The set of Energy Performance of Buildings (EPB) standards: spotlight on the (EN) ISO 52000 family

The set of Energy Performance of Buildings (EPB) standards has been published in summer this year (2017). About 30 documents as European standards (CEN) and about 17 as international standards at global level (ISO), in collaboration with CEN (EN ISO standards). All new EN ISO EPB standards are part of the new (EN) ISO 52000 family of EPB standards. These include the backbone of the whole set of EPB standards. The series will help architects, engineers and regulators assess the energy performance of new and existing buildings in a holistic way. Technical support and more information is found at the website of the EPB Center.

Keywords: energy performance of buildings, EPB, EPB regulations, energy performance rating, ISO 52000, EPB Center

A comprehensive series of European (CEN) and international (CEN & ISO) standards has been prepared, aiming at international harmonization of the methodology for the assessment of the overall energy performance of buildings. This set of EPB standards has been introduced in earlier issues of the REHVA Journal (e.g. [1], [2], [3], [4], [6]).

This article focusses specifically on the subset formed by the (EN) ISO 52000 family [5] and the option of a step-by-step implementation at national level.

Complete overview now available at EPB Center

More information on the set of EPB standards, with extensive background information and explanation, is provided at the website of the EPB Center [7].

One of the recently added features of the website is a complete overview of all EPB standards and their accompanying technical reports (http://epb.center/support), with information about how the documents can be obtained. For each document a link is provided to the page in the ISO catalogue or CEN database where a summary and other information about the document can be found.

Holistic approach

From energy using product to energy efficient building systems

In the past, energy performance requirements were set at component level: minimum thermal insulation levels and minimum efficiencies of products. However, a product or component with a high performance under standardized conditions may perform significantly less good when installed in a building, due to fluctuating weather conditions, varying occupants’ demands and a possible negative influence of or interference from other components. And vice versa: several new technologies are designed to make the best out of varying operating conditions. Thus, energy performance requirements that are restricted to the performance of individual components create a barrier to the necessary technology transitions.

The holistic approach to assess the overall energy performance of buildings and the built environment, provided by the set of EPB standards (inclusive the EN ISO 52000 family of standards), is a key tool to overcome these barriers.

The EN ISO 52000 family of standards will enable to assess the overall energy performance of a building. This means that any combination of technologies can be used to reach the intended energy performance level, at the lowest cost. Due to this ‘competition’ between different technologies, the holistic approach is a key driver for technological innovation and change.

CEN and ISO

In CEN, the set of EPB standards has been prepared to support the EU Directive 2010/31/EC on the energy performance of buildings (EPBD).

This implies that the EPB standards need to be fit to be used in the context of building regulations and codes. Therefore, all EPB standards follow specific rules to ensure overall consistency, unambiguity and transparency.

At the same time, all EPB standards provide certain flexibility with regard to the methods, the required input dataand references to other EPB standards. This enables national or regional authorities to tailor the energy performance assessment to a specific (national or regional) situation. For each option, a clear template is provided in Annex A of each EPB standard, supplemented by an Annex B with informative default choices, as mentioned above.

Global relevance of the set of EPB standards

This approach also facilitates the applicability of the EPB standards at global (ISO) level. A good example is the overarching EPB standard, ISO 52000-1 (EN ISO 52000-1) that offers choices to tailor the assessment to any national situation, worldwide. The choices range from policy factors (e.g. primary energy factor values, choice of perimeter of the assessed object, appreciation of renewable energy surplus exported to the grid, …), building and space categorization, specification of standard indoor conditions for each building or space category, choice of the metric for the building size, etc.

One of the frequently asked questions concerning the preparation of EN ISO standards (collaboration between CEN and ISO) is the following:

Each International (ISO) Standard is relevant at global level, so also in Europe. So why are these standards published as combined European and global international (EN ISO) standard, instead of simply just ISO standards?

The short answer to this very relevant question: ISO standards are voluntary. European (CEN) standards may be mandatory in the context of European regulations. Take for example the CEN standards needed for or to support the declaration of performance of products as defined in the Construction Products Regulation (CPR) and to affix the CE marking. As mentioned above, the set of EPB standards supports the implementation of the EPBD.

New: the (EN) ISO 52000 family of EPB standards

Already 17 of the about 50 EPB standards are EN ISO standards, the result of collaboration between CEN and ISO. The other EPB standards are up until now only available at European (CEN) level.

Except for already existing standards that underwent only (minor) revisions, these EN ISO standards received an ISO 52xxx number, the series of numbers which have been reserved for the EPB standards. Only standards that meet the specific requirements for all EPB standards will be awarded such number.

