White Papers

on 'Safety Instrumented Systems'

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  • Permanent Electrical Safety Devices Will Verify Zero Electrical Energy

    Article 120.1 of the NFPA 70E establishes the procedure for creating an electrically safe work condition. Since this was written, the day-to-day practice of electrical safety has changed going beyond the precise language of Article 120.1(1-6). This is due to the increased usage of permanent electrical safety devices (PESDs) in Lock-out/Tagout procedures. The relatively new concept of permanent electrical safety devices actually improves the workers' ability to safely isolate electrical energy beyond that which was originally conceived when Article 120 was written. PESDs go beyond the high standard, yet they still adhere to the core principles found in Article 120.1. With PESDs incorporated into safety procedures and installed correctly into electrical enclosures, workers can transition the once-risky endeavors of verifying voltage into a less precarious undertaking that never exposes them to voltage. Since, every electrical incident has one required ingredient - voltage, electrical safety is radically improved by eliminating exposure to voltage while still validating zero energy from outside the panel.

    Grace Engineered Products, Inc.
  • Is There a One Size Fits All SPD?

    Frequently, our customers will ask for a "one size fits all" Surge Protective Device (SPD), eliminating the need to stock several different part numbers to meet their customers needs. Some manufactures claim to have a one size fits all Surge Protection Device (SPD), however there is absolutely no benefit of this to the end user. Why? The one size fits all approach could in most cases actually cause damage to the equipment it should be protecting.

  • Navigating the UL Safety Requirements for Surge Protection

    Specifiers and users of Surge Protective Devices (SPDs) are adjusting to new terminology and requirements. UL revised their 1449 Safety Standard for Surge Protective Devices to increase safety. The National Electrical Code (NEC) incorporated specific language to require the use of these safer products. This tip sheet will explain some of the changes affecting specifiers and users.

  • Buyer Beware: SPD and UL Markings? Are You Buying or Selling the Right Product

    Significant changes have taken place regarding Surge Protection Devices and UL 1449. With the changes has come different product marking requirements to identify those testing and product changes. Manufacturers of SPD equipment have long been testing to UL 1449 but only recently have such significant changes taken place regarding a whole product categories testing and performance.

    An updated UL 1449 standard was released titled UL Standard for Safety for Surge Protective Devices, UL 1449 Third Edition, and was dated September 29, 2006. The result was that all manufacturers were required to retest their SPD products to ensure compliance before 9/29/2009.

    The easiest way to notice a new SPD product versus an older product that still may be in inventory is the new gold UL holographic label on the product. The new label must have the SPD and not TVSS which was used during the later part of UL 1449- 2 edition.

  • Surge-Trap: North America vs. Europe

    In this global business environment, it is common for manufacturers in North America to ship equipment to Europe. North America and Europe each have their own standards for Surge Protective Devices (SPD's) which makes understanding the differences in electrical system terminology very important. In North America, all SPD products are associated with UL 1449 3rd edition whereas in Europe, IEC 61643-1 is used to provide standards. Recently 1449 3rd edition adopted new terminology and testing criteria to be more congruent with IEC 61643-1. However, system voltages and the how they are defined differ between the two standards.

  • Understanding Ratings for Surge Protection Devices

    Selecting the appropriate Surge Protective Devices (SPD) can seem like a daunting task with all of the different types on the market today. The surge rating or kA rating of an SPD is one of the most misunderstood ratings. Customers commonly ask for an SPD to protect their 200A panel and there is a tendency to think that the larger the panel, the larger the kA device rating needs to be for protection As we will explore in this paper, this is a common misunderstanding.

    When a surge enters a panel, it does not care or know the size of the panel. So how do you know if you should use a 50kA, 100kA or 200kA SPD? Realistically, the largest surge that can enter a building's wiring is 10kA, as explained in the IEEE C62.41 standard. So why would you ever need a SPD rated for 200kA? Simply stated - for longevity.

    So one may think: if 200kA is good, then 600kA must be three times better, right? Not necessarily. At some point, the rating diminishes its return, only adding extra cost and no substantial benefit. Since most SPDs on the market use a metal oxide varistor (MOV) as the main limiting device, we can explore how/why higher kA ratings are achieved. If an MOV is rated for 10kA and sees a 10kA surge, it would use 100% of its capacity. This can be viewed somewhat like a gas tank, where the surge will degrade the MOV a little bit (no longer is it 100% full). Now if the SPD has two 10kA MOVs in parallel, it would be rated for 20kA. Theoretically, the MOVs will evenly split the 10kA surge, so each would take 5kA. In this case, each MOV have only used 50% of their capacity which degrades the MOV much less (leaving more left in the tank for future surges).

