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Tag: Study type: Simplified LCA

B-21 Operational energy demand for new buildings – Consideration of user behaviour

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Aspect B-21 Operational energy demand for new buildings – Consideration of user behaviour
Description
 Several parameters influence the results of the energy calculation demand at the operational stage of buildings. Among others, user behaviour may have a major significance on the energy needs. The following section aims at providing guidance for screening, simplified and complete LCA of new buildings.

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 For stand-alone LCA, scenarios may reflect statistical, conventional or specific user behaviour.For comparative assertions, behaviour scenarios for the calculation of energy use should be identical for each alternative. Any deviation between scenarios should be reported and justified.
Rules from:
 EN 15978:
8.6.5 Scenarios for operational energy use – Module B6
Guidance
 For stand-alone LCA, sensitivity analysis should be carried out in order to estimate the significance of the use of a specific scenario instead of a conventional one.

B-22 Operational energy demand for existing buildings – Consideration of user behaviour

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Aspect B-22 Operational energy demand for existing buildings – Consideration of user behaviour
Description
 Several parameters influence the results of the energy calculation demand at the operational stage of buildings. Among others, user behaviour may have a major significance on the energy needs. The following section aims at providing guidance for screening, simplified and complete LCA of existing buildings, and the possibility of taking user behaviour into account regarding the goal and the scope of the study.

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 For existing buildings, if measured consumption data are available and applicable for the LCA analysis, user behaviour should be taken into account. Otherwise, the same guidance as for new buildings should be applied.
Rules from:
 EN 15978:8.6.5 Scenarios for operational energy use – Module B6
Guidance
 For stand-alone LCA of existing buildings, if measured historical consumption data are available and applicable (i.e. the objective and the scope of the study are consistent with available data, and future changes in the existing building will not impact on the energy uses), they should be used to calculate the energy demand.Otherwise, scenarios should reflect statistical or conventional user behaviour. Scenarios reflecting specific user behaviour may be used, but sensitivity analysis should be performed in order to provide evidence of the significance of this deviation. For comparative study of refurbishment alternatives for existing buildings, four different types of operation should be considered:

  • rehabilitation;
  • reference rehabilitation;
  • complete demolition and new construction;
  • maintenance of an existing building (maintain performances during a given period).

A rehabilitation operation consists of a deconstruction operation (removal of products) and a reconstruction operation (adding new products to replace discarded ones). Reference rehabilitation is a generic rehabilitation that implies the use of standard construction materials, designs and processes.

If historical data and/or energy monitoring and reflecting user behaviour (e.g. number of users, occupancy scenario etc.) are available, and if they are applicable (i.e. alternatives for refurbishment do not consider a change of use or other major modification of building systems or occupancy) , then scenarios derived from such data should be used to calculate the energy demand for each alternative.

Otherwise, scenarios should reflect statistical or conventional user behaviour. The same scenario should be used for each alternative.

B-23 Operational energy calculation – Allocation of energy production for on-site systems connected to grid”

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Aspect B-23 Operational energy calculation – Allocation of energy production for on-site systems connected to grid”
Description
 Current new buildings may not only be energy-efficient, but can also produce energy on site in multiple ways.The energy produced on site may not only be consumed inside the building, but can also be exported. When energy is produced on site by grid-connected systems (photovoltaic, wind turbines, boiler connected to heating grid etc.), how is this calculated? How are the impacts allocated for both product aspects (e.g. PV cells) and operational energy production?

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 The principles for the calculation of exported, imported and on-site energy production should be consistent with the provisions of EN 15978 (see especially reference cases, annex B).

  • Additional provisions for grid-connected systems: the boundaries (i.e. energy uses included) for the calculation of energy demand and exported energy should be homogeneous.
  • The calculation of exported energy and energy consumed on site should consider simultaneity between the consumption and the production.

