The Effect of Standardization on the Future of Sustainable Refurbishment of Existing Buildings

Abstract

There is a vast building stock of existing buildings and the exchange rate is low (up to 0.2% per year). Therefore, there is a very strong need to deal with the existing building stock in respect to circularity. The effect of (new) regulations and standards on this volume for refurbishment and recycling of building materials is therefore crucial to meet the targets of CO2 reduction by increasing aspects of circularity overall to support environmental sustainability. The influence of standards towards the harmonization of technical requirements for refurbishment of existing buildings is therefore essential for wider implementation and acceptance in the market. There is, however, a gap identified between existing relevant standardization efforts and research in the field of refurbishment in the context of circularity. The effect of newly released standards and regulation will be analysed and identified barriers are discussed such as the generation and dissemination process of these standards.

1 Introduction

In the context of the escalating global imperative to address climate change and environmental sustainability, decarbonization by 2050 constitutes a central focus within the European Union's overarching strategies for the upcoming years [1]. A central aspect to reach these goals is the strategy of Circular Economy (CE), which intends to reduce the use of primary resources by maximizing recycling and renovation in the building sector. The conversion of buildings for a different use, the partial reuse of building elements, and the recycling of materials, where appropriate, are the crucial elements in this proposed strategy. This initiative aligns with the objectives of the European Green Deal and the 2030 Agenda for Sustainable Development. The construction sector stands as one of the largest consumers of energy and is accountable for 40% of global CO2 emissions [2], along with being responsible for 60% of the global consumption of raw materials [3]. Despite the significant impact of this sector on both energy consumption and raw material use, there is a pressing need to accelerate building renovations. Current rates of energy renovations in the European Union (EU) hover around a mere 0.2% on average. In contrast, the EU has set ambitious targets to double these figures by 2030, also fostering deep renovations [4]. In this context, the present study focuses the vast building stock of existing buildings. The exchange rate is low (up to 0.2% per year). The effect of (new) regulations and standards on this volume for refurbishment and recycling of building materials is therefore crucial to meet the targets of CO2 reduction by increasing aspects of circularity overall to support environmental sustainability. The influence of evolving standards towards the harmonization of technical requirements for refurbishment of existing buildings is therefore essential for a wider implementation and acceptance in the market. The novelty of this paper is the analysis of the current and emerging standards in the context of refurbishment and the gap identified towards a link between research in the relevant field and the generation and dissemination process of relevant standards. The study is intended to flag the gap and barriers and builds upon a thorough examination of existing and evolving standardization efforts on national and international levels for refurbishment, reuse of existing building and recycling of building material.

2 Methodology

The research aims to identify regulations in the context of existing buildings for sustainable refurbishment and to discuss the relevance for research in the field. To reach this objective, the study conducts a comprehensive analysis of relevant standards and frameworks in the field in relation to existing state-of-the-art concepts for refurbishment and the water fall model for material reuse. The prime focus of this paper is the effect of new released standards and regulation in connection with the sustainable refurbishment of existing buildings. It imposes 6 stages from (0) Establish brief of the object of the assessment to (1) Evaluating the building to (2) Sustainable deconstruction, (3) Sustainable construction process, (4) Sustainable commissioning and (5) Sustainable in use. The discussion section describes multidimensional barriers that hinder the widespread adoption of relevant standards and identifies potential challenges, opportunities, and future prospects to better bridge the gap between research and regulation. It contributes to a more thorough understanding of the role standardization and how research can advance circularity in the building sector by tackling aspects in standardization.

3 Relevant Existing Standards for Circular Building Refurbishment

The influence of standards towards the harmonization of technical requirements in the use for building in particular has been relevant. For example, the framework for the EPBD and its recast had a strong effect on harmonizing the key building energy figures, and resulted in an usable building passport [5].

The material passport, another example, has been targeted by ISO 37101 (Sustainable development in communities - Management system for sustainable development - Requirements with guidance for use) with the aim to assess the performance. However, this is done on a general level and a clear metric for indexing of materials is not presented. Current regulation and legislation bodies of the EU have defaulted to naming convention “product passport”. The Eco design for Sustainable Products Regulation (ESPR) identifies a Digital Product Passport (DPP) as key for enhancing the traceability of products and their components. However, these Passports [6] will be targeted at products and is not fully able to cover the aspect of building materials and its indexing. As reference for circularity in the building industry, the Standard new EN 17680 (European Standard: Sustainability of construction works - Evaluation of the potential for sustainable refurbishment of buildings 17680) will provide a system for the sustainability assessment of buildings using a life cycle approach.

The material passport has been targeted by ISO 37101 (Sustainable development in communities - Management system for sustainable development - Requirements with guidance for use) with the aim to assess the performance. However, this is done on a general level and a clear metric for indexing of materials is not presented.

