Develop a Human Performance Modeling System for Process Safety Operations

Emrah Harputlu, Susan Murray, Ray A. Mentzer, and Sam Mannan

Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX

Operators have a crucial role in case of an emergency in a process facility. When an abnormality occurs in the process, the operator has a specific time to take corrective actions before system safety devices shut down the system. This time is required to be known by system designers and safety professionals before operations are initiated.

Specific research goals for this project include the following:

• Estimate the standard time data for operators to take corrective actions in emergency situations.
• Develop an easy-to-use computer based modeling system. This will allow design/process engineers to find the standard time required for the operator(s) to respond in emergency situations.

Current standard time data for carrying out tasks cover normal cases. However, the time required to take actions in emergency situations is different than normal cases. Because of the possibility of a process incident and danger, operators make corrective actions faster than normal cases. Therefore, current standard time data do not meet the requirement for standard time data for emergency situations. The shorter standard time data for emergency situations needs to be estimated.

Standard time data for the emergency situations will be estimated by using time studies. Emergency cases will be observed and videotaped. Then the operations will be decomposed into basic motions (such as stepping, turning, grasping, bending, arising, reading, etc.) by analysis of the video player's slow-motion. The times required to take these basic motions will be estimated. These estimated times will be compared to MODAPTS data, which is a predetermined time standard system. Comparing standard MODAPTS time intervals with those estimated from emergency situations, coefficients will be estimated for the various steps (e.g., factors such as 0.9, 0.75, etc.).

The estimated coefficient for emergency situations will be used in developing a user-friendly computer based modeling system. After the modeling system is complete, when the user enters tasks in the software, it will access MODAPTS, which is a predetermined time standard system, and take the necessary basic motion times and multiply them with the coefficients determined in this work. Therefore, the time required to do those tasks in an emergency will be provided to the user.