The method for allocating environmental impact for product aspects and operational aspects should be consistent with the guidance in EN 15978.
Rules from:
 EN 15978:
7.4.4.7 Boundary of the operational energy use (Module B6)
8.6.5 Scenarios for operational energy use (Module B6)Annex B (informative) Exported energy – Case studiesILCD:

6.8.4 Time-related representativeness

Guidance
 The methods for energy calculation should be consistent with the reference cases proposed in annex B of EN 15978.Supplementary recommendations are proposed for on-site energy-producing systems that are connected to the grid (case 3 of EN 15978), as follows.Boundaries for the calculation
The boundaries chosen for calculation of the energy demand should be consistent with those for calculation of the exported energy: if only building-related uses are included, the amount of energy that does not supply the uses considered should be considered as exported energy. Then two situations may be considered:

  1. Including only building-related uses in the scope of the assessment: other non-building-related uses are not accounted. The exported energy will be calculated without considering the energy demand for non-building-related uses, because these are considered to be beyond the system boundary.
  2. Including both building-related uses and non-building-related uses in the scope of the assessment: the two uses are taken into account for the calculation of exported, imported and on-site consumed energy.

Timescale for the energy calculation

For simplified and complete LCA, an hourly scale should be used in order to take into account simultaneity between energy demand and the on-site energy production.

The annual exported energy, imported energy and on-site energy consumption for the considered energy carrier i may be calculated as follows:

 where:

  • Energy production i,h is the amount of energy produced by building on-site systems at hour h for energy carrier i.
  • Energy demand i,h is the amount of  energy needed for the considered building energy use at hour h for energy carrier i.

Allocation of environmental data

Rules should be consistent with EN 15978 for both product and operational aspects.

For imported energy (Module B6) and exported energy (Module D) more representative environmental data should be used. For example. for electricity, hourly environmental data should be used in preference to monthly or annual average data. See the corresponding aspect ‘Dynamic LCA data for assessing the impact of electricity consumption’.

 

B-24 Dynamic LCA data for assessing the impact of electricity consumption

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Aspect B-24 Dynamic LCA data for assessing the impact of electricity consumption
Description
 Energy sources for electricity production may vary significantly according to the season (winter or summer months), the day (weekdays, weekends) and the time within a day. Environmental impacts are strongly influenced by the decision to use annual energy data (i.e. average LCA data) or energy data based on a shorter period (monthly, daily or hourly).

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 Annual average datasets for electricity production should be used in the baseline scenario. Deviating data can be analysed in additional scenarios with transparent documentation and a sensitivity analysis.
Rules from:
 EN 15978:
Not mentioned
Guidance

Dynamic LCA data can be produced by using the hourly data provided by electricity suppliers in each national context. For example, in France, RTE provides hourly data, broken down by source: fossil, hydropower or nuclear energy Based on these proportions, and LCI/LCIA data corresponding to each energy source, dynamic LCA data can be calculated. (Note: the LCI/LCIA data statically aggregate elementary flows.)

Such dynamic LCA data can also be linked to models to predict the environmental impacts in a dynamic way (although very few LCA tools for buildings currently provide such assessment). More detailed information on this aspect can be found e.g. in a French PhD thesis by G. Herfray [Herfray 2011] or in [LoRe-LCA 2011]

B-26 Assessment of operational water use in simplified LCA

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Aspect B-26 Assessment of operational water use in simplified LCA
Description
 The operational water use assessment includes water used during the operation of the building, together with the associated environmental impacts and aspects, including the production of drinking water and wastewater treatment. A link between domestic hot water and energy use should also be considered.

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 Assessment of the water consumption during the use phase should be included in the LCA studies in order to be consistent within the overall assessment methodology (the use of a ‘net fresh water’ indicator for the various life cycle phases). Water consumption during the use phase is usually the most important, compared with the other phases of the life cycle.Operational water use may be assessed using a top-down approach for simplified LCA (see guidance). The upstream and downstream processes linked to the operational water use may be modelled using generic LCA data.
Rules from:

EN 15978

 7.4.4.8 Boundary of the operational water use (Module B7)EN 15978 states that the boundary of operational water use should include water used during the normal operation of the building together with the associated environmental impacts due to its treatment (before and after use). This includes drinking water, water for sanitation, domestic hot water, irrigation, water for heating, cooling, ventilation and humidification, and other specific water uses (e.g. fountains, swimming pools and saunas). Water consumption of non-building-related equipment (e.g. dishwashers, washing machines) could be included within the assessment. This issue should be reported separately.

EN 15804

 7.3.3.3 B6, use of energy and B7, use of water
Guidance
 In order to calculate the water consumption for simplified LCA, a methodology based on a top-down approach could be followed. It consists in estimating the total consumption by taking into account the economies that can be achieved by using some water saving devices (e.g. dual-flush toilet systems) compared with the average water consumption (e.g. 50 m3/year/person, i.e. 115 m3/dwelling/ year) or the extra consumption due to some specific systems (e.g. fountains, swimming pools, saunas).In addition to the volume of water consumed, the environmental impacts linked to the production, respectively wastewater treatment should also be considered.For screening and simplified LCA only the most representative technologies should be considered by using generic LCA data available in background LCI databases (e.g. ELCD, GaBi or Ecoinvent).

