Ventilation Component EPDs and Building LCAs

Keywords: EPD, ventilation products, c-PCR, LCA

The need for c-PCR [1]standardisation for ventilation components arises from the current diverging national EPD programs, with core differences in the basic approach. Today, manufacturers face multiple diverging national EPD requirements, resulting in several EPDs per product, with different declared environmental information in each one. EPDs are expensive and time consuming to make, and the current situation is both undesirable and unsustainable.

With a coherent standardised c-PCR framework, European ventilation manufacturers should be able to meet current and future market demands for EPDs in a uniform and cost-efficient manner, with one EPD per product, valid across Europe. This remains the overarching objective of CEN/TC 156 Working Group 26, which is developing the common core rules for ventilation components. Following the CEN/TC 156 Plenary meeting, the work will be structured as a standard series, where the WG 26 standard provides the horizontal rules, with the possible addition of product group specific standards for Use stage-related requirements. The rules are complimentary to EN 15804, which apply in full. The purpose of the standardisation effort remains to ensure that Environmental Product Declarations (EPDs) for ventilation products are consistent across all European countries and EPD programme operators.

This article is part one of a two-part series providing a status report from CEN/TC 156 WG 26 “c-PCR for ventilation components” and the efforts towards a coherent European framework for ventilation component EPDs. This part addresses the context for the work and the key issues relating to the use of EPDs, while part two presents the WG 26 core rules, the standard series structure and the suggested approach towards a coherent European framework.

Achieving a coherent approach

The WG 26 work pertains to a new paradigm within the construction industry. A new way of thinking, with new priorities and requirements, which is still taking shape in regulations, standards and local interpretations. With a wide range of perspectives, it quickly became apparent that we needed to create common understanding of the issues at hand before solutions could be found. WG 26 has therefore spent the necessary time on discovery, before moving on to specific solutions and provisions. The results from a comprehensive problem statement exercise resulted a three-step project plan towards a coherent standardisation setup, tackling three main corner pieces to the c-PCR puzzle for ventilation components (Figure 1).

Figure 1. CEN/TC 156 WG 26 Three step project plan.

In more detail, the three steps include determining:

1.    Context

o   what EPDs are and why they are needed

o   what is the regulatory framework we must adhere to

o   what is the intended use and potential misuse of EPDs

2.    Content

o   what do the environmental information in EPDs consist of

o   what parts of the Life Cycle environmental impact can be declared with accurate and non-misleading information from the manufacturer

o   how should the required life cycle modules be declared

3.    Structure

o   what are common issues to be delt with horizontally, and what issues require vertical product group specific deviations (to be minimised)

o   what and how to acquire, structure and implement input from other CEN/TC 156 WGs

o   what issues must be delt with in the first release, what issues can be postponed and addressed in later revisions

WG 26 has been committed to investigate all matters with the required diligence for a coherent European standard, in line with the regulatory framework and the overarching goals. The status is reflected in the current WG 26 working draft and in this two-part article. With a wide competence base with experts from research science, industry associations, consultants and manufacturers of all types of ventilation components, all product groups within the CEN/TC 156 scope are well represented.

At the time the project plan was established, the objective was one common standard for the ventilation components within the CEN/TC 156 scope. Following the CEN/TC 156 Plenary meeting, the structure has been adjusted. The work will now be developed as a standard series, where WG 26 provides the horizontal core rules and where product group specific standards can address the B-stages with product group specific details.

Context

The context of EPDs – what they are and what they are used for – had to be established first: For ventilation components, EPDs are business-to-business communication of specific environmental information for use in building LCAs, as specified and prescribed in EN 15978.

For building LCAs, EPDs are not the only source of information. Detailed project specific energy calculations is a key part of the assessment, accounting for lighting, heating, cooling and ventilation, also considering the positive effects of heat recovery.

EN 15978 refers to EN 15804 for EPDs. The complimentary product category rules (c-PCR) are complimentary to the core rules specified in EN 15804. The regulatory framework that emerges is illustrated in Figure 2, with the WG 26 core c-PCR standard (and connected product group specific standards), resting on top of EN 15804. On the bottom we find EPBD implemented in local building codes, mandating building LCAs from 1 January 2028.