    Does this translate into surge "stopping power?" No, just because an SPD has 2 or 20 MOVs in parallel it does not mean it will limit the 10kA surge any better then a single SPD (of the same rating). The main objective of having MOVs in parallel is to increase the longevity of the SPD. Again, keep in mind that it is subjective and at some point you are only adding cost by incorporating more MOV’s and receiving little benefit.

    As mentioned before, panel size does not really play a role in the selection of a kA rating. The location of the panel within the facility is much more important. IEEE C62.41.2 defines the types of expected surges within a facility as:
    Category C: Service Entrance, more severe environment: 10kV, 10kA surge
    Category B: Downstream, greater than 30' from category C, less severe environment: 6kV, 3kA surge
    Category A: Further downstream, greater than 60' from category C, least severe environment: 6kV, 0.5kA surge

    How do you know what kA rating to use? The IEEE categories provide a good base for selecting kA ratings. There are many "right" sizes for each category but there needs to be a balance between redundancy and added cost. Qualified judgment should always be used when selecting the appropriate kA rating for an SPD.

  • What Is the Surge-Trap SPD?

    The Surge-Trap is a branded surge protection device (SPD)that utilizes Mersen's patented thermally protected metal oxide varistor (TPMOV) technology. This technology eliminates the need for fuses to be installed in series with the Surge-Trap SPD.

    which saves money and panel space. Surge-Trap SPD is typically installed in industrial control panels to protect sensitive electrical equipment from harmful voltage transients. Nearly 80% of all transients are caused by equipment or power disturbances within a facility.

    What Types of Ratings Do SPDs Have?
    Do SPDs have a current rating? This is a trick question! They do not have a continuous current rating however they do have other important current-based ratings. They are required to have a short circuit current rating (SCCR), which is the maximum rms current at a specified voltage the SPD can withstand.

    The nominal discharge current (In) is new to UL 1449 Third Edition (effective 9/29/09). This is the peak value of the current (20kA maximum) through the SPD (8/20μs waveform) where the SPD remains functional after 15 surges.

    There are two main voltage ratings for an SPD, the first is maximum continuous operating voltage (MCOV) which is the maximum rms voltage that may be applied to the SPD per each connected mode.

    Voltage protection rating (VPR) is determined as the nearest high value (from a list of preferred values) to the measured limiting voltage determined during the transient-voltage surge suppression test using the combination wave generator at a setting of 6kV, 3kA.

    How Do I Select The Correct SPD?

  • Murphy's Law Consequences in Automation

    The most popular rendition of Murphy's Law is, "What can go wrong will, and at the worst possible time…" In today's automation world, we are building ever more complicated automation and management systems, designed to eek the last bit of quality and production performance our of our processes. We are creating some fertile ground for the production of future Murphy's Law crops. Minimizing these risks, from all perspectives - Automation Vendor, System Integrator, and End User, is essential to create solutions that will degrade gracefully to minimize downtime.

    Why am I writing about this now? Two Words - Hard Drive. As Baz Luhrmann once said in a commencement speech turned into "Sun Tan Song," "The real troubles in your life are apt to be things that never crossed your worried mind; the kind that blindside you at 4pm on some idle Tuesday." OK, in my case it was 3:15 on a Monday and I had to do a hard boot. That was it – "Drive not recognized." New Drive in hand, some software upgrades at the same time, backups that were out of date and a day later of loading, copying, recovering and I was 90% whole again, (not what the plant manager would want to hear, right?). A few shortcuts to get back on line quickly – Antivirus software can wait, documentation of the new system setup can wait, I won't forget to update that temporary license I got from my software vendor, to get back up and running… By now you're likely shaking your head saying Yup, I've been there… Oh, but it gets better. The next morning I wake up to a message saying there is a problem with the Operating System, and the system can't boot. Recover with a Boot Disk, scan the drive and there are bad clusters. The Bathtub Curve still exists…

    Roy Kok, AutomationSMX
  • Analysis of the ICONICS GENESIS Security Vulnerabilities for Industrial Control System Professionals

    A number of previously unknown security vulnerabilities in the ICONICS GENESIS32 and GENESIS64 products have been publically disclosed. The release of these vulnerabilities included proof-of-concept (PoC) exploit code.

