By Gregory Hale
A successful safety profile is all about making quality risk assessments and the new ISO machine safety standard that is making the old EN 954-1 standard obsolete does that by increasing a manufacturer’s performance level.
“The standard provides a quantitative approach to risk assessment and safety validation,” said John D’Silva, marketing manager safety at Siemens during a webinar entitled “Transitioning to ISO 13849-1: Changes Required and Helpful Tools.”
“This makes sure that safety is not solely a matter of component reliability, but also relies on common-sense safety principles such as redundancy, diversity and fail-safe behavior. Under this standard, the risk assessment for a given safety function will yield a performance level, this helps eliminate both over- and under-engineering, a costly or risky result of EN954-1’s limitations.”
“The new standard accommodates the advances in technologies and that is the main advantage,” D’Silva said. “Further it corrects deficiencies in EN 954-1.”
ISO 13849-1 Safety of machinery: Safety-related parts of control systems (SRP/CS) provides safety requirements and guidance on the principles for the design and integration of safety for control systems, including the design of software.
It specifies characteristics that include the performance level necessary to carrying out safety functions. It applies to SRP/CS, regardless of the type of technology and energy in place whether electrical, hydraulic, pneumatic, mechanical, or others and for all kinds of machinery.
The new standard addresses the dramatic changes in technology the older standard (EN 954-1) was incapable of handling, in particular, determining the safety of programmable products.
D’Silva, an integrated safety expert at Siemens, gave an outline on software-based tools that assist in achieving compliance to the standards. The tools are SISTEMA (Safety Integrity Software Tool for the Evaluation of Machine Applications) and SET (Safety Evaluation Tool).
The SISTEMA software utility provides developers and testers of safety-related machine controls with comprehensive support in the evaluation of safety via ISO 13849-1. It enables one to model the structure of the safety-related control components based upon the designated architectures, thereby permitting automated calculation of the reliability values with various levels of detail, including the Performance Level (PL). The SISTEMA program is now available.
SET for the IEC 62061 and ISO 13849-1 standards is a TÜV-tested online tool that supports the fast and reliable assessment of your machines’ safety functions. One can realize a standard-compliant report that serves as documentation as a proof of safety.
Safety is becoming even more important today than ever before and the new standard will help users move toward the main functions of safety and that is to protect workers, property and the surrounding area. In addition, there are the needs to reduce cost pressures and maintain productivity. With the push toward globalization, there is an increased need for production and one of the ways to meet that need is to lose the old way of doing things and integrate safety.
It is simple, reducing risk means systems remain running, which means a higher level of productivity and increased profitability. While that sounds simple, getting from Point A to the Point B is often fraught with challenges.
The new standard is one area that can help eliminate those challenges.
Key changes incorporated into EN ISO 13849-1 to address deficiencies in the previous standard and accommodate new technologies:
• Addresses the programmable electronic safety devices used increasingly in modern machines.
• Accommodates new technologies now commonly used in safety systems.
• Provides a quantitative approach to risk assessment and safety validation.
• PL’s quantify the required and achieved level of safety in probabilistic terms.
• Defines measures for diagnostic capability and common cause failures.
• Increases customer confidence in safety and integrity of their product.