This first series in the (EN) ISO 52000 family comprises the overarching EPB standard (EN ISO 52000-1), complemented by a set of standards dealing with the calculation methods for heating and cooling needs and indoor temperature, performance of building elements, as well as aspects regarding energy performance indicators, ratings and certificates.

The (EN) ISO 52000 family was prepared in a unique collaboration between

·         ISO technical committees ISO/TC 163, Thermal performance and energy use in the built environment,

·         ISO/TC 163/SC 2, Calculation methods,

·         ISO/TC 205, Building environment design, and

·         the CEN (European) technical committees
CEN/TC 371, Energy Performance of Buildings project group, and
CEN/TC 89, Thermal performance of buildings and building components.

ISO 52000 family of standards: road ahead

Additional ingredients to expand the holistic approach are expected to be added to the EN ISO 52000 family in the near future, in cooperation with other technical committees in ISO and CEN. First new work item proposals have already been launched, dealing with specific parts of heating and cooling systems and building automation and control.

The intention is to come (eventually) to a complete and consistent set of EN ISO standards on the Energy Performance of Buildings (EPB).

Clear and consistent policy targets play an important role in driving innovation in the building sector. International Standards will be needed to harmonize the terms, definitions, assessment procedures and indicators in order to develop new concepts and technologies as well as monitor and evaluate progress.

Common quality criteria

For all EPB standards, including the (EN) ISO 52000 family

One of the main purposes of the EPB standards is to enable their use in laws and regulations to, in some cases, make them compulsory. This calls for a systematic, clear, comprehensive and unambiguous set of energy performance procedures.

The holistic approach to assess the overall energy performance of a building requires that many of the EPB standards are applied in an interactive way. Standards that do not properly fit in the set (with respect to input-output relations, methods, common features and overall quality) may compromise the quality of the whole set.

Consequently, each EPB standard (both in CEN and in ISO) needs to respect specific requirements (http://epb.center/epb/common-rules-all-epb-standards) to ensure overall integrity, consistency and quality of the whole set, as well as usability in the context of building regulations.

Thanks to these profound specific quality criteria, the ISO 52000 family is expected to become a strong brand mark.

Modular approach and national choices

In CEN, the set of EPB standards has been prepared to support the EU Directive 2010/31/EC on the energy performance of buildings (EPBD).

The aim is a systematic, clear, comprehensive and unambiguous set of energy performance procedures. At the same time, differences in national and regional climate, culture and building tradition, as well as policy and legal frameworks have to be taken into account.

In each EPB standard, different options are given, thus enabling specific choices in:

·         Calculation procedures (e.g. monthly or hourly calculation; specific simplified or detailed calculation method).

·         Input data and boundary conditions (e.g. national default values, climatic data, policy related data)

·         References to other EPB standards; see further on (Modular structure and step-by-step implementation)

For the correct use of the EPB standards, each EPB standard typically contains a normative template in Annex A to specify these choices. And informative default choices are provided in Annex B.

Example of a table from Annex A and Annex B is given in Figure 1aand Figure 1b.

Table A.2 — Choice between hourly or monthly calculation method (see 5.2)

Figure 1a. Example of the normative template for national choices (EN ISO 52016-1, Table A.2).

Table B.2 — Choice between hourly or monthly calculation method (see 5.2)

Figure 1b. Example of the informative default option for national choices (EN ISO 52016-1, Table B.2).

Note that in each EPB standard there may be many tables with a wide variety of choices, ranging from choices between calculation options to choices of specific coefficients or correction factors.

National annex or national data sheet

The main target groups for this document are architects, engineers and regulators.

In case an EPB standard is used in the context of national or regional legal requirements, mandatory choices may be given at national or regional level for such specific applications. These choices (either the informative default choices from Annex B or choices adapted to national / regional needs, but in any case following the template of this Annex A) can be made available as national annex or as separate (e.g. legal) document (national data sheet).

Note that in this case:

·         the regulators will specify the choices;

·         the individual user will apply the standard to assess the energy performance of a building, and thereby use the choices made by the regulators

Topics addressed in a standard can be subject to public regulation. Public regulation on the same topics can override the (informative) default values in Annex B of the EPB standard.

Legal requirements and choices are in general not published in standards, but in legal documents. In order to avoid double publications and difficult updating of double documents, a national annex may refer to the legal texts where national choices have been made by public authorities.

Different national annexes or national data sheets are possible, for different applications.

