Modern life would not exist as we know it without standards. Consumer-appliance power cords would vary by manufacturer, cars would be relatively unsafe, and even the newest light bulbs would chew through electricity. Within the ever-changing world of industrial standards, three broad categories emerge: Safety-related standards that keep workers and machines out of harm's way, platform norms that make parts connect more seamlessly, and green legislation to make products more environmental. Following are several new developments within each of these important areas.
Safety-related standards are arguably the most important category. ANSI/ISA 84, IEC 61508, and IEC 61511 are three established standards that ensure risk reduction in industrial settings and address both process and functional safety. (See "Standards resources" box on Page 3 of this article for links to more information on these and other important standards.) Another term with which to be familiar is SIL, or Safety Integrity Level. A SIL measures safety system performance according to four integrity levels: The higher the SIL level, the lower the chance of failure for the safety system. As SIL levels increase, system complexity (and cost) also tends to increase. Two notes: SIL levels apply to entire systems rather than individual components, and few systems are rated to SIL 4.
In recent safety news, IEC (International Electrotechnical Commission) has approved openSAFETY as a worldwide standard. The fieldbus-independent protocol was tested according to IEC 61784-3 FSCP 13 and approved by national IEC committees representing 27 countries including the U.S., China, and Germany, and is now released for international standardization. Because openSAFETY is bus independent, it can be used with all fieldbus or industrial Ethernet systems. At the HMI 2010 trade show in Hanover, Germany, openSAFETY was presented in applications using popular industrial Ethernet protocols, such as SERCOS III, Modbus TCP, EtherNet/IP, and POWERLINK. openSAFETY has been certified by TÜV Rheinland and TÜV Süd for SIL 3 applications. For more information, visit open-safety.org.
Another growing area of safety concern — and related standards — involves arc flash hazards. To shed some light on the topic, a new white paper from Rockwell Automation, Milwaukee, discusses the dangers of arc flash along with the standards guiding arc-flash safety, and details the role that arc-resistant motor control centers (MCCs) can play in helping to contain arc energy and reduce these hazards.
"Advances in Low Voltage MCC Technology Help Reduce Arc-Flash Hazards and Minimize Risks" outlines how changing industry standards are putting more focus on arc-flash risks, and highlights the key features and components of an effective arc-resistant MCC design. The paper also underscores the performance criteria that must be met before an MCC can be classified as an arc-resistant design. According to the paper, an arc-resistant MCC is designed and built to provide a complete structural solution in accordance with defined industry standards, such as NFPA 70E (Electrical Standard for Safety in the Workplace). Arc-resistant equipment is designed to minimize arc-flash exposure by extinguishing the arc, controlling the arc's spread, or channeling the arc pressure and energy away from personnel.
"As new codes and standards continue to raise the awareness of arc-flash hazards, users are looking for products capable of delivering higher safety levels," says John Kuroski, MCC product manager. For more information, visit literature.rockwellautomation.com and search "arc flash."
Seamless operation, productivity gains
Beyond the safety of workers and equipment, standards also aim to boost throughput and productivity. These gains often result from compatible components that are developed when different manufacturers adhere to the same rigorous standards. To that end, ISO recently published a CD-ROM compilation of 202 standards and related documents addressing the field of mechanical vibration, shock, and machine condition monitoring. Documents include the entire portfolio of ISO technical committee ISO/TC 108 (Mechanical vibration, shock and condition monitoring), as well as a selection of other related ISO standards.
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"ISO/TC 108 was established because of the recognition that the machines, vehicles, and structures upon which we depend for food, shelter, and livelihood are all either subjected to, or are the source of, mechanical forces," explains Dr. Bruce Douglas, ISO/TC 108 Chair. "These forces result in harmful mechanical vibration, shock, and acoustic energy that can damage or destroy a structure or its surroundings, as well as people's health. Machine and structural efficiencies can be gained through proper dynamic design and maintenance practices."
Another area where interoperability is a growing issue involves wireless devices for factory automation. In June, the ISA100 Wireless Compliance Institute (WCI) announced availability of its ISA100.11a Stack Conformance and Device Interoperability Test Kits designed to verify conformance to the ISA100.11a standard. Both kits verify the correct communication behavior of a wireless device as defined in the ISA100.11a standard and provide comprehensive packages and tools for troubleshooting, debugging, and regression testing of ISA100.11a products.
The ISA100.11a Stack Conformance Test Kit enables users to ensure a manufacturer's communication stack conforms to the formal ISA100.11a registration testing and will verify the correct communication behavior of a wireless device as defined in the ISA100.11a standard.
A subset of the Stack Conformance Test Kit, the ISA100.11a Device Interoperability Test Kit enables users to ensure that a manufacturer's device conforms to the formal ISA100.11a registration testing and to verify the correct communication behavior.
Both ISA100.11a Wireless Test Kits will be used by organizations developing products to the ISA100.11a standard. The test kits are typically used in R&D and quality assurance groups of supplier organizations. For more information, visit isa100wci.org.
