IUMI's Fixed-First Approach, Explained
IUMI's 2025 update made the priority order explicit: activate fixed systems before any manual intervention. The reasoning is sharper than most absorbed.
IUMI's September 2025 update to "Risk mitigation for the safe ocean and short-sea carriage of electric vehicles" is short on rhetoric and long on order-of-operations. The headline is the "Fixed First" approach: activate fixed firefighting systems promptly before any manual intervention. The rationale walks through the casualty record.
Why the order matters
- Manual entry to a vehicle deck during a Li-ion event puts crew within reach of toxic gas exposure (HF in particular) within minutes.
- CO2 flooding is only effective if the deck is sealed before crew enter — Felicity Ace demonstrated the failure mode of doing it the other way.
- Time spent locating the fire manually is time the fixed system is not running.
What it implies for the detection layer
Fixed-First only works if detection produces a trustworthy red state. A bridge that hesitates to seal a deck because the alarm has cried wolf before is back to the Felicity Ace failure mode in a different costume. The detection layer is upstream of the IUMI recommendation working in practice.
Sources
- IUMI — "Risk mitigation for the safe ocean and short-sea carriage of electric vehicles" (Sept 2025 revision).
- Larsson, F. et al. — "Toxic fluoride gas emissions from lithium-ion battery fires," Scientific Reports 7, 10018 (2017).
- IMO MSC.1/Circ.1638 — "Recommended actions to address risks of fires on ro-ro cargo spaces and special category spaces" (2021).
- IMO — FSS Code Chapter 5, Fixed Gas Fire-Extinguishing Systems.
- [VERIFY: Felicity Ace primary investigative jurisdiction is Panama Maritime Authority; NTSB involvement was via USCG-coordinated channels, not a primary NTSB report.]
Questions, answered
What is IUMI's Fixed-First approach?+
In its September 2025 update, IUMI made the priority order explicit: activate fixed firefighting systems promptly before any manual intervention. The rationale is drawn from the casualty record rather than rhetoric — it is an order-of-operations document for EV-era response.
Why does the order of operations matter for an EV deck fire?+
Manual entry to a vehicle deck during a Li-ion event puts crew within reach of toxic gas (HF in particular) within minutes; CO₂ flooding only works if the deck is sealed before crew enter, as Felicity Ace showed; and time spent locating the fire manually is time the fixed system is not running.
How does Fixed-First depend on the detection layer?+
Fixed-First only works if detection produces a trustworthy red state. A bridge that hesitates to seal a deck because the alarm has cried wolf before is back to the Felicity Ace failure mode in a different costume. The detection layer is upstream of the IUMI recommendation working in practice.
Continue the thread
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The cost isn't the few minutes of bridge attention — it's crew trust on every later alert. Two false alarms can take a detection layer offline.
Why CO₂ Flooding Failed on the Felicity Ace
The NTSB report on Felicity Ace reads like a case study in fixed-system design failure. The fix is not "more CO₂" — it is sealing and detection.
How Insurance Pricing Is Reshaping RoRo
After the 2022 PCTC losses, hull and cargo underwriters moved from an EV surcharge to outright capacity withdrawal on some routes. The fleet must respond.