Bitumen is a dense cargo packed in units that cannot be stacked high. The container it travels in is chosen by geometry and by destination road law, not by how much space is available.
A general purpose 20-foot container built to ISO 668 has internal dimensions of roughly 5.90 m long, 2.35 m wide and 2.39 m high — about 33 m³ of space — a tare of 2,200 to 2,300 kg and a maximum gross mass of 30,480 kg. That leaves a payload in the region of 28,200 kg. A full load of bitumen in drums weighs 12 to 15 tonnes. A full load in one-tonne bags weighs about 20 tonnes. In neither case does the box come close to its weight limit, and the reason is not caution on the shipper's part. It is the stack.
A steel bitumen drum of nominal 200 to 210 litres, dimensioned to the ISO 15750 series, is about 570 to 585 mm in diameter and 860 to 890 mm tall. Laid out on the floor of a 20-foot container, ten drums fit along the length and four across the width: forty drums per tier. Bitumen drums are stacked two tiers and no more, because the product inside softens in transit and a third tier will deform the drums beneath it. Ten by four by two is 80 drums, and that single number sits behind every loading figure quoted on this site:
The same arithmetic holds when drums are palletised, which is the more common arrangement for export. Four drums stand on a square pallet of roughly 1.1 m, ten pallets cover the floor and ten more go on top: twenty pallets, eighty drums. Palletising costs a little more, spreads the load onto the container's floor cross-members instead of into the plywood between them, and makes forklift discharge possible at a destination with no drum-handling equipment.
One-tonne jumbo and poly bags follow the same logic. Ten bags cover the floor, ten sit on top, and the load is 20 bags, 20 MT per 20-foot container. A bitutainer or tank container is a different proposition altogether: one unit carrying 20 to 25 MT, which only suits a buyer with heating and discharge capability at the receiving end.
A 40-foot general purpose container has double the floor area and double the cube of a 20-foot unit, but under ISO 668 it carries the same 30,480 kg maximum gross mass and a heavier tare of about 3,700 to 3,900 kg. Its payload is therefore lower than a 20-foot's: roughly 26,700 kg against 28,200 kg. Run the drum arithmetic and the problem is immediate.
The consequence is that a 40-foot container of bitumen can never be packed out. You load to a weight limit and stop, leaving metres of empty length that then has to be blocked, braced and dunnaged so the cargo cannot run to the door end in a seaway. Unfilled void is the most common single cause of shifted loads and burst drums in this trade. A 20-foot box packed tight from front wall to doors restrains itself.
The secondary reasons point the same way. A part-loaded 40-foot is harder to keep within the centre-of-gravity tolerance, because the cargo occupies only a section of the length. Many destination depots, side-loaders and inland yards handle 20-foot units only. And a part-loaded 40-foot pays a full 40-foot freight, so the cost per tonne of cargo rarely improves enough to justify the securing risk. 40-foot high cube containers are worse again: the extra height is pure volume, and volume is the one thing a bitumen load never runs short of.
The container's plated maximum gross mass is an absolute ceiling, but it is seldom the binding constraint. Road law at destination usually bites first, because the box has to be trucked off the terminal.
Deal with this at the order stage, not at the port gate. Ask the buyer for the maximum gross mass per container their haulier can legally move, and select the drum fill weight to suit. This is a large part of why 150 kg drums at 12 MT per container remain popular in markets where 180 kg drums would otherwise be the cheaper packing per tonne.
Series 1 freight container data to ISO 668, with the practical verdict for a cargo that reaches its weight or stack limit long before it fills the space.
| Container type | Internal volume | Typical tare | Max gross mass | Payload available | Verdict for bitumen |
|---|---|---|---|---|---|
| 20' general purpose (ISO 1CC) | ≈ 33 m³ | 2,200–2,300 kg | 30,480 kg | ≈ 28,200 kg | The standard unit. 80 drums or 20 bags, packed tight, effectively self-restraining |
| 40' general purpose (ISO 1AA) | ≈ 67 m³ | 3,700–3,900 kg | 30,480 kg | ≈ 26,700 kg | Lower payload than a 20-foot. Cannot be filled with drums without exceeding it |
| 40' high cube (ISO 1AAA) | ≈ 76 m³ | 3,900–4,100 kg | 30,480 kg | ≈ 26,500 kg | Extra height is unusable on a load limited by weight and stack height |
| 20' tank container / bitutainer | Shell typically 24–26 m³ | Varies by build; insulated and coil-heated units are heavy | 30,480 kg | 20–25 MT of product | Bulk delivery in a container slot. Needs heating and discharge capability at destination |
| Open top and flat rack | n/a | n/a | Per plate | Per plate | Not used. Bitumen packings need a weathertight, closed box |
Net cargo is what the buyer pays for. Cargo gross adds the packing, and the indicative verified gross mass adds the container itself. All three appear on different documents and all three must agree with each other.
