What is the difference between an ISO, EN-ISO and BS-EN-ISO Standard?

We often get asked this simple question: “What is the difference between an ISO, EN-ISO and BS-EN-ISO Standard?”  The simple answer is “Not much.”  But there’s more to it than that.

I’ve talked about this in a previous blog, but since the question still crops up with much frequency, I’m going to address the question again.

There are three issues at play in answering the question:  1. Location, 2.  Adoption, and 3.  Certification.

1.  Location:

An ISO document is developed as an international standard.  It is intended to have world-wide usage.  It is written under strict protocols with participation from delegates from all over the world.  Once released, it is publicly available for distribution.

An EN document is developed as a regional standard.  It is intended to be used in the European Union.  It is written under protocols with participation from delegates of the member states.  Once released, it is not available for public distribution.

A BS-EN document (or DIN-EN or AFNOR-EN, etc.) is a national standard.  It is published as each country in Europe adopts the EN document.  There are strict requirements for the withdrawal of any conflicting or duplicating standards.

2.  Adoption:

When an ISO document is released, countries have the right to republish the standard as a national adoption.  So, when the ISO-14971, for example, is issued, the European Union has the right to adopt and republish the standard.

When the EU chooses to adopt an ISO standard, they add a level of administrative overhead.  Thus, the EN adoption has a later issue date than the original ISO document, plus additional cover sheet information.

Usually, the true title of the EN standard will show you exactly what revision level of the ISO standard is being adopted.  So in our example of EN-ISO-14971, 2009 Edition, the title is “Medical devices – Application of risk management to medical devices (ISO 14971:2007, Corrected version 2007-10-01).”  As you can see, the complete title shows you what edition of the ISO document has been adopted.

However, as we noted above, the EN edition when issued is not actually available for public distribution.  Copies in English, French and German are supplied to each member of the EU.

The British Standards Institute publishes the official English language edition (in this case, BS-EN-ISO-14971), the German Standards Institute (DIN) publishes the official German language edition, and the French (AFNOR) publish the official French language edition.  The issue dates on each of these national adoptions will differ as the administrative time to review national standards for possible withdrawal varies.

3.  Certification:

As we have seen, we have a core ISO document that becomes increasing “wrapped” in layers of administrative adoption processes.  While our first impulse would be to go to the source document, I encourage you to take a moment to consider the political undercurrents involved.

Because the EN editions of all standards are called out in the European Union’s regulatory schema (the European Directives harmonization process), many certification professionals will only accept EN standards when reviewing customer facilities and practices.  Additionally, the EN editions have the Z Annexes, which do have an impact on your understanding of how the clauses in an individual harmonized standard relate to the relevant Directive.

So if you know that your trading partner in the European Union is in Germany and they want your auditor to come from a German firm, you may be well advised to get the English language editions of the DIN-EN standards where ever possible.

And if you are going to be audited by a firm based in England, like BSI for example, you should definitely consider purchasing the BS-EN editions of any ISO standard you use.  This can save you much time during your audit, even though it costs significantly more when you purchase the standard itself.

So, in conclusion, ISO, EN-ISO, and BS-EN-ISO documents all contain the same core information.  Only the administrative “wrapping” changes with each subsequent adoption level.

I hope this helps you understand this complex issue!

Let me know if you have any questions.  I can be reached by phone (650-591-7600), fax (650-591-7617) or email (info@document-center.com).  Or my expert staff can easily help you out.

Published by

Claudia Bach

Claudia Bach is the President of Document Center Inc. and a world-wide recognized expert on Standards and Standards Distribution. You can connect with her on Google+

39 thoughts on “What is the difference between an ISO, EN-ISO and BS-EN-ISO Standard?”

  1. Dear mam,

    I would thank you very much for above information which is satisfactory upto much extent.

    As per above answer it seems that content will be unaltered but whether it is always so or there can be addition or modification sometimes, would you please let us know?

