estimated service life of the windows. The factors for the standardized method for estimating service life with a given confidence limit are shown to have a wide range in values that give considerable uncertainty to the practical use of the standardized methodology. For example, it is shown that the estimated service life with an 80% confidence limit is much lower than the average service life. Thus, the question is posed whether there is any meaning in estimating the lower limit of service life.