CEPROCON.COM • BLOG ARTICLE • WEEK 7
A consultant’s practical walkthrough
A harmonised standard is not a light read. The first time most people open one, they encounter dense technical language, cross-references to other standards, tables with unfamiliar notation, and annexes that seem to follow different rules from the rest of the document. It is easy to feel lost within minutes.
Yet reading harmonised standards is a core skill for anyone working in CE marking for construction products. Whether you are a manufacturer trying to understand your obligations, a quality manager preparing a technical file, or an aspiring consultant building your expertise, there is no substitute for being able to open a standard and extract exactly what you need from it.
This article is a practical walkthrough. It explains how to approach a harmonised standard systematically — where to start, what to focus on, what to skip, and how to avoid the most common interpretation mistakes. The method described here is the same one experienced CE marking consultants use every day.
Before you open the standard: three things to confirm
Before spending time reading a standard in detail, confirm three things:
- Is this the current version? Check the Official Journal of the European Union (OJEU) list of harmonised standards under the CPR to ensure the standard is still cited and remains valid. Using a withdrawn version is a common and costly error.
- Is there an Annex ZA? Only standards published in the OJEU as harmonized standards include an Annex ZA linking the standard to CE marking under the CPR. If the standard you are reading does not have an Annex ZA, it is not harmonised under the CPR and cannot be used as the basis for CE marking.
- Has the co-existence period ended? The OJEU entry for the standard shows the date of applicability. If the co-existence period has not ended, CE marking based on this standard is voluntary, not mandatory. If it has ended, CE marking is mandatory for all products within scope.
Step 1: Read Clause 1 (Scope) with extreme care
The single most important clause in any harmonised standard is Clause 1: Scope. Everything else in the standard only applies if your product falls within this scope. Many CE marking errors — both applying a standard that does not apply and missing one that does — stem from insufficient attention to the scope clause.
When reading the scope, look for:
Product type definition
How precisely does the standard define the product type it covers? Look at the materials, construction methods, and product families included. Some standards are very broad (covering an entire product category), while others are tightly scoped to a specific configuration or material combination.
Intended use
Does the scope define where or how the product is to be used? Many standards specify intended uses such as “for use in walls”, “for external applications”, or “for load-bearing applications”. If your product’s intended use does not match what the standard describes, the standard may not apply — or may only partially apply.
Explicit exclusions
Most scope clauses include a list of products or applications that are explicitly excluded. These exclusions are not optional — if your product falls within an exclusion, the standard does not apply to it regardless of how similar it appears to covered products. Always read the exclusion list in full.
Pro tip: If after reading Clause 1 you are still not certain whether your product is in scope, move to the definitions clause (usually Clause 3) and check whether your product type is defined there. The definition often adds clarity that the scope clause alone does not provide.
Step 2: Go directly to Annex ZA
Once you have confirmed that your product is within scope, the next place to go — before reading the rest of the standard — is Annex ZA. This is the CE-marking-specific annex that maps the standard’s content to the requirements of the CPR.
Annex ZA typically contains three critical tables:
| Annex ZA table | What it tells you |
| ZA.1 — Characteristics and AVCP systems | Lists every essential characteristic covered by the standard, the clause(s) of the standard where the test method or assessment procedure is described, and the AVCP system that applies to each characteristic. This is where you establish exactly what needs to be assessed and by whom. |
| ZA.2 — Procedure for AVCP | Describes the specific tasks assigned to the manufacturer and, where applicable, to the Notified Body under each AVCP system. Tells you step by step what the manufacturer must do and what the Notified Body must do. |
| ZA.3 — CE marking and labelling | Sets out the minimum information that must appear on the CE mark label affixed to the product (or its packaging or accompanying documents), including which declared values must be included and how they should be expressed. |
By the time you have finished reading Annex ZA, you should know: which characteristics must be assessed, what AVCP system applies to each, whether a Notified Body is needed, and what the CE mark label must show. This is the essential framework for the entire CE marking project. Everything else in the standard fills in the technical detail.
Step 3: Navigate the technical clauses purposefully
With the scope confirmed and Annex ZA understood, you now know which clauses of the standard are relevant to your CE marking work. You do not need to read the entire standard from beginning to end — in fact, trying to do so often creates confusion rather than clarity.
For each essential characteristic identified in Annex ZA.1, go to the clause referenced and read it to extract:
- The test method or assessment procedure: precisely how performance must be measured or evaluated. Note any conditioning requirements, specimen preparation rules, or environmental conditions that apply.
- The classification or performance system: how the result is expressed — as a class (e.g. A1, B, C for fire), a numerical value, a threshold, or a pass/fail.
- Referenced test standards: many harmonised standards do not describe the test method in full but instead reference a separate test standard (e.g. EN ISO 11925-2 for ignitability). You will need that standard as well.
- Options and choices: some clauses offer alternatives — different test methods, different sampling frequencies, or different documentation approaches. Record which option is applicable or has been chosen, as this must be consistent across the technical file.