  2. Thanks so much for asking.
    The situation is this — When an ISO standard is adopted, it is adopted as written. When an IEC standard is adopted it usually is adopted as written. However, because of the national variations in the use of electricity, there may be some variation.
    In addition, the rules of the EU require each nation to review their standards prior to the adoption and publication of each EN standard. These rules require that any duplicate or conflicting standards be withdrawn in favor of the EN edition.
    You may find administrative information from the specific country that is publishing the standard in the cover sheet. This information (depending on the country) may offer insight into the documents that have been affected by the adoption and publication of the EN edition you’re using.
    I hope this is helpful to you.
    Best regards,

  3. Hello Document Center:

    Can you improve each document’s description on your website with full explanations of their titles? For EN-ISO-14971, why not list it as European Union regional standard (EN), English Language, of ISO 14971:2009? Why not make it as easy as possible for customers to to find and buy standards?

  4. Hi Dirk:
    Thank you so much for asking about this.

    Your idea is a great one! I always think of the problem of the various adoptions and republications as strictly an educational issue — Customers are not aware of the policies of the various standards organizations so this proliferation of document numbers is confusing.

    But I have not thought about actually providing an explanation of the situation in the results page on our site.

    It may take us a while to implement your idea, but we certainly will as it will make it much easier for folks to identify what copy they actually need to order.

    Thanks for bringing this to our attention!

    Best regards,
    Document Center Inc.

  5. dear Claudiaو
    thank you for this information

    I’d like to ask this question in different way,

    Is there any relationship between BS and EN? In addition, ISO?

    I’ll be very thankful if you could give me answer for this.

    many thanks


  6. Thanks for asking.

    There is a relationship between BS and EN. The EN organizations are a regional grouping for the countries that belong to the European Union. So the 2 EN standards bodies (CEN and CENELEC) are composed of representatives from each of the member nations. For the UK, that would be BSI (the organization that publishes the BS standards).

    Since the EN standards are not released to the general public as just EN standards, it is up to each nation in the EN system to publish each standard as it is adopted in that country. The official English language editions of the EN standards are always published by BSI as BS EN documents.

    OK. So far so good!

    Now what about ISO? ISO is the International umbrella organization for standardization. It is made up of representatives from various countries around the world.

    Since one major goal of standardization these days is to bring as much harmonization into the system as possible (the use of a single standard worldwide for a specific topic is the ideal), it makes a lot of sense for as many countries as possible to use ISO standards.

    In order to accomplish this in Europe, the process is for the EN to adopt an ISO standard. This becomes an EN ISO standard. But again, it cannot be publicly distributed as such. In comes each country in Europe with the publication of our EN ISO document as it is adopted for use. Now we have BS EN ISO standards. They are the official English Edition of the European Adoption of a specific ISO standard!

    Yipes! And yet, that’s the way the system works…

    Hope this is helpful.

  7. Thank you for the explanation. I am teaching design to HNC Engineering students from both electrical and mechanical backgrounds. The explanation is simple and makes easy reading. I will use this in my teaching notes (if you have no objections?).

  8. Hi John:
    I would be delighted to have you include this in your teaching notes. One of my primary goals in writing this blog is to help folks understand standards and how they’re properly used. And one important group for such education is in academia — specifically engineering students.
    Thanks so much for thinking of us! And do let me know if there’s other topics you’d like to have me post a blog on as well.

  9. Very nice explanation. I would like make sure that I got your example right:
    “So if you know that your trading partner in the European Union is in Germany and they want your auditor to come from a German firm, you may be well advised to get the English language editions of the DIN-EN standards where ever possible.”
    The English language editions is the one published by The British Standards Institute and referring to the same EN or is actually the translation of the official German language edition published by the DIN.
    If I have understood correctly the the English language edition (by the British Standards institute) and the DIN version, translated in English may have some differences due to national standards.
    Hope I have this right.
    Kind Regards,

  10. Hi Marco:
    And thanks for asking.

    So to make it easy on ourselves, here is the situation:

    EN provides official copies of all EN Standards to the European National Standards Bodies in three languages – English, French and German. The “official” English language copy is published as a BS EN document, the “official” French as the AFNOR EN and the “official” German as the DIN EN.