As reference for circularity in the building industry, various new developed regulations will provide a system for the sustainability assessment of buildings using a life cycle approach and specification for the use of indicators.

One of the most recent developments is the recast of the CEN/TR 17680 Sustainability of construction works - Evaluation of the potential for sustainable refurbishment of buildings [7]. It is formally approved in 2023 (1.12.2023 in Austria for example) and is therefore relevant and can be considered formally in the rank of state-of–the-art for sustainable refurbishment of buildings.

The regulation starts with a framework (Fig. 1) to position the various standards in the context of sustainability of buildings and positions the assessment of options for sustainable refurbishment on the level executed of work, in contrast to the product level of building materials such as environmental product declarations (e.g.: EN 15804 + A2).

Fig. 1.

Framework standards for sustainability of buildings.

The regulation intends to provide a 6-step process for application (0–6): from (0) Establish brief of the object of the assessment to (1) Evaluating the building to (2) Sustainable deconstruction, (3) Sustainable construction process, (4) Sustainable commissioning and (5) Sustainable in use are proposed. It is targeted at stakeholders at all instances that are using and running a building including facility management. It even includes visitors for some buildings as users and potential stakeholders. The standard continues to provide a strategy and methodology for sustainable refurbishment of an existing building and the evaluation of the potential of sustainable refurbishment, as a means of contributes to the circular economy to support the decision-making process (Fig. 2).

Fig. 2.

Decision making process.

It starts with a decision-making process to decide about renovation, refurbishment to the same use or for a new use. The options are whether to sustainably deconstruct, use as is or refurbish for same use or other use based on the evaluation of technical and environmental condition, usability and adaptability.

The performance of the building should be evaluated in respect to current and future needs [7]. In order to meet the requirement of recorded performance levels, existing conditions and performance needs to be assessed and evaluated according to a structured decision methodology (Fig. 3) to meet planned sustainable performance targets.

These goals are divided into economic, social and environmental targets.

Fig. 3.

Decision methodology.

The aim of Sustainable refurbishment is to “move” buildings, part of a building or portfolio of buildings into an improved area within the matrix, as shown in Fig. 4, by improving usability due to satisfactory adaptability.

Fig. 4.

Overall assessment of the building.

The CEN/TR 17680 regulation continues to provide a high level decision flow chart and presents a general procedure for the assessment to determine the achieved level of performance and condition of the building.

This study wants to focus on the consequence of this proposed assessment procedure in the CEN/TR 17680 regulation.

The standard provides a classification for the consequences in grade classes from 0 (No action necessary), 1 (Minor and medium action necessary), 2 (Essential action necessary can come in near future) to 3 (Major and serious action necessary).

These grad classes are linked to priority classes, priority action and action type to be taken. However, most of these proposed actions result in a cluster of repair, replacement and upgrade. The documents continue to recommend, that final decision on action shall be made on a building level or at an overarching, general level.

As a consequence, the document provides a matrix for a list of indicators for early decision-making in the refurbishment process in nine different categories from technical, adaptability, social aspects towards embodied environmental impacts.

In the focus of the relevant technical category 18 different indicators, to name a few, from foundation-load bearing system, windows/doors in facades, balconies, roof, heating, air conditioning, fire protection and seismic behavior are identified.

In respect to the step of sustainable deconstruction the category of reuse (Components for re-use on site or offsite, materials for recycling, materials for recovery) and another one for waste disposal are established.

In respect to re-use, there is a reference to the Environmental Product Declaration (EPD), which contains information related to the product environmental performance obtained using life cycle assessment methodology (according to EN 15804, EN 15978). Results are expressed for a detailed list of indicators declared for each stage of the construction product from the sourcing/supply of raw materials to the end of life [8]. However, detailed indicators for Components for re-use on site or offsite are not provided.

The standard CEN/TR 17680 qualifies the sustainable construction process as step 3. It continues to impose, that the rebuild process is similar to a new building process. After step 4 (commissioning), consequently step 5 is proposed to represent “sustainable in use’’.

Fig. 5.

Example of demand profile versus performance profile.

The diagram shows the representation of the demand profile versus the performance profile (Fig. 5).

The classification of indicators in performance and performance classes, from 0 to 3 provides a relation from class to performance and consequence. For example, if some technical indicator is qualified as class 3 (major or serious nonconformity), the description provides that “the building or part thereof has suffered or will imminently suffer total functional failure or need for immediate measures. Danger to life or health’’. The consequences are named as “catastrophic’’ (sic!) and action is needed.

The requirements for a successful implementation process are a unified taxonomy base in common standards. The use of the new proposed “Sustainability of construction works - Data quality for environmental assessment of products and construction work - Selection and use of data (Final draft) [9]”, that will suspend CEN/TR 15941 is a very good example of this need for a common understanding and the harmonization of Life Cycle Modules to index elements in relation to their origin, distance to the site, storing capability and aspects of reusability.