| Packing | Net per unit | Units per 20' FCL | Net cargo per FCL | Cargo gross incl. packing | Indicative VGM |
|---|---|---|---|---|---|
| New steel drum | 150 kg | 80 drums | 12.0 MT | ≈ 13,600 kg | ≈ 15,850 kg |
| New steel drum | 180 kg | 80 drums | 14.4 MT | ≈ 16,000 kg | ≈ 18,250 kg |
| New steel drum | 185 kg | 80 drums | 14.8 MT | ≈ 16,400 kg | ≈ 18,650 kg |
| Jumbo bag / bitubag | 1 MT | 20 bags | 20.0 MT | ≈ 20,100–20,600 kg | ≈ 22,350–22,850 kg |
| Poly / sealo bag | 1 MT | 20 bags | 20.0 MT | ≈ 20,100–20,600 kg | ≈ 22,350–22,850 kg |
| Bitutainer / tank container | 20–25 MT | 1 unit | 20–25 MT | Product in a tank, no packing | Close to the plated maximum — check the plate |
Between the load port and the discharge port nobody looks inside the box. Everything that will go wrong is decided in the half hour it takes to stuff it, and by the route it then takes.
A container is a beam supported at its four corner castings, and it is designed to be filled evenly. The reference document is the IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units, known as the CTU Code, and its central instruction is that cargo should be spread across the whole floor so that the combined centre of gravity sits close to the middle of the unit in both length and width. As a working tolerance, keep the longitudinal centre of gravity within roughly a tenth of the container length either side of the mid-point, and keep the transverse centre of gravity on the centreline.
Two separate things go wrong when it is not. A container with its weight bunched at one end loads its frame and corner castings unevenly during a lift. And once it is on a chassis, an off-centre load produces an illegal axle weight at destination even when the total gross mass is perfectly legal. The party who discovers this is the buyer's haulier, at the port gate, with demurrage running.
Concentrated load matters as much as total load. Container floors are proof-tested under ISO 1496-1 using a two-wheeled test device that imposes an axle load of 5,460 kg — 2,730 kg per wheel, each wheel bearing on a contact area of 142 cm² — so the floor is built to take forklift traffic — but a proof test is not a licence to point-load it. Palletising drums, or laying timber bearers under a floor-loaded tier, transfers weight onto the cross-members rather than into the plywood spanning between them.
Timber used for pallets, bearers, blocking and bracing is wood packaging material and falls under ISPM 15. It has to be heat treated or fumigated and to carry the IPPC mark. Australia, New Zealand, China and the United States enforce this strictly, and non-compliant dunnage gets the entire container fumigated, held, re-exported or destroyed at the shipper's cost. It is a trivial detail that stops shipments.
A closed steel container stowed on deck under tropical sun is an oven. Internal air temperatures well above 50 °C are routinely reported, and the air in the top of the box in direct sun runs higher still. Set that against the material inside. Softening point, measured by the ring and ball method to ASTM D36 or EN 1427, is the temperature at which a binder loses load-bearing stiffness:
A softer paving grade routed through the Red Sea, the Gulf, the Indian Ocean or the Malacca Strait in summer can spend days at or above its own softening point. Nothing is chemically wrong with the binder afterwards and the Certificate of Analysis still holds — but the cargo has moved, and how badly depends entirely on what it is packed in.
Steel drums keep their shape whatever the contents do, so heat shows up at the closures and in the stack. Bitumen expands as it warms at roughly 0.00061 of its volume per °C, so product loaded at 30 °C and carried at 65 °C occupies about 2 % more space. A drum filled to the brim has nowhere to put that, and the pressure goes into the lid seal or the seam. Drums must be filled with ullage — headroom deliberately left at the top — for exactly this reason. Where product does weep, drums bond to each other and to the container floor, markings become unreadable, and the lower tier deforms under the softened weight of the upper one.
Bags behave completely differently, because a jumbo or poly bag has no structure of its own. It is a fabric skin around a one-tonne block of bitumen, and the block is the structure. Once the core passes its softening point the block slumps, the bag takes the shape of whatever it is resting against, adjacent bags fuse into one another, and the lifting loops finish up buried or bearing on material that no longer supports them. A container of bags that has been heat-cycled across the tropics can discharge as a single 20-tonne mass rather than twenty separately liftable units. This is the most important practical difference between the two packings, and on a hot route it should decide the choice.
