(145b) Know Your Limits

Forest, J. J., Celanese
Know Your Limits[i]

Jerry Forest

Sr. Director, Process Safety


225 E. John Carpenter Freeway Suite 1200

Dallas, TX 75234

(214) 417-1920



As process safety professionals we continue the elusive search for effective leading indicators. We search for the one variable that if monitored and corrected will prevent process safety incidents. API RP 754 has already defined Tier 3 leading indicators as challenges to safety systems. These challenges include safe operating limit excursions as well as demands on safety systems. If chosen correctly, safe operating limits can be successful leading indicators in that response to an excursion can prevent an incident. In fact, safe operating limits can be a leading indicator to other safety system challenges, including pressure relief devices and safety instrumented system activations.

This paper will describe the process Celanese used to revamp our safe operating limits (SOL) which we call Know Your Limits. The process involves a rigorous review of SOL set points that includes complete documentation and a technical basis for selection, documentation in standard operating procedures and operator certification/recertification, training, reporting, and integration with other process safety elements including alarm rationalization and management. A method to measure program effectiveness will be presented. We will show how implementation of Know Your Limits has contributed to our success in reducing the lagging loss of primary containment incidents.

[i] The term Know Your Limits related to Safe Operating Limits was first introduced by Dawn Wurst of Flint Hills Resources


This paper has an Extended Abstract file available; you must purchase the conference proceedings to access it.


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