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Case studyPublished: September 2026Author: Veress Árpád · Explosion-protection expert

From "What Belongs in the BowTie" to "What Does It Mean on Shift?"

The BowTie question shifts from what belongs in the diagram to what it means on shift. The article centres on one scenario: an Ex-critical barrier degrades at 14:00, production wants to continue, and the Ex specialist is not available. Working through who is informed, what information must be at hand, who assesses, who recommends, who decides, which temporary controls are acceptable, and who authorizes restart effectively defines the Head of Operations role. The point that needed challenging: Operations does not make every technical judgment, but somebody with defined operational authority owns the continue, restrict or STOP decision.

Infographic depicting a bow-tie risk analysis: preventive measures and possible consequences around a central hazard source, with an industrial plant and a professional in the background.

Head of Operations asked me the following question: “what belongs in the BowTie?” to “what does the BowTie mean for the Head of Operations in practice?”
I structured your meeting notes around one central question:
When Ex control becomes uncertain or a barrier is degraded, what exactly is the Head of Operations expected to know, decide, delegate and document?
Key discussion points for the meeting - see image below.


Table of fourteen operational Ex topics, from accountability and decision authority to restart, KPIs and learning, each with the question to resolve with the Head of Operations and the expected outcome.


There is one point in the attached graphic that I specifically challenged during the meeting:
“Operations ensures that continued operation is subject to an authorized, evidence-based decision whenever an Ex-critical barrier is degraded.”
That avoids the way of thinking that the Head of Operations personally makes every technical Ex judgment.
Engineering/Ex specialists provide the technical basis; Maintenance may restore the barrier; HSE may have independent authority; Top Management may retain ultimate accountability. But somebody with defined operational authority must own the continue/restrict/STOP decision.
Usecase:
An Ex-critical barrier is degraded at 14:00 during production. Production wants to continue. The Ex specialist is not immediately available.
Then ask:
Who is informed → what information must be available → who assesses → who recommends → who decides → what temporary controls are permissible → when must the plant STOP → how is the decision recorded → who verifies restoration → who authorizes restart?
If you can answer that end-to-end, you have effectively defined the Head of Operations role in Operational Ex.
VISIBLE → ASSESS → DECIDE → ACT → VERIFY → RECORD → LEARN
Operational governance system that keeps all barriers alive throughout the lifecycle.

Topic