Barytes: IMSBC Code Schedule and Carriage

Barytes (barite, the mineral form of barium sulphate, BaSO4) is one of the densest commodities carried in bulk, and the IMSBC Code assigns it a stowage factor of 0.34 cubic metres per tonne against a bulk density of 2,941 kilograms per cubic metre. That single pair of numbers governs almost everything that matters about loading it: the cargo will fill perhaps a third of a hold by volume and still bring the ship to its marks, so the operational problem is never finding room, it is keeping tank-top pressure and trim within limits. The cargo sits in Group C of the IMSBC Code, the residual class for materials that neither liquefy nor present a chemical hazard, and its schedule carries the plain entry “This cargo is non-combustible or has a low fire risk.” The one live precaution is dust. To classify a parcel against the live schedule and pull the declared parameters, use the IMSBC cargo finder and the dedicated barytes (BaSO4) calculator.

The trade exists because of a single industrial fact: a drilling fluid needs weight, and barite is the cheapest dense, inert, soft mineral available to supply it. The U.S. Geological Survey reports that more than 90% of barite sold in the United States goes into drilling fluids for oil and gas wells, where the weighted mud counters formation pressure and prevents a blowout. World barite mine production reached an estimated 8,500 thousand tons in 2023 per the USGS, and the seaborne share moves on Handysize and Supramax bulk carriers from a small number of exporting countries to drilling regions worldwide. The tonnage tracks the global rig count closely, which is why barite freight demand rises and falls with the oil price cycle rather than with general dry-bulk trends.

What barytes is and why it is shipped

Barite is barium sulphate, BaSO4, a sulphate of barium that crystallizes in the orthorhombic system. Its defining property is density. Pure barite has a specific gravity near 4.5, and even after milling and the inevitable inclusion of gangue minerals, drilling-grade ground barite is held to a high minimum density by specification. The American Petroleum Institute set the long-standing drilling-mud weighting standard at 4.2 specific gravity, and in 2010, responding to concern over dwindling reserves of 4.2 material, the API issued an alternate specification for 4.1-specific-gravity weighting agents. That regulatory shift matters to the shipper because it widened the pool of acceptable ore grades, but it does not change the marine handling problem: whether 4.1 or 4.2, the milled cargo is far denser than the iron ore and concentrate cargoes that already test a bulk carrier’s tank-top scantlings.

The mineral is soft, with a Mohs hardness near 3, and chemically inert. Barium sulphate is so insoluble and non-reactive that ultrapure grades are swallowed as the contrast medium in X-ray and CT examinations of the gastrointestinal tract. That same inertness is what makes the cargo a Group C entry rather than a Group B chemical hazard: it does not self-heat, does not emit gas, does not react with water, and does not support combustion. The IMSBC schedule field for hazard reads “This cargo is non-combustible or has a low fire risk,” and the subsidiary hazard, MHB, IMDG class, and UN number fields are all marked not applicable.

The drilling-mud weighting role

A drilling fluid does several jobs at once: it carries rock cuttings up the annulus, cools and lubricates the bit, seals the borehole wall with a filter cake, and, above all, exerts a hydrostatic column pressure that holds back the fluids in the formation being drilled. That last job is what weighting agent supplies. Barite raises the mud density from the roughly 1.0 of plain water-based mud toward 2.0 or higher specific gravity, and the column of weighted mud in the wellbore is the primary barrier against a kick or blowout. The USGS notes that barite is a component of almost all drilling fluids and can make up more than 40% by weight of a heavyweight oil-based mud. Because there is no cheap substitute at scale, barite demand for this use is close to inelastic against price; the USGS lists calcium carbonate, hematite, ilmenite, and manganese tetroxide as the only common alternatives, each used in specific circumstances rather than as a general replacement.

Drilling-grade barite is milled fine, but the cargo that moves in bulk is frequently the crushed, not-yet-ground ore. The IMSBC barytes schedule describes a coarse size distribution: roughly 80% lumps from 6.4 to 101.6 millimetres and 20% fines below 6.4 millimetres. That coarse fraction is important to the marine engineer for two reasons. It means most barytes parcels drain freely and do not approach a liquefaction condition, which is why the cargo sits in Group C and not Group A. It also means the fines fraction is the source of the dust that drives the one precaution the schedule does carry.

