SOLAS II-2/20 Explained: New Fire Safety Requirements for Ro-Ro Ships in 2026

Resolution MSC.550(108) rewrote SOLAS II-2/20 and MSC.555(108) rewrote the FSS Code behind it, both in force 1 January 2026. Together they change five things on a ro-ro ship: detection type and spacing, video monitoring, water-based suppression on weather decks, boundary insulation, and where openings may be cut. Almost all of it binds passenger ships. A cargo ship gets a much shorter list.

This is the whole amendment in one place, by ship type and construction date, with the numbers that actually appear in the class summaries rather than the headline. If you only need one answer — does this apply to my car carrier? — it is at the top of the next section, and the short version is: far less than the 2026 headlines suggest.

Which ships, and from when

Four rows decide everything, and ABS Regulatory News 15/2025 tabulates them. Read your ship's row before reading anything else:

• Passenger ships constructed on or after 1 January 2026 — the full package: individually identifiable detection, combined smoke and heat detectors, detection aligned to deluge sections, weather-deck detection, video monitoring with 7-day replay, A-60 boundaries, the openings rules and the ventilation rules.
• Passenger ships constructed before 1 January 2026 — a reduced retroactive set, to be met no later than the first survey on or after 1 January 2028: fixed detection with combined smoke and heat detectors throughout, and video monitoring with at least 24-hour replay. Structural fire protection and openings stay as they were.
• Cargo ships constructed on or after 1 January 2026 — fixed detection to FSS Code Chapter 9 with detector type, spacing and location subject to Administration approval, tested under normal ventilation. No video monitoring row. No new structural requirements.
• Cargo ships constructed before 1 January 2026 — the requirements prior to MSC.550(108) remain applicable. Nothing new is imposed.

A pure car and truck carrier is a cargo ship. If it was built before 2026 this amendment asks nothing of it; if it is a newbuild it gets one detection paragraph and no cameras. That gap is not an oversight — the vehicle-carrier package is still in draft at IMO, with SOLAS text no earlier than 2032, which the companion posts on II-2/20 and the compliance calendar cover in full. 'First survey' is defined by MSC.1/Circ.1290 as the first annual, periodical or renewal survey falling due after the date.

Detection: the part with actual numbers

This is where the amendment is most specific, and where a retrofit gets expensive. MSC.555(108) amends FSS Code Chapter 9 for ships constructed on or after 1 January 2026, and the spacing table is the load-bearing detail:

• Heat detectors — maximum 37 m² floor area per detector, 9 m between centres, 4.5 m from bulkheads.
• Smoke detectors — maximum 74 m², 11 m between centres, 5.5 m from bulkheads.
• Combined smoke and heat detectors — maximum 74 m², but 9 m between centres and 4.5 m from bulkheads. The area allowance is a smoke detector's; the spacing discipline is a heat detector's.
• Linear heat detection — sensor cables maximum 9.0 m apart and 4.5 m from bulkheads, tested to EN 54-22:2015 and IEC 60092-504, with alternatives at the Administration's discretion.
• Detectors below movable ro-ro decks must meet the same spacing — a point worth pricing before a hoistable-deck retrofit is quoted.
• On passenger ships the detection system must align with the deluge system sections where a water-based deluge system is fitted, so a detector zone maps to a valve.

Two operational provisions matter more than their word count suggests. On ro-ro passenger ships built from 2026, alarm presentation is regulated: a consistent scheme for wording, vocabulary, colour and position; alarms immediately recognisable on the navigation bridge and not compromised by noise or poor placement; and an interface providing alarm addressability, identification of alarm history and the most recent alarms, and suppression that still leaves alarms with ongoing trigger conditions clearly visible. That is a human-factors specification written into a fire rule, and the corpus's Commodore Clipper case study shows precisely why.

The second is the loading exemption. Smoke detector function in special category and ro-ro spaces may be disconnected during vehicle loading and unloading — but the disconnection time must match the loading duration and reset automatically, the central unit must indicate the disconnection status, and disconnection of the heat detection function and of manual call points is not permitted. The practice of muting a deck during loading is now bounded rather than discretionary.

Video monitoring, suppression and the weather deck

Video is passenger-ship only, and it is not a detection system. The amendment requires an effective video monitoring system in vehicle, special category and ro-ro spaces for continuous monitoring, with immediate playback, cameras high enough to see over cargo and vehicles after loading, camera-to-extinguishing-section correspondence displayed near the monitor, and replay retained at a continuously manned control station for at least 7 days on new ships and 24 hours on existing ones. ABS's summary adds the line that settles its purpose: continuous crew monitoring is not required. The companion posts cover what that means in practice.

On weather decks intended for vehicle carriage, MSC.555(108) specifies fixed monitors for ro-ro passenger ships built from 2026: the protected area is the entire length and width of the deck plus superstructure boundaries up to 8.0 m horizontally from vehicle storage areas; combined monitor capacity at least 2.0 L/min/m² of protected area with no individual monitor below 1,250 L/min; even distribution; the distance from a monitor to the farthest extent of its protected area forward not exceeding 75% of the monitor's throw in still air; and each monitor sited outside the area it protects.

