Identifying System Boundaries in a few easy steps: so easy a cave man can do it!

Identifying System Boundaries in a few easy steps: so easy a cave man can do it!

CavemanSystem boundaries are the foundation of the Engineering lifecycle.  These boundaries identify where one system ends and another begins.  System boundaries define the scope of a system and assist in the management of Validation, Maintenance and Change Management processes.  Without these boundaries defined, the chances of omitting components or lines during validation or maintenance increases which can increase your chances for a regulatory finding. Identifying boundaries on the Process and Instrumentation Diagrams (P&IDs) is ideal to ensure that they are also aligned with maintenance activities, but at a minimum these boundaries should be clearly called out within the scope of the commissioning and qualification protocols.

The task of identifying system boundaries seems like it should be easy to accomplish, however there are several things to consider ensuring that boundaries are defined consistently to all systems.

  • Does this system supply multiple systems (water, steam, …)?
  • Is your system a packaged system or skid (autoclave, washer, chromatography skid, …)?
  • Does your system supply critical and non-critical systems (Clean compressed air vs. instrument air)?

Here are a few best practices and tips to make the decision process easier if they are not predefined on P&IDs:

  • For utilities, use the last valve prior to the system being supplied and include that valve as part of the supply utility.  This valve could be used as a Lock Out Tag Out (LOTO) point for that utility.
  • For skids and packages systems, you can use the advice above, or use the physical connections to the system such as tri-clamp connections or flanges,
  • For critical/non-critical systems, like air or HVAC systems, use the filter as your boundary between systems. 

Though there are many ways to approach and define system boundaries, we hope this will give you a few ideas on how to approach them. 

Article by: Tim Johnson, Managing Consultant, ICQ Consultants Corp.

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