B-12 (Buildings) / B-07 (Products) Replacement frequency

Aspect B-12 Replacement frequency
The frequency of replacement is related to the reference study period and the reference service life of the component to be replaced. The ratio between them could lead to a partial number of replacements (e.g. where the reference study period is 30 years but the reference service life for a component is 20 years). Should replacement cycles be calculated as ‘whole-number/full number’ of replacements, or does it make sense to calculate ‘proportionate/partial’ cycles of replacement?

related study objective

stand-alone LCA comparative assertion

related study phase

goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for

new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions As the baseline scenario, replacement cycles have to be calculated in whole numbers, according to EN 15978 and EN 15804 (examples are given there). Only whole numbers of replacements are allowed (no partial replacements). The number of replacements is related to the reference study period and the reference service life of the component to replace. The number of replacements must be rounded up unless justified.In order to show the effect of improved durability, a scenario with partial replacement cycles can be made. This scenario has to be documented and justified, and a sensitivity analysis conducted by comparison with the baseline scenario.
Rules from:
EN 15978:
8.6.4 Scenarios for refurbishment – Module B5

9.3.3 Replaceable components and number of replacements

EN 15804: B1–B5 Use stage information modules related to the building fabric: – B4 Replacement

6.10.3 Considered alternatives, the functional unit, and assumptions
Provisions: 6.10 Comparisons between systems

Partial replacement numbers should be avoided. Replacement numbers should be rounded up, unless justified as described below:
The last replacement of components may be skipped, provided:
-       the component is not essential to security, health or comfort;
-       the absence of replacement is based on actual practice;
-       the final replacement occurs during the last 10% of the study period;
-       a specific maintenance scenario is developed in this case.
This guidance needs to be applied homogeneously in comparisons. For example, for a study period of 50 years, in the case of an internal paint with a 15-year reference service life the last replacement could be ignored (i.e. two replacements rather than three).

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