(89a) Mechanical Integrity for Research Scale Environments

Mechanical integrity is an important element in an overall safety management system and is applicable in a wide variety of industrial settings. This presentation will define mechanical integrity, discuss why it is a key ingredient to improve and maintain safe operations in a research scale environment using cases from industrial research settings. It will also describe the components to include when building a sustainable program.

Method:

A Mechanical Integrity program is a means of risk management. The program applies to equipment that when failure occurs, it’s most likely to cause personal injury or environmental insult. The main equipment categories are:

• Flexible Hoses
• Glass and Brittle Devices
• Vessels / Tanks / Process Containment
• Pressure Relief Devices

Well intended designs may lack components to ensure safe operations. Improper inspections and maintenance provide a false sense of security. Several cases are examined and discussed:

• The reactor’s rupture disk discharge line was routed to the back of the hood although inadequately secured to restrict movement when the rupture disk burst. The force of the rupture bent the discharge line toward the lab, dislodging the hood sash and projecting a fire ball into the lab.
• Liquid Nitrogen Dewars that have the Liquid Withdraw Device, equipped with 2 staged pressure relief valves. The Dewar warmed, the liquid nitrogen thermally expanded, and both staged pressure relief valves failed catastrophically.

Result:

The contents of a sustainable Mechanical Integrity program:

• Requirements: describes what to do, and what is required for the Mechanical Integrity program.
• Guidance: how to do it, that is - how to achieve the requirements listed in the Standard.
• Maintaining: team effort responsible for maintaining the guidance and keeping it evergreen with the learning’s.

Use a practical failure mode and mitigation approach consisting of five (5) components.

1. Define the Process: Think through the process (flows, operating temperatures, and pressures, etc.).
2. Define the Equipment: Determine the design limits of the equipment (pressure rating, max. volume, etc.).
3. Identify Failure Scenarios: Think about any scenarios that could instigate equipment failure.
4. Consider Failure Mode: Think about how the equipment would fail.
5. Employ “Mitigation Methods” or “layers of protection” to prevent or mitigate the effects of failure.

Conclusions:

Mechanical Integrity is a program to manage risks to prevent injury and environmental insult by use of proper:

• Design of the equipment to ensure it is suitable for the application.
• Inspections needed to ensure continued safe operation of the equipment.
• Maintenance of the equipment to ensure the equipment is always fit for service.

Mechanical Integrity is a “Key” ingredient to improve and maintain safe operations.

• Well intended designs may lack components to ensure safe operations.
• Improper inspections and maintenance provide a false sense of security.

Components of a sustainable program:

• Define the Process
• Define the Equipment
• Identify Failure Scenarios
• Consider Failure Mode
• Employ “Mitigation Methods”