Standards and how they support the design of safe products


The use of Standards in complying with European product safety Directives is not compulsory, but they can be useful when designing products.


The use of Standards in complying with European product safety Directives is not compulsory, but they can be useful when designing products.

However, some European standards have a special legal status and define minimum acceptable levels for health and safety by supporting the essential requirements of these Directives, and if followed fully may give a presumption of conformity to the relevant Directive's essential requirements.

Standards may deal with broad general principles, aspects of safety common to many products, or be product specific.

Standards can exist at many levels and include:

  • international standards (prefixed by "ISO" or "EN", sometimes by both)
  • national standards (eg British Standards prefixed by "BS")
  • industrial/sector
  • even in-house 

Standards have been defined as "an agreed, repeatable way of doing something" (BSI). Normally they are published documents containing technical information to guide or define practice in a consistent way, and are usually used by designers and manufacturers of products. They are also used by customers when specifying products, and authorities when checking product compliance, particularly where the use of a standard is listed in the Declaration of Conformity or the technical file

Normally the use of standards is voluntary and they do not impose legal responsibilities. However, in some cases legislation may "call-up" a specific standard effectively giving it legal force, or their use by a manufacturer may be declared, effectively binding that person and their product, to the requirements of the standard.

The British Standards Institute BSI is the UK's National Standards Body, and publishes in English all National, European and many International standards. In many cases standards are double prefixed "BS EN" which means this is the UK version in English of a European harmonised standard (in some cases the prefix may be "BS EN ISO" where an international standard has been adopted by Europe as a European standard).

Transposed harmonised standards

In the field of European product safety transposed harmonised standards are a group of standards with special status. Their status is confirmed by their listing in the Official Journal of the European Union, although usually an indication of the status of any particular standard is given in the standard, and any limits on its coverage in it's own Annex Z.

Although their use remains voluntary, if a transposed harmonised standard is followed in full by a product designer it can confer presumption of conformity with one or more essential (health and safety) requirements, provided the product is within scope of the standard and the standard supports the relevant product safety Directive without qualification.

This means in effect that by following the requirements of a transposed harmonised standard a designer knows that his product will comply with the parts of the Directive applying to his product. The use of such standards can save designers much time in assessing risks and adopting strategies for safety, particularly where the standard deals with all essential requirements relating to a particular product.

Standards dealing with a particular type of product are often referred to as "C" standards (eg BS EN 1493:1999 Vehicle Lifts). Those dealing with common safety issues (eg BS EN 574:1997 Two-hand control devices) are often referred to as "B" standards, and those dealing with the fundamental principles for safety (eg BS EN ISO 12100:2010 Safety of machinery - General principles for design - Risk assessment and risk reduction as "A" standards.

European standards typically follow a similar style and format, and knowing something of the structure can help reading and understanding them. The following is typical of a machine specific "C" standard supporting the Machinery Directive:

  • the European standard (EN) may be inside a BSI "wrapper" with a National forward, inside that will be an unaltered copy of the EN as published by CEN or CENELEC and listed in the Official Journey of the European Union
  • the front page (along with Annex Z, which normally is at the end) of the standard describes the status and origin of the EN 
  • the scope of a standard is fundamental as here the products to which the standard applies, and in some cases does not apply, are detailed 
  • a section listing other Standards referenced within - these are of two types: "normative" references which form a legal part of the Standard, and "informative" references which are for information and do not form part of the Standard
  • a section Defining terms used in the standard, and sometimes the products
  • a hazard analysis section
  • a section listing the Safety Requirements for each hazard
  • a section indicating measures for product verification
  • a section outlining what the Instructions for Use should contain
  • and may be accompanied by a number of Annexes - these may be Normative (which directly support the Safety Requirements), or Informative, including
  • usually in Annex Z, the origin, status, and extent to which the standard supports relevant Directives

Note: there may be significant exclusions listed in both the Scope and Annex Z disapplying the standard either to certain products, and / or to certain essential requirements, and the application of a standard may be further qualified by a note alongside its reference in the Official Journal. 

Lists of standards applying to particular Directives are also available:

Use of transposed harmonised standards

In many cases transposed harmonised standards define the state of the art for either a product or safety feature. For example:

BS EN ISO 13857 Safety of machinery - Safety distances to prevent hazard zones being reached by upper and lower limbs which was prepared under a mandate given to CEN by the European Commission and the European Free Trade Association (more information on the process of developing standards is available). This standard provides one means of conforming to Essential Requirements of the New Approach Directive 2006/42/EC on machinery, by defining the safe minimum distances through different sized holes in guards to prevent access to dangerous parts. 

Nevertheless, the use of even this standard remains voluntary, fundamental as it is for defining safety distances. All a product designer /manufacturer has to do is meet the objectives of the essential requirements of the relevant Directives, and show this in his technical file. The standard shows one way this can be done, and if followed gives presumption of conformity.

However, in certain circumstances, and where justified, even fundamental standards such as this need not be followed, provided the designer /manufacturer can show compliance with the essential requirements in his technical file by another equally effective method so the level of risk reduction is at least as good as if the standard had been used. For example, the physical nature of a product may ergonomically constrain access to dangerous parts even though the safety distance is less than that defined in BS EN ISO 13857, and so it may be justified in particular circumstances to not follow the standard in full. 