Boundaries, openings and ventilation

The structural half applies to new passenger ships and is the part most likely to be missed at design review. On passenger ships carrying more than 36 passengers, boundary bulkheads and decks of special category and ro-ro spaces must be insulated to A-60, reducible to A-0 where category (5), (9) or (10) spaces adjoin, or where fuel oil tanks sit below a special category space. Where those spaces have internal deck subdivisions, the deck rating follows the fixed water-based system's capacity: A-30 if the system cannot cover above and below simultaneously, with ramps and doors between decks in steel and as tight as practical.

Openings are now geometrically constrained. Openings in the side plating, ends or deckhead of ro-ro spaces must be positioned so a fire cannot endanger survival craft stowage, embarkation and assembly stations, or accommodation, control stations and normally occupied service spaces above — and are prohibited on decks directly below those spaces within a minimum 6.0 m horizontal safety distance. Where openings sit below accommodation, the ship's side must be A-60 across a rectangle 6.0 m forward and aft and two deck levels up; an A-0 window protected by a water curtain delivering at least 5.0 L/min/m² may be accepted as equivalent. On ventilation, mechanical openings for ro-ro and special category spaces are permitted below accommodation and control stations if protected by steel or fire-resistant closing devices operable from accessible positions and not vulnerable to being cut off by fire — but are prohibited below survival craft, emergency generators and engine-room air intakes.

What it means for owners, class and underwriters

Three different conversations, depending on the row you read at the top. For a ro-pax newbuild the amendment is a design-review item touching detection layout, camera count, deluge zoning, boundary insulation and the general arrangement itself — not a bolt-on. For an existing ro-pax the 2028 first survey is the real date, and the scope is narrower than the newbuild package: combined smoke-and-heat detection throughout, and video with 24-hour replay. For a car carrier the honest answer is that this amendment is not yours, and the risk is the opposite one — assuming it is, and buying to a passenger-ship specification that no surveyor will ask you for.

For class and underwriters the useful reading is that the amendment finally quantifies things that were previously judgement: detector spacing, replay retention, monitor capacity, boundary ratings, opening distances. Those are auditable. What it does not do is set a detection performance standard — there is still no required time-to-alarm for a vehicle-deck fire, which is why the EMSA FIRESAFE work that produced this package, and the interim guidelines now being drafted for vehicle carriers, remain the better guide to where the next requirement lands.

Sources

• 1. IMO Resolution MSC.550(108), Amendments to SOLAS Chapters II-2 and V, adopted 23 May 2024, in force 1 January 2026; Resolution MSC.555(108), amendments to FSS Code Chapters 7 and 9. IMO press briefing, 'Raft of shipping rules in force from 1 January 2026', for the video monitoring wording quoted here.
• 2. ABS Regulatory News No. 15/2025 (December 2025), 'Fire Safety Requirements for Ro-Ro Passenger and Cargo Ships' — read in full from the published PDF. Source of the four-row application table; the detector spacing table (heat 37 m²/9 m/4.5 m; smoke 74 m²/11 m/5.5 m; combined 74 m²/9 m/4.5 m); linear heat cable spacing and EN 54-22:2015 / IEC 60092-504 testing; the alarm-presentation and alarm-addressability provisions; the loading-disconnection conditions; video monitoring retention of 7 days / 24 hours and 'continuous crew monitoring is not required'; A-60 / A-0 / A-30 boundary ratings; the 6.0 m opening distance and 5.0 L/min/m² water-curtain equivalence; ventilation-opening rules; and the weather-deck monitor performance figures (2.0 L/min/m², 1,250 L/min minimum, 75% of throw). References MSC.1/Circ.1290 for the definition of 'first survey'.
• 3. Lloyd's Register Class News 07/2026 (1 April 2026), 'SOLAS amendments: Fire Safety Requirements for ro-ro Passenger Ships', covering MSC.550(108) and MSC.555(108): application to cargo ships and ro-ro passenger ships constructed on or after 1 January 2026, and existing ro-ro passenger ships not later than the first survey on or after 1 January 2028.
• 4. EMSA — FIRESAFE I (2016) and FIRESAFE II (2017–2018), the research that produced this package, and IMO MSC.1/Circ.1615, the interim guidelines carrying some of their outcomes.
• 5. Companion RoRoSAFE analyses — 'What Does SOLAS II-2/20 Ask of a Car Carrier?' (the cargo-ship reading in depth), 'Does the 2026 SOLAS Rule Reach Old Ships?', 'Is Individually Identifiable Detection Required?', 'What Does SOLAS 2026 Video Monitoring Require?', 'SOLAS 2026 Video Monitoring: Who Is Watching?' and 'Does Car-Carrier Fire Compliance Arrive in 2027?'.