The National Transportation Safety Board has released its conclusions and recommendations from a study designed to examine how pipeline companies use SCADA systems to monitor and record operating data and to evaluate the role of SCADA systems in leak detection. The study was prompted by the number of hazardous liquid accidents in which leaks went undetected after indications of a leak on the SCADA interface.
The study describes SCADA systems being used at pipeline companies that transport hazardous liquids and examines the extent to which the SCADA system design helps or hinders controllers in detecting leaks and acting to limit the amount of product released.
For this study, the NTSB examined the role of SCADA systems in the 13 hazardous liquid line accidents that the Safety Board investigated from April 1992 to October 2004. In 10 of these accidents, some aspect of the SCADA system contributed to the severity of the accident.
Based on surveys, personal interviews, and previous accident investigations, NTSB outlined a set of recommendations for the Pipeline and Hazardous Materials Safety Administration at a public meeting on Nov. 29.
- Require operators of hazardous liquid pipelines to follow the American Petroleum Institute’s Recommended Practice 1165 for the use of graphics on the SCADA screens.
- Require pipeline companies to have a policy for the review/audit of alarms.
- Require controller training to include simulator or non-computerized simulations for controller recognition of abnormal operating conditions, in particular, leak events.
- Change the liquid accident reporting form (PHMSA F 7000-1) and require operators to provide data related to controller fatigue.
- Require operators to install computer-based leak detection systems on all lines unless engineering analysis determines that such a system is not necessary.
A full synopsis of the public meeting is available at http://www.ntsb.gov/publictn/2005/SS0502.htm.