Service Life Of Building Components Research Articles

Degradation Assessment of Natural Stone Claddings over Their Service Life: Comparison between Tehran (Iran) and Lisbon (Portugal)

Now more than ever, the construction sector is aiming to adopt more sustainable solutions. To achieve this purpose, more durable solutions must be adopted, making rational decisions at the design and maintenance stages regarding the conditions of environmental exposure and use. In this sense, knowledge regarding the service life of building components is crucial. This knowledge should not be a general concept, or a standard value, and adapting practices from one country to another is extremely challenging. In this sense, this study analyses the service life of natural stone claddings. We adopt a methodology initially proposed for Lisbon (Portugal), intending to evaluate its applicability to other geographical contexts, in order to perform a more reliable service life prediction of stone claddings located in Tehran (Iran). An estimated service life of 65 years was obtained for a sample of 162 stone claddings directly adhered to the substrate, located in Tehran, which were analysed by in situ inspections. The impact of different conditions (e.g., type of stone and environmental exposure conditions) on the service life of stone claddings in Tehran was quantified, which revealed that the exposure to environmental agents, such as wind, rain and pollutants, is the main cause of degradation of the natural stone claddings.

Preliminary Service Life Estimation Model for MEP Components Using Case-Based Reasoning and Genetic Algorithm

In recent decades, building maintenance has been recognized as an important issue as the number of deteriorating buildings increases around the world. In densely populated cities, building maintenance is essential for ensuring sustainable living and safety for residents. Improper maintenance can not only cause enormous maintenance costs, but also negatively affect residents and their environment. As a first step, the service life of building components needs to be estimated in advance. Mechanical, electrical, and plumbing (MEP) components especially produce many maintenance-related problems compared to other components. In this research, a model was developed that applies the genetic algorithm (GA) and case-based reasoning (CBR) methodologies to estimating the service life of MEP components. The applicability of the model was tested by comparing the outputs of 20 randomly selected test cases with those of retrieved similar cases. The experimental results demonstrated that the overall similarity scores of the retrieved cases were over 90%, and the mean absolute error rate (MAER) of 10-NN was approximately 7.48%. This research contributes to the literature for maintenance management by not only presenting an approach to estimating the service life of building components, but also by helping convert the existing maintenance paradigm from reactive to proactive measures.

Sustainability Assessment of a Residential Building using a Life Cycle Assessment Approach

Building and construction industry is responsible for resource scarcity, global warming impacts, land use changes and the loss of bio-diversity, which have direct and indirect socio-economic implications. Sustainable building design is thus inevitable through the selection of highly durable and less energy intensive-materials that could reduce environmental degradation in an economically viable and socially acceptable manner. This paper presents the life cycle sustainability assessment (LCSA) framework to assess the environmental, social and economic objectives of residential buildings. Two buildings of different material compositions have been used to test this framework. Firstly, the service life of this building has been calculated as durability of building materials play a key role in enhancing resource conservation for the future generations. A factor method has been used to carry out the service life of each component of the building envelope. The minimum estimated service life of building systems is considered as the overall service life of building components. Secondly, a life cycle assessment framework utilising environmental life cycle assessment, life cycle costing and social life cycle assessment have been utilised to determine environmental, economic and social indicators of the studied buildings. All these triple bottom line indicators in this framework have been calculated on an annual basis in order to capture the advantage of increased service life of buildings. This framework will be applied to assess the sustainability performance of alternative buildings for comparative analysis and to find out the most sustainable building option.

A probabilistic tool for evaluating the effectiveness of financial measures to support the energy improvements of existing buildings

LCC procedures are commonly used in building retrofit interventions for the evaluation of the costs and benefits of different solutions. LCC methods are also commonly applied to energy retrofit interventions according to UNI-EN 15459. However, these procedures can give significantly different results in relation to the methods used to define the economic and technical parameters used in the calculation. Several authors have highlighted how the uncertainties related to the quantification of the costs of initial investment and maintenance, the economic scenarios (inflation and interest rates), the costs of energy and labor and the "service life" of the components strongly influence the results and the assumption of different data sets can result in significantly different results. Several authors pointed out that it is necessary, prior to these procedures, to perform sensitivity analyzes, useful for understanding if and how each of these parameters can influence the results, which leads to the need to use probabilistic methods. The study reported here analyses the influence that different assumptions about the service life of building components have on the economic benefits brought by interventions of energy requalification. Specifically, through a specially developed probabilistic procedure, the influence on the global costs of different assumptions about the probability distributions and the specific parameters characterizing each of them related to the service life of components useful to realize the thermal insulation was evaluated. the envelope of existing buildings. In particular, four different probability distributions (normal, uniform, left triangular, right triangular), different values of the median have been taken into consideration for the same distribution amplitude and the global costs and the return time values have been evaluated. investment considering different alternative economic scenarios for inflation and interest rate.

