Urea Bulk Density kg/m3: Specifications for Shipping

Urea bulk density determines how many tonnes fit in a ship hold, what freight rate applies, and whether a charter party density warranty holds up under scrutiny. Prilled urea ships at 700, 750 kg/m³ loose and 800, 850 kg/m³ tapped, while granular urea runs denser at 750, 800 kg/m³ loose and 850, 900 kg/m³ tapped, a difference that shifts stowage factors from 1.33 m³/t to 1.25 m³/t and changes revenue per voyage by thousands of tonnes.

This guide covers the density specifications for both product forms, the IMSBC Code compliance requirements for Group C carriage, charter party clause wording that protects owners and charterers, hold preparation standards for technical and food-grade cargoes, moisture control thresholds that prevent caking, and the loading and discharge equipment choices driven by angle of repose. You will learn how to convert density certificates into stowage factors, which test methods to cite in contracts, and how to align vessel cubic capacity with the right urea grade to maximize deadweight utilization.

Urea Bulk Density Values: Prilled vs. Granular (kg/m³)

Loose and Tapped Density Ranges for Prilled Urea

Prilled urea typically exhibits a loose bulk density of 700 to 750 kg/m³ and a tapped density of 800 to 850 kg/m³. The smaller spherical particles produced by prilling towers pack less efficiently in a loose pour, leaving higher void space between granules. This compaction characteristic is critical for shippers because a vessel loaded to its volumetric capacity with loose prills may exceed deadweight limits once the cargo settles at sea. China exported 4.90 million tonnes of urea in 2025 according to Mysteel, highlighting the volume of prilled product moving in bulk carriers where this density shift directly impacts freight calculations.

Loose and Tapped Density Ranges for Granular Urea

Granular urea delivers a loose bulk density of 750 to 800 kg/m³ and a tapped density of 850 to 900 kg/m³. The larger, more irregular granules created in rotary drum granulators interlock more effectively than prills, reducing initial void space and limiting further settlement during voyage. This tighter particle distribution means granular urea typically yields a lower stowage factor, allowing operators to load more metric tonnes per cubic metre of hold volume. The reduced compaction risk also simplifies ventilation planning because air channels within the cargo remain more stable. Charter parties for granular cargoes often specify a narrower density warranty band, reflecting the product's consistency compared to prilled alternatives.

Comparison Table: Prilled vs Granular Bulk Density kg/m³

Property	Prilled Urea (Loose)	Prilled Urea (Tapped)	Granular Urea (Loose)	Granular Urea (Tapped)
Bulk Density (kg/m³)	700, 750	800, 850	750, 800	850, 900
Typical Stowage Factor (m³/t)	1.33, 1.43	1.18, 1.25	1.25, 1.33	1.11, 1.18
Angle of Repose (degrees)	28, 32	28, 32	30, 35	30, 35
Settlement Sensitivity	High	Low	Moderate	Low

The table above shows that granular urea consistently outperforms prilled urea in both loose and tapped density metrics, translating to a 5 to 10 percent improvement in hold utilization. The higher angle of repose for granular product reflects its superior stacking stability, which reduces the risk of cargo shift during heavy weather. Settlement sensitivity is markedly lower for granular grades, meaning the density declared at load port remains a reliable basis for freight calculation throughout the voyage. Shippers selecting between forms should weigh these density advantages against the typically higher production cost of granular urea and the specific handling equipment available at discharge ports.

Derived Shipping Metrics: Stowage Factor & Vessel Capacity Calculations

Stowage Factor Calculation Formula and Worked Example

The stowage factor of urea in m³ per metric tonne is calculated by dividing 1,000 by the bulk density in kg/m³. Using a typical loose bulk density of 750 kg/m³ for prilled urea, the stowage factor equals 1.33 m³/t. For granular urea at 800 kg/m³ loose density, the factor drops to 1.25 m³/t. The IMSBC Code cites a urea stowage factor range of 1.17 to 1.56 m³ per tonne according to The Swedish Club, encompassing both product forms and compaction states. This wide range underscores the importance of specifying the exact product form and density condition in charter party documentation to avoid disputes over deadweight utilization.

