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IEC Committee TC 31: memories, challenges and opportunities

15 August 2014

In this valedictory article, Jim Munro, our TC 31 Standards columnist for the last three years, looks at how the committee has developed over the years and what lies in store in the future. This will be his last column in Hazardex, although we hope not his last contribution to the journal and website.  

Jim Munro
Jim Munro

I expect that this will be my last standards update article as Chair of IEC Committee TC 31 Equipment for Explosive Atmospheres, although not my involvement with TC 31.  As indicated in my last article, due to changes in the rules of IEC, when my current terms finishes in July 2014, I will have served 15 years as Chair of TC 31 and will therefore not be eligible for reappointment. 

So I have decided to use the article as an opportunity to talk about my experiences with TC 31 and to also talk a little about some of the challenges I see for its future.

I attended my first meeting of TC 31 in Fort Lauderdale, Florida USA in 1981. The meeting was conducted in both English and French. It focused on area classification and the first edition of the non-sparking standard which later became IEC 60079 – 15.

In 1992, I became Chairman of the new subcommittee SC 31L on gas detectors.  Then in 1999, I became chair of TC 31. 

I have seen many changes of course over the period of my involvement in TC 31. When I first started attending TC 31 meetings, the standards being produced by TC 31 were rarely if ever adopted unchanged by national committees. In Australia we tended to use the drafts as a starting point for our own home grown Australian standards.

Even when I took over the chairmanship of TC 31 this was still the case for most countries, although Australia was starting to adopt IEC standards. In Europe CENELEC was still meeting actively to develop European standards and in many instances these had then been forming the basis of the IEC standards.  A first indicator of change occurred at my first meeting when the Europeans decided not to separately develop a new standard for Ex m and instead to work with IEC to develop the standard. It was not too long after this that CENELEC started the process of parallel voting IEC standards for acceptance in Europe as European norms and separate active standards development CENELEC began to diminish.

Now the majority of countries in the world accept IEC TC 31 standards without change or with minor changes to suit local requirements.

Perhaps the most significant change that has occurred during my time as chair of TC 31 is the creation of subcommittee SC 31M  Non-electrical equipment and protective systems for explosive atmospheres.  I have included more information about the creation of this subcommittee in an earlier article.  But in summary, it has enabled TC 31 to develop non-electrical equipment standards that are published as ISO or ISO/IEC dual logo standards, thus providing a more integrated and consistent approach to development of standards for explosive atmospheres. 

Another major development during the period has been the advent of the IECEx System and the close involvement of TC 31 with that system.  In particular, the standards being produced by TC 31 have provided the rock on which IECEx is based.  The partnership has been recognised as 'best practice' by the United Nations.
However, I think that an indicator of significance of TC 31 today are the statistics that relate to its composition, operation and output as follows: 

  • 1 main committee
  • 3 sub-committees
  • 17 working groups (3 joint, 2 ad-hoc)
  • 4 project teams
  • 23 maintenance teams
  • 34 participating countries (P-members)
  • 13 observer countries (O-members)
  • Responsible for approximately 40 standards, published or under development
  • Approximately 50 meetings a year of the various groups above and nearly different 500 people involved in those meetings
  • For each group listed above there are often mirror groups in the various member countries of TC 31.  So in practice there are many thousands of people involved directly or indirectly in the work of TC 31. 
While there are paid employees of IEC acting in support roles, all of the technical involvement of people in the committee and its groups is voluntary, with no payment coming from IEC for time or expenses.  Such payment, if it does occur, comes from the participants' companies, their national committees or from their own pockets.  Perhaps this is the most significant measure of how important all those involved including their associated companies think the work of TC 31 is.

So let's see if we can put a value on it.  If we assume the average time for the 50 meetings is 1.5 days and the average attendance at the meetings is 15 people, we have a figure of 1 125 man days spent each year on meetings operated under the TC 31 umbrella.  If we assume that the average value of time and cost of expenses of those attending is USD 2,000 per day, the value of that work is USD 2,250,000. 

For corresponding work by national committees, let's make some more some assumptions.  Let's assume that of the 47 countries that are members of TC 31, approximately half that, say 25, have active mirror committees and working groups.  Let's also assume that they spend about a fifth of the IEC days on their mirror committee meetings and have an average of 10 people attending these meetings. 

Since the travelling time and other expenses are likely to be less we could put the average value of their time and cost of expenses at USD 1,500 per day.  This gives us an additional 3, 750 man days spent on the work by the national committee members, giving an additional value of the work of USD 5,625,000.  This gives a total value of USD 7,875,000.  If we factor in the time spent by the chairman and secretaries of the main committee and subcommittees, and the various convenors and project leaders, plus those with similar roles for the national committees, it is reasonable to assume that the real figure is USD 10 million or more.

It effectively makes TC 31, a multi-million dollar enterprise.  It is mostly run by and participated in by people, giving freely of their time, with a common goal and passion, to make the world a safer place.

So I believe that, as I finish my term as chair of TC 31, I leave it as an active, professional and effective organisation.

So what is the future of TC 31?  You only need to look at some of the working groups in TC 31 to see that some of the future challenges are defined in the working groups that we have established.  This includes creepage and clearance distances, electrochemical cells and batteries, effect of very low temperatures, safety devices related to explosion risk, and high voltage.  Developing more electrical standards that can readily be used for the purposes of certification, I believe will prove to be part of our ongoing challenge as we don't have all the relevant history or experience that we bring to the exercise of producing or revising electrical standards.

I believe there is one other major challenge that I think would be good for TC 31 to address: maintaining some form of traceability on the critical items we include in our standards.  TC 31 was formed in 1948.  Its first standard (for flameproof enclosures) was Publication 79 published in 1957.  But that was a 'recommendation'. 

It took some time longer before more rigorous standards that could be used for certification started to appear.  Until recently, there was generally someone of that early generation of developers that either was on a committee or could be tracked down if people wanted to find out the background of critical requirements.  But they are nearly all gone from our committees and many are no longer with us at all.

I , and others of my vintage,  probably fit into the next generation and many are now retiring and disappearing.  Not only do you lose our knowledge but you lose the benefit of the information we have gleaned through mixing with the earlier generation.  So I believe we need to find a method to replace that personal corporate memory. 

An approach that I suggest might work is to have a form of archive attached to each standard incorporating the key publications and unpublished documents that have formed the basis for decisions.  Where the decision process has been complicated, it might also be possible to include in the archive some background about the basis for the decision.  This might take a bit more time in the current development process but could save significant time in the future revisiting decisions. 

So let's hope TC 31 can rise to the challenge.


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