    All national EN publications can have national cover sheets. Some National Standards Bodies use those cover sheets to tell you administrative information like when they process the standard internally, what other of their standards might have been withdrawn in favor of the EN and so on.

    Each National Standards Body has the right to publish any EN standard in any of the three language editions that come from EN. So they can publish that same source EN document in English as BSI does, for example. They also have the right to publish a national translation.

    Most countries publish one of the three official language copies rather than going to the trouble of translating. So no matter where in Europe you get your copy, as long as it’s one of those three official language editions, it’s always the same (with the exception of the administrative cover sheet material).

    I hope this is helpful to you!

  11. Claudia,

    Your initial blog explanation and responses to the follow-up questions are crystal clear. Brilliant. Thank you …

    I am re-educating myself on security, crisis management and business continuity standards as I am preparing for job interviews. Researching the various standards in these areas; ‘what is the difference’ was an obvious question, which you answered comprehensively yet very clearly. Many thanks!


  12. Thanks so much, Graham!
    I’m glad you found this to be of assistance.
    Other questions? Let me know. I always welcome the chance to help people be more effective standards “consumers”!

  13. Very nice article Claudia!
    I am hoping you can clarify one more thing for me. Since there is no difference in the core text between the ISO and EN ISO Standards, do you know if it is a requirement to purchase both standards if the company is being certified for example to both EN ISO 13485 and ISO 13485? We already have all applicable BS EN ISO standards and I think buying the ISO standards would just be a duplicate since the core text remains unchanged.

    Thank you,


  14. Great article Claudia! I posted a comment this morning but I don’t see it in the thread so hopefully this won’t be a duplicate.
    Do you know if a company is required to purchase both the BS EN ISO standards and the ISO standards if the quality management system is certified to both EN ISO 13485 and ISO 13485? We currently have all applicable BS EN ISO standards, but I am not sure if it is also a requirement to buy the ISO standards since the certification will be for both EN ISO 13485 and ISO 13485.
    Since the content of the core text remains unchanged between the EN ISO and ISO standards, I don’t think it would be necessary to buy both EN ISO and ISO standards but I am not sure if the notified body would expect us to have duplicates of all standards. Hopefully you can shed some light.

    Thank you,


  15. Hi Sabrina:
    Thanks so much for asking.
    My understanding is that Notified Bodies will not accept the ISO Edition in lieu of the EN ISO Edition. However, for certifying just to the ISO Edition, there can be many versions to choose from and any (including the EN ISO’s) are acceptable as long as there are no national exceptions.
    I hope this answers your question!

  16. Dear Claudia,

    My questions to you would be :
    1/ BS 8903 talks about sustainable procurement
    2/ ISO 20400 also considered the same except one additional elements included.

    Is it possible to state that both Standards are same in terms of comparing them ? And secondly, why in the UK, they have ISO and BS separately ? Are they not same ?

  17. Dear Claudia,

    First of all, Thank you so much for the valuable piece of information.

    While reviewing the technical documents in my organization, I’ve came across similar codes with varying standardization.

    BS ISO 7121- Steel ball valves for general-purpose industrial applications.
    BS 7121- Code of practice for safe use of cranes.

    In this case please clarify how should i distinguish these codes with respect to our discussion or subject.

  18. Thanks so much for asking, Adithyan:
    These are two separate documents.

    One is a British Standards series — The BS 7121 series on cranes. You’ll find them as BS-7121-1, BS 7121-2, etc. They are British standards for use in Britain only.

    The second is the British adoption of an ISO standard. This item was originally published as International Standard ISO 7121 on steel ball valves. When the British reviewed this publication, they determined that they would like to adopt it as an official British standard. So because they belong to ISO and helped to write the standard, they can indeed adopt it. The method by which they adopt standards is to republish them in full with an administrative cover sheet. So now you have the BS ISO 7121 which has the British cover sheet and the inclusion of the original ISO 7121 as the text of the standard.