Additional guidance

Some of the labelling schemes (e.g. DGNB) also use a water indicator that is based on the average water consumption of the sanitary system, rainwater and greywater use. Such an indicator may be of help in calculating operational water use for simplified LCI (Module B7).

Any comparative assertion should be supported by a sensitivity analysis of the various parameters and hypotheses considered during the assessment, especially regarding user behaviour. The baseline scenario should be developed by using default values for all the parameters, defined according to statistics on the most common current values. Regular updating is therefore necessary (as the various equipment characteristics evolve relatively quickly).

B-09 Modelling of water use

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Aspect B-09 Modelling of water use
Description
 Is B7 relevant at a product level? How should the operational water use be modelled?

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 In general, the user has to decide whether  this aspect is important for the product; the consideration of operational water use in Module B7 is necessary only for complete LCA studies.
Rules from:

EN 15804

 6.3.4.4.3 B6–B7 use stage information modules related to the operation of the building
Guidance
 The regulated water use of building-integrated technical systems is determined by the design and use of the building.Attention should be paid to avoid double counting between the product and the building scale.

B-28 (Buildings) / B-10 (Products) Accounting of different types of waste water treatment

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Aspect B-28 (Buildings) / B-10 (Products) Accounting of different types of waste water treatment
Description
 The environmental impacts are different for the various methods of waste water treatment. The system boundaries for waste water treatment considered within the studies (e.g. public sewage system, on-site treated water) and the classification of waste water treatment need to be consistent.

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 This aspect should be modelled only when it is a special focus of the study, or for a complete LCA, unless it is believed to be a dominant contributor to the environmental impacts of the assessed system. In this case, the real situation should be modelled, and alternative scenarios can be developed as sensitivity analyses. These scenarios should be documented as transparently as possible.
Rules from:

EN 15978

 8.6.6 Scenarios for operational water use (Module B7)According to EN 15978, For building studies, water use (treatment and supply) and waste water treatment should be considered in Module B7.  Energy to heat or cool water used would be included in Module B6.

EN 15804

 6.3.4.4.3 B6 – B7 use stage information modules related to the operation of the building:According to EN 15804, Module B7 deals with operational water use within the building.  As such, in product LCA it would be included only where building integrated technical system products have an operational water demand. Additionally, the impacts of waste water treatment should be considered for the water used.Product-related water use and waste water treatment during the extraction or manufacturing process should be included in Modules A1–A3, during construction in Module A5 and from maintenance (e.g. cleaning) in Module B2.
Guidance
 In general, waste water treatment as part of material production is included in background datasets. The use of generic waste water treatment data from background databases may ease the assessment of this aspect, and should typically be sufficient for construction-related LCA studies (except for studies that include processes with significant pollution of waste water, such as varnishing processes with high waste water runoff).Regarding the way to treat wastewater in an improved model e.g. for a complete LCA, all types of wastewater treatment should be considered: 1) on-site treatment (different technologies); 2) public sewage system (combined sewer system, both rain and grey/blackwater or separate sewer system); 3) combined technologies (e.g. one technology for on-site treatment and one technology for the  public sewage system). Specific LCA data representative of each technology should be used (if available).

B-30 Transport of the users of the building

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Aspect B-30 Transport of the users of the building
Description
 For building LCA, the environmental impacts of transportation of people during the use stage may influence the decision between alternative construction sites (e.g. is the building located near public transport services?), or between alternative projects for the same site. Generally speaking, if the transport of building occupants is included within the system boundaries,  it can have a significant impact on the results of the use stage. However, it is not always relevant for inclusion in LCA studies.When and how should the transport of people be included for building LCA?