The reason barite is milled rather than shipped as run-of-mine fines is the same density that defines the cargo. A weighting agent that settles out of the mud is useless, so the ground product is sized to stay suspended in the circulating fluid. Even so, the very density of barite drives a known drilling problem the industry calls barite sag, the gravity-driven settling of the weighting solids in a deviated or horizontal well, which lightens the mud column at the top and risks a kick from below. The marine carriage condition does not reproduce sag, since the cargo travels dry and packed, but it explains why the receiver mills the ore to a controlled fineness and why the parcel that reaches a drilling region is often the coarse ore destined for a shore mill rather than the finished product. The API specification that the milled barite must meet, the 4.2 or 4.1 specific-gravity grade, is set against this settling behavior, not against any marine requirement.

Other end uses

The non-drilling fraction of barite consumption is small but varied, and it explains why some parcels move to chemical and industrial receivers rather than to oilfield service terminals. The USGS lists barite as a filler, extender, or weighting agent in paints, plastics, and rubber, including automobile brake and clutch pads and paint primer. Because barium blocks X-ray and gamma-ray emissions, ground barite is used as aggregate in high-density radiation-shielding concrete around X-ray units, nuclear power plants, and research facilities. A separate chemical route converts barite into barium carbonate, barium chloride, precipitated barium sulfate (blanc fixe), and other barium compounds. These end uses absorb a modest share of tonnage but a receiver expecting chemical-grade or filler-grade material will hold the parcel to whiteness and purity specifications that have no bearing on the marine carriage condition, which remains Group C regardless of grade.

The IMSBC schedule and its fields

The IMSBC Code is the IMO’s mandatory instrument for solid bulk cargoes, adopted as Resolution MSC.268(85) and in force under SOLAS Chapter VI since 1 January 2011. Every named cargo has an individual schedule in Appendix 1, a standardized data sheet that the master, chief officer, and cargo surveyor read before loading. The barytes schedule is short because the cargo is benign, but every field carries operational weight. The data below is the live schedule entry consolidated from the IMSBC Code, current under the 07-23 amendment adopted by Resolution MSC.539(107) and mandatory from 1 January 2025.

The Group C designation is the headline. It tells the master that no transportable moisture limit (TML) test is required, no certificate of moisture content and flow moisture point need be presented, and no hold atmosphere monitoring for flammable or toxic gas applies. That is the practical difference between this schedule and the ones for iron ore concentrate, copper concentrate, or coal, which carry Group A or Group B obligations. The barytes shipper still owes a full cargo declaration under SOLAS VI/2, and that declaration must now state the cargo’s bulk density, an obligation tightened across the Code under SOLAS regulation XII/10 so that the loading terminal and the ship can plan tank-top loading correctly.

Bulk density and stowage factor as a pair

The schedule’s 2,941 kg/m³ bulk density and 0.34 m³/t stowage factor are reciprocals of one another and describe the same physical quantity from two directions. Bulk density is mass per unit of stowed volume, including the void space between lumps. Stowage factor is the inverse: the volume one tonne occupies in the hold. The two are tied by the single relation

where $SF$ is the stowage factor in m³/t and $\rho_b$ is the bulk density in kg/m³, so dividing 1,000 by the schedule’s 2,941 kg/m³ returns 0.34 m³/t to two decimals, confirming the two fields are the same number stated twice. Read together they tell the loading officer that one cubic metre of stowed barytes weighs nearly three tonnes, so a 50,000-tonne parcel needs only about 17,000 cubic metres of hold space. A Supramax with around 60,000 cubic metres of grain capacity carries a full barytes deadweight in roughly a third of its volume. The cargo therefore stows as a low, dense block on the tank top with large empty volume above it, the opposite of a volume-limited cargo like grain or wood pellets. That arithmetic is the basis of the barytes density and stowage calculator.

Angle of repose marked “not applicable”

The schedule records the angle of repose as not applicable. Angle of repose, the steepest slope at which a heap of loose material rests without sliding, is the parameter the Code uses to set the maximum surface slope in a partially filled hold and to flag shift-prone cargoes. For barytes the field is dispensed with because the cargo’s coarse lump fraction and high density make a free-flowing slump irrelevant to the carriage risk; the cargo is trimmed for structural reasons, not to control an unstable angle. Where a quantitative angle is needed for a related coarse mineral cargo, the IMSBC angle of repose calculator handles the surface-slope computation. The practical consequence for barytes is that trimming is governed by Code sections 4 and 5 and by tank-top loading limits, not by an angle-of-repose threshold.

