Recent Developments in Robot Safety Standards
| By: Jeff Fryman, Director, Standards Development
This has been a particularly exciting year for developments in robot safety standards. However, most of these developments have taken place outside the United States, so for many of us they have gone relatively unnoticed. Since I have been an active participant in these developments, I would like to take this opportunity to share details about them with you.
The year started out on a very high note with the Canadian Standards Association (CSA) introducing their newly revised Canadian robot safety standard, CSA Z434:2003. This new edition (updated from 1994) has the unique distinction of being a truly North American Standard. While the Z434 standard is based firmly on the ANSI/RIA R15.06-1999 standard, the technical committee responsible for the document made some distinct national changes. To comply with the Z434 is to fully comply with the R15.06; thus making it a standard usable throughout North America. The national changes do mean, however, that following the R15.06 standard in Canadian installations would result in an approximate five percent shortfall in compliance requirements. I should note here that any existing installation which followed the R15.06 guidelines remains compliant as there are no additional retrofit requirements.
I expect that some of you may be curious as to what the differences in the two documents are, so I will highlight a few of the changes. For the most part the changes are purely editorial, adding clarity and making the Z434 even more easily understood than the R15.06. A few technical changes are worth noting, but all are in the spirit and intent of the R15.06 and promote harmonization with existing Canadian and International standards. The performance requirements for Control Reliability are specifically identified as being dual channel with monitoring – in line with the original intent of the R15.06 committee. Barrier guard heights are harmonized with other Canadian machine guarding requirements. The risk assessment matrix has been ‘tweaked’ resulting in a slightly more conservative safeguarding strategy. And finally, the clearance requirement is changed from 18 inches to 20 inches (one half meter) consistent with International requirements.
The Robotic Industries Association (RIA) was very pleased to team up with the CSA in sponsoring the March 2003 North American Robot Safety Conference in Toronto. This very successful event marked the formal introduction of the Z434 standard, and included a complete program of presentations related to industrial robot safety, compliance with the standard, and the Ontario provincial requirements for pre-start health and safety reviews. I am looking forward to seeing this terrific event repeated next year and hope that even more of you can join us.
Some very interesting developments are also taking place with the International Organization for Standardization (ISO) and the ISO 10218 standard (the international equivalent of R15.06). In 2002 the ISO committee (TC184/SC2) responsible for the 10218 standard voted to revise the 1992 edition. Work has been ongoing since. Following the international committee’s fourth meeting in June 2003, the working draft for part 1 of the revised ISO 10218 was submitted for balloting as a Committee Draft, step two in a four step process.
What started as a ‘‘simple’‘ harmonization effort between the 1992 edition of ISO 10218, the 1999 edition of ANSI/RIA R15.06 and the 2003 edition of CSA Z434 has turned into a genuine development effort introducing new and exciting concepts to the world of industrial robot safety. Because of the varying approach to standards writing across the world, it is essential to create a document that can be used in Europe, the Americas, and Asia.
North American safety standards tend to be ‘‘user centric’‘, talking to the end user of the equipment consistent with work place safety requirements and compliance with government regulations. European safety standards tend to be ‘‘producer centric’‘, speaking to the equipment manufacturer and implementing the manufacturers’ responsibility under European legislation. For this reason, the revised ISO 10218 is being proposed as a two part document. With the overall title of the revised ISO 10218 being ‘‘Robots for Industrial Environment – Safety’‘; Part 1, entitled ‘‘Design, Construction and Installation’‘, is intended to be fully compliant with the European Machinery Directive and expected to replace the existing EN775 in due course. Part 2, work on which has just begun, has a working title of ‘‘Application and Use of Robots in the Work Place’‘ and is intended to address work place safety requirements and is directed more to the user than the manufacturer. Combining parts one and two will allow the revised ISO 10218 to eventually replace the existing U.S. and Canadian standards as well as be adopted in Asia.
Work on the revision to ISO 10218 is far from complete, but I think that it is important to share with you some of the work that has been done up to this time. I should caution that my comments are based on the proposals on the table today, and are subject to (complete) change as the draft document is further refined. Also, my comments are based on differences from the R15.06 standard, not from the 1992 edition of ISO 10218.
The safety-related control circuitry performance of ‘‘Control Reliability’‘ has been agreed to be (as a minimum) the same as ‘‘Category 3’‘ requirements as described in ISO 13849. Clearance requirements, as noted above, change from 18 inches to 0.5 meters (20 inches). However, the requirement for additional safeguarding could disappear completely if you invest in appropriate new and enhanced capabilities and features in the robot control system itself. Looking into other future capabilities and features of industrial robots, the committee is developing appropriate safety criterion for wireless and detachable control pendants. Also all of the appropriate ISO and IEC standards for safeguarding devices are being recognized and referenced, as is risk assessment from ISO 12100 and ISO 14121.
The committee is also developing requirements for several proposed new modes of operation. These modes include: ‘‘synchronized’‘ robot control where multiple robots are working with common mathematically coordinated movements; ‘‘assisting’‘ robots which work in a ‘‘collaborative workspace’‘ with the operator; and ‘‘mobile’‘ robots mounted on Automated Guided Vehicles (AGV).
And finally, let’s not overlook work right here in the United States. The R15.06 committee is busy at work again, this time with a ‘‘technical report’‘ that is intended to outline ‘‘best practices’‘ for teaching more than one robot in a common safeguarded space. This has been identified as an area in the R15.06 that can use some clarification as to what the appropriate safeguarding strategy could be.
This technical report is envisioned as providing more detail and include examples of allowable safeguarding practices that all fall within the current guidelines of the 1999 edition of the R15.06. Participation in this and other standards sponsored by the RIA are open to anyone with an interest in the topic.
All of these developments mean that robot safety continues to be an active process with new and more effective methods of personnel safeguarding continually being introduced.