Why is alarm management an issue?
Optimising alarm system design is important to facilitate accurate and timely fault prompting and diagnosis to operators, and hence more effective plant management. There is a great deal of evidence relating to the role of poorly design alarm systems in major incidents, for example the staff at Milford Haven Refinery were faced with a barrage of alarms for five hours preceding the incident.
Key principles of alarm management
- Alarms should direct the operator's attention towards plant conditions requiring timely assessment or action
- Alarms should alert, inform and guide required operator action
- Every alarm should be useful and relevant to the operator, and have a defined response
- Alarm levels should be set such that the operators have sufficient time to carry out their defined response before the plant condition escalates
- The alarm system to accommodate human capabilities and limitations
More information on alarm management
- Extract from inspectors human factors toolkit
- Better alarm handling HSE information sheet
- The explosion and fires at the Texaco Refinery, Milford Haven, 24 July 1994: A report of the investigation by the Health and Safety Executive. Background reading on alarm handling - key incident report.
- Alarm systems, a guide to design, management and procurement, Engineering Equipment & Materials Users Association Publication No 191 ISBN 0 85931 076 0. Available from EEMUA (Tel. 020 7628 7878/ Fax 020 7628 7862).
- The management of alarm systems Contract Research Report 166/1998
- Human factors aspects of remote operation in process plants Contract Research Report 432/2002. Useful guidance on the often-unconsidered risks of centralising control (eg to a central control room) - eg communications often suffer and operators can lose their previous (hands-on) overview of the real plant.
- Human-System Interface Design Review Guidelines (NUREG 0700).
The United States Nuclear Regulator (Nuclear Regulatory Commission) has developed a detailed technical guide to human-system interface design, which includes information on alarm system design. This is a very detailed document and can be applied to all industry sectors. - The Management of Alarm Systems, Contact Research Report 166/1998
A review of current practice in the procurement, design and management of alarm systems in the chemical and power industries