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 The transport of people may be taken into account if it is relevant for the goal and scope of the building LCA study (e.g. during the early design of a building, when a construction site needs to be chosen). If included, all relevant results should be documented separately, and the results should be subject to sensitivity analyses.
Rules from:

EN 15978

 No provisions
Guidance
 Generally speaking, when LCA is used during the design process of a building, this aspect is not relevant when the construction site has already been defined. Conversely, in the early design stages of the building project, assessment of the transport of people may be relevant if the goal and scope is to assess different options for the construction site (e.g. choosing between a site in the suburbs, in the countryside or in the city centre). In this case, the share of this aspect in building LCA results may be significant.In specific cases during the stages of the building project, this aspect may also be included if LCA practitioner needs to focus on it (e.g. for assessment in urban structures, or in large retail buildings).If the transport of people is included, the practitioner should identify the key parameters to calculate this contributor outside the scope of the EN 15978 standard, or otherwise use existing calculation rules within the building LCA software used. Such parameters may include:

  • the type of building (e.g. detached houses or office buildings);
  • the location of the building (e.g. in the countryside, in the suburbs, or in the city centre);
  • the number of people who commute to the workplace every working day, and for other activities if relevant (e.g. shopping, leisure etc.);
  • the mode of transport (e.g. bicycle, public transport including tramway, trains, autobus, individual car etc.);
  • the transportation distances between the building site and the workplace, and the distances from the public transport network.

Assessment of the transport of people then needs both default values and scenarios to be defined, particularly for:

  • the different modes of transport (e.g. bicycle, public transport including tramway, trains, autobus or individual car);
  • the transportation distances (e.g. below 10 km, between 10 and 100 km etc.) and the respective fuel consumption (if relevant);
  • the number of people in the building.

The LCA data on transportation processes should be taken from existing generic LCA databases (e.g. Ecoinvent, ELCD, ESUCO). The reference flow of the functional unit of the generic data of transportation processes is generally expressed as tons*km or persons*km. The data usually include a default scenario for fuel consumption and the average load (e.g. an average load of 2.5 persons in a car with a maximum capacity of 5 persons can be assumed in some generic LCA data). As the load factor may influence the results, a sensitivity analysis is needed on this parameter if the corresponding mode of transport significantly influences the results.

B-31 (Buildings) / B-11 (Products) Distinction between Modules B2, B3, B4 and B5

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Aspect B-31 (Buildings) / B-11 (Products) Distinction between Modules B2, B3, B4 and B5
Description
 Modules B2 to B5 cover the impacts related to the service life of building and building parts, whether it is a light modification, such as a small maintenance operation or an important retrofit (rehabilitation).It is sometimes difficult to determine which module a specific operation should be attributed to. The present aspect proposes a common definition of these modules, plus recommendations on how to use them at the product and building scale.

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 Standards EN 15804 and EN 15978 provide definitions and examples of aspects B2 to B5. The LCA practitioner should refer to these standards.B2 – Maintenance encompasses all actions related to maintaining a product or building part – i.e. replacement or reparation of a used, damaged or worn part of the product (a part, but not the entire functional unit) in a state in which it can perform its functions [EN 15978]. According to EN 15978, this applies to planned actions, and should include:

  • preventive and regular maintenance operations;
  • cleaning operations.

Maintenance actions are part of the ‘intended use’ definition that should be provided with a product’s reference service life (see EN 15804, annex A and 7.3.3.2 Reference service life). The reference service life (RSL) is valid under a specific set of conditions, notably the in-use environment (e.g. UV, heat, humidity, etc.), and proper implementation and maintenance that comply with the producer’s recommendations and with state-of-the-art practices. The RSL should be used to calculate the number of replacements. See the aspects: ‘Definition of the service life of a building product’ and ‘replacement frequency’ for additional information.

B3 – Repair encompasses all actions related to returning a product or building part to an acceptable condition in which it can perform its required functional and technical performances [EN 15804], including:

  • corrective, responsive or reactive treatment of a construction product;
  • replacement of a broken component or part because of damage (replacement of a whole element should be assigned to replacement).

The example given in EN 15978 and EN 15804 is a window with a broken pane.

–> Although the distinction between the maintenance and repair modules is not straightforward, the example given for repair falls outside the scope of the intended use that defines reference service life.

B4 – Replacement covers the replacement of a whole construction element [EN 15804], including the production and installation of a new (and identical) construction element. Examples given in EN 15978 include replacement of a partition wall, and replacement of a boiler or heating system.

–> The replacement module is distinguished from the maintenance and repair modules by the fact that a complete component or part is replaced (maintenance include the replacement of subcomponents, and repair the replacement of damaged parts). Although this ultimately depends on the breakdown of the building into subcomponents, it seems reasonable to understand it as the replacement of a complete functional unit such as defined in the EPD.