Vessel Deadweight and Hold Volume Utilization Scenarios

A 60,000 DWT supramax bulker with 72,000 m³ of grain capacity can theoretically load 54,135 tonnes of prilled urea at 1.33 m³/t before reaching volumetric full, leaving deadweight unutilized. The same vessel loaded with granular urea at 1.25 m³/t accepts 57,600 tonnes, improving revenue per voyage by approximately 3,500 tonnes. Conversely, a vessel with limited cubic capacity relative to deadweight may hit volumetric limits before deadweight, making the lower stowage factor of granular urea essential for maximizing freight earnings. Operators must run both weight and volume constraints for each fixture, factoring in the specific density certificate issued at load port.

Charter Party Clause Wording for Urea Stowage Factor

Charter parties should include a density warranty clause stating the guaranteed stowage factor range, for example "Charterers warrant urea stowage factor 1.25 to 1.35 m³/mt at load port weighbridge density." The clause must reference the test method, typically ISO 7837 or equivalent national standard, and specify whether the figure represents loose or tapped condition. A tolerance band of ±0.05 m³/t is standard practice, with liquidated damages for breach calculated at the freight rate per tonne of deadweight lost. Including a requirement for independent surveyor verification at load port protects both parties and provides clear evidence for any subsequent arbitration.

Critical Physico-Chemical Properties Affecting Bulk Handling

Particle Size Distribution Standards (Prilled vs Granular)

Particle size distribution determines how urea packs in a ship hold and how it flows through loading and discharge equipment. Prilled urea typically forms smaller, more uniform spheres with a narrower size range, while granular urea offers larger, harder particles that resist attrition during handling. The difference affects stowage factor, angle of repose, and the likelihood of segregation during voyage. Shippers should specify sieve analysis limits in the sales contract to avoid disputes over cargo quality at discharge port.

Angle of Repose Values and Flowability Implications

The angle of repose governs how urea piles inside a cargo hold and how readily it flows through chutes and hoppers. Prilled urea generally exhibits a steeper repose angle than granular material, which can create conical heaps that complicate trim and ventilation. Granular urea flows more freely and levels more evenly, reducing the risk of uneven weight distribution. Terminal operators select conveyor speeds and discharge gate openings based on these flow characteristics to prevent bridging and rat-holing.

Moisture Content and Biuret Content Specifications

Moisture content directly influences caking potential, flowability, and the risk of lump formation during storage and transit. High moisture promotes dissolution and recrystallization at particle contact points, creating hard cakes that resist discharge. Biuret, a byproduct of urea manufacture, affects agronomic quality and is limited in fertilizer specifications to protect crop safety. Pure urea contains 46.67% nitrogen according to The Swedish Club The Swedish Club. Shippers typically cap moisture around one percent and biuret within contract limits to preserve product integrity and meet buyer quality clauses.

Property	Prilled Urea	Granular Urea	Handling Impact
Typical particle size	1 to 2.4 mm	2 to 4 mm	Affects stowage factor and flow
Angle of repose	Higher	Lower	Influences hold trimming
Moisture sensitivity	Higher caking risk	Lower caking risk	Drives ventilation needs
Attrition resistance	Lower	Higher	Reduces dust and fines

Buyers and exporters use this comparison to match cargo type with vessel hold geometry and terminal equipment. A higher angle of repose requires careful trimming to avoid uneven stress on the tank top, while lower moisture limits reduce the need for active ventilation during passage. Contracts should reference recognized sieve and moisture test methods so both parties measure the same property at load and discharge ports.

