Preventing incidents: Effective process safety management

17 December 2018

To prevent dangerous process incidents from occurring, facilities should employ effective communication, provide workers with appropriate training, and have strong and up-to-date policies and procedures in place. Gregory Hale highlights 11 key principles.

Process unit startups and shutdowns are significantly more hazardous than normal oil refinery or chemical facility operations. A startup is a planned series of steps to take a process from an idle, at rest, state to normal operation. A shutdown is the reverse sequence. 

To prevent these types of incidents from occurring, facilities should employ effective communication, appropriate training, and have strong and up-to-date policies and procedures in place for hazardous operations starting with these 11 key principles.

1. Implement written operating procedures for startup following an emergency shutdown such as conducting and completing a thorough pre-startup safety review, following proper safe work practices for opening lines and equipment following a shutdown, and conducting a management of change (MoC) analysis.

2. Written operating procedures need to have sufficient detail to avoid the likelihood of valve misalignments during startups and shutdowns. Written checklists and diagrams to verify proper valve positioning should be provided.

3.A review of the MoC policy should occur to ensure it adequately addresses changes due to operational variance. To maximize the effectiveness of MoC, safe limits for process conditions, variables, and activities should be defined. Personnel also needs to be trained to recognize significant changes. Combined with knowledge of established operating procedures, this additional training will enable personnel to activate the MoC system when appropriate.

4. Ensure the facility’s lockout/tagout (LOTO) program requires that equipment is rendered safe prior to opening for inspection or maintenance. Equipment opening procedures should contain a stop work provision that requires higher levels of management review and approval when safe opening conditions, such as equipment depressurisation, cannot be verified.

5. Ensure proper procedures are used to isolate equipment after a shutdown. Do not rely on one block valve closure, which may leak. Instead, use a double block and bleed; insert a blind flange, or physically disconnect the piece of equipment to ensure it is isolated properly. For equipment placed in ‘standby mode’, continue to monitor critical parameters such as pressure and temperature.

6. Computerised control systems should include a process overview and, as appropriate, material balance summaries to ensure full process oversight by operators.

7. In complex and critical process systems, multi-channel communication with feedback provides the best opportunity for operators to establish and maintain a mutual understanding of the process unit and its expected future state. 

8. Ensure operators are supervised and supported by experienced, technically trained personnel during unit startups and shutdowns and that they are sufficiently trained on the control systems they will be operating. 

9. For high-hazard processes, establish a shift work policy to minimize the effects of fatigue. The shift work policy should aim to manage normal shift patterns/rotations and temporary situations by limiting the number of working hours per 24-hour period and the number of consecutive days at work.

10. Newly installed computer controls need to be calibrated and tested for functionality before being used in a unit startup.

11. Critical safety devices must not be bypassed during troubleshooting operations or during unit startups and shutdowns. 

Gregory Hale is the editor and founder of Industrial Safety and Security Source.

This article originally appeared in www.controleng.com


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