    Having lots of different standards organizations using alpha numeric designations like this can be confusing. Remember, first look at the initial alpha component of the number — It usually is an acronym that tells you what organization(s) issued the document. Then the numeric part tells you what unique document it is from that organization.

    Let me know if you still have questions. And thanks again for asking!

  19. Hi Claudia

    Thank you very much for all the clarification above. Its helped throw some light into some of the confusion I have been facing.

    Could you please help me with the following.

    1) You have indicated that the EN standard is released in three languages to the EN countries, and that once the respective countries adopt them, they are then commercially available as say, BS EN 123456, DIN EN 123456. Does that mean that the standard “EN 123456” per se, is not available at all for purchase by the public?

    2) You have indicated that once a country adopts a EN standard, it may include some minor changes such as (voltage, etc.). Besides these nuances, are the adopting countries required to adopt the full context of the EN Standard. I am particularly interested in the potential variation of EMC test procedures, and EMC immunity and emission limits – are they required to follow the same.

    3) Having considered the differences between EN, BS EN, could you please throw some light on differences with IEC.

    Thanks Claudia.

  20. Hi again, Satha:
    I can easily answer question 1. Any EN is only available in a national adoption. So all EN’s are not available as the source document given to each of the national bodies. You must purchase them in a national edition only.

    Question 2. Certainly, the technical issues involved in the adoption of the IEC standards are beyond my technical expertise. However, it is my understanding that any deviations from the text of the source document must be notated in the cover sheet administrative information. I will check in with my sources to see if I can get you a more definitive answer.

    Finally, with regards to testing requirements. I would strongly suggest that you use a reputable testing lab and follow their expertise for these issues.

    Hope this is helpful!
    Best regards,

  21. Hello Claudia,

    Thank you for the informative write-up and comments. This has usually been a source of confusion for me, and apparently others as well, so I just want to confirm my understanding. Apologies if this is completely repetitive:

    1) ISO standards are international/global and the foundation for which all subsequent standards of the same number (i.e. 13485, 14971, 62366, etc.) are based.

    2) EN ISO standards are the ISO standards specifically adopted for the European community (whatever those changes might be). When dealing within Europe, the EN ISO standards supersede the ISO standards.

    3) BS EN ISO is the English language version of the European standard, DIN EN ISO is the German language version of the European standard, and so on.

    Your confirmation of my understanding or any further clarification is greatly appreciated.

    Best regards,

  22. Hi Jonathan:
    By Jove, you’ve got it!

    I will note that the reason that the EN ISO are used exclusively in Europe is that the EN documents are specifically referred to in the Directives. So when dealing with Europe, as you noted, only the EN ISO’s need apply.

    And one further note, even though a DIN EN ISO is the “German language edition,” often times it will be published in both German and English language editions. The English language edition is identical to any other English language edition published in Europe, including the BS EN ISO one.

    This blog is my most popular posting! I am amazed at how many people need assistance with this particular topic. I’m glad to be of assistance to you all with this one!


  23. Hi Claudia,

    Thank you for your great explanation!

    I do have a question though.

    For instance, ETSI EN 301 489-1 has recently been updated and is citing EN 61000-4-4:2012 as one of its normative references.

    Will a lab be required to purchase the EN 61000-4-4:2012 standard if it already has IEC 61000-4-4: 2012?

  24. Hi Deane:
    Thank you so much for asking.

    I know that CEN and CENELEC (the other 2 European Standards Bodies) have instituted a mandate to use the EN editions of all referenced standards (if available)in their publications. So in my opinion, you’ll need the EN edition of the 61000-4-4 for ETSI as well. Please confirm this with your testing lab and certification body.

    One of my staff members and I were just thinking about the World Standards Day theme from a decade or so back – “One Standard, One Test, Accepted Everywhere.” The protocols of adoption and distribution for the EN standards in particular seem to make this goal feel more distant than ever!


  25. Hi Claudia,

    Thank you for your response.
    That clears up my confusion about the need for EN version.