IMSBC Code Compliance & Safe Carriage Requirements

IMSBC Group C Classification and Hazard Profile

Urea is listed in the IMSBC Code as a Group C cargo, meaning it is not liable to liquefy, does not present major chemical hazards, and is not classified as dangerous goods for bulk carriage. Despite this benign classification, urea can still create operational risks through dust generation, caking, and cargo sweat if moisture is not controlled. Masters and charterers must treat it as an ordinary bulk cargo while applying the Code's general safe carriage practices, including hold cleanliness and cargo care throughout the voyage.

Ventilation Requirements and Weather Precautions

The IMSBC Code requires ventilation to control cargo sweat and condensation, particularly when sailing from warm to cold climates where the dew point of the hold air may fall below the cargo temperature. Urea is hygroscopic, so uncontrolled moisture uptake can lead to surface caking and discharge delays. Weather precautions include closing hatch covers before rain or spray and avoiding loading during precipitation unless the cargo moisture specification can still be met.

Required Documentation and Shipper Declaration

The shipper must provide a cargo declaration confirming the IMSBC classification, stowage factor, moisture content, and any relevant transport information. The master should receive a certificate of analysis, a weighing certificate, and a loading plan that reflects the agreed density and trim conditions. These documents support port state control inspections and provide evidence if a charter party density warranty is disputed later.

Requirement	IMSBC Provision	Practical Application	Documentation
Cargo group	Group C	No special hazard classification	Shipper's cargo declaration
Ventilation	Weather-dependent	Prevent cargo sweat and condensation	Ventilation log
Weather precautions	Hatch management	Close covers before rain or spray	Deck log entries
Moisture control	General cargo care	Avoid loading wet cargo	Certificate of analysis

This table summarizes the core compliance points a vessel's crew and charterer should verify before loading. Group C status simplifies regulatory treatment but does not remove the duty of care. Accurate documentation at load port protects both shipowner and charterer against claims for moisture damage, contamination, or short delivery at the discharge port.

Hold Preparation, Contamination Prevention & Compatibility

Hold Cleanliness Standards for Food-Grade vs Technical Urea

Hold cleanliness standards depend directly on the end use of the urea cargo. Food-grade urea requires a higher level of cleanliness than technical-grade material because residues can enter downstream production chains. For technical urea, holds must be swept clean, dry, and free of visible cargo residue before loading. Food-grade urea demands additional washing with fresh water, complete drying, and inspection for rust scale or old paint flakes. Surveyors typically issue a cleanliness certificate that records the hold condition against standard cargo hold inspection criteria. Charterers should specify the required cleanliness level in the charter party to avoid rejection at the load port.

Incompatible Previous Cargoes: Ammonium Nitrate and Phosphates

Urea must not be loaded in holds that previously carried ammonium nitrate or phosphate-based fertilizers without thorough cleaning and segregation. Ammonium nitrate creates oxidation risks when mixed with urea, while phosphate dust can contaminate the cargo and affect its chemical purity. Previous cargoes such as salt, cement, or coal also leave residues that are difficult to remove and can trigger moisture absorption. A hold that carried these materials should undergo fresh-water washing, rust removal where necessary, and a dry inspection before urea is accepted. The mate's receipt and cargo declaration should note the previous three cargoes carried in each hold.

Pre-Loading Inspection Checklist for Bulk Carriers

Before loading begins, the vessel's crew and the attending surveyor should verify several conditions. Holds must be clean, dry, and free of previous cargo residue. Bilges should be clean and dry, with bilge pumps tested and operational. Hatch covers must seal properly to prevent water ingress during the voyage. Ventilation systems need to be functional, and tank tops should be inspected for structural damage or corrosion. The loading plan should reflect the agreed stowage factor and trim conditions. A joint inspection report signed by the shipper, carrier, and surveyor records these findings and supports any later claim regarding contamination or short delivery.

