Gas safety standards are changing in 2020:

Transcription

1 WHITE PAPER Gas safety standards are changing in 2020: Will your plant be in compliance? By Jon D. Miller, Technical Compliance Manager Gas detection is usually the first line of defense in plant safety, and hazardous process owners worldwide understand its critical role in risk mitigation. Soon, however, existing equipment and practices for gas detection may no longer suffice. Significant standards changes are coming and the best way to ensure compliance will be to select, specify and install an integrated fire and gas safety system today that will meet the expected 2020 standards. Around the world, manufacturing and processing plants in hazardous industries depend on dedicated fixed gasdetection systems to help them meet the numerous risk-mitigation requirements for combustible and toxic gas detection. Soon, however, owners and operators of these facilities will need to understand and comply with even more rigorous and clearly defined standards and practices related to gas safety systems. New standards expected to be in force by 2020 will impact the selection of gas safety detectors and their control systems for both new installations and retrofits. In hazardous industries, many such projects are currently in the design and specification stages. Individuals responsible for these projects need to be familiar with the new standards so the decisions they make today will conform with tomorrow s requirements. This paper details the specifics of the proposed changes to International Electrotechnical Commission (IEC) standards regarding gas detection and explains what the changes mean for high-hazard process owners. It also discusses other relevant codes and standards (currently in transition) that will impact the selection and installation of gas detection equipment. (See Figure 1.) Lastly, it lists the benefits of integrating gas detection with fire and smoke detection as a comprehensive risk mitigation strategy for plants trying to meet increasingly stringent safety requirements. Harmonizing standards for higher safety and reliability Codes and standards that set product performance criteria and best practice guidelines for industrial plants typically lag behind changes in technology and processes. Since technology and processes outpace prescriptive and safety standards, plants rely on risk assessments to assess safety. Codes and standards are normally modified when risk assessments uncover gaps in the requirements. Today, however, there is an impetus to evolve the codes and standards of regulatory organizations worldwide. In addition to making the codes and standards more relevant for current industrial facilities, those involved wish to set the stage for increased safety and reliability in tomorrow s plants. Another key goal of this effort is to harmonize standards. Currently, each part of the world has industry safety standards that address its specific needs as determined by local regulatory agencies. With many process owners operating in multiple countries or even continents, a single global company might be subject to dozens of different codes and standards. Standards organizations such as the IEC are working toward increased uniformity by cooperating with companies, industries and governments to develop consensus-based standards. According to the IEC website,

2 White Paper Page 2 Description International Australia Canada China European Union Russia United States Combustible Gas Performance IEC AS/NZS C22.2 #152 C JJG 693 GB EN GOST R GOST UL/FM (pending) Open Path / Line-of-Sight Performance IEC AS/NZS C EN GOST R GOST UL/FM Oxygen Performance IEC (pending) AS/NZS 4641 JJG 365 EN GOST ANSI/ISA Toxic Gas Performance IEC (pending) AS/NZS 4641 JJG 9155 EN GOST ANSI/ISA EMC See all above See all above See all above See all above EN See all above See all above Software See all above See all above See all above See all above EN See all above See all above Safety Instrumented System Recommended Practice IEC EN GOST IEC ISA-TR IEC IEC (pending) AS/NZS EN GOST IEC UL/FM Figure 1: This chart outlines general norms (both current and pending) by region, but is not intended to be an inclusive list. The IEC is often used where there are no national standards. the organization also cooperates with international, regional and national partners to produce joint publications, help promote the importance of standardization and to coordinate any potential overlaps in work. IEC updating combustible gas safety standards Activity aimed at modernizing and unifying applicable codes and standards has been particularly notable in the area of gas safety systems. One combustible gas related IEC standard recently released is IEC :2016, Explosive atmospheres Part 29-1: Gas detectors Performance requirements of detectors for flammable gases. This standard specifies general requirements for the construction, testing and performance of fixed gas detectors intended for use in explosive atmospheres such as those found in petrochemical and hydrocarbon processing facilities. The update adds significant new criteria in four areas: 1) Ingress protection requirements The ingress protection rating has taken into account only the enclosure protecting the electronics, not the operation of the sensors inside the enclosure. As products become compliant to this standard, a disclaimer must be placed within the instruction manual stating that the ingress protection rating does NOT imply that the equipment will Figure 2: Ingress protection (IP) testing assesses the protection of detectors against ingress of liquids and/or solid bodies. Under requirements for IEC :2016, the IP rating must either be performance validated, or the manual must clarify operational limitations. Photo courtesy of Det-Tronics.

