Simplified Safety: UL Introduces New Functional Safety Marks
UL has introduced two new functional safety marks: the UL Functional Safety Listing Mark and the UL Functional Safety Recognized Component Mark.
Functional safety is that part of overall safety that depends on the correct functioning of safety-related control systems. It includes evaluations of:
- Environmental Factors (e.g., electromagnetic compatibility, EMC)
- Safety Lifecycle Management Processes
Functional safety examines the efficacy of the safety-related system by considering the input variables to a device and confirming that the activating quantities of the output are within its designed parameters/ratings. So it goes beyond the fire and electric shock safety associated with the traditional UL Listing Mark.
A unique aspect of a functional safety certification is the functional safety lifecycle management system audit. The functional safety lifecycle management audit is a mechanism used to help reduce systematic problems from appearing in the design of a product. If, for example, you have a manufacturing process, the quality control measures that go into that process really dictate the quality of the product coming out. Many of these measures may be procedural in nature, and tied to documentation having to do with the product specification or functional safety standard to which the product aspires. So the functional safety lifecycle management audit looks at those elements of the manufacturer’s process that may impact the quality of the functional safety of the product being produced.
Functional safety management concerns both the development of new products and the maintenance of safety processes for released products, to make sure that should there be any changes in the product or failures in the field that these developments are considered carefully and correctly, and, when indicated, prompting modifications in accordance with the functional safety requirements.
Functional safety standards require the customer to specific a safety rating. IEC and EN standards call this safety rating a Safety Integrity Level (SIL). SILs range from 1-4 with 1 being the lowest and 4 being the hardest or most difficult to achieve. ISO standards call the safety rating a Performance Level (PL). PLs range from A-E with A being the lowest and E being the hardest or most difficult to achieve.
In its Functional Safety Listing Mark, UL puts a product’s safety rating directly on the mark. This makes it simple for users to understand exactly what has been certified according to functional safety standards. UL’s Functional Safety Recognized Component Mark covers components or materials intended for use in an end product functional safety certification, whose safety cannot be certified by looking at the material or component alone, but has to be used in a specific context to satisfy functional safety requirements. Although additional considerations need to be looked at when integrating the component, the recognized component mark shows that UL has already evaluated the fundamental functional safety characteristics, which makes it easier for end users to integrate the component into their system.
The new marks can be added for those qualifying companies in the process of getting a traditional listing from UL. The UL Functional Safety Listing Mark is available in U.S., Canadian and European designations. The UL Functional Safety Recognized Component Mark is available in U.S. and Canadian designations.
In essence, the Functional Safety Listing Mark replaces the traditional UL Listing Mark on products certified for functional safety. Manufacturers are not obliged to put both marks on their products; the Functional Safety Listing Mark is sufficient. However, those manufacturers wishing to put both marks on their product are welcome to do so.
“Once an integrator or manufacturer sees the UL Functional Safety Listing Mark and identifies a product as a component in their system, they can then look at the listing card for that product on UL’s Internet-based online certification directory to find more specific information such as hardware fault tolerance,” says Thomas Maier, principal engineer, functional safety, at UL. “This allows proper integration of the component into a larger system and maintains the safety level of the overall system. Knowing that this component is recognized for use in, say, up to SIL 3 systems, can streamline the process appreciably for the end user."
Manufacturers using these two new UL Marks will see immediate benefits, as both end users and systems integrators immediately have a higher level of confidence when using the marked product.
Among the functional safety standards UL can certify for the Functional Safety Listing Mark:
IEC 61508: Functional safety of electrical/electronic/programmable electronic safety-related systems
ISO 13849: Safety of machinery — Safety-related parts of control systems
IEC/EN 62061: Safety of machinery — Functional safety of safety-related electrical, electronic and programmable electronic control systems
IEC 61511: Functional safety — Safety instrumented systems for the process industry sector
IEC 61800-5-2: Adjustable speed electrical power drive systems — Part 5-2: Safety requirements — Functional
IEC 61496: Safety of machinery — Electro-sensitive protective equipment
EN 50271: Electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen
EN 954: Safety of machinery. Safety related parts of control systems. General principles for design
ISO 10218: Robots for industrial environments — Safety requirements
UL 1998: Software in Programmable Components
UL 991: Safety-Related Controls Employing Solid-State Devices
ISO 26262: Road vehicles — Functional safety (draft standard; publish date 2011)
CSA C22.2 NO 0.8: Safety functions incorporating electronic technology
For more information on UL’s new functional safety marks, please contact: Kevin Connelly, 631-546-2691, email@example.com
Or go to the web: www.ul.com/functionalsafety; Copyright 2011 Underwriters Laboratories Inc. All rights reserved. Used with permission for the Siemens Simplified Safety Newsletter.
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