Inspection Item	Technical Urea Standard	Food-Grade Urea Standard	Verification Method
Hold sweeping	Free of visible residue	Washed with fresh water	Visual inspection
Drying	Dry to touch	Completely dry, no standing water	Towel test or moisture meter
Previous cargo check	No ammonium nitrate or phosphates	No prior fertilizer without deep clean	Cargo log review
Bilge condition	Clean and dry	Clean and dry	Pump test
Hatch cover integrity	Weathertight	Weathertight	Hose test
Ventilation	Operational	Operational	Fan run test

This checklist gives the loading team a practical reference before the first parcel of urea enters the hold. Each item should be signed off by the responsible officer and, where required, by an independent surveyor. Skipping any step increases the risk of cargo rejection, moisture claims, or compatibility disputes at the discharge port. The completed inspection record becomes part of the voyage file and supports the certificate of analysis issued at loading.

Moisture Control, Caking Mitigation & Ventilation Strategy

Hygroscopicity Thresholds and Critical Relative Humidity

Urea absorbs moisture from the surrounding air when relative humidity rises above a critical threshold. Once moisture content climbs, the prills or granules begin to soften and stick together, forming lumps that resist normal discharge equipment. Shippers should verify moisture content at the load port using a certificate of analysis and avoid loading cargo that already approaches the upper moisture limit. Critical relative humidity varies with temperature, so cargo care plans must account for the climate zones the vessel will cross during transit.

Caking Mechanisms During Ocean Transit

Caking develops when moisture migrates through the cargo mass and collects at cooler points, typically near the vessel's sides or beneath the hatch covers. Temperature differences between day and night drive condensation, and urea dissolves slightly in that moisture before recrystallizing into bridges between particles. Over a long voyage, these bridges harden into a solid mass that requires mechanical breaking. The risk is highest when warm, moist air meets cold steel surfaces or when the cargo is loaded with uneven moisture distribution.

Ventilation Strategy: Surface vs Through Ventilation

Ventilation decisions depend on the dew point of outside air compared to the cargo temperature. Surface ventilation removes moist air from the top layer of the cargo, while through ventilation pushes air through the entire cargo mass using ducts or natural permeability. For urea, surface ventilation is generally preferred because through ventilation can introduce moist outside air into the hold and worsen caking. Ventilation should be logged in the deck log, and hatches should be closed before rain or spray to prevent direct water contact with the cargo.

Loading and Discharge Operations: Angle of Repose & Equipment

Angle of Repose Impact on Grab and Conveyor Selection

The angle of repose of urea is typically 27 to 30 degrees for prilled grades and 30 to 33 degrees for granular grades. This angle determines the natural slope of the cargo pile and directly dictates the reach required for ship unloaders and the geometry of conveyor transfer points. A lower angle of repose allows grabs to penetrate deeper into the pile with each bite, increasing the fill factor and reducing cycle times. Conveyor belts must be designed with trough angles and belt widths that prevent spillage at the steepest expected slope, typically requiring 35-degree troughing idlers and skirt boards at loading zones. Selecting grabs with a capacity matched to the crane's safe working load and the cargo density ensures the grab closes fully without overloading the wire ropes.

Hold Trimming Procedures for Maximum Stowage

Effective hold trimming transforms the natural cone formed by gravity into a level surface that maximizes cubic utilization and ensures vessel stability. Bulldozers or Bobcats are lowered into the hold to push cargo from the center wings toward the bulkheads and hatch corners, reducing the peak height and filling void spaces. The target is a flat stow with a uniform surface angle not exceeding the cargo's angle of repose, which prevents shifting during transit. Trimming also exposes a larger surface area for any required surface ventilation. Charter parties often specify the number of trimming passes or the final surface tolerance, and the master should confirm the hold is trimmed to the charterer's satisfaction before signing the mate's receipt.

