By Bob Felton
With the expiration of a 5-year window for non-European manufacturers to acquaint themselves with the standard, the prevailing European Machinery Directive requires American machinery manufacturers shipping to Europe comply with ISO 13849 effective January 1, 2012.
Though the new standard contains much that will be familiar to safety engineers, much of it uses vocabulary that might be unfamiliar.
“The traditional systems have been dealing with Type A, B, and C standards,” said Scott Krumweide, safety manager for RWD Technologies during the Siemens webinar entitled “Achieve Higher Safety Performance Level with EN ISO 13849-1,” “and with the new ones coming in a lot of them are dealing with Type A and B standards down to the B1 level.”
The new standard adds Mean Time to Dangerous Failure, Diagnostic Coverage and Diagnostic Coverage Average, Performance Level and Performance Level Required, Category, and Common Cause Failure – all statistical measures of different aspects of the expected performance.
The safety-related components of control systems may be hardware and software, and may be separate from, or integral to, control. All components must comply with ISO 13849. “We now have to assess quite a bit in our electrical circuits,” Krumweide said. “So it is becoming more intricate to complete the risk assessment.”
“The basics are still there,” he added. “You still have to go to the machine, or the process, or the system, identify all those tasks associated with that system, or machine or process, and then relate your hazards to each one of those, and develop a mitigation strategy for each one of those.” The new guidelines strongly encourage hazard identification before design actually begins, however, aiming to steer manufacturers toward intrinsically safe designs.
Beginning January 1, the risk assessment paperwork package must ship with the machinery.
Bob Felton is a freelance writer based in Wake Forest, NC.