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Step 2: Conformity Assessment

Introduction to Conformity Assessment

Conformity assessment in the framework of the CE marking directives is the process by which compliance with Essential Requirements is determined. In the next video, we explain what conformity assessment is, which types of ‘modules’ for conformity assessment there are and how conformity assessment can be conducted.

Essential Requirements

Every CE marking directive has a section in which the so-called ‘essential requirements’ for the products covered by the directive are prescribed. In most cases, the essential requirements can be found in the Annexes to the applicable directives. The essential requirements are the legal requirements that products must comply with. And compliance with the essential requirements is one of the points that are investigated during the conformity assessment (certification).

In this lesson, you’ll discover the essential requirements that apply to your products. We’ll also discuss the various conformity assessment procedures that exist in CE marking directives, and we’ll determine which conformity assessment procedure/procedures you may apply.

What are Essential Requirements?

Essential requirements lay down the necessary elements for protecting public interests. The essential requirements can be found in one of the annexes to the directive (for example Annex I to the Machinery Directive) and in some cases in its body text (for example the EMC directive). They are mandatory, legally binding obligations, and they deal in particular with the health and safety of users (typically consumers and workers), and sometimes cover fundamental requirements such as the protection of property or the environment.

Examples of Essential Requirements

The following are two examples of essential requirements. One example is taken from Directive 2006/42/EC (‘Machinery Directive’), and the second example is from Directive 88/378/EEC (the previous ‘Toys Directive’).

Example 1:

1.1.8 Annex I Machinery Directive
Article 1.1.8 of Annex I of the Machinery Directive

Example 2:

Annex II2c Article 3
Article 3, Part II of Annex II to the Toys Directive

The Purpose of Essential Requirements

The CE marking directives’ essential requirements are designed to provide and ensure a high level of protection. The requirements either arise from certain risks (hazards) associated with the product (e.g. physical and mechanical resistance, flammability, chemical, electrical or biological properties, hygiene, radioactivity, accuracy), or refer to the product or its performance (e.g. provisions regarding materials, design, construction, manufacturing process, instructions drawn up by the manufacturer), or lay down the principal protection objective (e.g. by means of an illustrative list). And often they are a combination of these.

As essential requirements must be applied as a function of the risk (hazard) inherent with a given product, manufacturers need to carry out hazard analysis to determine the essential requirement applicable to that particular product. This analysis should be documented and included in the technical documentation.

Essential requirements define the results to be attained, or the risks (hazards) to be dealt with, but do not specify or predict the technical solutions for doing so. This flexibility allows manufacturers to choose the way to meet the requirements. It allows also that, for instance, the materials and product design may be adapted to technological progress. Accordingly, CE marking directives do not necessitate regular adaptation to technical progress, since assessment of whether requirements have been met or not is based on the state of technical know-how at a given moment.

Although no detailed manufacturing specifications are included in the essential requirements, the degree of detailed wording differs between directives. The wording is aimed to be precise enough to enable the assessment of conformity with those requirements, even in the absence of harmonized standards or in case the manufacturer chooses not to apply them.

How to conduct the conformity assessment?

As said, conformity assessment is the process of determining compliance with the Essential Requirements of the directive. As you have seen in the previous step, the Essential Requirements can be found in the text of the directives. Basically, you read provision by provision and determine a) whether the provision applies, and b) if so, determine if the product complies with the requirement. The conformity assessment against the Essential Requirements must be documented. For some directives we’ll provide you with a checklist for the conformity assessment against the essential requirements of the directives that apply to your products. (Please note: since the Essential Requirements for the EMC Directive, Low Voltage Directive and Construction Products Directive are either limited or abstract, we have no checklists for these directives. The conformity assessment for these directives are done on the basis of standards or testing.) These checklists will help you to document the compliance with the provisions. Filling out this checklists (when available) is the first step in the conformity assessment.

Conformity assessment can be carried out with or without the use of standards. This last principle is important to manufacturers of new or innovative products for which standards do not yet exist. In other words, the use of standards is not obligatory, even if these standards have the status of European harmonized standards that pertain to a particular CE marking directive. (Please note however that if you don’t apply the standards, you may be required to involve a 3rd party certification body). We will talk in more detail about standards and European harmonized standards later in a next lesson. Conformity assessment against the applicable European harmonized standards is recommended as the second step in the conformity assessment. In some cases, these standards may require testing, but often visual inspections are sufficient to determine non-compliance or compliance.