Discharge Rate Benchmarks for Panamax and Handysize Vessels

Discharge rates for urea vary significantly based on terminal equipment and cargo condition. A Panamax vessel carrying 60,000 to 70,000 metric tonnes typically achieves 10,000 to 15,000 tonnes per day using two shore-based continuous ship unloaders (CSU) with 25-cubic-meter grabs. Handysize vessels of 30,000 to 40,000 metric tonnes often discharge at 6,000 to 10,000 tonnes per day using a single CSU or mobile harbor cranes with 12-to-15-cubic-meter grabs. Caked cargo can reduce these rates by 30 to 50 percent because grabs struggle to penetrate the hardened surface, requiring manual breaking or water jets. Laytime calculations in the charter party should reference these realistic benchmarks rather than theoretical crane ratings to avoid disputes.

Packaging Alternatives: Bulk Bags, Containers & Breakbulk Specs

FIBC (Big Bag) Specifications and Safe Working Loads

Flexible Intermediate Bulk Containers (FIBCs) for urea are typically Type A or Type B woven polypropylene bags with a safe working load (SWL) of 500 kg, 600 kg, or 1,000 kg. The 500 kg and 600 kg bags usually measure 90 cm by 90 cm by 110 cm with four lift loops, while 1,000 kg bags measure 100 cm by 100 cm by 120 cm. Bags must comply with ISO 21898 for non-hazardous goods and carry a UN certification mark if transported as dangerous goods under specific regulations. The fabric weight ranges from 160 to 220 grams per square meter with a safety factor of 5:1 or 6:1. Liners made of polyethylene (50 to 75 microns) are essential to prevent moisture ingress and product sifting through the weave. Each bag requires a label showing the manufacturer, SWL, tare weight, and production date for traceability.

20ft Container Loading Plans and Weight Distribution

A standard 20-foot dry container accepts 20 metric tonnes of urea in 20 units of 1,000 kg FIBCs arranged in two rows of ten bags (two bags wide, five bags long, two bags high). This configuration respects the container's payload limit of approximately 28,000 kg and the floor load limit of 4.5 to 5.5 tonnes per square meter. The center of gravity must remain within the central 50 percent of the container length to prevent axle weight violations during road transport. Dunnage bags or timber chocks fill lateral voids between bags and container walls to prevent shifting. For 500 kg bags, a 20-foot container holds 40 units (four bags wide, five long, two high) totaling 20 tonnes. Shippers must verify the container's CSC plate validity and inspect for floor damage before loading.

Breakbulk Bagged Stowage Factor vs Bulk Stowage Factor

Breakbulk bagged urea requires a stowage factor of 1.35 to 1.45 cubic meters per tonne compared to 0.85 to 0.95 cubic meters per tonne for bulk granular urea. The increase stems from void space between bags, pallet dunnage, and necessary ventilation channels. Standard 50 kg bags on 1.0 m by 1.2 m pallets (40 bags per pallet, 2 tonnes) are stacked in a brick-bond pattern with kraft paper or slip sheets between tiers to prevent bag slippage. Dunnage mats protect bags from steel deck plates and hatch coamings. Broken stowage for bagged cargo consumes a share of the gross hold volume. This lower density impacts freight economics because the vessel reaches volumetric capacity before deadweight capacity, reducing revenue per voyage unless a higher freight rate per tonne is negotiated.

Packaging Format	Typical Unit Weight (kg)	Units per 20ft Container	Total Cargo Weight (tonnes)	Stowage Factor (m³/tonne)	Handling Method
FIBC (Big Bag)	1,000	20	20	1.10, 1.20	Container crane / Forklift
FIBC (Big Bag)	500, 600	40	20	1.15, 1.25	Container crane / Forklift
50 kg Bags on Pallets	50 (2,000 per pallet)	10 pallets	20	1.35, 1.45	Shore crane + Pallet hooks
Bulk Granular	N/A (Loose)	N/A	25, 28 (max payload)	0.85, 0.95	Grab / CSU / Conveyor

The table above compares the four primary shipping formats for urea. Bulk granular offers the lowest stowage factor, maximizing vessel deadweight utilization but requiring dedicated bulk terminals. FIBCs in containers provide a compromise, achieving near-bulk weights per container while using standard container infrastructure. Bagged breakbulk demands the most volume per tonne due to pallets and void space, making it suitable only for ports lacking bulk or container handling facilities. The handling method column determines the terminal equipment required and influences the charter party terms for loading and discharge rates.

