J.B. Titus

Articles

Safety Standards April 3, 2010

Cableless (Wireless) Operator Panel Applications

Cableless (wireless) operator panels for machine applications, in my opinion, need special application considerations for appropriate and safe use. True, we often talk about how a wireless field bus and a wired field bus have many similarities. Even when they are safety certified for functional safety applications they continue to have many similarities.

By J.B. Titus
Safety Standards March 25, 2010

Wireless Operator Panels & Machine Safety (Is There A Design & Build Standard?)

Wireless operator panels (including cableless) for machine applications have been steadily growing over the past several years. The early versions of these portable operator panels were cabled for power and control/communication which limited their range via the length of the cable. The concept was for a panel builder or engineering group to design and build a conventional operator panel but that it needed to be portable and still conform to the same industry standards and regulations as fixed operator panels.

By J.B. Titus
Safety Standards March 16, 2010

Machine Safety – Cableless vs Wireless

Machine Safety and “cableless” vs “wireless” has been an ongoing discussion over the past two years as this technology rapidly travels through its evolution cycles to the plant floor. Personally, I’ve sat in a dozen discussions over these two terms and how to choose a word that best describes the application as well as the issues. To wrestle this one to the ground it’s my recommendation that we choose an application like - cableless pendant control.

By J.B. Titus
Wireless February 24, 2010

Machine Safety & Cableless (Wireless) Safety – with comments

Machine Safety and Cableless Operator Stations with Safety! Did I just say all of that in the same sentence? Is this Doctor Spoc in Star Trek or is it the 21st Century? Well, beam me up Scotty because my radar screen sees something on the horizon. For several years now we’ve seen applications of safety functions being performed in machine architectures using safety certified and listed products where portions of the safety certified communications bus is wireless. So, does it make common sense that a natural migration of innovation would provide cableless operator stations with safety functions as added functionality?Cabled pendants in robot cells have been used for years and several years ago they evolved to cableless (meaning they have their own power source).

By J.B. Titus
Safety Standards February 22, 2010

EN 954-1: 1996 – Five Years Of Cessation

EN ISO 13849-1: 2006 was approved on or about October 2006 and simultaneously it was announced that EN 954-1: 1996 would cease to be an active standard at the end of 2008. Effectively this provided a two year period for industry (primarily in Europe) to transition to the new and incremental requirements of EN ISO 13849-1: 2006 for conformance to the Machinery Directive. Since then, the cessation of EN 954-1: 1996 has been extended twice and is currently scheduled for December of 2011.

By J.B. Titus
Safety Standards February 12, 2010

Machine Safety and “reasonably foreseeable misuse”

In the world of machine safety it is commonly understood today that a risk analysis is required by the supplier and/or end user to identify and mitigate all hazards to acceptable levels. We get numerous questions on this process around the question of how to address the intent of the term “reasonably foreseeable misuse”? This term is actually defined in ANSI B11 - 2008, approved August 4, 2008 on page 16, clause 3.58 as: “reasonably foreseeable misuse:  The use of a machine in a way not intended by the supplier or user, but which may result from readily predictable human behavior.”  Furthermore, one can also find in Wikipedia a very thorough discussion with legal slant : https://en.wikipedia.org/wiki/Negligence. However, in the machine tool industry it mostly has to do with human behavior and applying thought to predicting certain possible actions.  Quite commonly the life cycle of a machine is taken into account in identifying tasks and hazards as part of the risk assessment process because hazards not identified can create substantial unknown risks.  The standards also say that reasonably foreseeable hazards that are not related to tasks shall also be identified. Some given examples often include “explosive environments, noise, instability, equipment failures or operational errors such as using an inappropriately sized workpiece, mechanical failure of a chuck, operating at incorrect speed, etc.” In addressing questions like this - [what is the intent of the term “reasonable foreseeable misuse?”] - my advice is always: Look up the term in several US machine tool standards Research the term on the internet Remember - interpretation is almost always required Some additional background information can be found at the following links: https://www.productsafetyletter.com/news/5569-1.html Before sale of a new product, every manufacturer should engage in a risk assessment of its product.

By J.B. Titus
Safety Standards February 2, 2010

Machine Safety & Residual Risk

Residual risk is a term used for the past several years referring to a level of risk for a given hazard after applying protective measures (risk reduction measures). ANSI B11.TR3; 2000, ANSI B11 - 2008, ANSI / ISO 12100-1:2007, ISO 14121:2007, …..to mention a few, all tend to be harmonized on this definition. However, tolerable risk and acceptable risk are two additional terms also in the mix.

By J.B. Titus
Safety Standards January 16, 2010

EN ISO 13849-1; 2006 – Are We Ready?

EN ISO 13849-1; 2006 is definitely on its way to US industry.  It’s also true that there have been several delays for required compliance caused by extensions in Europe that have slowed broad acceptance here in the US. Last week in this blog I talked about the various segments of industry and what drives behavior to adopt or comply with safety standards. For example, don’t hold your breath for OSHA to enforce compliance to this International Standard any time this century.

