Fiber-Optic LHD Pilot: Open Deck, 6 Weeks
A distributed fiber-optic linear heat detection run on an open vehicle deck of a 6,500-CEU PCTC. Used as a benchmark against our per-vehicle grid.
The operator wanted to know whether they should be running distributed fiber-optic LHD on their open vehicle deck or whether the per-vehicle grid generalised across both deck types. We ran both, side by side, on the same vessel for six weeks. The answer was less either/or than the question implied.
What fiber did well on the open deck
- Continuous coverage along the run — no blind spots between vehicles.
- Immune to wind-driven thermal mixing that defeats point smoke sensors.
- Single interrogator unit, simple cabling, low maintenance overhead.
Where the per-vehicle grid won
- Per-vehicle localisation — fiber gave deck-section coordinates, grid gave bay coordinates.
- Earlier detection on staged cell-level events (smaller deltas resolvable at narrow FOV).
- Coherence check across cells suppressed solar gain that fiber alone could not isolate.
Recommendation back to the operator
Fiber on weather decks and open ramps as a continuous coverage primary; per-vehicle grid on enclosed decks as the localising primary. Both, not either. The cost delta between the two architectures across a full vessel is smaller than the coverage delta.
How RoRoSAFE helps
This benchmark set RoRoSAFE's per-vehicle grid against fibre-optic linear heat detection. Fibre did well on the open deck; the grid was stronger where it reads each vehicle individually and adds a vent-gas channel. For operators the lesson is to match the technology to the deck, and RoRoSAFE's grid is designed for enclosed vehicle decks.
Pilot: one deck · installed alongside the berth · no drydock · 6 months of dashboard access
Questions, answered
Should an operator run fiber-optic LHD or a per-vehicle grid on an open deck?+
The six-week side-by-side pilot found the answer is both, not either. Distributed fibre (420 m) ran against 660 thermal cells on an adjacent deck, and each won where its physics suited the deck — the cost delta between the two architectures across a full vessel is smaller than the coverage delta.
What did fiber-optic LHD do best on the open deck?+
Continuous coverage along the run with no blind spots between vehicles, immunity to wind-driven thermal mixing that defeats point smoke sensors, and low maintenance with a single interrogator unit and simple cabling. It is a strong continuous-coverage primary on weather decks and open ramps.
Where did the per-vehicle grid outperform fiber on the same deck?+
Per-vehicle localisation (bay coordinates versus the fibre's deck-section coordinates), earlier detection on staged cell-level events because smaller deltas resolve at a narrow field of view, and cross-cell coherence that suppressed solar gain the fibre alone could not isolate. The recommendation was fibre on weather decks, grid on enclosed decks.
Continue the thread
Fiber-Optic Linear Heat Detection on RoRo
The FSS Code has required heat detection in vehicle spaces since 1 January 2026 — and a line-type detector answers that with a cable, not a grid.
FIRESAFE II: Open-Deck Detection Lessons
EMSA's 2018 study full-scale tested two detection technologies, not five, and named ventilation as what both delays and displaces an alarm.