What can actually be done about it:
Bitumen shipped in drums and bags arrives cold and is not a burn hazard in that state. The risk appears at melt-out and transfer at the receiving plant. If hot bitumen contacts skin at any stage, cool the area with clean cold running water for at least 20 minutes. Do not peel adhered bitumen off the skin and do not attempt to strip it with solvent; removal is a clinical decision for medical staff. Keep the Safety Data Sheet with the discharge team rather than in the document file.
This is the most consequential and most common error in containerised bitumen trade. The maritime Incoterms rules were written for cargo the seller can physically place on board a ship, and a container is not that cargo.
The International Chamber of Commerce divides the eleven Incoterms 2020 rules into two families by mode of transport. Seven of them — EXW, FCA, CPT, CIP, DAP, DPU and DDP — carry no mode restriction at all and work for road, rail, air, sea or any combination of those. The remaining four — FAS, FOB, CFR and CIF — are restricted to sea and inland waterway transport, and the restriction is not decorative. Those four were drafted for a seller who physically places goods alongside or on board a named vessel: bulk parcels, break-bulk and conventional cargo. A sealed box handed to a terminal is not that transaction.
Under FOB the seller delivers, and risk passes, when the goods are on board the vessel at the named port of shipment. Under CFR and CIF the delivery point is identical; the difference is only that the seller additionally contracts and pays for carriage, and under CIF for insurance. In all three, the moment risk changes hands is the moment the cargo crosses onto the ship.
A container of bitumen never goes to the ship's side under the seller's control. It is stuffed at a drum plant or a packing yard, trucked to a container terminal, gated in, stacked in a yard, and loaded to the vessel by the terminal on the carrier's schedule. From the moment it passes the terminal gate the seller has no access to it, no ability to inspect it, no influence over how it is stacked and no say in when it is lifted. Gate-in to loading is routinely several days, and longer where the vessel rolls.
Write FOB across that shipment and you have opened a gap. Risk stays with the seller through a period of custody the seller cannot supervise, inside a facility the seller cannot enter, under a carriage contract the buyer arranged. If the box is dropped, crushed in a stack collapse, flooded in a yard or simply mislaid between gate-in and loading, the loss falls on the seller even though the buyer's carrier held it throughout. Worse, both parties' cargo policies are usually written to a delivery point that no longer matches the facts, which is how a claim ends up with neither insurer accepting it.
CPT and CIP deliberately separate the point at which risk passes from the point to which the seller pays. That is the design of the rules, not a defect in them, but it has to be understood. A buyer who reads "CIP Mumbai" as "the seller carries the risk to Mumbai" has misread it — risk passed at the container terminal in the country of origin. Name both points precisely in the contract, the place of delivery and the place of destination, and the ambiguity disappears.
The reason exporters keep putting FOB on containers is documentary, not legal. A letter of credit will normally call for a bill of lading bearing an on-board notation, and since FCA delivery is complete before the box ever reaches the ship, the document that falls out of it naturally is a received-for-shipment bill. Incoterms 2020 supplies the remedy in the FCA A6/B6 delivery-document provisions: where the parties have agreed it, the buyer must instruct its carrier — at the buyer's cost and risk — to issue a transport document stating the goods have been loaded on board, and must then pass that document to the seller for tender under the credit.
Two conditions attach, and both are missed regularly. The mechanism operates only if it has been written into the sale contract, and the credit has to be opened in terms that will accept the document the mechanism produces. Get one and not the other and the seller has traded a risk gap for a documentary discrepancy. Get both, and no documentary argument for running a container on a maritime rule survives.
They allocate delivery, risk, cost and obligations between seller and buyer. They do not transfer title, they do not set payment terms, they do not govern breach, sanctions or force majeure, and they are not a contract of carriage or of insurance. Always cite the edition — "FCA Jebel Ali container terminal, Incoterms 2020" — because the rules change between editions, and the CIP insurance level is a live example of why the edition matters.
