Machine & Operator Safety
Making sense of international standards development
November 27, 2012 by Doug Nix
Standards development is one of those activities that seems mysterious to many.
The Technical Committees (TC) are made up of people from industry, academia, government, user associations and the general public for standards developed within a country, like the CSA standards we use in Canada. In the international arena, things are a bit different. ISO and IEC TCs are made up of delegations from member countries. The delegates come from the same sources within each country as the national standards TCs, and the work is generally organized by national standards bodies. In Canada’s case, this is the Standards Council of Canada. If you are qualified and there is space available, all you need to do is volunteer to participate, and then be ready to contribute by attending meetings, preparing submissions and traveling to meetings.
In September, a meeting of ISO TC199 – Safety of Machinery, Joint Working Group 1 (JWG1) was held in Paris, France. This group is working on merging two important machinery standards: ISO 13849-1 and IEC 62061. If you design machinery that uses electrical or electronic controls as part of the safety system, then one of these standards may apply to your designs. How do you know if you should be using one of these standards? Ask yourself a few questions:
1. Do we use interlocked guards or other safeguarding devices like light curtains, two-hand controls or presence-sensing mats to reduce risks from our designs?
2. Do we use complementary protective measures including emergency stop systems in our designs?
3. Where do we sell our machinery?
4. Do we foresee a time in the next few years where we may want to expand our market internationally?
If you answered ‘YES’ to either or both of the first two questions, these standards may be used to analyze the reliability of these systems. If you answered, ‘just Canada’ or ‘just North America,’ then these standards could be used to replace sections of the CSA or ANSI standards covering control reliability that apply to your machinery, but this is not required.
If you sell outside of North America and the European Union, using ISO and IEC standards for your designs means that your products are much more likely to be ready for foreign markets, with few changes needed to meet local requirements.
If you sell in the European Union, both of these standards are harmonized under the Machinery Directive, so using these standards helps to open the door to a market of 27 countries. If you are selling only in Canada or North America, and you can foresee a time in the near future when you will want to branch out into international markets, supplementing the Canadian and U.S. National Standards with ISO and IEC standards will help get your product ready for these markets.
There is a problem, however, and JWG1 was assembled to deal with it. The two standards, while not in conflict, use different terminology and different methodology to assess control reliability. The results of the analysis are described as ‘Performance Levels’ or ‘PL’ by the ISO standard, or as ‘Safety Integrity Levels’ or ‘SIL’ by the IEC standard, and this is just the tip of the iceberg. Why are there two standards, and what are the advantages and disadvantages for each? These problems have to be resolved, and JWG1 is making plans to do just that.
JWG1 needs help from users of these standards. There is a short, on-line questionnaire available that you can use to contribute to the work of the committee. As a member of the Canadian committee working on this problem, I want to appeal to you to take a few minutes to contribute. The questionnaire closes on Nov. 30, 2012. Here is the link:
If you have concerns about this work that you don’t feel were covered by the questionnaire, please write to me with your concerns. I will take your concerns to the committee for consideration along with all of the other concerns we are hearing from around the world. The next meetings are being planned now.
Doug Nix, A.Sc.T., is Managing Director & Principal Consultant, Compliance InSight Consulting Inc. Reach him at firstname.lastname@example.org. This article originally appeared in the November/December issue of Manufacturing AUTOMATION.