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B10s at work for machine guarding

Here's a sneak preview of a few of the new requirements transforming machine guarding in the U.S. from a qualitative approach to a quantitative approach and more similar to the process industry.

August 20, 2010


Much of industry has historically addressed machine guarding by asking the question – is it safe now? We have far better machine safety solutions at hand today via a combination of savvy innovation and improved safety regulations and standards. And, with this paradigm shift comes some new requirements such as component B10 values. Simply enter “Machine Guarding B10 Values” into your search engine and you’ll be amazed by the abundance of information and guidelines for how to apply these values in assessing your hazards and solutions. You’ll also be confronted by the fact that B10 values are only the tip of the ice berg. Practically all machine safety experts agree that these emerging new requirements from European and International standards will in fact improve overall machine safety and therefore reduce employee injuries. However, isn’t there a concern for general industry about how we get there?

Let’s take a sneak preview of a few of the new requirements transforming machine guarding in the U.S. from a qualitative approach to a quantitative approach and more similar to the process industry. The following new terms come from information I found on page #1 of my browser offered by; Rockwell Automation, Siemens, SMC, PILZ, Weiland, Rexroth, ZVEI Automation, and Profibus International…….to mention a few:

  • B10 – the number of cycles until 10% of a random sample of components fail.
  • MTTFd – Mean time to fail dangerous.
  • PFHd – Probability of dangerous failures per hour.
  • CCF – Common cause failure.
  • PLr – Required performance level.
  • DCavg – Average diagnostics coverage.
  • HFT – Hardware fault tollerence.

I don’t mean to scare you into some catatonic state if you’ve never heard of this sampling of new requirements already in use in Europe and soon to be required here in the US. What I do mean to suggest is that some form of “local” training needs to be available across the land that will prepare general industry to apply these new requirements. It’s not a question of - does industry want to improve our machine guarding and provide better solutions? In my opinion, it’s all about how industry accomplishes the transitions to a quantitative approach regardless of company size or infrastructure.

Some of the companies listed above, as well as several more not listed, offer some limited training classes and others even offer “tools” which also need training classes. However, I think something needs to happen that will help industry get ready on a local basis. For example, very few of the small to medium size companies even know that a change is on the tracks coming their way. Does anyone know a solution to this problem? Like across Europe, will we also encounter several delays in the adoption date? This past January the European Machinery Directive (law) approved another two year delay for their mandated adoption as industry argued that they weren’t ready. How can we in the US not follow the same path as our European colleagues?

Hopefully some of you agree with my thoughts on this issue and have some ideas on how to resolve this emerging issue? Leave your thoughts using the comment tool below.

If you or your company would like to become more cost efficient and at the same time improve yields, productivity, and safety compliance – contact: www.jbtitus.com.

Related articles:

It's Official - EN 954-1:1996 Is Extended By The EU;

Machinery Directive 2006/42/EC & EN ISO 13849-1; 2006; and

EN 954-1: 1996 – Five Years Of Cessation.



For more than 30 years, J.B. Titus has advised a wide range of clients on machine functional safety solutions, including Johnson & Johnson, Siemens, General Motors, Disney, Rockwell Automation, Bridgestone Firestone, and Samsung Heavy Industries. He holds a Bachelor of Business Administration degree from Oklahoma University in industrial management and an MBA from Case Western Reserve University in marketing and finance. He is a professional member of the American Society of Safety Engineers and is OSHA-certified in machine guarding. Titus is also TUV-certified as a Functional Safety Expert and serves on several American National Standards Institute, National Fire Protection Association, and National Electrical Manufacturers Association national safety and health standards committees. Reach him at jb(at)jbtitus.com and via www.jbtitus.com.