The Machinery Directive and the Medical Devices Directive both require the manufacturer to perform a risk assessment as a part of the conformity assessment. In the next lesson, you’ll discover which methodologies there are to conduct the risk assessment.

Checklist(s) for Conformity Assessment

Get Your Checklists
For many directives we have checklists that can help to do the conformity assessments. Click the button below and request the checklists to be made available to you. Please mention which CE directives and EN standards you have found to be applicable.

Conformity Assessment Against Standards

Besides doing an assessment against the essential requirements of the CE directives or regulations, we recommend you also to conduct a conformity assessment against any relevant European harmonized standards or other European or international standards (or to have it conducted by a test laboratory or consultant).

Assessment against the requirements of standards means the following:

1. You obtain the relevant standard(s);*
2. you read the text of the standard(s);
3. you make an inventory of the provisions that apply and that do not apply;
4. you assess the product against compliance with the text of each relevant provision;
4. you document for each relevant provision whether the product complies Yes/No.

* the product specific (or type “C” standards) are the most important, because these standards have been developed particularly with the product in mind. If there are no type “C” standards, you apply standards that are relevant for product families (e.g. “electrical safety of industrial machinery”, or for certain product aspects (e.g. vibration)

Our company, typically uses a three column table to document compliance. The first column of the table gives the reference of the provision of the standards and sometimes even the text of that provision. In the second column we indicate “Yes” for compliance, “No” for non-compliance and “N/A” in case a provision is not relevant. In the third column we provide the motivation or arguments for our judgment, and possibly references to supporting documents. In ‘The Six Step CE Marking Framework‘, we have a few of these tables for a few standards. But as there are thousands of standards, we cannot provide these for every standard. This is not a big problem, because it is easy to make such a checklist/table yourself in a word processing software program like MS Word, Excel or Mac OS X Pages.

Some conformity assessments against standards will have to be done by test laboratories, because your company may not have all the required test facilities. If so, you will receive a test report that will state whether the product complies with the standard(s).

About Conformity Testing

Sourcing Test Laboratories

Do the applicable conformity assessment procedures prescribe you to involve a third-party certification body and you have no clue where to find them? Or do you need to have particular compliance testing done and you want to find a reliable organisation with fair fees? Let us know and we will direct you toward some trustworthy sources.

As you will also read in the next steps, you can get into many different issues with your test lab or engineer that performs the conformity assessment. Many companies focus on price when choosing a test lab or conformity assessment body. However, it is much more important to choose a knowledgeable organization, that is also informed about the latest regulatory and engineering developments. We recommend also taking into account the reputation of the body, as it may save you a lot of discussion with customers or competent authorities later on. If at a later stage the test reports are disputed, and you need to re-test with another lab, your cheap lab’s offer all of a sudden is not so appealing anymore…

As a minimum for the final assessments and testing, we recommend you choose a body that holds an accreditation for the particular tests and standards that are relevant to your products. You can check whether the lab or body has a certificate for the ISO 17025. This ensures their reliability, competence and independence.

Preparation of Samples and Documentation for Testing

The lab manager of an EMC and electrical safety laboratory I frequently visit for my clients? test projects recently told me something that shocked me: Almost 80% of the products offered for compliance testing fails the first compliance test. Even more shocking: In most cases, the non-conformity can be prevented if the manufacturer is better prepared for the compliance testing. Can you imagine? So many companies waste money on a first compliance test, which they aren’t likely pass because they did not prepare their samples, or they failed to provide the right documentation.

You will dramatically increase the chances of your products passing compliance tests if you are informed about the requirements as well as about the ways the laboratory will conduct the compliance tests. If you understand the requirements and the test to be performed, you can prepare the test sample properly.

Almost without exception, test laboratories conduct compliance tests according to the specifications of standards. If you find out which standards will be applied (you may simply ask the lab to tell you), you may obtain a copy of the standards and study them. In some cases, it is even possible to simulate the tests in-house. Either way, it will allow you to verify whether your product is ready to pass the tests that test laboratories or certification bodies are going to conduct.

Another tip: After you have determined which standards apply, and you have read the texts and checked if your products can comply (if not, you’ll need to consider a redesign), you can contact test labs and ask them if they can do a “preliminary test” or “pre-compliance test”. During such a test, not the full scope of the standard is tested, but the most relevant parts, or those parts where you expect problems. Typically, the costs of such a test are a lot less, and it helps to determine if your product is ready for the final test.


Finally, the big day of the conformity assessments has come. In some cases, the tests, inspections or assessments can be performed “in situ“: at your site, or at your customer’s site. In many cases, tests will be performed at the laboratories.

