CEPROCON.COM • BLOG ARTICLE • WEEK 5
The technical backbone of CE marking for construction products
Harmonised standards CPR construction products — this article explains what they are and how to find the right one. If the Construction Products Regulation (CPR) is the legal framework, harmonised standards are the technical engine that makes it work in practice. Without harmonised standards, CE marking for construction products would be an abstract obligation with no way to fulfil it. They are the documents that tell manufacturers exactly what to measure, how to measure it, and how to express the results.
Yet harmonised standards are widely misunderstood — even by professionals who work with them regularly. Many manufacturers know they need to “follow a standard” but have only a vague sense of what that actually means, which parts of the standard are legally binding, and how to find the right one for their product.
This article demystifies harmonised standards: what they are, how they are structured, what gives them legal force, and how to identify and obtain the right one for your product.
What is a harmonised standard?
A harmonised standard is a European standard (EN) developed by one of the three European Standards Organisations — CEN, CENELEC, or ETSI — under a mandate from the European Commission. In the context of construction products, the relevant body is CEN (the European Committee for Standardisation).
What makes a standard “harmonised” — rather than simply a European standard — is that its reference has been published in the Official Journal of the European Union (OJEU). This publication step is what gives the standard its legal force under the CPR. A CEN standard that has not been published in the OJEU is not harmonised and does not trigger CE marking obligations.
Harmonised standards under the CPR are identified by an “EN” prefix and typically follow a naming convention such as EN 13501 (fire classification of construction products) or EN 14351 (windows and doors). Many standards have multiple parts: EN 13501-1, EN 13501-2, and so on, each covering a different aspect or product type.
What legal force does a harmonised standard actually have?
This is one of the most important and most frequently misunderstood points about harmonised standards. The standard itself is not directly binding EU law, but working within it creates a “presumption of conformity” with the requirements of the CPR.
What this means in practice is that a manufacturer who correctly applies a harmonised standard — uses its test methods, assesses the relevant essential characteristics, applies the correct AVCP system — is presumed to have fulfilled the corresponding CPR requirements for those characteristics. They do not need to separately justify their approach to regulators.
Crucially, however, only Annex ZA of the harmonised standard is directly linked to CE marking. The rest of the standard — which may include many additional technical specifications, classification rules, and test methods — is not legally mandated for CE marking purposes, even though it may be commercially required or referenced by other regulations.
Understanding the distinction between the normative content of a standard and the CE-marking-specific content of Annex ZA is one of the core skills of anyone working seriously with the CPR.
How a harmonised standard is structured
Harmonised standards follow a broadly consistent structure. Understanding this structure makes them much easier to navigate:
| Section | What it contains and why it matters |
| Clause 1 — Scope | Defines precisely which products and intended uses the standard covers. This is the most critical clause for determining applicability. Read it carefully before assuming a standard applies to your product. |
| Clauses 2–4 — Terms, references, and definitions | Sets out the terminology used throughout the standard. Essential for interpreting other clauses correctly. |
| Clauses 5+ — Technical requirements and test methods | The main body of the standard: product characteristics, classification systems, test methods, performance levels or classes, and marking requirements. |
| Annex ZA | The CE-marking-specific annex. Lists the essential characteristics covered by the standard, the AVCP system(s) that apply, and the minimum content required for the Declaration of Performance. This is the annex that directly links the standard to the CPR. |
| Informative annexes | Non-mandatory annexes providing guidance, examples, or background information. Useful for understanding but not legally required. |
How to find the right harmonised standard for your product
There is no single, perfectly organised database that makes finding the right harmonised standard completely straightforward. In practice, you need to use several sources in combination:
Step 1: The Official Journal of the European Union (OJEU)
The OJEU is the authoritative source. The European Commission periodically publishes lists of harmonised standards under the CPR in the OJEU, showing the standard reference, title, and the dates of publication, start of co-existence, and end of co-existence (i.e. when CE marking becomes mandatory). Search the OJEU for “Regulation 305/2011” to find the most recent list.
Step 2: The European Commission’s CPR standards list
The European Commission maintains a searchable list of harmonised standards on its internal market website. This is often easier to navigate than the raw OJEU and allows you to filter by directive or regulation. However, always cross-check with the OJEU for the official dates.
Step 3: The CEN catalogue
CEN’s online catalogue (standards.cencenelec.eu) allows you to search by keyword, standard number, or product category. It shows current standards, draft standards under development, and withdrawn standards. This is useful for identifying which standards exist in your product area, but it does not replace the OJEU for legal dates.