High density, stability, and structural loading

The defining engineering problem of a barytes cargo is its weight concentration, not its chemistry. A bulk density of 2,941 kg/m³ is higher than typical iron ore lump and roughly double that of coal, and it sits at the dense end of everything a general bulk carrier loads. The cargo will bring the ship down to its load line while occupying a shallow layer on the tank top, and that layer transmits a high pressure to the double-bottom structure directly beneath it.

Tank-top loading limit and weight distribution

Every cargo hold has a maximum permissible tank-top load, expressed in tonnes per square metre, fixed by the strength of the inner-bottom plating, the double-bottom girders, and the floor spacing. For a typical Supramax that limit falls in the region of 15 to 25 tonnes per square metre depending on the design, and it is published in the ship’s loading manual. A dense cargo loaded into a tall pile can exceed that limit locally even when the total hold weight is well within the ship’s deadweight. With barytes the temptation is exactly that: because the cargo finishes loading with the hold only partly full by volume, an unwary loading sequence can build a high central cone that overstresses the inner bottom beneath it. The defense is to spread the cargo across the full tank-top area and keep the layer as even as the loading gear allows. The bulk carrier loading manual states the per-hold limit, and the chief officer checks the planned stow against it before the terminal commits to a pour sequence.

A worked sense of the magnitude helps. A flat, evenly spread barytes layer one metre deep imposes about 2.9 tonnes per square metre of static load, so the tank-top limit is not reached until the layer is several metres deep, which on most ships corresponds to the full intended parcel spread evenly. Put a number on the failure mode and the contrast is sharp. Take a hold with a usable cargo volume of 6,200 cubic metres and a tank top about 1,100 square metres in plan: a full even layer of 18,200 tonnes sits roughly 5.6 metres deep and presses on the inner bottom at about 16 tonnes per square metre, inside a typical 18 tonnes-per-square-metre limit. Pile that same tonnage into a central cone over 600 square metres and the local depth climbs past 10 metres and the peak load to roughly 30 tonnes per square metre, well over the limit and over plating never designed to carry it. The risk is never the average; it is the local peak under a cone. This is why the barytes schedule’s loading guidance, brief as it is, points back to the general trimming provisions in Code sections 4 and 5 rather than treating the cargo as exempt.

Stability: a stiff ship, not a tender one

Dense cargo loaded low in the holds places the cargo’s center of gravity well below the ship’s vertical center of gravity, which raises the metacentric height GM and makes the ship stiff. A barytes-laden bulk carrier is the opposite of a tender ship: it has a large positive GM and a short, sharp roll period. That is safe in the capsize sense but punishing in a seaway, because a stiff ship returns to the upright with high angular acceleration and subjects the hull, the cargo, and the crew to violent rolling. The loading officer accepts the stiff condition as inherent to a heavy low cargo and plans the voyage, including weather routing and speed in beam seas, around the short roll period rather than trying to soften it by lifting the cargo, which the tank-top limit forbids anyway.

Because barytes does not liquefy, the free-surface effect that destroys the stability of a Group A cargo does not arise here. There is no fluidized cargo mass and no slumping free surface to erode GM during the voyage. The stability condition computed at departure holds for the passage, which is one of the genuine simplifications of carrying a Group C cargo. The ship’s intact stability calculation and the trim and list check are performed once for the load condition and remain valid, subject only to fuel and water consumption changing the displacement.

Longitudinal strength and hold distribution

The other structural concern is longitudinal: the distribution of the dense cargo among the holds drives the still-water bending moment and shear force along the hull girder. Loading all the barytes into alternate holds, a common practice for heavy cargoes to lift the cargo’s effective center of gravity and ease the stiff-ship motion, concentrates weight at intervals along the length and raises shear at the bulkheads between loaded and empty holds. The loading manual’s permissible bending-moment and shear-force envelopes constrain this distribution, and the cargo plan must keep every intermediate stage of loading and discharge within those envelopes, not just the final condition. Alternate-hold loading of dense cargo is allowed only where the loading manual and the class-approved loading instrument confirm the ship is strengthened for it; many bulk carriers carry a “heavy cargo, holds may be empty” notation that records exactly which holds may be left empty. The interaction of cargo density with hull-girder strength is the reason SOLAS Chapter XII imposes additional structural standards on bulk carriers, and it is why barytes, despite its benign chemistry, demands the same loading-manual discipline as iron ore.