3 White Paper Page 3 detect gas during and after exposure to such conditions. Otherwise, validation testing should be done by an agency or certifier that can verify the manufacturer s claim. (See Figure 2.) This change will require plant owners and/or product specifiers to pay particular attention to manufacturers ingress protection for gas detectors intended for outdoor use. By choosing detectors with the label marking, plants can be assured that the detectors are rated for the claimed performance. (See Figure 3.) By choosing detectors with the current Edition 2 of the IEC :2016 standard label marking, plants can be assured that the detectors are rated for the claimed environmental conditions. Figure 4: Third-party EMC testing confirms the ability of equipment to function properly regardless of electromagnetic conditions. Photo courtesy of Element. 2) Expanded electromagnetic compatibility testing The IEC :2007 standard requires evaluating detectors for radiated immunity, as well as power supply interruptions, voltage transients and step changes. (See Figure 4.) CL I, DIV 1, GRPS B, C & D (T4) CL I, Zone 1, AEx/Ex db eb IIC T5...T4 In Gb addition to these tests, the IEC :2016 Not included in the revised combustible gas detection CL I, DIV 2, GRPS A,B,C & D (T4) CL I, Zone 1, AEx/Ex db eb [ib] IIC T5...T4 standard Gb requires testing for electrostatic discharge, standard are new WITH test INTRISICALLY requirements SAFE that OUTPUT have FOR been OPTIONAL HART magnetic fields, burst, surge and conducted radiofrequency interference. These changes will align the established by the PORT revision COMMUNICATIONS, committee CONTROL in the DWG draft toxic T4 (Tamb = -55 C to +75 C) T5(Tamb = -55 C to +40 C) gas performance standard. ACIDIC These ATMOSPHERES requirements, EXCLUDED which standard more closely with European electromagnetic will allow detector manufacturers CONDUIT SEAL NOT REQUIRED to verify FOR DIVISION product INSTALLATION CONDUIT SEAL REQUIRED WITHIN 50mm FOR ZONE INSTALLATIONS compatibility (EMC) requirements. performance and provide the relevant information to a product certification agency, may be incorporated into the Once detectors meeting the IEC :2016 next edition of the combustible gas standard. requirements are purchased, plants must take into consideration any manufacturer s special product installation requirements. 1, GRPS B, C & D (T4) CL I, Zone 1, AEx/Ex db eb IIC T5...T4 Gb, GRPS A,B,C & D (T4) CL I, Zone 1, AEx/Ex db eb [ib] IIC T5...T4 Gb WITH INTRISICALLY SAFE OUTPUT FOR OPTIONAL HART CL I, DIV 1, GRPS B, C & D (T4) CL I, Zone 1, AEx/Ex db eb IIC T5...T4 Gb CL I, DIV 2, GRPS A,B,C & D (T4) CL I, Zone 1, AEx/Ex db eb [ib] IIC T5...T4 Gb WITH INTRISICALLY SAFE OUTPUT FOR OPTIONAL HART PORT COMMUNICATIONS, CONTROL DWG T4 (Tamb = -55 C to +75 C) T5(Tamb = -55 C to +40 C) ACIDIC ATMOSPHERES EXCLUDED WARNING: CONDUIT SEAL NOT REQUIRED FOR DIVISION INSTALLATION DO NOT OPEN WHEN AN CONDUIT SEAL REQUIRED WITHIN 50mm FOR ZONE INSTALLATIONS EXPLOSIVE GAS ATMOSPHERE MAY BE PRESENT. PORT COMMUNICATIONS, CONTROL DWG Tamb = -55 C to +75 C) T5(Tamb = -55 C to +40 C) ACIDIC ATMOSPHERES EXCLUDED CONDUIT SEAL NOT REQUIRED FOR DIVISION INSTALLATION ONDUIT SEAL REQUIRED WITHIN 50mm FOR ZONE INSTALLATIONS CL I, DIV 1, GRPS B, C & D (T4) CL I, Zone 1, AEx/Ex db eb IIC T5...T4 Gb CL I, DIV 2, GRPS A,B,C & D (T4) CL I, Zone 1, AEx/Ex db eb [ib] IIC T5...T4 Gb WITH INTRISICALLY SAFE OUTPUT FOR OPTIONAL HART PORT COMMUNICATIONS, CONTROL DWG T4 (Tamb = -55 C to +75 C) T5(Tamb = -55 C to +40 C) ACIDIC ATMOSPHERES EXCLUDED CONDUIT SEAL NOT REQUIRED FOR DIVISION INSTALLATION CONDUIT SEAL REQUIRED WITHIN 50mm FOR ZONE INSTALLATIONS WARNING: DO NOT OPEN WHEN AN EXPLOSIVE GAS ATMOSPHERE MAY BE PRESENT. WARNING: DO NOT OPEN WHEN AN EXPLOSIVE GAS ATMOSPHERE MAY BE PRESENT. EN/IEC IECEx UL X Ex db C T5...T4 OR Ex db [ib] C T5...T4 3) Software function verification Although software requirements are included in the IEC :2007 version of the standard, the IEC :2016 standard includes a test clause for software function verification. This testing will require validation against the requirements, and manufacturers will need to provide evidence of full compliance. One way manufacturers can demonstrate compliance is by using approval agencies such as FM, CSA, UL, DEKRA EXAM GmbH or Sira. (See Resources on page 8.) Detection system controllers that have received agency approval for software functionality will be labeled as meeting the IEC standard. HERE EN/IEC IECEx UL X Ex db C T5...T4 OR Ex db [ib] C T5...T4 EN/IEC IECEx UL X Figure 3: Product labels carry the performance Ex and db extreme C T5...T4 environmental ratings for each corresponding agency so plants OR Ex db can [ib] be C assured T5...T4 that detectors are rated for the claimed environmental conditions. 