Hazardous area installation challenges and solutions

ISA has published the latest in a series of technical reports that support the understanding and application of the widely used ANSI/ISA-18.2-2016, Management of Alarm Systems for the Process Industries.

ISA-TR18.2.7, Alarm Management When Utilizing Packaged Systems, provides guidance on how to integrate packaged systems into basic process control system-based centralized alarm systems. The technical report addresses various issues that can arise when ISA-18.2 work processes are applied to facilities where packaged systems are used, and gives guidance on how to successfully apply ISA-18.2 in these situations.

A packaged system, in the context of the technical report, can be visualized as existing outside of the basic process control system. It is a separate entity, usually containing an embedded microprocessor, controller, or hardwired logic, which performs specific tasks for a piece of equipment or a process operating within a facility. Most packaged systems can be configured to send alarm or status information to a basic process control system, directly to an alarm annunciation system, or both.

"Packaged systems have long been a great source of frustration for automation professionals, especially when it comes to integrating them into the plant control system environment," points out Graham Nasby, water SCADA and security specialist - Water Services, City of Guelph, Ontario. Nasby served with Joseph Alford as a co-chair of the ISA18 working group that developed the technical report. "Drawing on the experiences of end users, designers, vendors, and system integrators, the technical report provides guidance on how to successfully integrate alarms from packaged systems into plantwide control systems. It is an effective guide for how to apply alarm management principles in plants that use packaged systems."

The technical report addresses alarming-specific issues that can arise when packaged system interfaces are specified, designed, and implemented. Pros and cons of several design techniques are discussed from an alarm system point of view; the system designer should select the best packaged system interface option to use for the given application. Previously published ISA18 technical reports that support the ISA-18.2 standard include:

  • ISA-TR18.2.2-2016, Alarm Identification and Rationalization, addresses alarm identification and rationalization for facilities in the process industries for such purposes as improving safety, environmental protection, product quality, equipment protection, and plant productivity. The methods described are applicable to batch and discrete processes as well as continuous processes.
  • ISA-TR18.2.3-2015, Basic Alarm Design, provides guidance on implementing the practices set forth in ISA-18.2. Following the life-cycle model of ISA-18.2, the document assumes that alarms to be addressed in basic alarm design have completed rationalization where attributes, such as alarm set point and priority, have been defined.
  • ISA-TR18.2.5-2012, Alarm SystemMonitoring, Assessment, and Auditing, provides guidance on the use of alarm system analysis for both ongoing monitoring and periodic performance assessment. Monitoring, assessment, and audit are essential to achieving and maintaining the performance objectives of the alarm system. These activities can identify improvement opportunities in the other life-cycle stages, such as philosophy, rationalization, detailed design, implementation, operation, maintenance, and management of change.
  • ISA-TR18.2.4-2012, Enhanced and Advanced Alarm Methods, helps users to evaluate when to use enhanced and advanced alarming methods, what benefits they can achieve, and what challenges and costs to expect. Per ISA-18.2, enhanced and advanced alarm methods typically go beyond the basic methods and techniques that are usually, or at least initially, applied. While significant improvement in alarm system function and performance can usually be made by following the basic alarming methods and principles, in some cases they may not be sufficient to achieve the goals for performance and operator guidance stated in the alarm philosophy.
  • ISA-TR18.2.6-2012, Alarm Systems for Batch and Discrete Processes, covers the application of alarm management principles in ISA-18.2 to batch and discrete processes. The general principles and techniques described are intended for use in the life-cycle management of an alarm system based on programmable electronic controller and computer-based human-machine interface technology. Following the guidance will help to identify and address alarm specification, design, implementation, and management opportunities that are important to batch and discrete processes. It will also help minimize the generation of nuisance alarms that could complicate and frustrate an operator's awareness, understanding, and response to abnormal situations.

For information about viewing or obtaining ANSI/ISA-18.2-2016, the new ISA-TR18.2.7-2017, and the additional ISA18 technical reports, please visit www.isa.org/findstandards. For information on ISA18, contact Charley Robinson of ISA Standards, crobinson@isa.org.

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