Step 4: National standards body catalogues
National standards bodies such as DIN (Germany), BSI (UK), AFNOR (France), PKN (Poland), or ÖNORM (Austria) publish harmonised standards under local designations (e.g. DIN EN 14351, BS EN 14351). These are identical in technical content to the European standard but sold under the national body’s branding. Purchasing from your national body is often the most practical route.
Worked examples: common construction products and their standards
To make this concrete, here are some of the most widely encountered harmonised standards under the CPR:
| Product type | Standard | Key essential characteristics |
| Windows and external pedestrian doors | EN 14351-1 | Resistance to wind load, air permeability, watertightness, thermal transmittance, reaction to fire |
| Thermal insulation products (factory-made) | EN 13162 – EN 13171 (series) | Thermal resistance, reaction to fire, compressive stress, dimensional stability |
| Wood-based panels | EN 13986 | Reaction to fire, release of formaldehyde, thermal resistance, bending strength |
| Cement | EN 197-1 | Compressive strength, setting time, expansion, heat of hydration |
| Prefabricated concrete elements | EN 13369 + product-specific standards | Structural performance, fire resistance, reaction to fire, durability |
| Drainage pipes and fittings (concrete) | EN 1916 | Structural performance, watertightness, dimensional tolerances |
| Structural steel products (hot-rolled) | EN 10025 series | Yield strength, tensile strength, impact toughness, weldability |
| Adhesives for tiles | EN 12004-1 | Tensile adhesion strength, slip, open time |
Revised standards, withdrawn standards, and staying current
Harmonised standards are not static. They are revised periodically — sometimes to reflect advances in testing technology, sometimes to align with revised CPR requirements, and sometimes because the earlier version contained errors or ambiguities that created problems in practice.
When a revised standard is published in the OJEU, there is typically a co-existence period during which both the old and the new versions are valid. Once that period ends, the old version is withdrawn, and the new version becomes the sole basis for CE marking. A manufacturer still using a withdrawn standard is no longer compliant, even if their product itself has not changed.
Keeping track of standard revisions is therefore a live, ongoing responsibility — not a one-time task. Practically speaking, this means:
- Periodically checking the OJEU list for updates to standards relevant to your products.
- Subscribing to update notifications from your national standards body.
- Reviewing your Declaration of Performance whenever a relevant standard is revised to confirm the standard reference remains current.
- Assessing whether a revised standard requires re-testing or changes to your Factory Production Control system.
When no harmonised standard exists: the EAD/ETA route
Despite the breadth of the harmonised standard system, there are still many construction products for which no applicable harmonised standard exists — particularly innovative products, hybrid products, or products with very specific applications.
In these cases, the CPR provides an alternative route through European Assessment Documents (EADs) and European Technical Assessments (ETAs). A manufacturer applies to a Technical Assessment Body (TAB) for an ETA specific to their product. The TAB develops an EAD defining how the product’s performance is to be assessed, and the ETA is then issued on that basis.
The ETA route is significantly more resource-intensive than the harmonised standard route — both in time and cost. However, for genuinely innovative products, it is the only pathway to CE marking, and an ETA can itself become a significant competitive asset by preventing competitors from easily copying a validated approach.
Summary
Harmonised standards are the technical foundation of CE marking for construction products. They define what must be assessed, how it must be assessed, and — through Annex ZA — exactly what CE marking requires. Finding the right standard, understanding its scope, reading its Annex ZA carefully, and tracking revisions are all fundamental skills for anyone involved in CPR compliance.
Getting the standard right at the start of a CE marking project is one of the highest-value things a manufacturer — or their consultant — can do. Almost every subsequent step in the process depends on it.
Need help identifying or interpreting the right harmonised standard for your product?
Standard scoping and interpretation is one of the most common points where CE marking projects go wrong. At CEProCon, we help manufacturers identify the correct standard, understand what it requires, and build a compliant CE marking programme around it. We also cover harmonised standards in depth in our professional training.
Once you’ve identified the right standard, the next step is applying it correctly. Our guide on how to read and interpret a harmonised standard walks through a practical six-step approach. And if you’d like an expert review of your overall compliance approach, our CPR Compliance Audit & Gap Analysis and Technical File & Declaration of Performance Preparation services can help.
contact@ceprocon.com • ceprocon.com