If the default values, choices and references to other EPB standards in Annex B are not followed due to national regulations, policy or traditions, it is expected that:

·         national or regional authorities prepare data sheets containing the choices and national or regional values, according to the model in Annex A. In this case the national annex (e.g. NA) refers to this text;

·         or, by default, the national standards body will consider the possibility to add or include a national annex in agreement with the template of Annex A, in accordance to the legal documents that give national or regional values and choices.

Template for national annex or national datasheet at the EPB Center

The EPB Center has developed a template for national annex or national data sheet to EPB standards. This template consists of a model national annex or national data sheet with extensive guidelines and useful tips. It is intended as a tool for the implementation of the EPB standards at national or regional level.

This template for national annex or national data sheet to EPB standards can be downloaded from the support section of the website (http://epb.center/support/support).

Modular structure and step-by-step implementation of the set of EPB standards

Modular structure

For the set of EPB standards, an overarching modular structure is used:

·         to identify all required parts of the assessment procedure and to provide an overview;

·         to identify the modules covered by the EPB standards;

·         to identify the input-output connections between the EPB standards (e.g.: calculation, expression of the energy performance).

The over-arching modular structure has the following four main areas:

·         M1 Overarching standards

·         M2 Building (as such)

·         M3 - M11 Technical Building Systems under EPB

·         M12 - M13 Other systems or appliances (non-EPB)

More details can be found at the EPB Center website (http://epb.center/implementation).

Step by step implementation at national level

The modular EPB structure and the “Annex A/Annex B” approach, in particular with the option to (preferably for a limited transition period) reference to a specific national standard instead of a specific EPB standard, strongly facilitates a step by step implementation of the set of EPB standards by individual countries or regions.

In order to make this possible, in the EPB standard the other EPB standards are not referenced by the standard number, but by the module number.

Example (from EN ISO 52016-1):

·         Instead of referring to the other EPB standard directly:

·         The reference is to the module number:

This is further illustrated in Figures 2a, 2b and 2c. The left columns in the tables presented in these figures contain the referenced module numbers, the other columns are: empty (template, Figure 2a), completed with informative default choices (Figure 2b) and completed with (an example of possible) national choices (national annex or national data sheet, Figure 2c).

The references, identified by the EPB module code number, are given in Table A.1.

Table A.1 — References

Figure 2a. Example of the normative template for national choices in references to other EPB standards (extract from EN ISO 52016-1, Table A.1).

The references, identified by the EPB module code number, are given in Table B.1.

Table B.1 — References

Figure 2b. Example of the informative default choices in references to other EPB standards (extract from EN ISO 52016-1, Table B.1).

The references, identified by the EPB module code number, are given in Table NA.1.

Table NA.1 — References

Figure 2c. Example of national choices in references to other EPB standards (extract from a possible Table NA.1 in a national annex or national data sheet for EN ISO 52016-1).

The EPB Center

Having these standards available is a first step. Implementing them needs dissemination actions at the level of building regulators as well in our professional community.

The EPB-Center, where REHVA is a stakeholder and where the current expertise is concentrated, is expected to support this process.

The EPB Center activities are to plan, coordinate and guide the process of promoting implementation, use maintenance and further development of the set of EPB standards and safeguard the coherence of their technical content.

It is also important to support regulators and national standardization bodies in the implementation of the standards by providing guidance on the completion of the national annexes or national data sheets.

More information, including an overview of all EPB standards, extensive background information and explanation, is already provided at the website of the EPB Center [7].

References

[1]    The REHVA European HVAC Journal, issue: "Focus on EPB standards", Vol. 52, Issue 1, January 2015 (various articles).

[2]    The REHVA European HVAC Journal, issue: "EPB standards", Volume 53, Issue 3, May 2016 (various articles).

[3]    The REHVA European HVAC Journal, issue: EPB standards published for formal vote,Volume 53, Issue 6, Dec. 2016.

[4]    The REHVA European HVAC Journal, editorial, The implementation of the new EPB-standards will boost product and HVAC system innovation and create new market opportunities for the HVAC industry, Jaap Hogeling, Volume 54, Issue 1, February 2017.

[5]    ISO News, ISO 52000 leads the way on clean energy building solutions, Elizabeth Gasiorowski-Denis, June 28, 2017.

[6]    The REHVA European HVAC Journal, Boosting energy efficiency of buildings through ISO’s holistic approach, Jaap Hogeling, Volume 54, Issue 4, August 2017.

[7]    The EPB Center: see website: www.epb.center.