18: Design Issue

Node Design Issue

Definition/Typical Issues

This major root cause category addresses issues related to the design process, including the design input data and the design output.

Was the incident caused by problems related to the design process or problems related to the design and inherent capabilities of the equipment?

Was there a failure to consider all the appropriate design inputs during the design phase? Was the design output, such as drawings and specifications, complete? Were the design input and output inconsistent? Did the design review process fail to detect errors? Was there a failure to perform an independent design review?

Note 1: The Human Factors Issue (#146) node addresses issues that are related to how the output of the design processes addressed the specific needs of the humans that will use the system or equipment. For example, the Human Factors Issue (#146) node includes issues such as:

  • Tools/equipment
  • Workplace layout
  • Workplace environment
  • Physical workload
  • Mental workload
  • Error mitigation

Examples

Example 1

  • A valve failed because the designer used obsolete materials requirements. As a result, a small spill occurred.

Example 2

  • A process upset occurred because one of the flow streams was out of specification. The design input did not indicate all the possible flow rates for the process. The pump was incorrectly sized for the necessary flow requirements.

Example 3

  • A line ruptured because a gasket failed. The gasket was constructed of the wrong material because the design did not consider all the possible chemicals that would be in the line during different operating conditions. A chemical that was not considered caused the gasket to fail.

Typical Recommendations

  • Develop a preconstruction planning and review process to help ensure that all the specifications are in agreement.
  • Conduct a feasibility study prior to beginning design to ensure that the criteria can be met.
  • Develop a tracking system for specification changes and design changes to help ensure that the final design includes all changes.
  • Eliminate duplicate copies of design information to avoid confusion of which is the "official" version.
  • Develop standards for symbols and terminology.
  • Implement methods to control access and changes to design information.
  • Develop methods for approving changes to design documentation.
  • Ensure that appropriate personnel are aware of recommended practices contained in recognized and generally accepted good engineering practices (RAGAGEPs) and apply their requirements.

Cross-References

Version 10 Element(s)
Node ID Node Name
15 Design Input/Output

 

Maritime Element(s)
Node ID Node Name
6 Design Problem
20 Design Input/Output
31 Design Review/Verification
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