A wider implementation of harmonized assessment methods is based in a common taxonomy.

Another regulation concerning aspects of material treatment is the standard for Dis-mantling of buildings as a standard method for demolition [10]. Relevant for the construction industry to become circular is the process of reuse of already used building material that comes from the end of life-cycle of objects in use. The remodelling and demolition process (ÖNORM B 3151) is to be organized in a structured way.

The waterfall model as of today contains 5 steps.

• 1. Avoid waste material by maximizing the re-use of buildings or building elements.

• 2. If there is no direct reuse possible, prepare usable building elements with cleaning and testing for their reuse and store them appropriately.

• 3. If the re-use is not possible, then the demolition elements and materials should be separated to their original destination material and brought into a recycling process such as glass -or wood recycling.

• 4. Only in the case of no appropriate recycling of the elements or material composites, a sustainable and also economic destination can be the deposition at a site, where there is a requirement for landfill or the waste material has enough thermal quality to burn the material, with the demand, that this measure is without any negative impact to air quality and similar.

• 5. Only if there is no possibility for any of the previous mentioned steps, there is the last option of putting the waste material under fully controlled conditions into a depot of waste material in an assigned area.

It is mandatory, for example in Austria since 2016, to have an investigation of pollutants and of impurities, a dismantling concept and an obligation to separate demolition waste.

4 Discussion

There is an identified gap between research and the creation of relevant regulations and also in relation to the dissemination of standards. This does cause a considerable risk in the usability of the standards and also in the adoption in the relevant market.

For example, in CEN/TR 17680, Sustainability of construction works the indicator for Air –conditioning (Indicator 9) is qualified Class 3 with the specification: “Older than 20 years and parts with shorter service life are not replaced. No zoning unsatisfactory capacity. Need for renovation or replacement. Or no air-conditioning in-stalled.’’

If this is taken literary, it can be read as absence of air conditioning will lead to a Class 3 qualification of a building, being “catastrophic“ and replacement (of the whole building) is needed. This would, of course, impose quite a big impact on the European building stock, that are current without an air-condition.

Furthermore, there is the problem of decision process within the regulation committees.

The formulation and decision-making process of standards, in particular also in CEN/TR 17680. For example, in many national committees the decision-making is based on an electronic reply within 30 days to consent to a proposed regulation text. To consent or to sustain, only one single mouse click is necessary. In order to disagree, a full statement including various levels of explanation and improvements are required. So there is very often the case, that a new standard gets less than half of approvals (in relation to participating members), the majority abstained and no disagreement. This leads finally to a unanimous acceptance, since no vote was against it and the sustained votes do not count.

Standards are very important for the harmonization of rules. Furthermore, professionals have to respect the current state of the art in their executed work. In legal terms it means very often, to respect the standard (national or international on the topic). Whereas all legal documents have to be publicly available (such as legal databases with free access), there is no equivalent rule for national or international standards. The documents have to be purchased for quite a high price, with even no free access for judges in court or for research purpose. It is an industry of its own by the national standardization entity, although the members of committees do not receive any compensation or salary.

This is probably one reason for low involvement of universities and researchers sent to standardization committees. It does not increase the research budget of participating universities. On the contrary, it takes person-month, or least hours, from the research institution with no compensation. On the individual level of the researcher, the contributions do not count for publication and are anonymized.

On the other hand, relevant research initiatives start with a literature review. These searches do not include current (under development) or finalized national or international standards in most cases.

To prove this, testing of two search engines, Google Scholar and JSTOR, with the keyword 1: Sustainability of Construction Works and keyword 2: Indicators and keyword 3: standards did not bring up CEN/TR 17680, Sustainability of construction as a reference bibliography.

In respect to establishing a framework for sustainable refurbishment, standards can be a supporting element to harmonize terminology, taxonomy and general accepted principals and decision models (Fig. 6). However, the nature and methodology for application is very often not fully adequate and too generic to specific challenges and do not substitute real research tasks.

Fig. 6.

Decision flowchart.

5 Conclusion

The task of sustainable refurbishment of existing buildings is one of the biggest challenges in the building sector in the next years. The requirements for a successful process are a unified process of refurbishment and taxonomy, together with a common understanding of an index of building-materials and elements in relation to their origin, distance to the site, storing capability and aspects of reusability.

By reviewing relevant regulations, their potential usability in respect to sustainable refurbishment was analysed and discussed.

However, some barriers were discovered, such as the weak link between research and the generation of standardization due to lack of compensation for research entities and universities, the formal decision process within the committees itself and the lack of a royalty free access towards these standards and regulations to be included in bibliography findings.