In any case, it is highly recommended that one of the design engineers will witness the tests. The engineer can assist in setting up the test sample. This may help to reduce the time investment. Also, the design engineer can provide back ground information that will help the test engineers to better understand the intended purpose of the product, and thus to interpret the rules and the test results. And in case the product will not pass the testing, the design engineer can witness directly what the issues are, and discuss with the test engineers the possible solutions.

Test Reports

As we discussed before, by affixing the CE marking to its products, your company indicates that the product complies with the relevant EU requirements AND that it has evidence for it. That means also that the testing, inspection, or conformity assessment must be documented. We have already discussed the documentation of assessments, and where relevant, we have provided checklists for some of the assessments.

When you subcontract tests or assessments to a test lab, ensure that you will receive a test report and test certificate. (Tip: check if this is included in the price!) There is not a specifically prescribed format for test reports in the EU directives and regulations, but you can check if some key elements are there. One of the most important aspects to a test report is that it ensures traceability of the test results. Not only do you need accurate descriptions of the (test) samples, of the date and location of the testing/assessment, but also the (test) engineer needs to be identified. And where test equipment was used, it needs to be described as well (with reference numbers). The test report will also specify according to which standards and which sections from the standards the assessment was conducted.

Perhaps you did not know, but for some product tests/assessments there are standards that specify what needs to be included in the test report. For example:

  • BS ISO 10328-8:1996 – Prosthetics.Structural testing of lower-limb prostheses. Test report.
  • BS ISO/IEC 25062:2006. Software engineering. Software product quality requirements and evaluation (SQuaRE). Common industry format (CIF) for usability test reports.
  • BS ISO 8178-6:2000. Reciprocating internal combustion engines. Exhaust emission measurement. Report of measuring results and test.
  • ISO 16100-4:2006 Ed 1. Industrial automation systems and integration – Manufacturing software capability profiling for interoperability -. Part 4: Conformance test methods, criteria and reports.
  • BS EN 30326-1:1994+A2:2011, ISO 10326-1:1992. Mechanical vibration. Laboratory method for evaluating vehicle seat vibration. Basic requirements.

Role of Suppliers in Conformity Assessment

Both vendors and distributors play an important role in product compliance. For example, components and parts may require CE Marking of their own, or may have a decisive influence on your product’s compliance. I can illustrate this with a story: One of my clients manufactures and sells electrical ‘well-being’ products. These are powered by power adapters, which are purchased from China. For the purpose of the electrical safety tests and the electromagnetic compatibility tests, the power adapter is considered an integral part of the test sample. The EMC test results showed that the sample failed the tests. When we investigated what caused the problem, it turned out that the power adapter was not CE-compliant. In other words, the product could not be CE approved and had to be re-tested because a vendor supplied non-compliant part.
A power adapter is a product that is required to be CE-approved. And while the adapter in this story did in fact carry a CE Mark, the tests showed that the CE Mark was not affixed legitimately. Be aware that even if a part or component has the CE Marking affixed to it, you have no way of making sure that it is CE approved unless you have a test certificate or test report from an accredited laboratory.

At the other end of the spectrum, compliance problems may be introduced by distributors or retailers. Another example comes to mind, where a manufacturer of highly sensitive electronic devices was refused approval by their certification body due to the fact that an external warehousing company, which handled part of their warehousing and shipping needs, was not able to provide the documented evidence that they controlled the storing conditions. This meant that they could not ensure that the units arrived at the warehouse fully CE-compliant. But, because quality control was not complete, it was not possible to ensure the quality of the products stored in the warehouse. The only options left were to replace the quality control by performing a random type test, which would raise the costs of CE certification drastically, or to help the warehouse get its storage control and quality procedures in order.

The vendors and distributors may also contribute to cutting the costs of CE certification. Some products are assembled exclusively from CE Marked components purchased from vendors. In such cases, the EMC Directive does not require you to test the whole assembly again. And for the Machinery Directive, you would not have to investigate the parts and components again, but you may focus on the areas where parts and components are integrated with the machine.
Or, take the example of a machine, for which the control panel is supplied by a vendor. If the vendor takes care of the CE compliance of the control panel, the manufacturer of the machine does not have to assess the conformity again, on the condition that the manufacturer can show the documents that prove compliance of the control panel (e.g. Declaration of Conformity, certificate, Technical File). You can imagine that this saves the manufacturer a very substantial amount of money.

In the following video of a recording of a webinar we did a while ago, it is explained how you can check yourself if your suppliers’ products comply: