SEP-OCT 2017

Issue link:

Contents of this Issue


Page 14 of 57

INTECH SEPTEMBER/OCTOBER 2017 15 PROCESS AUTOMATION FAST FORWARD l Creating effective alarms does not hinge on having a specific number, but on making the right choices. l ANSI/ISA-18.2 is a very helpful tool if it is applied appropriately at critical points in the process. l Ultimately, alarms must support situational awareness so operators can make good operational decisions. standard departed from ISA's normal nuts-and-bolts ap- proach and focused on a broader vision of work processes rather than mechan - ics. It recognized that alarm management has a significantly human component. Although systems and mechanisms are in - volved, most of the processes are driven by people. Building on the prior work of the Abnormal Situation Management Consortium (ASM), the Engineering Equipment and Materials Users Association (EEMUA), and NAMUR, the pet - rochemical industry has now been using this standard for nearly a decade. It has recently been getting tremendous traction in other in - dustries as well, and should be required reading for all process automation professionals. The standard focuses on alarms found in modern process automation systems like distributed control systems, supervisory control and data acquisition systems, and programmable logic controllers. Its scope targets all varieties of pro - cess manufacturing methods—batch, continu- ous, and everything in between—so its applica- tion is universal. Because ANSI/ISA-18.2 is a standard, and not just a guideline or suggestion, it carries the weight of being "recognized and gener - ally accepted good engineering practice." This means that groups such as the Occupational Safety and Health Administration, the Chemi - cal Safety Board, and the American Petroleum Institute use it as a yardstick when evaluating systems and investigating events. Understanding the alarm life cycle Traditional and ANSI/ISA-18.2 methods are similar in some respects, since both are about reducing the number of alarms. The former approach starts with many alarms and then reduces them to a manageable number, while the latter approach builds from the ground up with a heightened sense of selectivity. ANSI/ ISA-18.2 changed prevailing thought by setting a higher standard for implementing an alarm, based on the notion that if more thought is giv - en to selecting alarms in the first place, there should be fewer of them. It also clarified the alarm rationalization process as just one step of a holistic life-cycle approach, beginning with plier in the game, numerous applications have been developed to tame the alarm problem. These generally follow the same principal goal of reducing the quantity and rate of alarms to which operators must respond. Nonetheless, the focus on these topics only addresses part of the goal. The ultimate objective is not an opti - mal number of alarms, but instead to create an environment where the alarm system provides the most critical information the operators need at any given time and in any possible situation. Help from ANSI/ISA-18.2 In 2003, ISA began developing a standard to give more direction to alarm management. After six years of work, the ANSI/ISA-18.2- 2009, Management of Alarm Systems for the Process Industries, standard was released, and that version has recently been updated. This Figure 1. Control room operators are often faced with an overwhelming number of alarms, courtesy of modern control systems.

Articles in this issue

Archives of this issue

view archives of InTech - SEP-OCT 2017