    While we are currently unaware of any malware or cyber attacks taking advantage of these security issues, there is a risk that criminals or political groups may attempt to exploit them for either financial or ideological gain.

    The products affected, namely GENESIS32 and GENESIS 64 are OPC Web-based human-machine interface (HMI) / Supervisory Control and Data Acquisition (SCADA) systems. They are widely used in critical control applications including oil and gas pipelines, military building management systems, airport terminal systems, and power generation plants.

    Of concern to the SCADA and industrial control systems (ICS) community is the fact that, though these vulnerabilities may initially appear to be trivial, a more experienced attacker could exploit them to gain initial system access and then inject additional payloads and/or potentially malicious code. At a minimum, all these vulnerabilities can be used to forcefully crash system servers, causing a denial-of-service condition. What makes these vulnerabilities difficult to detect and prevent is that they expose the core communication application within the GENESIS platform used to manage and transmit messages between various clients and services.

    This White Paper summarizes the current known facts about these vulnerabilities. It also provides guidance regarding a number of possible mitigations and compensating controls that operators of SCADA and ICS systems can take to protect critical operations.

    Learn more about Tofino at www.tofinosecurity.com/blog

    Eric Byres, P. Eng., ISA Fellow, Joel Langill, CEH, CPT, CCNA, Tofino Security | SCADAhacker.com
  • How Stuxnet Spreads - A Study of Infection Paths in Best Practice Systems

    The Stuxnet worm is a sophisticated piece of computer malware designed to sabotage industrial processes controlled by Siemens SIMATIC WinCC, S7 and PCS 7 control systems. The worm used both known and previously unknown vulnerabilities to spread, and was powerful enough to evade state-of-the-practice security technologies and procedures.

    Since the discovery of the Stuxnet worm in July 2010, there has been extensive analysis by Symantec, ESET, Langner and others of the worm’s internal workings and the various vulnerabilities it exploits. From the antivirus point of view, this makes perfect sense. Understanding how the worm was designed helps antivirus product vendors make better malware detection software.

    What has not been discussed in any depth is how the worm might have migrated from the outside world to a supposedly isolated and secure industrial control system (ICS). To the owners and operators of industrial control systems, this matters. Other worms will follow in Stuxnet's footsteps and understanding the routes that a directed worm takes as it targets an ICS is critical if these vulnerable pathways are to be closed. Only by understanding the full array of threats and pathways into a SCADA or control network can critical processes be made truly secure.

    It is easy to imagine a trivial scenario and a corresponding trivial solution:
    Scenario: Joe finds a USB flash drive in the parking lot and brings it into the control room where he plugs it into the PLC programming station.
    Solution: Ban all USB flash drives in the control room.

    While this may be a possibility, it is far more likely that Stuxnet travelled a circuitous path to its final victim. Certainly, the designers of the worm expected it to - they designed at least seven different propagation techniques for Stuxnet to use. Thus, a more realistic analysis of penetration and infection pathways is needed.

    This White Paper is intended to address this gap by analyzing a range of potential "infection pathways" in a typical ICS system. Some of these are obvious, but others less so. By shedding light on the multitude of infection pathways, we hope that the designers and operators of industrial facilities can take the appropriate steps to make control systems much more secure from all threats.

    Tofino Security | Abterra Technologies | ScadaHacker.com
  • What U.S. Environmental Protection Agency Greenhouse Gas Regulation Changes Mean to You

    There is an upside for forward-thinking manufacturers regarding EPA blueprint for the way state and local regulatory agencies use the Clean Air Act permitting process to regulate greenhouse gas emissions in the United States.

    U.S. Environmental Protection Agency blueprint for the way state and local regulatory agencies use the Clean Air Act permit process to regulate greenhouse gas emissions in the United States is defined in their November 17 document: PSD and Title V Permitting Guidance for Greenhouse Gases.

    The greenhouse gases that will be regulated include carbon dioxide, methane, nitrous oxide, sulfur hexafluoride and a number of refrigerants.

    The Agency believes that these compounds are responsible for changing the planet's climate and is thus taking steps to reduce emissions of the gases throughout the nation. In taking this action, EPA is breaking new ground, by not only defining a broad new class of air pollutants, but by changing the way that the Agency regulates emissions of those pollutants.