Dust: the one live precaution

The barytes schedule carries no fire, gas, moisture, or reactivity precaution, but it does carry a dust precaution, and it is the one part of the schedule a careless operator gets wrong. The fines fraction, the 20% below 6.4 millimetres, and any ground-grade material generate a fine, dense, abrasive dust during loading and discharge. The schedule’s wording is specific: appropriate precautions are to be taken to protect machinery and accommodation spaces from the dust of the cargo, and persons who may be exposed are to wear protective clothing, goggles or other equivalent dust eye-protection, and dust filter masks as necessary.

Why barite dust matters

Barium sulphate is chemically inert and not classed as toxic in this sulphate form, so the dust hazard is not a poisoning hazard the way soluble barium compounds would be. The hazard is physical and operational. The dust is dense and abrasive, and it works into bearings, ventilation intakes, and electrical equipment, where it accelerates wear and can foul accommodation air handling. Settled barite dust on deck and in machinery spaces is heavy and tenacious because of its density. The respiratory concern is the standard one for any fine mineral dust: prolonged inhalation of an inert dust loads the lungs, which is why the schedule mandates filter masks for exposed personnel rather than treating the cargo as dust-free. The protective measures are the same suite used for cement and other dusty Group C minerals: seal accommodation and machinery ventilation intakes during cargo work, run engine-room ventilation on recirculation where the design allows, and issue eye and respiratory protection to deck crew supervising the operation.

Practical dust control during cargo work

Control begins at the terminal. Enclosed conveyor transfer points, chutes that reach down into the hold to cut the fall height, and water-spray suppression at the loader head all reduce the airborne fraction at source. On the ship side, the chief officer closes and dogs the accommodation doors and ports on the working side, confirms machinery-space ventilation is set to keep dust out, and keeps non-essential personnel clear of the working hold. Discharge by grab is dustier than loading because the grab drops cargo through air repeatedly, so the dust precautions apply with more force at the discharge port than at the load port. None of this is unique to barytes; it is the standard dusty-mineral routine, but the cargo’s density makes the settled dust heavier and the cleanup more laborious than for a lighter mineral.

Settled barite dust is a maintenance problem in its own right after cargo work is done. It is heavy, so it does not blow off deck in the wind the way a lighter mineral dust does; it stays where it lands and has to be swept and washed off. It works into hatch-coaming drain channels, cleat threads, and the tracks of side-rolling or folding hatch covers, where it grits the bearing surfaces and, left in place, can foul the rubber-to-steel seal that keeps the next cargo dry. Deck machinery and any exposed electrical fittings on the working side are wiped down and checked, since a dense conductive-when-damp mineral dust bridging a terminal block or packing a motor housing is the kind of fault that surfaces a week into the next voyage rather than at the berth. The cleanup is part of the cargo operation, not an afterthought, and a master who treats barite as a benign Group C cargo and skips it pays for it later in seized cleats and weeping hatch seals.

Hold preparation

Barytes is a Group C cargo with no special hold-cleanliness requirement in its schedule, which means the standard “normal clean” condition applies rather than the “grain clean” or “hospital clean” standards reserved for sensitive cargoes. The holds must be clean, dry, and free of the previous cargo’s residue, with bilge wells clear and bilge suctions tested. The full sequence for each cleanliness grade is set out in the cargo hold preparation standards article. For barytes the governing concern is not the cleanliness grade but contamination in the other direction: barite is a dense, fine, tenacious material that is itself hard to remove, so a ship that loads barytes and then a sensitive next cargo, grain in particular, must plan a thorough wash-down at the discharge port.

What “normal clean” requires here

A normal-clean hold for barytes is swept and washed free of the prior cargo, dried so that no free water remains on the tank top, and checked for loose rust scale or paint flakes that would contaminate a white or chemical-grade parcel. The receiver’s grade expectation sets the real standard: a chemical-grade or filler-grade barite parcel destined for paint or barium-chemical manufacture is held to whiteness and contamination limits that a drilling-grade parcel is not, so the hold must be clean enough that rust streaks and residual coal or ore dust do not stain the cargo. Bilge wells are covered and protected so that the fine cargo does not pack into them and block the suctions, a real risk with a fine dense material that flows into every gap.

Moisture and the bilges

The schedule lists a moisture content of 1% to 6%, low enough that the cargo poses no liquefaction risk, but high enough that free water must not be allowed to collect under it. Holds are loaded dry, hatch covers are weathertight-tested before the voyage, and the bilges are sounded routinely during the passage. Because the cargo packs down densely, any water that does reach the tank top tends to sit beneath the cargo rather than draining cleanly, so the protection of the bilge suctions during loading is the practical safeguard. There is no weather precaution in the schedule beyond the general one of keeping the cargo dry, since wetting a Group C barytes parcel degrades it commercially without creating a safety hazard.