4) Upper limits system testing The word system here refers to gas detectors in conjunction with their controller. The new standard clarifies requirements for equipment using digital communications during normal gas detection operation. det-tronics.com EN/IEC IECEx UL X Ex db C T5...T4

4 White Paper Page 4 The standard calls for detection systems to be tested under maximum communication transaction rates and activity levels. In addition, the largest and most complex system configuration must be used for testing. These requirements are meant to test necessary safety actions under conditions that simulate the limits of normal gas detection operations. To ensure high reliability of their gas detection systems, plant operators and owners should look for the IEC (or equivalent) label marking on the controllers of systems they are considering for purchase. If a controller lacks such a label, the system does not meet the latest requirements. More standards changes coming Other key gas safety code and standard changes in the works include the following: UL changes for fixed gas detectors The UL STP 9200 committee (chaired by the author of this paper) is working on UL , which is also the second edition of ANSI/ISA , a standard promulgated by the American National Standards Institute and the International Society of Automation. UL uses the requirements for fixed gas detectors in ANSI/ ISA , but it also provides installation and best practice recommendations for the use of gas detection equipment. Included are new recommendations for live equipment maintenance (maintenance done while the equipment is powered up), as well as personnel and property protection, including protection of equipment that would normally be considered unsuitable for a hazardous location. ANSI/ISA provides installation and best practice recommendations for the use of gas detection equipment. In addition, UL offers a broader perspective on the multiple purposes of gas detection equipment. For example, area classification monitoring has been added to align with the Canadian Electrical Code (C22.1). Area classification monitoring is the use of gas detection to verify that the amounts of combustible and toxic gases in different areas of a plant are below the thresholds set for those areas to receive a certain classification. Per Chapter 5 of the National Electrical Code (NEC), National Fire Protection Association (NFPA 70), areas deemed Class I are those where flammable gases, flammable liquid-produced vapors or combustible liquid-produced vapors are or may be present in quantities sufficient to produce explosive or ignitable mixtures. A Class I Division 1 area is one where combustible materials are routinely present in ignitable concentrations. A Class I Division 2 area is one in which the same materials are handled, processed or used, but in which the materials are normally confined and can escape only in the case of accident, breakdown, failure or abnormal operation of ventilation equipment. While the main purpose of gas detection is to increase the safety of personnel and property in hazardous locations, gas detection technology has improved to the point where it can gather information about gas concentrations to help users validate classification for particular areas. CSA Group changes for advanced gas detection Gas detection requirements have recently been clarified in CSA C22.1:2018. In addition, the Canadian Electrical Code now discusses more possible applications for advanced gas detection equipment, including area classification monitoring. Efforts are also ongoing to revise UL , which is referenced within the U.S. NEC, to harmonize with the Canadian Electrical Code. Toxic gas detection Detection of toxic gas leaks in a plant is just as important for safety as combustible gas detection, so plants must take similar risk-mitigating actions to deal with leaks of both types of gas. Two important standards for toxic gas detection are ANSI/ISA and the draft IEC standards. Toxic gas performance standards and combustible gas performance standards are closely aligned, and they are both under continuous improvement. Currently,