B5 – Refurbishment covers concerted programmes of maintenance, repair and/or replacement activity across a significant part or whole section of the building [EN 15804]. Examples provided include: ‘a major change of the internal layout (partitioning)’, a ‘change of the technical system related to heating’ and ‘modification for the purpose of a […] change of use’ [EN 15978].

–> The refurbishment module addresses important modifications that would impact on several building components, and modify building performances and/or functions.

All these aspects are related to the notions of durability and service life planning, as described in the ISO 15686 series. Relations between the type of operations and performance of a given product or building part could be represented as follows:

Figure 18: Example of performance over time relation depending on operations [EN 15804]

This figure is shown only for explanation purpose, and many other cases are possible, such as:

  • performance stability over the reference study period;
  • overall decrease of performance despite maintenance operations;
  • failure at implementation.

Furthermore, “service life planning can only address foreseeable changes. Since service life planning is concerned with foreseeable risks, it is not applicable to the estimation of obsolescence […] or to defective performance resulting from unforeseeable events or processes” [ISO 15686-1, part B.8.2.].

In the case of sound statistical feedback on the replacement rate of a specific product for a given country or region, it is unlikely that a clear distinction between the causes of replacement could be easily made. In that specific case, replacement causes would naturally encompass all cases: i.e. premature failure, failure due to foreseeable ageing (i.e. RSL) and obsolescence. The figure below presents a hypothetical distribution of replacement rate according to the main causes of replacement (including building deconstruction).

Figure 19: Replacement rate [EN15804]

 
Rules from:

EN 15978

 7.4.4.1 General
8.6.3 Scenarios for maintenance, repair, replacement

EN 15804

 6.3.3. Reference service life
6.3.4.4.2  – B4 Replacement
Annex A
Guidance
 As the distinction between Modules B2 to B5 is not straightforward, it is recommended that the following principles be applied when developing product and building LCA. These principles are based solely on the distinction between the causes of end of life:–> For end of life related to performance decrease over time (e.g. aging, decay, degradations, etc.):

  • causes related to foreseeable events (i.e. related to reference service life) in a defined set of conditions lead to maintenance and replacement scenarios;
  • causes related to unforeseeable events lead to repair scenarios.

–> For end of life related to modification of expectations regarding the building’s performance level or functionalities (e.g. obsolescence, such as modification of activities inside the building, modification of regulation, etc.):

  • causes lead to refurbishment scenarios.

B2 – Maintenance:

For product LCA, this module should cover all operations necessary to maintain the performance of products, or to return them to their original level, including scheduled replacement of parts and subcomponents. Example include: scheduled replacement of boiler parts; scheduled replacement of light bulbs from luminaires; repainting of a wall, door or window frame; replacement of small elements of roofing, such as tiles (e.g. a certain number of tile per 10 years per square metre), etc.

For building LCA, maintenance should take into account maintenance modules as provided within EPD, as well as additional information if needed (e.g. current or state-of-the-art practices, recommendations, etc.).

–> Maintenance should be understood as the set of operations performed under normal conditions. This applies in a given context (e.g. maintenance of a product could change, depending on the climate). Product modification and operations caused by accidents, improper installation or handling, unforeseeable events (such as flood), etc. should be covered by the repair module (see below).

–> Maintenance scenarios at the building scale should be consistent with the building’s physical structure: maintenance of a given component should take into account the influence of neighbouring components (e.g. accessibility).

B3 – Repair:

For product LCA, the repair module should not be included in the baseline scenario.

For building LCA, the repair module should not be included in the baseline scenario. The repair module may cover all operations related to product modification outside the scope of the maintenance module – that is, outside the scope of normal conditions, including improper use of a product, unforeseeable events such as flood or vandalism, etc.

–> For existing buildings, repair scenarios could be based on the history of the building (i.e. examples based on previous reparation);

–> For new buildings, repair scenarios could be used to assess the environmental impacts of a specific risk (e.g. the impact of reparation due to flood, the impact of improper installation that causes damage, etc.).

B4 – Replacement:

Replacement is necessarily related to the reference service life. Replacement occurs at the end of life of a product: that is, when it does not meet its initial performance requirements (modification of the requirements after product installation should be considered as obsolescence, and be covered by a specific scenario: see below). The number of replacements is further described in the aspect ‘Replacement frequency’.