Loading and trimming

Barytes loads by shore conveyor and shiploader at the high rates typical of mineral terminals, often well above 1,000 tonnes per hour, but the loading rate is constrained by tank-top stress and by the need to spread rather than pile the dense cargo. The loading plan is the controlling document. It sequences the holds to keep the still-water bending moment, shear force, and tank-top load within the loading manual’s limits at every stage, and it specifies whether the cargo goes into all holds or into alternate holds under the ship’s heavy-cargo notation.

Trimming the dense block

Trimming in the bulk-cargo sense means leveling the cargo within the hold. For a Group A cargo, trimming controls the free surface and the shift risk; for barytes the purpose is structural, to spread the dense cargo across the full tank-top area so that no local cone exceeds the inner-bottom loading limit. The coarse lump fraction does not flow far under the shiploader spout, so a barytes stow needs active trimming, by moving the spout across the hold during loading and by bulldozer or trimming machine afterward, to achieve an even layer. The Code’s general trimming provisions in sections 4 and 5 apply; the schedule itself adds no special trimming condition because the cargo’s stability behavior is benign once the structural distribution is right.

Loading sequence and de-ballasting

Because barytes brings the ship to its marks at a shallow cargo depth, the loading sequence is interleaved with de-ballasting in the usual way, and the dense cargo means the ship reaches each draft mark with comparatively little cargo aboard. The chief officer and the terminal’s loading-master coordinate pour rate against de-ballast rate so that the hull-girder loads stay inside the envelope through the operation. The BLU Code provisions on the ship-shore loading interface, the agreed loading plan, the ship-shore safety checklist, and the terminal representative, apply to barytes as to any bulk cargo, even though the cargo presents no chemical hazard at the berth.

Carriage

Once loaded and trimmed, barytes is among the least demanding cargoes to carry. The schedule lists no special ventilation, no special carriage condition, and no atmosphere monitoring, because the cargo does not self-heat, emit gas, or liquefy. The carriage task reduces to keeping the cargo dry and managing the ship’s motion in the stiff load condition.

Routine voyage care

Hatch covers are kept weathertight and the seals checked after heavy weather, since the commercial value of a white or chemical-grade parcel depends on it staying dry and uncontaminated. Bilges are sounded on the standard schedule and pumped if water appears, with the source investigated rather than simply discharged, because water on the tank top under barytes signals a hatch or ballast-line leak. There is no requirement to ventilate the holds for the cargo’s sake; if the holds are ventilated at all it is to manage condensation, the standard dew-point comparison between hold air and outside air that governs whether ventilation helps or harms. Beyond that, the cargo is inert and stable for the passage, and the watch routine treats it as a benign Group C stow.

Motion and the stiff condition

The one carriage concern that follows from the cargo’s nature is the ship’s motion. The low, dense stow gives a high GM and a short roll period, so the master plans speed and heading in beam and quartering seas to avoid synchronous rolling and to spare the hull and cargo the accelerations of a hard roll. This is a seamanship matter rather than a schedule requirement, but it is the direct operational consequence of carrying a cargo this dense this low, and it distinguishes a barytes passage from the carriage of a lighter cargo with a gentler roll.

Discharge

Barytes discharges by grab-fitted shore cranes at oilfield-service terminals, chemical receivers, and general bulk berths, and at most receiving ports it is grabbed straight from the hold into hoppers and onto conveyors or trucks. Grab discharge of a dense cargo is efficient by weight but slow to clean up the last of the cargo, because the fine fraction packs into the tank-top corners and the bilge-well covers.

Grab work and hold cleaning

The dust precaution applies with full force at discharge: repeated grab drops through air generate more dust than loading did, so accommodation and machinery ventilation intakes are sealed on the working side and exposed personnel wear eye and respiratory protection. After the bulk of the cargo is out, the remaining heel is gathered by bulldozer and grabbed, and the holds are then swept. Because barite is dense, fine, and tenacious, a thorough wash-down follows if the next cargo is sensitive; residual barite in the bilges and tank-top corners will contaminate a grain or clean-product parcel.