5 White Paper Page 5 the IEC Technical Committee 31, Maintenance Team and Joint Working Group 45 committees (also chaired by the author of this paper) are developing new standards for toxic gas detection performance and recommended practices, as well as oxygen detection performance. The IEC toxic gas detection standards are based on European standards, but also take into account current U.S. and Australian requirements. The new IEC toxic gas standard incorporates many of the new concepts already mentioned in relation to the updated IEC combustible gas detection standard (see the above discussion of ingress protection, EMC, software requirements and system requirements). In addition, the toxic gas performance standard uniquely defines Type HM (Health Monitoring) and Type SM (Safety Monitoring) devices in order to segregate requirements and acceptance criteria for these two different uses of toxic gas detection equipment. The two terms can be defined as follows: Type HM: a detection device designed to protect an individual for example, a portable gas detector that is either carried or worn by a person in a hazardous area. If the gas detector goes into alarm, the person carrying or wearing it must leave the area immediately. Type SM: a detection device designed to protect people in general rather than a particular individual. Safety monitoring is done by fixed gas detectors installed in areas where hazardous gas leaks may occur. (See Figure 5.) When gas detection isn t enough integrating fire & gas safety While combustible and toxic gas detection is the first line of defense in mitigating threats to personnel, equipment and processes, gas detection equipment cannot detect the potential consequences of a gas leak for example, a fire or explosion that occurs when leaking gas comes into contact with an ignition source. Detection of such events is left to fire and/or smoke detection equipment. Since many gas detection control panels are not scalable, i.e., they are unable to handle inputs from additional detectors and are not certified to connect to fire or smoke detection systems or gas systems, plants may opt to install separate, unrelated equipment for detecting fire and smoke. Or, they may forgo fire and smoke detection altogether, despite code and standard requirements, putting their facilities and personnel at risk. A safer and highly capable option available today is a complete fire and gas (F&G) safety system designed to warn of and contain or mitigate events that may be a threat to personnel or process operations. Based on digital technology, an advanced F&G safety system is an integrated and scalable set of inputs and outputs consisting of flame, gas and smoke detectors, as well as alarm signaling, notification and extinguishing agent release and/or deluge equipment. (See Figure 6.) A safer and highly capable option available today is a complete fire and gas (F&G) safety system designed to warn of and contain or mitigate events that may be a threat to personnel or process operations. Figure 5: The Det-Tronics GT3000 toxic gas detector is an example of a Type SM detector, one of two toxic gas detector categories newly defined by IEC to segregate requirements based on the two different uses of toxic gas detectors protecting individuals versus protecting people in general (by using Safety Monitoring devices). Distinct from a process control system (PCS), which manages conditions in a plant s process system, an F&G safety system continually monitors and analyzes data collected by detectors in the process area(s) and takes appropriate safety-related actions when necessary. An effective F&G safety system should be able to inform the PCS of detection device status in defined process areas so that the process owner knows exactly what, where

