Marine Fire Insulation: Materials & Standards (SOLAS)
Marine fire insulation keeps A-class divisions within SOLAS/IMO limits. Rock wool is the workhorse; ceramic fiber covers the hot zones. Here is the practical material map.
Marine fire insulation keeps a ship's A-class divisions, engine-room boundaries, and exhaust uptakes within SOLAS/IMO temperature limits during a fire. The workhorse material is rock wool — A1 non-combustible, dimensionally stable, and a decent acoustic absorber. Ceramic fiber steps in where exhaust or uptakes run hot.
What SOLAS / IMO Demand
A-class bulkheads and decks must limit the temperature rise on the unexposed side to 139°C above ambient, with no point exceeding 180°C, during the standard fire test. That is a thermal-duty spec, not just "non-combustible."
Material Choices
- Rock wool blanket and board — the default for A-class divisions and accommodation boundaries. A1, service to about 650°C continuous, naturally water-repellent, good for both fire and noise. See rock wool blanket.
- Ceramic fiber blanket — for hot spots: exhaust uptakes, incinerator casings, and high-temperature penetrations where rock wool would break down. Continuous use to 1000–1260°C. See ceramic fiber blanket.
- Stone and glass wool composites — used where combined thermal and acoustic performance is specified.
Where It Goes
- Engine-room boundaries (A-60 / A-30 / A-15 divisions)
- Exhaust gas uptakes and silencer casings
- Accommodation and corridor ceilings (fire plus acoustic)
- Pipe and duct penetrations through fire divisions
Practical Notes
- Pair insulation with certified cladding or jacketing rated for the division.
- Watch compression: over-compressed rock wool loses R-value and can open fire paths.
- On hot uptakes, ceramic fiber modules outperform blanket for vibration and thermal cycling.
Frequently asked
What insulation is used for marine fire protection? +
Primarily A1 rock wool for A-class divisions and accommodation; ceramic fiber for hot exhaust uptakes and penetrations where rock wool would break down.
What temperature must marine fire insulation withstand? +
SOLAS/IMO limit the unexposed surface to 139°C above ambient (max 180°C) in the standard fire test — a thermal-duty limit, not just non-combustibility.
Is rock wool allowed on ships? +
Yes. Rock wool is A1 non-combustible and the standard choice for marine A-class divisions; it is also naturally water-repellent, useful in engine rooms.
Rock wool or ceramic fiber for exhaust uptakes? +
Ceramic fiber — uptakes run hot enough to break rock wool down (rock wool caps near 650°C continuous). Ceramic fiber serves 1000–1260°C.