    That being said, I do have a question relating to standards that have their status withdrawn. Can we still make use of a withdrawn standard for reference if that particular standard has an updated version, say for example, ENxxx: 2004 has been replaced by ENxxx: 2012?

    Best Regards,

  26. Hi Deane:
    Another good question.

    First, some contracts do call out obsolete versions of standards. This can be for a number of reasons, usually involving replacement parts. So we do find any number of folks using obsolete standards at any given time.

    However, I think your question is more about transition dates. A common question is how much time do I have before I have to move to the new Edition of a standard?

    For EN standards that are on a harmonized list (like the harmonized list of standards for the Medical Device Directive), a new Edition of a reference standard has to be formally accepted. This is done by publication in the Official Journal. Once that happens, the new Edition is put on the harmonized list. And a “Cessation Date” is provided. This date is when the old Edition is no longer valid. You must be compliance with the new edition after that date.

    Many standards are not on the harmonized list. So, sometimes you need to see what the regulations are in the jurisdictions you’re going to be selling your product. You need to meet the legal requirements and sometimes that includes specific editions of a standard.

    If there are no specific legal requirements regarding which edition to use, then it is up to you. I would caution that using out-dated standards comes with a legal liability. Standards represent “best practice,” using the most up-to-date protocols. This provides you with a level of protection against lawsuits based on negligence.

    Hope this is helpful!

  27. Hi Claudia,

    Can the UK, Germany, France issue an “official language” version of an IEC/ISO standard if the EU has not yet recognized it yet? My understanding is that until a standard is recognized as an EN standard in the European Official Journal, it is not recognized as a harmonized standard for use in the EU. However, I’ve started seeing BS/EN/ISO versions of standards before the EN/ISO version is recognized in the OJ.
    Case in point; EN 60601-2-49:2001 is the latest version in the OJ, but BSI has issued BS EN 60601-2-49:2015.
    Any insight into this is appreciated.

  28. Great question, Bill.
    We have to think about the EN standardization process as a separate activity from the EU adoption as a harmonized standard.

    There’s lots of EN standards. But only a few are part of the harmonized standards set. Why? Because standards development is in the hands of CEN/CENELEC. Adoption as a harmonized standard is a process for “EU Regulators.” Many are called, but few are chosen, as they say.

    Take the EN 60601-2-49:2001. This standard is harmonized and found on the list. Why is there a 2015 edition without publication as a harmonized standard? Because an EN standard is written, adopted and published before the administrative review for adoption as a harmonized standard.

    After the publication of the 2015 Edition, the document was submitted back to the regulators for acceptance. And for some reason, the administrators rejected it. Somehow it didn’t meet the specifics of the directive anymore. Thus it was not published in the Journal, so it is not harmonized. But it is still an accepted EN standard because publication came before the administrative review.

    Confusing? You bet! Just remember: Harmonized EN standards are developed at the request of the regulators. If they are not satisfied with the results, they won’t publish. But the standard has been developed and accepted by either CEN or CENELEC none-the-less. So it’s out there whether they like it or not. But if it isn’t harmonized, it doesn’t meet their criteria as set forth in the directive. It’s just a standard, not a harmonized standard.

    I hope this makes sense!

  29. Thanks, Claudia – It was a very insightful article. I have a follow up question. I work with medical device company and currently am tasked with finding all applicable standards associated with our products. This company has R&D and manufacturing facilities in USA, Europe, and Asia. Compliance with harmonized standards is a requirement of our design controls. ISO16061, 13485 and 21CFR are our guiding lighthouses. When I am referring to standards around sterility, cleaning, packaging. biocompatibility etc, what would be a good practice to follow ISO, EN ISO or BS EN ISO?

  30. All EN documents are adopt from ISO documents? or it may make some standards in European CEN committee member’s

  31. Thanks so much for asking, Yuvaraj:
    There are a wide variety of EN standards. Some are developed within the EU by CEN, CENELEC and ETSI. Some are adoptions of standards developed by others, most notably ISO and IEC. Generally, if an EN standard is an adoption of another organization’s document, it will say so in the title of the publication. Certainly, that information is noted in the foreward for sure.