Sometimes the first step in achieving interoperability is as simple as all parties involved in a particular technology using the same terms. Case in point: Design engineers may be somewhat familiar with recent advances in rapid prototyping, but may not realize that the technology has a new name: Additive manufacturing. It's been called rapid technology, rapid prototyping, and layered manufacturing, but additive manufacturing now has a universal name and a universal language, due to collaboration between the Society of Manufacturing Engineers and ASTM International.
In an effort to eliminate confusion over terminology, design, testing methods, materials, and processing differences, SME's RTAM (rapid technologies and additive manufacturing) community approached ASTM to develop the industry's inaugural standards. ASTM then formed Committee F42 on Additive Manufacturing, including members of the RTAM community, to write new standards. The initial result is the publication, "Standard Terminology for Additive Manufacturing Technologies," now available online. Committee F42 also plans to develop other key industry standards, including test methods. For more information, visit sme.org/rtam.
Environmental and efficiency standards
As the global economy gets increasingly serious about confronting environmental challenges, standards are evolving to ensure that individual countries and governments are all on the same page, so to speak. That's where international standards can play a key role. Two developments design engineers should be aware of include a new brochure on ISO 14000 (environmental management) and a draft international standard on energy management, ISO 50001.
ISO, the International Organization for Standardization, recently published an updated brochure providing a basic introduction to Environmental management - The ISO 14000 family of International Standards. The 12-page color brochure is the latest edition of a publication first released in 1998, two years after the launching of the first standards in the ISO 14000 family. Since then, the ISO 14000 standards have achieved a worldwide impact and the brochure gives a concise idea of how the family has evolved.
The brochure was authored by experts from ISO technical committee ISO/TC 207, Environmental management. They point out that the ISO 14000 standards provide environmental benefits, as well as significant tangible economic benefits, including reduced raw material use, reduced energy consumption, improved process efficiency, reduced waste generation and disposal costs, and utilization of recoverable resources.
The brochure includes an overview of the standards making up the ISO 14000 family including the most familiar standard, ISO 14001:2004. By the end of 2008, this standard was in use by organizations in 155 countries as a framework for environmental management systems (EMS) to better manage the impact of their activities on the environment and to demonstrate sound environmental management. The free brochure is available at iso.org.
In other ISO news, the organization is one step closer to finalizing its new energy management standard, ISO 50001. In July, the organization approved a Draft International Standard for the energy management system, which is based on common elements found in ISO's management system standards. As such, the new standard will be highly compatible with ISO 9001 (quality management) and ISO 14001 (environmental management).
ISO 50001, forecast to become an international standard by early 2011, will establish an energy management framework for industrial plants, commercial facilities, and other organizations. The voluntary standard is expected to broadly apply to many economic sectors, so could influence 60% of the world's energy usage, according to ISO officials. Anticipated benefits include establishing a framework for integrating energy efficiency into management practices, making better use of energy-consuming assets, and promoting energy efficiency throughout the supply chain. ISO 50001 also addresses benchmarking, measuring, documenting, and reporting of energy intensity improvements and their projected impact on reductions in greenhouse gas (GHG) emissions.
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When ISO 50001 is complete, it is expected to replace ANSI's Management System for Energy (MSE) standard, ANSI/MSE 2000-2008, currently the national standard for energy management in the U.S. The U.S. Dept. of Energy (DOE) also plans to use ISO 50001 as the organizing framework for the Superior Energy Performance (SEP) energy management certification program it is developing in conjunction with the U.S. Council for Energy Efficient Manufacturing (USCEEM).
NFPA 79 and cordset use
National Fire Protection Agency (NFPA) 79 is the standard for electrical safety of industrial equipment, outlining acceptable practices for non-hazardous industrial applications with the intent to “promote safety to life and property” (NFPA, 2006, 79-6). When NFPA 79 was revised in 2002, it deemed cordsets permissible for use in place of time-consuming pulled wire and conduit configurations for power distribution. Molded-on cordsets, using exposed-run cable with the same impact and crush resistance as conduit, can now be used alongside multiple loads on a branch, making system design and installation easier. This arrangement allows for distribution of power to multiple loads, control enclosures, and other configurations, although each load and conductor still must be properly protected.
NFPA requires that a cordset must be appropriate for its intended application; if a cable is used in an application where water is present, for instance, the cable must be water-resistant. Additionally, cordsets should be used within the manufacturer's listed temperature and voltage ratings to ensure proper operation. After selecting a cordset, users must check the code to determine the suitable ampacity of the cordset, which is determined by NFPA 79 based on the number and size of conductors.
To determine the wire gauge required for an application, users must calculate the continuous load on the conductors. This is achieved by adding the continuous loads of all devices on the circuit or branch. The NFPA 79 code provides Table 12.8.2 as a reference point for determining the ampacity for which the cordset is suitable. Also included in NFPA 79 is Table 7-2-10-4, which indicates the over-current device selection required for motors and motor controllers.
Information courtesy of Jay Bartsias of TURCK Inc., turck-usa.com
American National Standards Institute
International Electrotechnical Commission
International Society of Automation
International Standards Organization
National Electrical Manufacturers Association
EISA coming soon
The Energy Independence and Security Act (EISA) is new legislation that will regulate, among several other things, the efficiency of motors that can be legally bought and sold in the United States. EISA goes into effect December 19, 2010. For more information, visit motionsystemdesign.com/EISA.