Quality building components: durability

The durability of building components is a quality that shows the time behavior of building components and is defined by the UNI 11156, "Evaluation of the durability of building components," such as the ability to perform the functions required during a specified period of time, under the influence of agents expected to exercise.

The propensity of the component performance studied in relation to the requirement of durability is obtained from learning of his life accompanied by the reliability of the component itself. The technical element is suffering a natural drop of performance over time in relation to the useful life also own the materials used to make it.

Beyond a certain threshold limit the performance of the component reaches values below which is no longer able to provide an effective response in relation to the function. Putting themselves in line with ISO 15686 "Buildings and constructed assets. Service life planning ", which provides the general framework at the international level on the assessment and management of the useful life of the building, the UNI 11156 circumscribes this life of the component as the period of time after installation during which the ' technical element maintains performance levels greater than or equal to the limits of acceptance.

The evaluation of the useful life lies in the value of the so called "spontaneous duration" the input data for evaluation (this duration is obtained through aging tests under the action of stressing agents).

In addition, the Service Life is then divided into a rating of "reference service life" and "estimated useful life", depending on who carries out the assessment and an objective arises. The evaluation of the "reference service life" is addressed to those bodies responsible for checking durability of the technical elements in the production phase that is to be inserted as an additional test to be made by producers to obtain the CE mark.

The term "reference" is thus the boundary conditions assumed by the manufacturer certifying the durability of its product outside the system and considering conditions of use and degradation plausible and that on average they occur. The "estimated useful life" is instead calculated by the designer and relative to the actual conditions in which it appears his project.

Looking at the data length declared in the Reference service life, the designer can make them more real by changing the terms of reference adopted by the manufacturer because they are more truthful than the conditions in the specific context of the project.

The standard provides the designer several methods based on statistical analyzes of both the context stressing that the behavior of materials. Both the ISO 15686 standard UNI 11156 Finally, the term also part of Design Life or "life project" which denotes the useful life of the designer aims, in terms of duration, of his.

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Translated via software

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Source:

Italian version of ReteArchitetti.it

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