Leveraging BIM for digital built environment asset management

A National Institute of Standards and Technology (NIST) study shows that all stakeholders in the capital facilities industry waste a huge amount of money looking for, validating, and/or recreating facility information that should be readily available. The total cost of these activities within the capital facilities industries in the United States was conservatively estimated at $15.8 billion in 2002, with two-thirds of that cost occurring during the facilities’ operations and maintenance phase. This is confirmed by the International Facility Management Association (IFMA) Maintenance Survey in 2009, which states that the loss of information generates an added cost of 12.4% of total annual mean OM (2) management of mechanical equipment status; (3) qualitative condition assessment of buildings; and (4) appraisal of the service life of building components and systems according to ISO 15686-8. These four tools allow to compute and control some key indicators of the asset, with also the possibility to compare them inside a portfolio. This paper presents the four tools, paying also attention to the workflows to be followed and to the different data needs of the stakeholders involved.

Deformation of multi-storey flat slabs, a site investigation

Traditional reinforced concrete slabs and beams are widely used for building. The use of flat slab structures gives advantages over traditional reinforced concrete building in terms of design flexibility, easier formwork and use of space and shorter building time. Deflection of the slab plays a critical role on the design and service life of building components; however, there is no recent research to explore actual deformation of concrete slab despite various advancements within the design codes and construction technology. This experimental study adopts the Hydrostatic Levelling Cells method for monitoring the deformation of a multi-storey building with flat slabs. In addition, this research presents and discusses the experimental results for the vertical deformation.

Application of the factor method to the prediction of the service life of external paint finishes on façades

The main goal of this study is to predict the service life of external paint finishes and contribute to the subject of construction elements´ durability. The service life is estimated using the factorial method proposed by ISO 15686, since, despite some criticism, this method excels as a simple and efficient tool with great potential for use in the planning of maintenance operations. The model proposed is based on a field survey of 323 coatings. The factor method estimates the service life of building components by multiplying their reference service life by weighting values applied to several factors affecting the performance of the elements under study. In this study the durability factors are obtained through iterative simulations. The results are analysed based on a set of criteria and statistical indicators. The results are suitable and reliable for most of the deterioration variables considered and the factor method proves to be an efficient tool to evaluate the service life of external paint finishes. This work is intended as a contribution and reference for future developments within the subject of durability in the construction industry as knowledge on the performance of given materials or constructive systems over time allows estimations of when to invest in maintenance/repair and of the amount of resources that will be required.

Modeling the Degradation Rate of the Wood Frame Doors and Windows of the National Palace of Sintra, Portugal

AbstractModeling the service life of building components is a key requirement for several purposes, including the implementation of an effective and efficient asset-management system, life-cycle assessments, or life-cycle cost calculations. Because the phenomena underlying the degradation of building components is highly complex, it is common to use statistical approaches for modeling purposes. This paper is focused on the statistical modeling of the service life of the wood frame doors and windows of the National Palace of Sintra. A review of the main factors of degradation of traditional linseed-based painted wood frame doors and windows and of the approaches that have been used to model the service life of building materials and components is presented. The influence of the exposure to weather agents on the degradation rate of external wood frame doors and windows is investigated and a model to estimate the average condition level is proposed. The proposed model takes into account radiation and wind-dr...

Development of corrosion risk map for Peninsular Malaysia using climatic and air pollution data

Malaysia has catapulted to an era of major transition. This rapid transition has also cause impact to the environment. The human activities contribute to pollutions. Buildings and it component's performances are affected directly or indirectly by air pollutions and climate factors. It has triggering and accelerating degradation processes. When deterioration start, service life of the buildings and its components will decrease. This paper presents initial development of corrosion risk map for Peninsular Malaysia using Geographical Information System (GIS). The air pollution and climate data obtained from Malaysia Meteorology Department (MMD). The air pollution data was the salt ion deposition of nitrate, chloride and sulphate in a form of wet fall out (WFO). The corrosion risk map generated using geographical information system (GIS) using inverse distance weighing (IDW) and weighted overlay method. It found that the corrosion risk map can be generated with further site verification and it can be used by engineers for further prediction of service life of building components in achieving sustainable construction design.