By J.B. Titus
Safety Standards January 8, 2010

Machine Safety in the US – What Drives Safety Behavior?

Machine safety standards abound here in the US.  And of course we also have OSHA regulations which form the basis for Federal enforcement. Book shelves are loaded with books and publications with the single theme of addressing these two sentences. We also have employee injuries & insurance companies, productivity & operating efficiencies, the legal thing, and just plain “Best Practices”….to mention a few.  With all that said and for any company in the US, what drives domestic machine safety behavior?  Let me offer one opinion. In my forty plus years of experience I would offer the following generalized priority: OSHA Regulations - because it’s the law, local regulations (i.e.: state, city, municipality, etc.), business demands/policy, and perhaps the legal threat. US based consensus standards, performance requirements in a purchase order, cost savings programs, and company safety policies. International standards influence, best practices, competition, and image. The purpose of this list is not to be absolutely accurate, but instead, to drive some thinking as to where a new international standard like EN ISO 13849-1; 2006 plays a role in my business.

By J.B. Titus
Safety Standards December 30, 2009

It’s Official – EN 954-1:1996 Is Extended By The EU

On Monday of this week in Brussels the Official Journal of the European Union, 2009/C 321/09, announced the prolongation of EN 954-1 until Dec. 31, 2011. They also published a correction from EN ISO 13849-1:2006 to EN ISO 13849-1:2008.

By J.B. Titus
Safety Standards December 10, 2009

Machinery Directive 2006/42/EC & EN ISO 13849-1; 2006 – with comments

The EC Machinery Working Group met on Dec. 8, 2009 and voted to prolong the cessation of EN 954-1; 1996 beyond Dec. 31, 2009 and, therefore, to provide presumption of conformity to the new Machinery Directive 2006/42/EC which also becomes effective at the end of this month.

By J.B. Titus
Safety Standards December 2, 2009

Be Safe – Don’t Be A Turkey – manufacturing hazards have no holiday

Machine Safety is 24/7 - so don’t be a turkey. In the annual tradition, my family gathered around the Thanksgiving table as the turkey was served. The turkey was carved, we gave thanks, and we enjoyed a wonderful meal of abundance.

By J.B. Titus
Safety Standards November 18, 2009

Lean and Green Becomes Lean and Safe

For some time now we’ve been hearing the buzz words of “Lean and Green” only to be confirmed if one were to Google the term. Little needs to be said for anyone to have an understanding of this concept or the related importance as driven by corporate executives for sustainability of operational excellence. However, hold onto your hats.

By J.B. Titus
Safety Standards November 3, 2009

E-Stops Have A Yellow Background, Right?

You bet! Who could not possibly know by now that practically all electrical/safety/machine guarding standards now clearly call out that an emergency stop button must be red, mushroom shaped, and have a yellow background in order to be called an emergency stopping device? Well, to quote my four year old grandson - probably a trillionmegabazillion! You guessed it, he’s paying far too much attention to cable news lately. However, in my experience, I’ve been asked far too many times by engineers, maintenance, and plant operations personnel over recent years if they really need to update their operator stations to comply with this requirement? My answer has consistently been, yes - that is my recommendation. With the added caveat of course that this requirement is one of OSHA’s most frequent violations. In my opinion, the intent behind this requirement is to unequivocally differentiate the e-stop button from other red devices in the area of the emergency stop device.

By J.B. Titus
PLCs, PACs October 27, 2009

E-Stops and Your Compliance

STOP! Are you confusing stopping categories and risk categories? Do you wire your e-stops to a standard (non Safety) PLC or controller in order to comply with the mandatory category 0 or 1 stop? And, does your identified hazard require redundant circuits with continuous self checking and automatic diagnostics? Think twice is my advice! Yes, safety standards such as NFPA 79, clause 9.2.5.4.1.3 requires that an e-stop “shall function as either Category 0 or a Category 1 stop” as determined by the risk assessment. These are stopping functions with categories as defined by NFPA 79, clause 9.2.2. Furthermore, your required risk analysis may require mitigation of a risk or hazard identified as Cat. 3 or 4.

By J.B. Titus
Safety Standards October 22, 2009

Machine Safety’s Paradigm Shift – It’s Time for Change

It’s been seven years since NFPA 79, 2002, the Electrical Standard for Industrial Machinery, first changed the world (in the US) allowing businesses the opportunity to utilize either hard-wired safety systems or implement integrated safety and automation systems. Now, seven years later, several new and updated standards open many more new options that were not allowed previously. Today we see safety functions being applied to safety PLC’s, safety drives, safe motion, and even safe wireless.

