Ro-Ro Fire-Water Density, Simultaneous Zones, Pump Flow, 125% Drainage, Scupper Capacity, Accumulated Water, Free Surface & Residual GM

Ro-Ro Vehicle Deck Fire Water Demand, Drainage & Stability Tool

Size the water-based protection problem and the drainage problem together. Calculate prescriptive fire-water demand by deck height and system type, simultaneous deluge-section flow, fire-hose contribution, pump margin, finite water-source endurance, gravity scupper and drainage-pump capacity, the SOLAS 125% drainage screen, accumulated deck water, flood depth, added weight, free-surface correction, residual GM, off-centre water heel and the time available before a drainage shortfall becomes a stability issue.

Currency
Currency selector changes display only. No exchange-rate conversion is performed.

Vessel & Fire-Protection Basis

The 2026 SOLAS amendments add stronger fire detection, patrol and video-monitoring requirements for vehicle, special-category and ro-ro spaces. The water-demand engine below uses MSC.1/Circ.1430/Rev.3 prescriptive densities where applicable.

Simple Protected Deck

m.
m.
m from deck to ceiling of protected area.
L/min/m², used for Custom or heights outside prescriptive table.
m², used for Custom approved system.

Advanced Fire-Zone Register

Enter the protected zones / sections. The calculator ranks their individual hydraulic demand and sums the highest-demand simultaneous zones. For a deluge system the IMO prescriptive basis requires two adjacent sections; use at least 2 unless an approved design establishes otherwise.

L/min/m² for rows marked Custom or outside prescriptive height range.
Zone Area m² Breadth m Free height m System Custom density

Fire-Water Pumps, Hoses & Water Source

m³/h available to the vehicle-deck protection system.
L/min each.
m³. Used when finite-tank source is selected.
minutes, owner / class / approved design criterion.

Drainage, Scuppers & Blockage

% of selected spray-pump basis + required hose flow. 125% is the SOLAS screening basis in the relevant arrangements.
Installed pump capacity is the more conservative SOLAS wording screen.
m³/h.
mm each.
m. Screening head driving gravity discharge.
% of nominal scupper + drainage-pump capacity.
minutes for accumulated-water and stability screen.

Accumulated Water & Stability Screen

t.
m.
m. Used with current GM to infer initial KG.
m above keel.
m.
m. Transverse breadth strongly drives free-surface correction.
m from centerline for estimated heel screen.
m. Use approved stability criteria for the vessel.
mm operational screening threshold.
t/m³.

2026 Detection, Monitoring & Decision Support

%.
% of vehicle / ro-ro space visible with vehicles loaded.
minutes for operational response screen.

Retrofit / Survey Cost Context

Fire protection and stability screening only: This tool is not a class-approved hydraulic calculation, nozzle layout, FSS Code type approval, SOLAS survey, MSC.1/Circ.1430/Rev.3 fire-test approval, MSC.1/Circ.1320 drainage design, intact / damage stability calculation, CFD fire model or authorization to alter vehicle-deck fire systems. Performance-based systems must use their approved nozzle characteristics, coverage area, minimum pressure and water-delivery rate. Final drainage and stability effects must be verified against the ship's approved drawings and stability information.
Regulatory / engineering basis: Amendments to SOLAS Chapter II-2 entered into force on 1 January 2026 with enhanced fire detection, patrol and video-monitoring requirements for vehicle, special-category and ro-ro spaces, plus related FSS Code provisions. MSC.1/Circ.1430/Rev.3 provides current revised design / approval guidance for fixed water-based systems. Its prescriptive tables use 6.5 L/min/m² for wet / dry systems and 5 L/min/m² for deluge at free heights up to 2.5 m; 15 / 15 / 10 L/min/m² respectively above 2.5 m to 6.5 m; and 20 / 20 / 15 L/min/m² above 6.5 m to below 10 m. Prescriptive deluge systems are designed for the two adjacent sections with the greatest hydraulic demand. SOLAS drainage provisions in the relevant vehicle / ro-ro arrangements use a drainage capacity of at least 125% of the combined water-spraying-system pump capacity and required fire-hose nozzles and require free-surface stability effects to be considered where accumulation cannot be prevented.
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