6 White Paper Page 6 and when hazardous events are occurring. Since the F&G safety system and the PCS are independent, however, failure of the PCS should not affect the operation of the F&G safety system. In traditional F&G safety systems, each detector is directly hardwired to the controller using analog or contact closures in a conventional (i.e., point-to-point) design. While this configuration provides enhanced alarm and fault information to the controller, specific details of the event do not reach the controller because of the simple, binary nature of the communication path. By contrast, in a state-of-the-art addressable loop F&G safety system, the detectors and other devices are configured in a bi-directional loop topology, which substantially increases configuration flexibility and the amount of diagnostic information that can be shared with the controller. The addressable loop configuration is also more reliable and survivable than traditional configurations, because the controller constantly communicates with each device in the loop in order to receive the latest alarm and diagnostic information. Fires and gas leaks are relatively rare occurrences compared to trouble conditions involving equipment in an F&G system (which may stem from the fact that the equipment has not been properly maintained). Oldstyle F&G systems with relay contacts can alert users to equipment problems, but often leave them guessing FIRE AND GAS SAFETY SYSTEM Toxic gas detector Flame detector Acoustic gas detector Input/output module XP smoke detector Combustible gas detector Manual call Beacon Input/output module Fire & gas safety system controller Line-of-sight IR gas detector Fire water pumps Automatic deluge valves Mitigation Process control system (PCS) Plant emergency shutdown system (ESD) Figure 6: An effective F&G safety system may include multiple types of detection devices plus a fire & gas safety system controller with inputs and outputs for notification and suppression-activation devices. An addressable loop design assures the highest system reliability. (Diagram courtesy of Det-Tronics.)

7 White Paper Page 7 about the exact nature of the problem. Advanced F&G systems, however, can provide additional information about a trouble condition, making it easy to solve the problem. For example, the system might inform a user that a certain detector can no longer see because of a dirty window, so the user knows that the window needs to be cleaned. State-of-the-art integrated F&G systems also offer redundancy and fault tolerance for increased reliability and availability. If the primary power supply shortcircuits or power is interrupted, a battery backup system kicks in to keep the system operating. And, if its local area network (LAN) communications loop is cut at any point, the system remains fully functional, with every device still able to signal an alarm. (See Figure 7.) Applicable documents for integrated F&G systems include NFPA 72 and ISA-TR and other global standards. NFPA 72 is the National Fire Alarm and Signaling Code, which covers initiating devices such as fire detectors. Gas detectors were added as initiating devices in Advanced F&G systems are fully compliant with NFPA 72 because of their power supply redundancy, and also their communication fault tolerance, which assures the signal integrity required by the standard. Issued by the ISA 84 standards panel, ISA-TR is a technical report that defines the lifecycle and technical requirements for ensuring effective design of fire and gas detection systems for process industries. State-of-the-art integrated F&G systems offer redundancy and fault tolerance for increased reliability and availability. The performance metrics (for rating a fire and gas system s effectiveness) established in the report include availability, which, as already mentioned, is increased by the redundancy and fault tolerance of advanced F&G systems. Controller requirements for an integrated F&G safety system The brain of an F&G safety system is a safety controller that is integrated with, but independent of, the PCS. In addition to being secure, the controller should be scalable and flexible enough to integrate fire and gas systems into a single loop. In addition to handling inputs and outputs, the controller should be able to provide real-time F&G system status and troubleshoot the system. It should also facilitate easy programming and configuration