By J.B. Titus
Safety Standards October 12, 2009

Machine Safety Acceptable Risk, Tolerable Risk, 5 Comments

Machine Safety - to understand machine safety, you have to understand the concepts of “acceptable” versus “tolerable” risk. First, “tolerable risk” is the term used for the past several years referring to a level of residual risk for a given hazard after applying risk reduction measures. ANSI B11.1- 2009, Safety Requirements for Mechanical Power Presses, defines tolerable risk in clause 3.90.1 “Risk that is accepted for a given task (hazardous situation) or hazard”. In my opinion a more current term has come to life replacing tolerable risk as more focus continues to be directed at integrating the safety mindset into all phases of a machine life cycle. “Acceptable risk” is the new term that is beginning to appear in many updated standards and which in my opinion more clearly represents the implied intent of both evaluation and mitigation.

By J.B. Titus
Safety Standards October 2, 2009

Machine Safety Standards, Additional Costs?

EN ISO 13849-1: 2006, in my opinion, will launch a paradigm shift that could force some businesses into financial difficulty if fully implemented in the US. Several reports have crossed my desk indicating that some machine safety standards are considering including the incremental compliance requirements of 13849-1. These incremental requirements involve engineering and analytical skills far and above the skills needed for task based risk assessments and the qualitative Category based hazard analysis process.

By J.B. Titus
Safety Standards September 24, 2009

EN ISO 13849-1; 2006 – US Bridges Needed For Transition – Comment: Integrators, OEMs not ready

This week the issue of the EU extending EN 954-1; 1996 to 2012 is still the talk of machine safety. Some camps appear to feel comfort in the three additional years of needed time for industry to prepare for the new compliance requirements. I agree with other camps that are expressing a sense of discomfort because we believe the new EN ISO 13849-1; 2006 provides improved safety performance and machine operating efficiencies.

By J.B. Titus
Safety Standards September 17, 2009

News Flash – The Landscape of SIL, Cat, & PL Changed Last Week – Comment: Breathing Room

Last week while I was writing my blog on this subject the European Union (EU) met and decided to extend EN 954-1; 1996 for up to three more years or 2012. This was announced internally in the United States to those of us who participate in standards writing on committees. EN 954-1 was scheduled to expire in October of 2009 and this importance drove last week’s blog.

By J.B. Titus
Safety Standards September 2, 2009

What’s UP With SIL, Cat and Now PL? Safety Integrity Levels, Categories, and Performance Levels of Machine Safety

We all know by now about safety rated devices according to SIL(safety integrity level) and Cat(category). Recently, a new term has emerged from Europe via ISO 13849-1; 2006 introducing PL (performance level). Most everyone agrees that both SIL and PL are hazard ratings that are quantitatively derived and can be directly related.

By J.B. Titus
Safety Standards August 24, 2009

The Safety Standards Maze, 3 Comments: More Standards, Validation

A frequent question raised by industry is where can I go to get a comprehensive listing and understanding of machine safety standards? Most often it seems that awareness of certain safety standards are developed over time within any one company. Influences have come from knowledge on the part of individual employees, references from suppliers, educational seminars, OSHA, and more……..but  there’s no one place anyone can go to research their safety standards. Like, a data base that’s both current and offers comprehensive information about all U.S.

By J.B. Titus
PLCs, PACs August 14, 2009

Integrated Safety – or Not! …Plus 6 Comments; Do You Agree?

We’ve all heard lots of arguments both for and against a fully integrated architecture for safety and general control. In the process world they’ve maintained a separate SIS (Safety Instrumented System) solution for safety creating a separate layer in their architecture for performing the safety functions. However, in the machine world when PLC’s were introduced in the 1970’s, standards groups rushed to exclude PLC’s from anything safety because the early technology wasn’t very reliable.

By J.B. Titus
Safety Standards August 1, 2009

All That Wire & Is It Safer? Comment: Simpler is Better

The possible answer to this question totally changed in 2002 with the new issue of NFPA 79 allowing safety PLC’s and safety busses. Previously, NFPA 79 clearly required anything “safety” must be hard wired. Now, seven years later, hundreds of safety PLC’s are reported to be in use in the U.S.

By J.B. Titus
Motors & Drives July 20, 2009

Safety Relays vs CAT 4; Comments on Safety, Redundancy, Risk

July 20, 2009 Recently I visited a manufacturing company to discuss their machine guarding strategy for the control system on automated palletizer machines. After some discussion, I asked for a plant floor tour to see these machines being manufactured. During the tour they showed me a CAT 4 application mitigated by applying a CAT 4 rated safety relay.

By J.B. Titus
Power July 13, 2009

What’s Up With Wireless Safety? Comment: Failsafe, Yes, But a Nuisance?

Wireless communication has been around for several years, experiencing many ups and downs. Today - it’s largely considered just another communications bus with its own set of design and application criteria. Its maturity and acceptability has now created the launching pad for adding safety functionality over wireless.

By J.B. Titus