    The original set of EN standards was created by accepting standards in use by various countries in Europe. So some of the EN standards also are similar to older BS, DIN, AFNOR, and other European standards.

    I hope this answer is helpful.


  32. Hi Sharm:
    Thanks so much for asking and sorry to be delayed with my response. I lost my husband in March and it’s taken me some time to catch back up with myself.

    When choosing the proper edition of a standard for use within your organization, there are some guidelines that I can offer you.

    Since your company has locations and sales within Europe, you probably will be looking for EN versions of the standards you use. This would be to protect you should use of any of your standards be related to meeting the requirements of one or more of the Directives for that region. Why do I say this? Because the list of Harmonized Standards relating to specific Directives calls out the EN editions of each. Further, the introductory material states that any standard referenced in a Harmonized standard should be used in the EN edition as well.

    Nothing is more irritating that finding out you need a different edition of a standard you already own. Good news is that any national edition of an EN standard is acceptable in most cases. So you can choose from any number of copies, each with a different starting acronym. Some examples are DIN-EN-, BS-EN-, SS-EN-, AFNOR-EN, and so on.

    I hope this is helpful!

  33. HI Claudia,

    Sorry to hear you lost your husband.
    I need to say it’s a great blog as this topic is so confusing.

    I am working for a global medical device company:
    Dealings with all regions all over the world.
    Tasked with global watchlist and process for standards and regulations.
    1) we have a company who is watching updates for us and notifies us about the new revision etc once we choose the standard to be watched.
    2) I am confused on which version I should have of a specific standard as selling to Germany , France US etc. Should I watch and buy all of them?
    3) I do have same standards with different versions but I am not sure which date is the date I should be following the standard (we need gap assessments to be done , which take sometimes a lot of time)
    4) Which dates I should have o my radar. Date of announcement, publication, withdrawal? Should I monitor the OJ all the time? The company that provides notification is usually few months behind..
    5) I am not sure how to ensure I cover all the required standards for devices we sell. For example biocompatibility, sterilisation, packaging. Should I use the harmonised standards for EU from OJ, what about US so on.
    6) is there any good book, webinar, way to get to the bottom of the topic you could recommend?

    Thanking you in advance for shading a light to the above.
    Best Regards

  34. Thanks Aga!
    So here at Document Center Inc., we too track and monitor standards for many organizations like yours. However, we do try to work with you so that you understand what you’re tracking and why!

    So, regarding the document dates: This one is confusing I’ll say. First, you have to remember that the EN copy is generated first and is given several dates. Review the bibliographic information on the CEN and CENELEC sites to get the full details for each EN standard. Important thing is that the first issue date is the core EN standard. Since that core document is not distributed to users but only to national bodies, it will not be your publication date.

    To distribute EN Standards, each national body in the EU administratively accepts the document first. Then they republish the core EN standard with their own cover sheet material. This means each national adoption has it’s own publication date, depending on how fast the EN standard moves thru the national adoption process. So the BS EN ISO 9001 can have a different publication date than the DIN EN ISO 9001. Yet, since each contains the same core EN ISO 9001 material, the editions are considered identical!

    This is why your notifications seem to be slightly out-of-date. Depending on which national edition you’ve chosen to monitor, the issue date may be relatively fast or slow.

    Having said this, I urge you to use the Harmonized list to determine when new issues of the required documents come into force. Usually you get 3 years to make your transition from one edition to any update. And since the Harmonized Lists are updated when the OJ publication of the document is made, again you’ll be keeping up with your regulatory requirements that way.

    There are a number of great web-based organizations to help you with all this. I monitor a number of them. Reach out to me offline at claudia.bach@document-center.com and I’ll look up some of them for you.

    With regards to choosing which national edition you use, I have blogged about this before. There are some industries that do need to keep multiple national editions on hand. However, for medical devices I have never heard of any auditor requirements more than 1 EN edition for any given standard.

    OK! You’ve really asked a lot of good questions here. I hope my response has been helpful.

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