Fiber-Optic Linear Heat Detection on RoRo
Distributed fiber-optic sensing (DAS/DTS) turns a deck-length cable into one continuous temperature sensor — solving cameras' line-of-sight problem.
Distributed fiber-optic temperature sensing (DTS) and distributed acoustic sensing (DAS) turn a single fiber cable into a continuous temperature or strain measurement along its length. On open ro-ro decks, the technology covers ground that point-source detectors cannot. The FIRESAFE II programme and vendor field data both back this up.
What the technology does well
- Continuous coverage along the cable run — no blind spots between point sensors.
- Immune to environmental issues that defeat optical sensors (smoke obscuration, condensation on lenses).
- A single interrogator unit reads kilometres of fiber — installed cost scales with cable, not with sensors.
- Intrinsically safe — no electrical power along the sensing length.
Where it is the wrong primary
- Spatial resolution is metres, not centimetres. Per-vehicle localisation is approximate.
- Temperature resolution at distance is modest — small per-vehicle deltas can be missed.
- On enclosed decks with dense vehicle packing, the fiber cannot run close to every pack.
Where it complements the per-vehicle grid
On weather decks and open vehicle spaces, distributed fiber as the primary and per-vehicle thermal as a deeper-deck secondary is a defensible architecture. The opposite split — fiber on enclosed decks, grid on weather decks — is the worse fit.
Questions, answered
What is distributed fiber-optic heat detection, and where does it win?+
DTS and DAS turn a single fibre cable into a continuous temperature or strain measurement along its length. On open ro-ro decks it covers ground point-source detectors cannot: continuous coverage with no blind spots, immunity to smoke obscuration and lens condensation, a single interrogator reading kilometres of fibre, and intrinsic safety with no electrical power along the sensing length.
Why is fiber-optic the wrong primary on enclosed decks?+
Its spatial resolution is metres, not centimetres, so per-vehicle localisation is approximate; temperature resolution at distance is modest, so small per-vehicle deltas can be missed; and on densely packed enclosed decks the fibre cannot run close to every pack. Those are exactly the demands of enclosed-deck detection.
How do fiber-optic sensing and the per-vehicle grid fit together?+
They suit different decks of the same vessel. On weather decks and open vehicle spaces, distributed fibre as primary with per-vehicle thermal as a deeper-deck secondary is defensible; the opposite split — fibre on enclosed decks, grid on weather decks — is the worse fit. They are not competitors on the same deck.
Continue the thread
Thermal Cameras vs Thermal Grids at Sea
Both can image temperature. They fail in different places. On a cargo deck the failure modes are what determine the answer.
Weather Deck vs Enclosed Deck Detection
SOLAS II-2/20 covers weather-deck suppression. Detection on the same deck differs materially from a deck below — wind, solar and visibility all matter.