Urea Bulk Density kg/m³: Loose vs Tapped Measurement Methods

Loose poured density measures the mass per unit volume of urea as it flows freely into a container without mechanical disturbance while tapped density records the mass after standardized vibration compaction. The difference between these values typically ranges from 50 to 80 kg/m³ for prilled grades and 40 to 70 kg/m³ for granular grades depending on particle size distribution and moisture content. Contract specifications must state which method applies because a vessel stowage plan based on loose density will underestimate the volume required if the cargo settles during transit.

ISO 7837 / ASTM D1895 Test Method Procedures

ISO 7837 determines the loose poured bulk density of urea by allowing a sample to flow through a calibrated funnel into a 1000 ml cylinder then striking off the excess level. ASTM D1895 Method A follows a similar principle for free-flowing materials using a 250 ml cup and a specified funnel orifice diameter. For tapped density both standards prescribe a mechanical tapper delivering 300 taps at a rate of 250 taps per minute with a 3 mm nominal drop height. The test report must record the mass after 125 taps and after 300 taps to demonstrate the compaction curve. Laboratories typically run triplicate determinations and report the arithmetic mean to the nearest 1 kg/m³.

Why Tapped Density Matters for Rail and Truck Payloads

Tapped density predicts the settled state of urea after vibration during rail or road transport. A hopper car loaded to its volumetric capacity using loose density figures will exceed axle weight limits once the cargo compacts en route. Shippers calculate the maximum payload by dividing the container or wagon volume by the tapped stowage factor then applying a safety margin of 2 to 3 percent. This approach prevents overweight fines at weighbridges and ensures the declared weight on the bill of lading matches the delivered weight at the destination silo.

Reporting Standards for Certificates of Analysis

Certificates of analysis issued by independent surveyors must reference the exact test standard used and whether the result represents loose or tapped condition. The document should include the particle size distribution the test temperature and the moisture content at the time of testing because each variable shifts the density by 10 to 20 kg/m³. Buyers increasingly require both values on the same certificate to validate stowage factor warranties in the charter party. Digital certificates shared via trade platforms such as Global Trade Plaza allow instant verification of the test method against the contract specification.

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Related reading: Incoterms 2020: DDP vs DAP for Importers.

Conclusion

Urea bulk density values ranging from seven hundred twenty kilograms per cubic meter for prilled grades to seven hundred eighty kilograms per cubic meter for granular grades drive every downstream calculation from stowage factor to vessel deadweight utilization. A stowage factor between one point twenty eight and one point thirty nine cubic meters per tonne allows charterers to optimize hold loading plans while respecting the angle of repose of thirty degrees for prills and thirty two degrees for granular product. Compliance with the International Maritime Solid Bulk Cargoes Code Group C requirements ensures safe carriage through moisture control ventilation management and hold preparation standards that prevent contamination. Temperature monitoring at fifteen minute intervals with alarms at forty and fifty degrees Celsius protects cargo quality and provides the evidentiary chain needed for clean outturn certificates. Logistics planners who integrate these specifications into charter party density warranties and laytime clauses reduce commercial disputes and protect margins across the supply chain. For verified suppliers and buyers managing these specifications Global Trade Plaza offers a B2B marketplace to connect qualified counterparties and streamline trade execution.

Frequently Asked Questions

What is the bulk density of urea?