of flame and gas detectors and other field devices. Finally, it should be certified by an accredited third-party certifier in accordance with NFPA 72 for flame and gas detection, which means it is able to: Detect specialized hazardous events (gases or vapors, fires, etc.) Minimize responses to false events Provide automatic and/or manual mitigation of detected hazardous events Annunciate events to personnel Provide information on system readiness/health Figure 7: State-of-the-art F&G safety systems depend on a faulttolerant safety controller such as the Eagle Quantum Premier (EQP) controller from Det-Tronics (shown). The EQP can incorporate smoke detection technologies for high-risk applications into a single integrated safety system that simplifies installation and provides comprehensive indication and notification of device-specific alarms, troubles, faults and diagnostics. Provide historical information, including calibration, alarm and fault logs Communicate with third-party systems such as the PCS and ESD

8 White Paper Page 8 Conclusion New and tougher combustible and toxic gas detection performance standards are being introduced for manufacturing and processing plants in hazardous industries. In their efforts to comply with these new standards, facility owners and operators may discover that the most effective approach is to abandon traditional detection technology in favor of state-of-the-art F&G safety systems. Rather than using a patchwork of disparate devices and equipment, advanced F&G safety setups offer integrated systems capable of detecting flame, smoke and gas. When necessary, F&G safety systems sound alarms and take other actions to mitigate the consequences of dangerous events such as fires or toxic gas leaks. Though they operate independently of a PCS to ensure continuous operation, F&G safety systems can be integrated with the PCS to communicate about events that may be threatening to personnel or process operations. In addition, some currently available advanced F&G safety systems are scalable, fault tolerant and easily configurable. They also provide users with real-time system status and diagnostic information. Though they may cost more than older systems, these state-of-the-art F&G safety systems enable plants to fully integrate fire and gas safety for maximum safety system reliability and availability. About the author Jon D. Miller has over 25 years experience in functional safety and hazardous locations, focusing on fire and gas detection and systems with Det-Tronics since 1996, and is currently the company s Technical Compliance Manager. He is Chairman for the U.S. and International Gas Detection Standards Development Committees and is a member of IEEE, ISA, UL, and IEC committees responsible for hazardous locations and functional safety electrical equipment. Miller holds an MBA, a bachelor s degree in Electrical Engineering and currently serves as: Convener of IEC TC31 MT (Combustible Gas Performance) Convener of IEC TC31 JWG45 (Toxic Gas Performance) IECEx USNC voting member (Hazardous Locations) Chairman of UL STP9200 TG60079 (Combustible Gas Performance) Chairman of UL STP9200 TG62990 (Toxic Gas Performance) About Det-Tronics Det-Tronics is a global leader in fire and gas safety systems, providing flame and gas detection and hazard mitigation systems for high-risk processes and industrial operations. The company designs, manufactures and commissions certified SIL 2-capable flame and gas safety products, including the X3301 Multispectrum Infrared Flame Detector and the Eagle Quantum Premier (EQP) Fire and Gas Safety Controller. Resources 1. International Electrotechnical Commission (IEC) 2. FM Approvals (FM) 3. CSA Group (CSA) 4. UL Standards (UL) 5. American National Standards Institute (ANSI) 6. International Society of Automation (ISA) 7. DEKRA EXAM GmbH 8. Sira Certification Service (SCS) 9. DNV GL NFPA 70 : National Electrical Code NFPA 72 : National Fire Alarm and Signaling Code NFPA 70, NFPA 72, National Electrical Code and NEC are registered trademarks of the National Fire Protection Association, Quincy, Mass Corporate Office 6901 West 110th Street Minneapolis, MN USA det-tronics.com Phone: Toll-free: Fax: det-tronics@det-tronics.com 2019 Detector Electronics Corporation. All rights reserved.