The cleaning effort is greater than for a lighter mineral of the same tonnage simply because there is more dense fine material packed into the same corners. Where a lighter cargo of equal weight spreads through a larger stowed volume and a deeper, looser heel that a grab clears in fewer passes, the dense barytes heel sits shallow and packed into the tank-top margin plate and the bilge-hat covers, and it resists both the grab and the sweep. The wash water carries fine barite and is handled under the ship’s MARPOL Annex V cargo-residue and hold-washing procedures before any overboard discharge, with the classification of the residue and the permitted discharge distance from land governing where the wash-down can lawfully take place. Because barium sulphate is inert and not a marine pollutant in this form, the constraint is the Annex V hold-washing regime rather than any chemical-spill rule, but the volume of dense fine residue still makes a barytes wash-down a longer job than the cargo’s benign chemistry suggests.

Where barytes ships from and to

The seaborne barytes trade reflects the geography of barite mining and of oilfield demand. The USGS Mineral Commodity Summaries 2024 put estimated world mine production for 2023 at 8,500 thousand tons, with India the largest producer at about 2,700 thousand tons, followed by China at about 1,900, Morocco at about 1,200, Kazakhstan and Laos at about 600 each, Iran at about 300, Mexico at about 260, and Russia and Turkey at about 250 each. The United States mined barite in Nevada through three companies in 2023, with figures withheld for proprietary reasons, and remained a net importer with import reliance above 75% of apparent consumption.

The flows follow drilling demand. The USGS recorded U.S. barite import sources over 2019 to 2022 as India 36%, China 30%, Morocco 17%, and Mexico 13%, which traces the principal seaborne routes to the U.S. Gulf and offshore drilling regions, where the USGS notes imported barite is used because ocean freight undercuts the rail and truck cost of moving domestic Nevada barite to the coast. Indian barite from the Andhra Pradesh deposits and Moroccan barite into the Mediterranean and Atlantic markets are the other large seaborne movements. The whole trade rises and falls with the rig count: the USGS tied an estimated 3% rise in 2023 world barite production to a 9% increase in the non-U.S. average rig count through October 2023, the clearest demonstration that barite freight is an oilfield derivative.

See also

• IMSBC Code: the parent mandatory instrument and its structure
• IMSBC Group C cargoes: the classification barytes belongs to
• Bulk carrier: the ship type and its tank-top and hull-girder limits
• Cargo hold preparation standards: cleanliness grades referenced for hold readiness
• Iron ore: IMSBC Code schedule and carriage: another dense, low-stowage-factor cargo
• Iron ore concentrate: IMSBC Code schedule and carriage: a Group A concentrate of comparable density
• Manganese ore: IMSBC Code schedule and carriage: related dense ore cargo
• Chrome ore: IMSBC Code schedule and carriage: another heavy mineral cargo
• SOLAS Chapter XII: additional structural standards for bulk carriers
• Free-surface effect: the liquefaction hazard barytes does not present
• IMSBC cargo finder: classify a parcel against the live schedule
• Barytes (BaSO4) calculator: pull the schedule parameters for barytes
• Barytes density and stowage calculator: cargo-intake and tank-top load
• IMSBC angle of repose calculator: surface-slope computation for coarse minerals

Limitations

This article describes the barytes IMSBC schedule and its operational consequences for guidance; it does not replace the in-force IMSBC Code text, the ship’s loading manual, or the shipper’s cargo declaration, all of which govern any actual shipment. The schedule values cited here, Group C, bulk density 2,941 kg/m³, stowage factor 0.34 m³/t, angle of repose not applicable, moisture 1% to 6%, are the published figures under amendment 07-23; the master and surveyor must verify against the edition of the Code in force at the time of loading, since the Code is amended on a two-year cycle and a future amendment can change any field. The bulk density a particular parcel exhibits depends on grade, moisture, and compaction and can differ from the schedule value, which is why SOLAS XII/10 requires the shipper to declare the actual density. The tank-top, bending-moment, and shear-force limits used in any loading plan are the specific ship’s class-approved figures, not generic values, and the heavy-cargo and alternate-hold notations differ from ship to ship. The dust precaution is mandatory regardless of grade; the absence of a chemical hazard does not remove the duty to protect machinery, accommodation, and personnel from the cargo dust. Where a parcel is a barium compound other than the inert sulphate, such as barium nitrate (UN 1446, IMDG Class 5.1), an entirely different and hazardous schedule applies, and the benign treatment described here does not extend to it. None of the cross-linked calculators is a substitute for the approved loading instrument required by SOLAS for the structural check.