    Traditionally, EPA has set definitive, measurable goals when seeking to reduce air pollutant emissions, both in terms of how much a compound a facility is allowed to emit and in terms of the maximum amount of the pollutant that can be in the air we breathe. The Agency will not take the same approach when it comes to greenhouse gases. Instead, they will be asking facilities to reduce emissions to the greatest extent possible and economically feasible.

    And, yes, there is upside for forward-thinking manufacturers.

    Catalytic Products International
  • MESA Global Education Program

    This initiative is the first step in filling a noticeable void in industry - the lack of independent competency training in the Operations Management (MES/MOM) arena. This lack of wide-scale competency is recognized as a major barrier to plant and supply chain optimization and global operations excellence.

    With members in 85 countries globally, MESA is an independent, objective community of like-minded people and enterprises working to make Operations more reliable, capable and profitable. Some of the foremost experts across the Operations Management landscape are leading the knowledge sharing within the MESA community by offering programs across 4 continents by mid-2011.

    MESA Certificate of Competency (CoC) for MES/MOM* Methodologies: A 4-day, comprehensive program of MES/MOM Methodologies courses aimed at Systems Analysts, Architects, Programmers, Project Managers and Consultants.

    MESA Certificate of Awareness (CoA) for MES/MOM Business Awareness: A 2-day, high-level program of MES/MOM Business Functions courses geared for executives, manufacturing/operations and IT personnel and sales professionals. The CoA courses are higher level, short versions of the CoC program.

    Learn more.

  • Cybersecurity Through Real-Time Distributed Control Systems

    Critical infrastructure sites and facilities are becoming increasingly dependent on interconnected physical and cyber-based real-time distributed control systems (RTDCSs). A mounting cybersecurity threat results from the nature of these ubiquitous and sometimes unrestrained communications interconnections.

    Oak Ridge National Laboratory
  • Using Tofino to Control the Spread of Stuxnet Malware

    This application note describes how to use the Tofino Industrial Security Solution to prevent the spread of the Stuxnet worm in both Siemens and non-Siemens network environments.

    What is Stuxnet?
    Stuxnet is a computer worm designed to target one or more industrial systems that use Siemens PLCs. The objective of this malware appears to be to destroy specific industrial processes.

    Stuxnet will infect Windows-based computers on any control or SCADA system, regardless of whether or not it is a Siemens system. The worm only attempts to make modifications to controllers that are model S7-300 or S7-400 PLCs. However, it is aggressive on all networks and can negatively affect any control system. Infected computers may also be used as a launch point for future attacks.

    How Stuxnet Spreads
    Stuxnet is one of the most complex and carefully engineered worms ever seen. It takes advantage of at least four previously unknown vulnerabilities, has multiple propagation processes and shows considerable sophistication in its exploitation of Siemens control systems.

    A key challenge in preventing Stuxnet infections is the large variety of techniques it uses for infecting other computers. It has three primary pathways for spreading to new victims:
    - via infected removable USB drives;
    - via Local Area Network communications
    - via infected Siemens project files

    Within these pathways, it takes advantage of seven independent mechanisms to spread to other computers.

    Stuxnet also has a P2P (peer-to-peer) networking system that automatically updates all installations of the Stuxnet worm in the wild, even if they cannot connect back to the Internet. Finally, it has an Internet-based command and control mechanism that is currently disabled, but could be reactivated in the future.

  • ISA100 and Wireless Standards Convergence

    ISA100 is one of three standards competing in industrial wireless sensing. What is distinctive about ISA100? What are the prospects for convergence of standards? What would convergence be worth to the industrial wireless market?

    ISA100 is a major standards initiative managed by the International Society of Automation (ISA). In addition to standards development, a new organization, the ISA100 Wireless Compliance Institute (WCI), is charged with delivering compliance certification services for the work of ISA100.

    The ISA100 committee establishes standards, recommended practices, technical reports, and related information for implementing wireless systems in the automation and control environment, with an initial focus on the field level. Given the committee's broad scope, they have formed a number of working groups to pursue specific tasks. The primary deliverable from the Committee thus far is the standard ISA-100.11a, "Wireless Systems for Industrial Automation: Process Control and Related Applications". However a quick glance at the list of working groups shows that several other topics will be addressed by future ISA100 deliverables.