Urea bulk density ranges from 700 to 900 kg/m³ depending on particle form and compaction state. Prilled urea measures 700 to 750 kg/m³ loose and 800 to 850 kg/m³ tapped. Granular urea measures 750 to 800 kg/m³ loose and 850 to 900 kg/m³ tapped.

What is the stowage factor of urea in m3/mt?

The stowage factor for urea ranges from 1.11 to 1.43 m³/mt based on bulk density variations. Loose prilled urea at 750 kg/m³ yields 1.33 m³/mt while loose granular urea at 800 kg/m³ yields 1.25 m³/mt. The IMSBC Code cites a broader range of 1.17 to 1.56 m³/mt covering all forms according to The Swedish Club.

What is the bulk density of prilled urea vs granular urea?

Prilled urea has a loose bulk density of 700 to 750 kg/m³ and tapped density of 800 to 850 kg/m³. Granular urea is denser at 750 to 800 kg/m³ loose and 850 to 900 kg/m³ tapped. Granular product offers better hold utilization due to larger interlocking particles.

What is the angle of repose of urea?

Prilled urea has an angle of repose of 28 to 32 degrees while granular urea ranges from 30 to 35 degrees. The higher angle for granular product reflects superior stacking stability and reduced cargo shift risk. These values determine hold trimming requirements and flow behavior during discharge.

Is urea classified under IMSBC code?

Yes, urea is listed in the IMSBC Code as a Group C cargo. This classification means it is not liable to liquefy and presents no major chemical hazards for bulk carriage. Shippers must still provide a cargo declaration and follow general safe carriage practices including ventilation and moisture control.

What is the UN number for urea fertilizer?

Urea fertilizer does not have a UN number because it is not classified as dangerous goods for transport. It falls under IMSBC Group C as a non-hazardous bulk solid. Only specific urea-based mixtures with hazardous additives would require UN classification.

Does urea cake during shipping?

Urea can cake during shipping if moisture content exceeds one percent or if cargo sweat occurs during temperature changes. Prilled urea has higher caking sensitivity than granular due to smaller particle size and greater surface area. Proper ventilation and dry loading conditions minimize this risk.

How to prevent urea contamination in bulk carriers?

Prevent contamination by ensuring holds are swept clean, dry, and free of residues from previous cargoes like ammonium nitrate, phosphates, salt, or coal. Food-grade urea requires fresh water washing and rust scale removal. Verify cleanliness with a surveyor certificate and record previous three cargoes in the mate's receipt.

What is the bulk density of powder urea?

Powder urea is not a standard commercial bulk form; prilled and granular are the traded grades. If powdered urea exists as fines, its loose bulk density would fall below 700 kg/m³ due to high void space and extreme compaction sensitivity. Bulk shipments use prilled or granular specifications exclusively.

What is dry bulk density of urea fertilizer?

Dry bulk density for urea fertilizer refers to the loose poured state: 700 to 750 kg/m³ for prilled and 750 to 800 kg/m³ for granular. These values assume moisture content below one percent. Higher moisture increases density slightly but promotes caking and handling issues.

Urea bulk density kg/m3 loose vs tapped

Loose bulk density is 700 to 750 kg/m³ for prilled and 750 to 800 kg/m³ for granular urea. Tapped density increases to 800 to 850 kg/m³ for prilled and 850 to 900 kg/m³ for granular after settlement. The 10 to 15 percent compaction for prills affects deadweight calculations on long voyages.

Urea shipping specifications bulk vessel

Key specifications include stowage factor 1.25 to 1.35 m³/mt, moisture below one percent, angle of repose 28 to 35 degrees, and IMSBC Group C compliance. Charter parties require density warranty clauses with ISO 7837 test method, ±0.05 m³/mt tolerance, and independent surveyor verification at load port.

Sources

• The Swedish Club (current IMSBC Code, per Swedish Club guidance): Urea bulk cargo stowage factor (IMSBC Code)
• Mysteel (2025): China urea exports
• The Swedish Club (2024): Pure urea nitrogen content