Management of Alarm Systems for the Process Industries
|Publication Date:||23 June 2009|
This standard addresses alarm systems for facilities in the process industries to improve safety, quality, and productivity. The general principles and processes in this standard are intended for use in the lifecycle management of an alarm system based on programmable electronic controller and computer-based Human-Machine Interface (HMI) technology. Implementation of this standard should consider alarms from all systems presented to the operator, which may include basic process control systems, annunciator panels, safety instrumented systems, fire and gas systems, and emergency response systems. The practices in this standard are applicable to continuous, batch, and discrete processes. There may be differences in implementation to meet the specific needs based on process type.
The Alarm System
The alarm system serves to notify operators of abnormal process conditions or equipment malfunctions. It may include both the basic process control system (BPCS) and the safety instrumented system (SIS), each of which uses measurements of process conditions and logic to generate alarms (see Figure 1). The alarm system also includes an alarm log and a mechanism for communicating the alarm information to the operator via a HMI, usually a computer screen or an annunciator panel. There are other functions outside the alarm system that are important to the effectiveness of the alarm system, which many include an alarm historian.
Process Sensors and Final Control Elements
Process sensors and final control elements are shown in Figure 1 to indicate alarms may be implemented in these devices. The design and management of process sensors and final control elements are excluded from the scope of this standard. The alarms and diagnostic indications from sensors and final control elements are included in the scope of this standard.
Safety Instrumented Systems
The safety instrumented system (SIS) is shown in Figure 1 to
indicate alarms may be implemented in these devices. The design and
management of safety instrumented systems are excluded from this
standard (refer to ANSI/ISA-84.00.01-20
The specification and design of annunciator panels is excluded from the scope of this standard. ISA-18.1-1979 (R2004), Annunciator Sequences and Specifications, provides information on alarm annunciator functions. The integration of independent alarm annunciator panels into an alarm system is included in the scope of this standard.
Fire Detection and Suppression Systems and Security Systems
Fire detection and suppression systems and security systems are governed by other standards and are excluded from the scope of this standard. The alarms and diagnostics from fire detection and suppression systems or security systems that are presented to the process operator through the control system are included in the scope of this standard.
The indication and processing of analog, discrete, and event data other than alarm indications are outside the scope of this standard. The analysis techniques using both alarm and event data are outside the scope of this standard.
Alarm Identification Methods
Required methods of alarm identification are not specified in this standard. Examples of alarm identification methods are listed.
Management of Change
A specific management of change procedure is not included in this standard. Some requirements and recommendations to be included in a management of change procedure are included.
In jurisdictions where the governing authorities (e.g., national, federal, state, province, county, city) have established process safety design, process safety management, or other requirements, these take precedence over the requirements defined in this standard.
This standard is not intended to be used as an alarm system purchase specification. It will not eliminate the need for sound engineering judgment. No particular technology is mandated.
This standard addresses the development, design, installation, and management of alarm systems in the process industries. Alarm system management includes multiple work processes throughout the alarm system lifecycle. This standard defines the terminology and models to develop an alarm system, and it defines the work processes recommended to effectively maintain the alarm system throughout the lifecycle.
This standard was written as an extension of existing ISA standards with due consideration of other guidance documents that have been developed throughout industry. Ineffective alarm systems have often been cited as contributing factors in the investigation reports following major process incidents. This standard is intended to provide a methodology that will result in the improved safety of the process industries. This standard is not the first effort to define terminology and practices for effective alarm systems. In 1955 ISA formed a survey committee titled Instrument Alarms and Interlocks. The committee evolved to Standard & Practices committee 18. In 1965 the committee completed ISA-RP18.1, Specifications and Guides for the Use of General Purpose Annunciators. In 1979 ISA released, as a product of the ISA18 and ISA67 committees, ISA-18.1-1979 (R2004), Annunciator Sequences and Specifications. In 1994 Amoco, Applied Training Resources, BP, Exxon, Gensym, Honeywell, Mobil, Novacor, Texaco, Shell, and others formed the Abnormal Situation Management Consortium (ASM) to develop a vision for better response to process incidents, with additional support in 1994 from the U.S. National Institute of Standards and Technology (NIST). In 1999 the Engineering Equipment and Materials Users' Association (EEMUA) issued Publication 191, Alarm Systems: A Guide to Design, Management and Procurement, which was updated in 2007. In 2003 the User Association of Process Control Technology in Chemical and Pharmaceutical Industries (NAMUR) issued recommendation NA 102, Alarm Management.
During the development of this standard every effort was made to keep terminology and practices consistent with the previous work of these respected organizations and committees.
This document provides requirements for alarm management and alarm systems. It is intended for those individuals and organizations that:
a) manufacture or implement embedded alarm systems,
b) manufacture or implement third-party alarm system software,
c) design or install alarm systems,
d) operate and/or maintain alarm systems,
e) audit or assess alarm system performance.