    In 2006, at about the same time ISA100 was forming, the ISA also created the non-profit Automation Standards Compliance Institute (ASCI). This organization manages certification, conformance, and compliance assessment activities in the ISA's automation domain.

    ASCI extends the standards work of ISA by facilitating the effective implementation and independent testing of ISA standards. It creates a vital link between the development of standards and industries' implementation of the standards. The ISA100 Wireless Compliance Institute (WCI) functions as an operational group within ASCI. Operating the ISA100 Wireless Compliance Institute within ASCI allows it to leverage the infrastructure of ASCI, which in addition to WCI, is shared by several ASCI compliance programs.

    ARC Advisory Group
  • Who Controls the Off Switch?

    We're about to acquire a significant new cybervulnerability. The world's energy utilities are starting to install hundreds of millions of 'smart meters' which contain a remote off switch. Its main purpose is to ensure that customers who default on their payments can be switched remotely to a prepay tariff; secondary purposes include supporting interruptible tariffs and implementing rolling power cuts at times of supply shortage. The off switch creates information security problems of a kind, and on a scale, that the energy companies have not had to face before. From the viewpoint of a cyber attacker - whether a hostile government agency, a terrorist organization or even a militant environmental group - the ideal attack on a target country is to interrupt its citizens' electricity supply. This is the cyber equivalent of a nuclear strike; when electricity stops, then pretty soon everything else does too. Until now, the only plausible ways to do that involved attacks on critical generation, transmission and distribution assets, which are increasingly well defended. Smart meters change the game. The combination of commands that will cause meters to interrupt the supply, of applets and software upgrades that run in the meters, and of cryptographic keys that are used to authenticate these commands and software changes, create a new strategic vulnerability, which we discuss in this paper.

    Posted pursuant to the creative commons license at http://creativecommons.org/licenses/by-nd/2.5/

    Ross Anderson and Shailendra Fuloria, Computer Laboratory
  • Understanding the Concepts Behind Short Circuit Current Ratings (SCCR)

    The date of January 1, 2005 sits vividly in the minds of manufacturers within the industrial control panel field. That's because that's the day when the National Fire Protection Association's (NFPA) National Electrical Code (NEC) 2005 Article 409 officially went into effect. The code required that short circuit current rating be clearly marked on the industrial control panels in order to be inspected and approved. The markings made it easier to verify proper over-current protection against hazards such as fires and shocks on components or equipment, whether it be for initial installation or relocation. It was the beginning of an era when things would become a little more complicated, but for all the right reasons of ensuring more safety within the industrial world.

    The main vision of the NFPA is to reduce or limit the burden of fire and other hazards on the quality of life by providing and advocating scientifically based consensus codes and standards, research, training and education. These codes and standards were established to minimize the possibility of and effects of fire and other risks. Due to misinterpretations, inconsistencies and advancements in technology over the years, they have had to update their codes with consistency in order to comply with existing standards.

    Therefore, the focus of this paper will look at the changes that occurred due to Article 409, the impacts that it had, who was affected by the code and how to comply with the code. Precautions like this article had been enforced in the past, but they were too vague, so people found ways to get around them.

    The biggest change that took place within the article was the new requirements adopted for industrial machinery electrical panels, industrial control panels, some HVAC equipment, meter disconnect switches and various motor controllers. For the purpose of this paper, we will be concentrating on industrial control panels which are specified as assemblies rated for 600V or less and intended for general use. All in all, it states that the above products must feature a safe design and be clearly marked with specific information concerning Short Circuit Current Rating (SCCR) in efforts of aiding with the designing, building, installation and inspection of the control panels. This way, the above users can both reference and apply all the needed requirements for all new products and installations as well as for modifying existing ones.

    Yaskawa Electric America
  • One Code to Save Millions: ASME Codes and Standards Guide Dominion in Efficiency, Cost Savings and Safety

    In order to stay on track with technology and provide the safest and most efficient working environment at Dominion's nuclear power plants, Dominion follows the codes and standards developed by ASME. ASME's mission is for its Standards & Certification organization "to develop the preeminent, universally applicable codes, standards, conformity assessment programs, and related products and services for the benefit of humanity." These codes and standards have a significant impact on the industry and save companies millions of dollars per year as well as assist in accident prevention and the development of more efficient production and operational practices. This case study illustrates how ASME has helped Dominion become more efficient, increasing cost savings and improving safety measures.

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