The three rules that fit containerised cargo, the four maritime rules that do not, and what each one actually does with risk, cost and insurance.
| Rule | Mode | Delivery and risk transfer point | Carriage paid by | Insurance obligation | Right rule for a container? |
|---|---|---|---|---|---|
| FCA — Free Carrier | Any mode or modes | On handover to the carrier at the named place | Buyer | Neither party obliged | Yes — the container replacement for FOB |
| CPT — Carriage Paid To | Any mode or modes | On handover to the first carrier | Seller, to named destination | Neither party obliged | Yes — the container replacement for CFR |
| CIP — Carriage and Insurance Paid To | Any mode or modes | On handover to the first carrier | Seller, to named destination | Seller, Institute Cargo Clauses (A) | Yes — the container replacement for CIF |
| FOB — Free On Board | Sea and inland waterway | When the goods are on board the vessel | Buyer | Neither party obliged | No — seller holds risk through terminal custody it cannot control |
| CFR — Cost and Freight | Sea and inland waterway | When the goods are on board the vessel | Seller, to named destination port | Neither party obliged | No — same delivery-point mismatch as FOB |
| CIF — Cost, Insurance and Freight | Sea and inland waterway | When the goods are on board the vessel | Seller, to named destination port | Seller, Institute Cargo Clauses (C) minimum | No — same mismatch, and minimum cover only |
| FAS — Free Alongside Ship | Sea and inland waterway | Alongside the vessel at the port of shipment | Buyer | Neither party obliged | No — a container is never placed alongside by the seller |
| DAP, DPU and DDP | Any mode or modes | At the named destination place or terminal | Seller | Neither party obliged | Workable, but the seller carries risk all the way to destination |
A container shipment carries the ordinary export document set plus three things a bulk cargo does not have: container and seal identity, a verified gross mass, and a wood packaging declaration.
| Document | What it must show for a container shipment | Why it matters |
|---|---|---|
| Commercial invoice | Grade, HS code 2713.20, quantity net of packing, unit price, and the Incoterms rule with a named place and the edition | The customs value and the letter of credit match point. A missing Incoterms edition is a routine discrepancy |
| Packing list | Container numbers, seal numbers, units per container, and net, tare and gross weight per container | The only document tying a specific drum or bag count to a specific box. Shortage claims are settled from it |
| Bill of lading | Container and seal numbers, marks, whether it is 'received for shipment' or 'shipped on board' with the date, and the shipper's load, stow and count clause | Under FCA the natural document is a received-for-shipment bill unless the on-board mechanism has been agreed in the contract and the credit |
| Verified gross mass declaration | The verified gross mass of the packed container, the method used, and the signature of the shipper named on the bill of lading | Required by SOLAS Chapter VI Regulation 2 since 1 July 2016. A container without a VGM must not be loaded to the vessel |
| Certificate of Analysis | Batch-specific measured values against the contract specification, with the test method beside each line | The quality evidence. Specification ranges copied across are not a Certificate of Analysis |
| Technical Data Sheet | Product specification, working temperatures and storage guidance | Requested by consulting engineers and by destination approval authorities |
| Safety Data Sheet | GHS-format sheet including flash point, handling temperature, personal protection and first aid | Asked for by terminals, hauliers and a growing number of destination customs authorities |
| Certificate of Origin | Origin of the goods, certified by a chamber of commerce | Duty treatment and preferential tariff claims at destination |
| Third-party inspection certificate | Quality, quantity, packing condition, container condition and sealing at the point of loading | Independent evidence from a report neither buyer nor seller wrote |
| Dangerous goods declaration and container packing certificate | Applies to cutback grades (UN 1999, tars liquid, Class 3) and to product carried hot in tank containers (UN 3257, elevated temperature liquid, Class 9) | Penetration-grade bitumen in drums or bags at ambient temperature is normally not regulated for sea carriage — cutbacks and hot tanks are |
| ISPM 15 evidence for wood packaging | The IPPC mark on every pallet, bearer and piece of blocking and bracing timber | Untreated dunnage triggers fumigation, detention, re-export or destruction at destination, at the shipper's cost |
| Insurance certificate, under CIP or CIF | Cover level, insured value and the claims agent at destination | Under CIP the required level is Institute Cargo Clauses (A); under CIF it is only Clauses (C) |
The container belongs to the carrier, but from the moment cargo goes into it the shipper owns every defect it has. Ten minutes at the empty stage prevents the claims that surface three weeks later at discharge.
Every container in international traffic carries a CSC plate under the International Convention for Safe Containers. Check it is present and legible and that the next examination date, or the ACEP marking that replaces it, has not expired. Read the maximum gross mass and the tare from the plate — those are the figures the verified gross mass calculation must use, never a published table value.
Inspect front wall, left side, right side, floor, ceiling and roof, the inside and outside of the doors, and the undercarriage. You are looking for repairs and patches, distorted corner posts, delaminated or springy plywood, and any sign the unit has been in a collision or a stack collapse.
Close the doors from the inside and look for daylight through seams, roof panels and door gaskets. A pinhole is a rain leak, and a rain leak turns a container of new steel drums into a container of rusting drums with unreadable markings. This is the highest-value minute of the entire inspection.
