Fixed CO₂ Fire-Extinguishing Cylinder Quantity, Flooding Concentration & Release Time Tool | ShipUniverse
SOLAS II-2 • FSS Code Chapter 5 • CO₂ Quantity • Cylinder Bank • Flooding Basis • Release Time • Alarms • Maintenance

Fixed CO₂ Fire-Extinguishing Cylinder Quantity, Flooding Concentration & Release Time Tool

Screen a shipboard high-pressure fixed CO₂ system from protected-space volume through statutory free-gas quantity, required cylinder count, installed charge margin, nominal flooding concentration, discharge-time capability, pre-release alarms, controls and service readiness. The tool separates the FSS quantity calculation from the approved hydraulic design and the operational release procedure.

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

Vessel & System Basis

Use the vessel's approved fire-control plan, system drawings and class/flag-approved design values. Do not substitute a generic volume percentage where the approved arrangement, ship type or protected-space rule is more specific.

Used for the reduced machinery-space percentages available to cargo ships below 2,000 GT.
kg/cylinder. Use the bottle nameplate/system-approved charge.
m³/kg. FSS Code quantity calculations use 0.56 m³/kg.

Protected Space & Quantity Basis

Controls whether the 20-second pre-discharge alarm screen is applied.
m³. Machinery-space 40%/35% alternative basis. Include only casing up to the FSS horizontal-area cutoff.
m³. Also used as the normal gross volume for cargo/ro-ro/custom spaces.
m³ free air. FSS chapter 5 requires this to be added when calculating machinery-space quantity.
% of gross volume. Used only when Custom basis is selected.
% of required charge delivered within the custom time limit.
minutes.

Advanced Protected-Space Register

Where one CO₂ bank protects more than one space, the FSS Code generally permits the available quantity to be based on the largest single requirement, provided the approved selector-valve arrangement directs the agent correctly. Each row below is screened independently and the largest requirement governs the common bank.

SpaceCategoryReduced vol m³Full vol m³Air receiver m³Custom %Required kgReq. cylindersRelease basis

Installed Cylinder Bank & Charge Condition

% of nominal charge across the bank, based on weighing or other accepted verification.
MSC.1/Circ.1318/Rev.1 says cylinders below 90% should be refilled.
Planning comparison only. Statutory minimum still governs.

Release Capacity & Flooding Time

The tool calculates the average mass-flow rate needed to satisfy the applicable FSS discharge-time requirement. Use the approved hydraulic calculation or manufacturer/class documentation for actual nozzle, pipe, manifold and orifice sizing.

kg/min average delivery into the selected protected space.
seconds. FSS Code minimum is 20 s for spaces requiring the pre-discharge warning.

Release Controls & Operational Readiness

Cylinder, Hose & System Maintenance

Passenger ships: at least biennially ±3 months. Cargo ships: at intermediate, periodical or renewal survey as applicable.
years.
One or more failures expands the test scope to 50%.
Further failure expands the scope to all cylinders.
years.
years. MSC.1/Circ.1318/Rev.1 caps the interval at 10 years.
MSC.1/Circ.1318/Rev.1: at least once every five years.

Service Campaign Cost Screen

per cylinder, for an undersized bank scenario.
%.
Fire-safety limitation: This is a screening and planning tool. It does not size CO₂ piping, nozzles, orifices or selector valves; prove agent distribution; authorize system modification; replace an approved hydraulic calculation; or replace the vessel's fire-control plan, SOLAS/FSS requirements, flag/class approval, manufacturer instructions, SMS, surveyor or competent fire-service technician. Never release CO₂ into a space until personnel have evacuated and the vessel's approved emergency procedure has been followed.
Regulatory / guidance basis: SOLAS chapter II-2 and FSS Code chapter 5 fixed gas fire-extinguishing systems, including CO₂ quantity, release controls and discharge-time requirements; MSC.1/Circ.1318/Rev.1 revised guidelines for maintenance and inspections of fixed carbon dioxide fire-extinguishing systems. The current IMO consolidated publication is the FSS Code, 2026 Edition. Ship-specific Administration, class, statutory survey, equipment approval and maker requirements may be more stringent.
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