Tanker Cargo Tank P/V Valve, Vent Mast, Vapour Flow & Pressure/Vacuum Capacity Tool
SOLAS II-2/11.6 • 125% Loading-Vapour Basis • P/V Capacity • Tank Pressure / Vacuum • Vent Main • Mast Velocity • Secondary Relief
Tanker Cargo Tank P/V Valve, Vent Mast, Vapour Flow & Pressure/Vacuum Capacity Tool
Convert tanker cargo-transfer rates into the vapour or replacement-air flow the venting system must actually pass. Screen per-tank P/V capacity, common vent capacity, opening-pressure margin, tank-by-tank vent demand, branch and vent-main losses, mast outlet velocity, thermal breathing, inert-gas support and future venting upgrades.
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Need much more depth? Click Advanced above.Advanced adds actual tank rates, valve derating, pressure/vacuum flow capacities, Darcy losses, tank pressure envelope, mast velocity, thermal breathing, purge/IG flow, future 0.20 bar crude-tanker readiness and upgrade economics.Fast10 primary inputs
Core answerFlow capacity + tank design margin
Loading ruleAt least 1.25 flow factor applied
Directional Venting Quick Screen
Run loading/pressure and discharge/vacuum separately. Simple assumes equal flow sharing between active tanks and uses certified directional capacity at the actual installed condition.
m³/h across the active tanks.
%. Loading values below 125% are automatically raised to the SOLAS/IBC sizing floor.
m³/h in the pressure or vacuum direction selected above.
m³/h for the selected direction.
bar. Enter positive magnitude for either pressure or vacuum.
bar. Enter the approved positive pressure or vacuum magnitude.
% above the flow demand after the gas/replacement factor.
Tanker, Cargo & Venting Basis
Draft MARPOL screen only as of September 2026.
°C actual-flow basis.
kg/m³.
mPa·s.
%. Regulatory sizing floor of 125% is applied.
% of liquid discharge rate.
% beyond the flow factor.
% after approved condition/derating basis. Do not invent fouling factors.
Advanced Cargo Tank Register
Enter actual simultaneous tank rates and certified valve capacities. Tank labels stay in the browser and are excluded from Tool Data.
| Tank | Gross m³ | Fill % | Load m³/h | Disch. m³/h | P/V qty | Pressure cap each | Vacuum cap each |
|---|
P/V Setpoints & Cargo-Tank Pressure Envelope
bar(g).
bar below atmosphere, positive magnitude.
bar(g), approved value.
bar below atmosphere, positive magnitude.
bar reserved between screened extreme and design limit.
bar at design flow, only if not already included in certified valve/line basis.
Vent Branch, Common Main & Mast
m.
mm.
mm.
m.
mm.
mm.
m³/h certified/approved.
m³/h certified/approved.
mm.
m/s when an approved high-velocity criterion applies.
m/s project/maker screening value.
Thermal Breathing, Purging & Inert Gas
°C absolute change.
hours.
m³/h.
m³/h.
% above liquid discharge volumetric rate.
Secondary Venting & Inspection Readiness
Loading-Rate Upgrade & Commercial Value
m³/h if venting currently constrains loading. 0 uses current calculated capacity.
m³.
selected currency/hour.
m³/h. 0 retains current row capacities.
m³/h. 0 retains current.
Venting-engineering screen only: this tool is not a class-approved vent sizing calculation, certified P/V valve flow curve, transient/surge model, cargo-vapour thermodynamic model, VECS compatibility study, flame-arrester approval or authorization to change valve setpoints. Certified device curves, gas properties, backpressure, line arrangement, flame-device losses, cargo properties, flag/class requirements and the approved cargo operations manual control.