New Life for Machine Safety Standard

Wednesday, April 27, 2011 @ 08:04 PM gHale

By Nicholas Sheble
“The standard is vague and needs updating,” Andras Szende, an expert in the fields of industrial machinery and functional safety and technical manager at TUV Rheinland of North America referring to EN954-1, said during a webcast Wednesday.

EN954-1 expires at the end of this year. EN ISO 13849-1, “Safety of Machinery – Safety Related Parts of Control Systems” will replace the control categories of this standard with categories/performance levels.

European safety standard for Industrial Machinery (i.e. EN 60204-1, EN ISO 12100 and others) now references EN ISO 13849-1 as standard.

This new method of evaluating the functional safety of equipment considers not only qualitative but also quantitative approaches to evaluate safety circuits.

Evaluation for each feature: Electrical, mechanical, hydraulic, or any other nature needs to be compliant throughout the circuit considering all the life stages of the machinery.

Automation technology company, Pilz said there are several reasons for revising EN 954-1: The standard doesn’t contain adequate requirements for programmable electronic systems; the relationship between risk level and category was not always plausible; there is a general feeling that probabilistic considerations ought to be included along with the safety aspects.

EN 954-1 has described the design of safety-related control circuits in the machinery safety sector since 1996.

EN ISO 13849-1 is the main standard for the design of safety-related control systems in the “machinery safety” sector. The European version of EN ISO 13849-1 (now in its 2008 version) kicked off in 2006.

EN ISO 13849-1 appears in the Official Journal of the EU as a harmonized standard under the Machinery Directive.

Officials speaking during the Siemens/TUV Rheinland webinar talked about the benefits for the user:
• There is a new approach for safety circuits, categories and definitions
• Risk assessment and safety circuits need to work together
• Basic requirements for programmable features
• Why it is a system requirement and not just a component specification to guarantee safety

Nicholas Sheble ( is an engineering writer and industry analyst.

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