The use of any standard by a designer or manufacturer is voluntary. But where compliance with any standard, and not just transposed harmonised standards, is declared by the Responsible Person without qualification on the Declaration of Conformity for the product, that person is bound to fully meet all requirements of those standards for his product.

Standards are not usually applied retrospectively to products first placed on the market before the standard is published, and may only define the state of the art at the time they were developed and published. European standards, like most others, are therefore subject to periodic review (normally the process starts 5 years after the date of publishing in the Official Journal), and so their provisions may change over time.

Standards should normally be referenced to a dated version. Where a standard is referenced undated, for example on a Declaration of Conformity or in a technical file, the market surveillance authorities can assume that the Responsible Person is referring to the latest version of that standard.

Designers and manufacturers should therefore keep aware of the current status of standards relevant to their product, and ensure that product documentation is similarly kept under review and updated as necessary.

Prior to the introduction to European product safety Directives, with supporting transposed harmonised standards, many products met National standards. In the UK for machinery we had a long standing comprehensive British Standard BS 5304 Code of practice for the safety of machinery. But any standards in conflict with or superseded by European standard have had to be withdrawn, including BS 5304: 1988 as it was superseded by various European standards which apply to new machinery.

However, much old existing machinery is still in use for which the new European standards can't be retrospectively applied, and so for this situation the text of BS 5304 (with some updating) was republished as Published Document PD 5304:2005 Guidance on safe use of machinery. So, for pre Machinery Directive equipment (that is put into use before 1995) this remains the guide to what is considered reasonably practicable for the safety of machinery.

Development of standards

Clearly, as described above, standards are very important for the safe design of new products, but first they have to be produced.  Member states wishing for a new European transposed harmonised standard to be developed should in most cases put a request to CEN, the European Committee for Standardization, or CENELEC, the European Committee for Electrotechnical Standardization.

In the UK this is done via the relevant BSI shadow committee as CEN and CENELEC already have a mandate from the EU Commission to produce standards to meet the supply Directives. If this is not the case a request to the European Commission for a new work item should be made. If it is supported the Commission will issue a mandate for either CEN or CENELEC to take on the new work item.

Either CEN or CENELEC, depending on the field and potential scope of the standard assign the work to a Technical Committee (TC), which then convenes a working group (WG) to prepare a draft standard. Both TCs and WGs depend on the voluntary participation of experts, manufacturers, and regulators in the field of the standards writing. These members are proposed by member states' National Standards Bodies, who will seek other input into the process from their own state.

The work of the TC/WG drafting the standard may be supported by CEN/CENELEC Technical Consultants, who will assess the standard for compliance with the Essential Requirements of the relevant Directive, but may also offer advice on the quality of the emerging standard. However the standard itself will depend on the skills, expertise, research, commitment and direction of the TC and WG members. The process essentially relies on a consensus being developed, and usually takes a number of years to complete.

When a complete draft is ready it will be made available in a published form for public enquiry for a period of usually 6 months, when detailed comments may be submitted by member states National Standards Bodies.  At this stage it is referred to as a "prEN", and should be accompanied by a date / version number as it is a draft text and liable to change. The TC/WG will then taking account of representations made re-draft the standard, and when finally ready it will be submitted to formal vote by qualified majority voting. 

All EU member states can vote at this stage, and the numbers of votes of each member state is weighted. No one large, or even now several member states can veto the process, which means the objections of a member state can be overruled.

Assuming a majority votes for the draft standard it then goes to the Commission and when ratified is published in the three official languages of the EU (identical text in English, French and German) as a European Norm with the prefix "EN" and is listed in the Official Journal). Member state national Standards bodies then have six months to publish the standard unaltered in their territory before it comes into effect, even if they voted against the standard.

This is why in the UK the new European standard, the "EN" is published unaltered inside a British Standard "BS wrapper". If there is any National comment to be made about the new European standard it will be made here. Due to this short delay some BSI EN standards may have a date one year later than the one listed in the Official Journal, eg one produced in December may not be published by BSI until well into the new year.

The process of preparing new standards ideally works by consensus. However, because of qualified majority voting and the make up of the WG, standards can be developed which can be found to be defective in some way or another (perhaps they do not reflect the state of the art for safety, or inadequately detail safety requirements).

The drafts produced may reflect the interests of those who drafted them, perhaps not taking account of recent technological developments, accident history, foreseeable misuse, etc. Not all European standards that have been published have fully met their mandate, and some have been published despite vigorous objection throughout the process, but there is a process to rectify this situation, by means of a formal objection from a Member State.

Objection to a standard

Under most product safety Directives the Commission can be asked by a member state through a formal procedure (generally known as a "safeguard action") to review or withdraw a standard which is considered as defective (for example as described by Article 10 of the Machinery Directive 2006/42/EC).

Following consideration by a committee of the EU Commission the status of the standard in the Official Journal may be changed. Ultimately this can result in full or part withdrawal of the presumption of conformity which a transposed harmonised standard gives, forcing manufacturers and designers to seek compliance with essential requirements directly instead of through that standard.

As stated above European standards are subject to regular review, and decisions like this, and other information, following consultation with member states will inform those reviews. These are opportunities to revise standards, whether defective or not, taking account of technological and other developments, following a similar voting and adoption procedure as when the standard was first being prepared.

Further information