Figure 2. Regulatory hierarchy.

The draft c-PCR mirrors EN 15804, as required, and builds on its well-established principles. One of the most important ones is the short description of what an EPD is intended for:

“An EPD communicates verifiable, accurate, non-misleading environmental information for products and their applications, thereby supporting scientifically based fair choices and stimulating the potential for market-driven continuous environmental improvement. “

For ventilation components, WG 26 must achieve this in a European wide setting. EN 15804 further states that comparison of products using EPD information shall be based on the product’s use in and impacts on the building, considering the complete life cycle.

The use of EPDs for direct comparison is clearly limited for all products used in the construction sector, perhaps even more so for ventilation components. To achieve any meaningful insight, products must be evaluated in the right context. This varies from building to building, from system to system, with a long list of important variables far beyond the control of component manufacturers. The potential misuse of EPDs, for direct product comparison outside of a meaningful context, will lead to suboptimal solutions and products. With ventilation systems being critical for environmental performance, indoor climate and operational costs of the building, there are several incentives in place to regulate this issue.

The role of product performance data

EPD life cycle assessment results are not the only source of information for building LCAs. Detailed project specific energy calculations are a key part of the assessment, for which product performance data is required (pls. see Figure 3).

Figure 3. Product information for use in building LCAs.

In the ventilation industry, accurate product performance data is readily available, and has been for many decades. The data is typically derived from laboratory measurements and is provided as functions of project specific input variables (curves, not static values). This enables the proper evaluation of product performance in any application within the functional envelope of the product. Such data are necessary engineering tools in the planning and design of ventilation systems, and crucial input for building energy calculations. Well-established third-party certification programs ensure the accuracy of the data.

EPD Content

The quantified environmental impact data (derived from LCA) in EPDs are standardised, with a core set of 13 pre-determined environmental indicators including Global Warming Potential. No indicator can be deemed “irrelevant” and omitted - all are mandatory.

EN 15804 has the perspective of the construction project. The construction works life cycle is divided into life cycle “Stages” (Product, Construction, Use, etc). These stages are further divided into “Information Modules” (A1, A2, A3 etc), as shown in Figure 4.

Figure 4. Life Cycle Stages and Modules.

The LCA derived environmental results (prelisted indicators w. more) in the EPD is declared on the basis of this structure, with clearly defined calculation boundaries for each Information module. EN 15804 allows for different EPD types to be provided, with varying scope.

The Use stage paradox

When evaluating which parts of the Life Cycle environmental impact should be mandated in the EPDs, we run into somewhat of a paradox:

The most significant part of the life cycle for ventilation components – namely the Use stage B6 operational energy use – cannot be declared with accurate and non-misleading information from the manufacturer, with data usable for building level assessments or product selection.

This has been demonstrated both through theoretical calculation examples and empirical data from manufacturers during the WG 26 project. The main issue is trying to move from accurate performance data on a component level, to a calculated share of the energy consumption that takes place in a ventilation system in a European building. Compounding the issue even further, is the fact that you must calculate the final environmental impact from that energy consumption, making the results dependent on the energy sources used in the building (Figure 5).

Figure 5. Performance data vs. environmental impact in the building.

There are simply too many variables to achieve this, most of them far beyond the reach and control of the manufacturers. The list includes (but not limited to):

·         Physical location and climate / Outdoor conditions

·         Air flow rate through the component

·         External pressure conditions

·         Temperature and humidity conditions

·         Operating hours per year

·         Control regime (VAV, CAV)

·         Maintenance regime

·         Energy carriers and sources - Electricity mix (origin), heat source (origin) and cooling source (origin).

The issue becomes obvious when looking at typical variability in ordinary European construction projects, and how much they affect the resulting environmental performance of the products. In the simple example which follows, three identical AHUs have been delivered to three ordinary projects in Europe, and we calculate the CO₂ emissions deriving from the electricity consumption for operating the fans (Table 1).

Table 1. Three identical AHUs to three ordinary projects

EPD accuracy is a debatable subject. However, if any indicator changes by ± 10 %, the EPD must typically be withdrawn, updated and re-issued by the manufacturer.