Step 4: Distinguish normative from informative content
One of the most important distinctions in any standard is between normative and informative content:
Normative content
Normative content is mandatory. It sets out requirements that must be met. The main body of the standard and normative annexes (labelled “Normative” in their title) are normative. Clauses using the word “shall” indicate normative requirements; clauses using “should” indicate recommendations that are not strictly mandatory.
Informative content
Informative content is not mandatory. Informative annexes (labelled “Informative”) provide background, examples, or guidance to aid understanding but do not impose requirements. The foreword and introduction of a standard are also informative. Reading informative content is useful for context but following it is not required for compliance.
This distinction matters enormously in practice. A manufacturer who treats informative annex content as mandatory may create unnecessary work. One who treats normative requirements as optional may produce a non-compliant technical file. Always check the status of every annex you are reading.
Step 5: Map the cross-references
Harmonised standards rarely stand alone. They typically reference:
- Test standards: separate EN ISO or EN standards describing specific test methods. These are usually referenced normatively and must be obtained and followed.
- Classification standards: particularly EN 13501 (fire classification) and EN ISO 10456 (thermal and hygric properties), which are referenced by many product standards for expressing and classifying results.
- General standards: such as EN 1990 (Eurocode: basis of structural design) or EN 13369 (common rules for precast concrete products), which set out principles that product-specific standards build upon.
When you first work through a harmonised standard, it helps to build a simple map of all the standards it references and mark which ones are relevant to your product’s CE marking assessment. This becomes your working library for the project — the set of documents you need to have to hand.
Step 6: Build a working interpretation record
As you work through a standard, document your interpretations and decisions as you go. This is not just good practice — it is essential for a defensible technical file.
A useful interpretation record should capture:
- Scope determination: which clause(s) and what reasoning support the conclusion that the product is within scope.
- Essential characteristics: the list of characteristics from Annex ZA.1 that apply to the product, with the applicable AVCP system noted for each.
- Choices made: where the standard offers alternatives (test methods, sampling frequency, documentation options), the choice made and the justification.
- Ambiguities and their resolution: where the standard language is unclear and an interpretation was required, what conclusion was reached and why. If the interpretation is significant, consider seeking clarification from the national standards body or the standard’s technical committee.
- Referenced standards to be obtained: a list of all normatively referenced test and classification standards that are needed.
The most common standard interpretation mistakes — and how to avoid them
Reading the title instead of the scope
Standard titles are often broad and can be misleading. A standard titled “Thermal insulation products for buildings” may actually be scoped only to factory-made products, excluding products prepared at the construction site. Always read Clause 1, not just the title.
Confusing ‘shall’ with ‘should’
In standards language, ‘shall’ means mandatory and ‘should’ means recommended but not required. This is a precise technical convention, not casual writing. Treating a ‘should’ as a ‘shall’ creates unnecessary obligations; treating a ‘shall’ as a ‘should’ creates non-compliance.
Ignoring the date of the referenced test standards
Harmonised standards reference test standards by number and sometimes by date. If a specific year is cited (e.g. EN ISO 1182:2010), that is the version that must be used — not a newer or older edition. If no year is cited, the most current version generally applies, but always verify.
Assuming Annex ZA covers all characteristics in the standard
Harmonised standards often contain many technical characteristics that are not listed in Annex ZA and therefore are not part of CE marking. These characteristics may be commercially relevant or required by national building regulations, but they are not CE marking requirements. Confusing the two leads to either over-testing or incorrectly including non-CE characteristics in the DoP.
Summary: the six-step reading approach
| # | Step | Key question to answer |
| 1 | Pre-read checks | Is this the current version? Does it have an Annex ZA? Has the co-existence period ended? |
| 2 | Clause 1 — Scope | Is my product and its intended use within scope? What is excluded? |
| 3 | Annex ZA | Which essential characteristics apply? What AVCP system? Is a Notified Body needed? What must the CE label show? |
| 4 | Technical clauses | For each relevant characteristic: what is the test method, how is performance expressed, and what standards are referenced? |
| 5 | Normative vs informative | Is this content I must follow (normative) or content that helps me understand (informative)? |
| 6 | Interpretation record | Have I documented my scope determination, choices, and interpretations for the technical file? |
Reading harmonised standards well is a skill that develops with practice. The first time through a new standard will always take longer than the fifth. But with a systematic approach — and a clear sense of what you are looking for and why — even a complex, multi-part harmonised standard becomes navigable.
If you need hands-on support applying a harmonised standard to your own products, our Technical File & Declaration of Performance Preparation and CPR Compliance Audit & Gap Analysis services can help. You can also see this approach applied in practice in our guides to CE Marking for Structural Steel and CE Marking for Insulation Products.
Want to develop this skill properly?
CEProCon’s professional training programme teaches participants how to read, interpret, and apply harmonised standards in real CE marking projects — not just in theory, but through worked examples using actual standards. If you are building expertise in construction products compliance, this is one of the highest-value skills you can develop.
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