–> It is recommended that replacement caused by events that are outside the scope of condition defined by the reference service life be treated as repair.

For product LCA, replacement covers the replacement of the whole functional unit by a new one after RSL. The boundaries of replacement include [EN 15978]:

  • production of the replaced component and ancillary products;
  • transportation of the replaced component and ancillary products, including production impacts and aspects of any losses of materials during transportation;
  • the process of replacing the components and ancillary products;
  • waste management of the removed component and of ancillary products;
  • the end-of-life stage of the removed component and of ancillary products.

Most of these may be similar to other modules for cradle-to-grave product LCA, for instance:

  • The transport scenario of the new component may be similar to A4 – Transport.
  • The replacement process may be similar to C1 – Deconstruction.

–> If no differences arises from a comparison between a replacement scenario and an installation scenario (including related production, transport, end of life, etc.) then a replacement scenario is not necessary. In any case, it should be clearly stated whether or not the assumptions regarding B4 modules are similar to those used for other modules (e.g. the replacement process is different from the initial implementation because of the building structure, etc.).

For building LCA, replacement should include:

  • replacement modules as described in cradle-to-grave EPDs (or cradle-to-gate EPD with corresponding option);
  • additional LCA data to cover components without EPD.

–> Replacement scenarios at the building scale should be consistent with the building physical structure. Replacement of a given component should take into account the influence of neighbouring components (e.g. accessibility, possible replacement of other components, etc.).

B5 – Refurbishment

For product LCA, no refurbishment module need be included in the baseline scenario, as this is highly dependent on information at the product scale.

For building LCA, the refurbishment module should not be included in the baseline scenario if the building service life is equivalent to the reference study period. Additional refurbishment scenarios may be developed. For example:

  • to assess the modification of building functions (e.g. switching from a commercial building to habitation);
  • to assess the effect of an expected regulation that would affect the buildings.

–> A refurbishment(or deconstruction/new construction) scenario should be developed if the service life of the building is less than the reference study period.

It is recommended that a refurbishment scenario be developed when long reference study periods (>100 years) are being considered, as modification of the building use is expected over such a period of time. Refurbishment scenarios could also be developed if the reference study period is longer than the reference service life of the load-bearing components and structural elements.

Additional recommendations:

The progressive loss of performance of some components will have an impact on the overall performance of the building (e.g. loss of performance of insulation may lead to an increase of energy demand for heating). If sufficient data are available, these aspects should be addressed using a sensitivity analysis.

According to NEN 15804 (Annex A), Reference service life “could be based on empirical, probabilistic or statistical data and shall always taking into account the intended use (description of use) as described in ISO 15686-1, -2, -7 and -8” [EN 15804, Annex A].

B-12 Robustness of data (LCA, service life) to model the life cycle of a building product

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Aspect B-12 Robustness of data (LCA, service life) to model the life cycle of a building product
Description
 How representative is a production process for a product?

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 In line with harmonized standards or technical approvals.
Rules from:

EN 15804

 6.3.3 Reference service life (RSL)
7.3.3.2 Reference service life8.2 LCA-related elements of the project report

Annex A Requirements and guidance on the reference service life

ISO 15686 Pt 1

 7.1.4 Taking account of variability and reliability
Guidance
 LCA studies may be conducted on a specific manufacturer’s product, in which case the use phase for that specific product can be considered, and service life data be generated in line with the relevant parts of ISO 15686.Where an LCA for an average product is being developed, the use phase may be harder to define robustly, owing to the variation in the use scenarios and application in the building, as well as in the products. It may be relevant to determine different use phase scenarios based on performance criteria for the products, although if this is associated with different manufacturing impacts (±10% for key environmental indicators), the product types should not be considered as a single average group.EN 15804 requires that, where an EPD is produced from more than one product’s data, the variance from the mean data reported in the EPD should be described in the project report for the verifier. Variance could be reported using the coefficient of variation or the standard deviation.

Some EPD programmes may have specific rules limiting the variance from the mean LCIA results for EPD covering a range of products, meaning that results must be reported for smaller groups of products with similar performance.

For simplified and screening LCAs, generic service life data can be used. For complete LCA, the service life for the specific product should be considered. Generic service life data are provided in various sources, including e.g. the national databases of different countries. It is recommended that practitioners refer to the service life data used in the context of the respective LCA study.