In the simple example above, the difference between the lowest and highest emitting application is 24 333 %. The AHU sent to the hotel in Poland ends up emitting as much CO₂ in one day, as the identical AHU sent to the kindergarten in Sweden does in 8 months of operation. However, the products themselves are identical, and must therefore have the same EPD.

With this degree of variability in the projects, any one-for-all scenario risks becoming non-representative for almost all practical applications. Only energy use for fans is included in the example - energy use for heating and cooling and heat recovery is left out. These factors can vary to the same degree, adding to the already large spread.

Fictive use stage scenarios for illustrative purposes, like some local EPD programs require, reveals another argument against one common generic B6 scenario: Any “positive” environmental impact from heat recovery, often more significant than the negative ones, is outside of the scope of the B6 module in the EPDs. On a product level, B6 scenarios therefore ends up highlighting the negative environmental effects of balanced mechanical ventilation, whilst hiding the more significant positive ones which it enables (i.e. heat recovery).

One of the determining factors in the calculation example is the design of the ventilation systems in which the AHUs are placed, and the resulting external pressure. In this regard, the example illustrates energy consumption and environmental impact from whole ventilation systems, not only the AHUs. However, the B6 is reserved for “active components” which consumes energy directly.

For “passive components” like ducts, supply and extract air devices, dampers etc. any indirect effects on energy consumptions are not permitted. For VAV dampers, key parts in any modern high-efficiency ventilation system, B6 would include the energy required to operate the damper motor - not the energy savings achieved on the fan-side. Having VAV-dampers compared and selected based on actuator power draw, instead of the significantly more important air volume control related properties, is a good example of the type of environmental suboptimization that should be avoided if any meaningful environmental improvements is to be achieved.

On the other hand, if the indirect B6 impact were allowed to be declare for passive components, one would run into the same exact issue as for the active ones: finding a relevant use stage scenario that ends up providing valuable information in a European wide setting, where external pressures in duct system design vary from 150 – 500 Pascals on a regular basis.

The practise of extrapolating from an arbitrary one-for-all use-stage scenario, in an attempt to generate meaningful insight for the building, is not only a futile exercise. It is the opposite of what is required for true environmental optimisation on a building level.

It also puts unnecessary bureaucratic burden on the manufacturer, complicating and increasing the cost of EPDs. It disables the possibility for fully digital workflows and EPD automation, and finally, it risks promoting the selection of random products and solutions based on in-accurate and misleading information derived from non-relevant scenarios.

Closing comments

The Use stage is the most important part of the life cycle of these products, sometimes by order of magnitude - both for the so-called passive and active components that makes up the completed ventilation system. The key issue is how to best facilitate the accurate assessment of it, how to enable the selection of the best products and solutions, and how to ensure communication of accurate and non-misleading environmental information for use in building level LCAs.

For ventilation systems, the environmental impact deriving from energy use is highly dependent on the building, the system design and the project specific operating conditions. Accurate assessment therefore requires detailed project specific energy calculations, where ventilation components are evaluated in their intended context, together with the effects of heating, cooling and heat recovery.

The investigations conducted in WG 26 have shown that Use stage scenarios are not capable of providing accurate and non-misleading environmental information for ventilation components in a European wide setting.

The issue is not a lack of importance, but rather the opposite: the Use stage is too important, and too dependent on project specific variables, to be represented through arbitrary generic scenarios detached from the building context. The work has therefore focused on identifying an approach which both supports the intended use of EPDs in building LCAs, and at the same time promotes meaningful environmental optimisation of ventilation systems and buildings.

However, the understanding of these issues is not yet common ground across all relevant product groups, national EPD practices and market interpretations. This is reflected in the further organisation of the standardisation work in CEN/TC 156. The original objective of WG 26 was to develop one common c-PCR standard for all ventilation components. Following the recent CEN/TC 156 Plenary, the work will instead continue as a series of connected standards.

WG 26 will develop the horizontal core rules, addressing the common issues and the modules which can be dealt with consistently across product groups. Provisions pertaining to the Use stage will be developed further in product group specific standards.

The current proposal from WG 26, and the suggested approach towards a coherent European framework for ventilation component EPDs, is presented in part 2 of this article series.