The field problem
Concealed Hazardous Facility
A sensitive concealed facility containing hazardous/flammable materials required lightning protection without revealing the protected structure.
The initial idea buried down conductors directly in fill above the structure.
why the obvious answer can be misleading
Concealment can conflict with inspection, mechanical protection and certainty of lightning-current routing. Personnel electrostatic charge also represented a separate ignition concern.
Why it failed
Concealment can conflict with inspection, mechanical protection and certainty of lightning-current routing.
Personnel electrostatic charge also represented a separate ignition concern.
Follow the engineering
Switch between the field condition and the engineering concept. Trace the path and examine what changes.
Inspect the engineering detail
What changes
Use a protected concealed service route/support system that preserves conductor continuity and inspectability beneath the camouflage layer; use a non-attached interception concept where required; add a personnel ESD touch point as a separate static-control layer.
Correction & verification
Use a protected concealed service route/support system that preserves conductor continuity and inspectability beneath the camouflage layer; use a non-attached interception concept where required; add a personnel ESD touch point as a separate static-control layer.
Verification recorded in the case
- Verify continuity and accessibility without publishing sensitive geometry. ESD controls are tested/managed separately from lightning touch/step considerations.
- Record as-built topology and connection points.
- Repeat the measurement or functional test under a defined condition.
- Confirm continuity and mechanical integrity of the corrected path.
- Document instrument/setup, environmental condition and test method.
- Close the NCR/case only when evidence supports the conclusion.
References & project context
References are reproduced from the PIS casebook. Select the governing edition and project acceptance criteria before using them for a design. The diagrams explain the concept, rather than define construction dimensions.
IEC 62305 principles; hazardous-area/ESD requirements. Public version intentionally omits sensitive dimensions and locations.
PIS reviewed field handbook · PIS-CS-035
The engineering lesson
Security requirements must be integrated into protection engineering, not used to justify an uninspectable current path.
Take the lesson into your next design review.