Methodologies for Service Life Prediction of Buildings

Application of the Factor Method to the Service Life Prediction of Etics

“…This methodology was initially proposed by Shohet, Rosenfeld, Puterman, and Gilboa (1999), who defined different degradation patterns; among these patterns, the "S-shaped" curve seems the most relevant to illustrate the overall degradation of ETICS, representing a degradation phenomenon whose intensity changes over time, i.e. the degradation of ETICS occurs initially at a faster pace, revealing the occurrence of anomalies in earlier years, which apparently stabilize over time, accelerating again near the end of their service life (Silva, de Brito, & Gaspar, 2011, Silva et al, 2016. Therefore, to obtain a "S-shaped" pattern, which illustrates the physical phenomenon, a third-degree polynomial line was adjusted to the scatter of points belonging to the sample, using a methodology similar to the one proposed by Gaspar and de Brito (2008) and adapted by Ximenes et al (2015).…”

“…In this study, two methodologies are applied in order to evaluate the service life of ETICS and in order to quantify the durability factors (Silva et al, 2016): i) the graphical method (GM), applying the extrapolation of the degradation curve for each point of the sample, estimating for each case study the age (x) in which the maximum allowable degradation level (y) is reached; i.e. the service life can be estimated for each case study through the graphical intersection between the curve for each case study and a horizontal line corresponding to the S w considered as the maximum allowable degradation level; ii) the degradation curves (DCs), in which an average degradation curve is plotted for each one of the durability factors considered, estimating the average predicted service life for each characteristic through the intersection between the maximum degradation level and the average curve.…”

“…The standard refers that the level of application of the model depends on the "actual purpose of the estimation, type and quality of available data and models, skill level and type of expertise of the user(s) making the estimation and resources and time available for the calculation". This methodology, admitted as a general framework for service life prediction (Emídio, de Brito, Gaspar, & Silva, 2014;Silva, de Brito, & Gaspar, 2016), allows obtaining an estimated service life based on a reference service life of a component or set of components, expected in current conditions of use, multiplied by different weighting coefficients related to the specific conditions of the element under analysis (Hovde, 2004). These parameters are crucial for the durability and performance of claddings and may, according to more or less favourable conditions, increase or decrease the expected service life (Gaspar & de Brito, 2008).…”

“…ii) the considerable dependence on modifying factors and the difficulty in quantifying and organizing them hierarchically; iii) the high sensitivity and the assumption of a constant rate of degradation, not allowing understanding and characterizing the components' degradation over time (Rudbeck, 1999;Moser, 2004;Gaspar & de Brito, 2008;Silva et al, 2016). However, Gaspar and de Brito (2008) states that, despite being subjected to these and other criticisms, the factor method is the one with greater acceptance in the scientific community, being addressed in several studies with numerous variations and developments.…”

Leveraging BIM for digital built environment asset management

“…Although some research claim that the factor method is too simple to cope with complexity of building component degradation phenomena [48] or that it does not give any clue about the reliability of the estimation [49], it is commonly admitted as a general framework for service life prediction [50,51]. Moreover, the use of the factor method in a BIM-based asset management process is eased by [52], an international standard that provides information and guidance on the use of standards for information exchange [53] for service life planning of buildings and constructed assets and their components.…”