Reject a box that is wet, that smells of a previous cargo, or that has residue, oil or flaking paint on the floor. Remove or blank out old placards and labels. Run a hand along the side panels for protruding nails and screw heads, which puncture jumbo bags and tear bag liners.
Work the locking bars, cams, keepers and hinges through their full travel and check the gasket is continuous and not perished. The door end is where water gets in and where the load presses hardest, and a container that will not close cleanly in the yard will not close cleanly at the terminal.
Decide whether the verified gross mass will be established by weighing the packed container on a calibrated weighbridge, or by summing cargo, packing, dunnage and container tare under a certified procedure. The second method requires drum, pallet and dunnage weights to be recorded as loading proceeds, so it cannot be reconstructed afterwards.
Empty container with the number visible, the first tier laid out, each completed tier, the dunnage and lashing at the door end, and the closed doors with the seal number readable. Photographs cost nothing and settle most cargo disputes before anyone appoints a surveyor.
Fit a high-security bolt seal to ISO 17712 on the right-hand door locking bar, and record the number identically on the packing list, the inspection report and the bill of lading. A seal number that appears two different ways on two documents is treated at destination as evidence of interference, not as a typing error.
Eighty drums go into the box, and the fill weight decides the tonnage: 150 kg net per drum gives 12 MT, 180 kg gives 14.4 MT and 185 kg gives 14.8 MT. Packed instead as one-tonne jumbo or poly bags, the same box takes 20 bags for 20 MT, and a bitutainer or tank container carries 20 to 25 MT in the same slot. Notice that none of those figures approaches the 30,480 kg plate limit. What sets the fill is the two-tier stack limit and, more often, the weight the buyer's haulier may legally move on the road out of the port.
Because it carries less. A 40-foot general purpose container has the same 30,480 kg maximum gross mass under ISO 668 as a 20-foot but a heavier tare, so its payload is roughly 26,700 kg against 28,200 kg. A full floor plan of 160 drums weighs about 27,200 kg even at the lightest common fill, so the box can never be packed out. You are left with several metres of void to block and brace, on a unit that costs a full 40-foot freight.
FCA. Under FOB, risk stays with the seller until the container is on board the vessel, which is typically several days after the seller lost all access to it at the terminal gate. FCA passes risk at the actual handover to the carrier, which is where physical control genuinely changes hands. The same logic replaces CFR with CPT and CIF with CIP.
Yes, provided the contract is drafted for it. The FCA A6/B6 provisions in Incoterms 2020 let the parties agree that the buyer will direct its carrier, at the buyer's cost and risk, to issue a bill of lading carrying an on-board notation, which the buyer then hands to the seller to present under the credit. None of this happens by default. If the sale contract is silent on the point, or the credit is worded so that only a document the seller has no way of obtaining will be accepted, the seller ends up tendering a received-for-shipment bill against a credit that demands an on-board one.
It does not become liquid, but it can and does pass its softening point. Bitumen 60/70 softens at about 49 to 56 °C by the ring and ball method, and internal air temperatures in a closed container stowed on deck under tropical sun are routinely reported well above 50 °C. The binder itself is unchanged and still meets specification. What changes is the cargo's shape: bags slump and fuse together, and drums weep at the closures and deform in the lower tier.
Drums. A steel drum keeps its geometry regardless of what the contents do, so the risks are limited to closure weep, stack deformation and bonding. A jumbo or poly bag has no structure of its own — the block of bitumen inside it is the structure — so once the core softens the bag takes the shape of its surroundings and adjacent bags fuse. A heat-cycled container of bags can discharge as one mass rather than twenty liftable units.
Penetration-grade bitumen shipped cold in drums or bags is normally not regulated for sea carriage. Two related products are: cutback grades fall under UN 1999, tars liquid, Class 3, because of the solvent, and product carried hot in a tank container at or above 100 °C falls under UN 3257, elevated temperature liquid, Class 9. Confirm the classification with the carrier and against the Safety Data Sheet before booking.
Verified gross mass, required by SOLAS Chapter VI Regulation 2 since 1 July 2016. It is the mass of the cargo plus all packing, dunnage and the container tare, established either by weighing the packed container or by summing the parts under a certified procedure, and it must be declared and signed by the shipper named on the bill of lading. A container without a VGM must not be loaded to the vessel.
Send the grade, packing, tonnage, destination port and the Incoterms rule you want quoted, together with any maximum gross mass per container your haulier is limited to. The loading plan, container count and document set will be set out in the offer before anything is booked.