Environmental impact of dwellings in use: Maintenance of façade components

The use of dwellings contributes significantly to human-induced environmental burden in a number of ways, including energy consumption and the maintenance and replacement of building components. The present study deals with the maintenance and replacement of external doors and windows in a Dutch reference dwelling and describes how life cycle assessment (LCA) methodology can be applied to quantitatively assess the environmental impact of various maintenance scenarios for the façade components. First, the most effective way to reduce the negative environmental impact in this context is to replace existing single and double glazing with high efficiency double glazing, thereby reducing energy consumption for space heating. Second, the use of timber frames causes less environmental impact than PVC frames with a steel core. Third, extending the service life of building components decreases the input of material resources, production processes and the waste processing of building components during the service life of a dwelling, which is beneficial to the environment. Maintenance activities should only be performed when needed, keeping the building components in good condition while minimising the transportation movements of maintenance workers. Finally, protecting timber components with an alternative paint that contains less solvent does not lower the assessed environmental impact, but low-solvent paint may be preferred because of health aspects both for maintenance workers and occupants of the dwelling.

Service-life assessment of building components: application of evidence theory

This paper deals with the assessment of the service life of in-service building components subjected to known environmental and usage conditions. This assessment is complex because of two primary features. First, the assessment has to be carried within a multiscale context: a geometric scale that ranges from the material or elemental to building scale; a range in the complexity of the degradation (phenomena that varies from a single phenomenon to the consideration of several degradation scenarios); a range of possible performance requirements, from one function to several; and consideration, as well, to the time over which the process is carried out that may span from the design stage to that of management and repair. Second, this assessment must also take into consideration the availability and features of service-life data that by nature is heterogeneous, imprecise, uncertain, and incomplete. In this context, a comprehensive methodology is developed using all available data on service life derived from existing methods of service-life assessment of materials, elements or building components. Such data may, for example, be extracted from fundamental studies on durability, accelerated short-term exposure tests, statistical methods, factorial methods, feedback from practice, or expert opinion or other sources. The main stages of this methodology are: (i) identification of all possible degradation scenarios provided by failure mode and effects analysis (FMEA); (ii) collection of all available service-life data (SL-data) associated with these degradation scenarios, transformation of this data into a fuzzy-set format, and assessment of its quality; (iii) processing of unification of data and aggregation of data; and (iv) assessment of the service life of building components. The case study of a window unit allows for: (i) service-life assessment of a building component to be processed by unification of data and aggregation of data and (ii) a conclusion to be deduced.

Service life prediction of exterior cladding components under standard conditions

An empirical method was developed for the prediction of the service life of building components, based on an evaluation of their actual performance and on the identification of failure mechanisms affecting their durability. The service life of exterior components subjected to normal service conditions is predicted. Four types of exterior claddings are exemplified: cementitious mortar, synthetic rendering, ceramic mosaic, and wet‐fixing stone cladding. The proposed prediction models yield high degrees of fit to the data (R 2 in the range of 0.86 to 0.93 at a 0.0001 level of significance). Life cycle costs (LCC) analysis – following service‐life prediction results – leads to the conclusion that maintenance and replacements costs account for 10–80% of initial capital costs. Synthetic rendering exhibited the highest LCC effectiveness, reflecting durability and low capital costs. The method can be used for planning preventive maintenance, evaluating economic implications of failures, and planning service life.

Accelerated Test Methods to Determine the Long-Term Behavior of Composite Highway Structures Subject to Environmental Loading

Research on fiber-reinforced plastic composites has explored the effects of selected aqueous environments on the mechanical and physical properties of these composites. The composite materials tested were produced using the pultrusion process. Resins included in the study were polyester and vinylester. Fibers included were E-glass, carbon, and aramid. Environments considered were air, deionized water, acetic acid at two concentrations, and ammonia at two concentrations. Temperatures considered were room temperature, 50 and 80°C. Mechanical testing included tension, flexure, and short beam shear tests. Weight loss, thermogravimetric, and calorimetric measurements were made to determine whether degradation was taking place in the fiber or matrix phases of the composite. Accelerating factors for the various environments were calculated using the framework outlined in ASTM E 632, Standard Practice for Developing Accelerated Tests to Aid in the Prediction of the Service Life of Building Components and Materials. It was observed that a combination of weight loss and thermogravimetric measurements are useful in determining whether degradation in the composite is due to fiber or matrix degradation. Trends in weight loss closely parallel loss of mechanical properties in polyester/glass rods.