I price forty to sixty quotes a week. Perhaps five of them tell me what the liquid is. That single omission causes more downstream problems than every other missing detail combined.
The arithmetic
One US gallon of water weighs 8.345 lb. Multiply gallons by that, then by the specific gravity of your product, then add the tare weight of the container.
A 275-gallon composite unit on a steel base has a tare of about 132 lb. A 330 is about 148 lb.
| Product | SG | 275 gal gross | 330 gal gross |
|---|---|---|---|
| Isopropyl alcohol | 0.79 | 1,945 lb | 2,324 lb |
| Diesel fuel | 0.84 | 2,060 lb | 2,461 lb |
| Soybean oil | 0.92 | 2,243 lb | 2,682 lb |
| Water | 1.00 | 2,427 lb | 2,902 lb |
| Ethylene glycol | 1.11 | 2,679 lb | 3,205 lb |
| Liquid fertiliser 28-0-0 | 1.28 | 3,070 lb | 3,673 lb |
| Corn syrup, 42 DE | 1.38 | 3,299 lb | 3,948 lb |
| 50% caustic soda | 1.53 | 3,643 lb | 4,362 lb |
| 93% sulphuric acid | 1.83 | 4,332 lb | 5,188 lb |
| Zinc bromide brine | 2.30 | 5,411 lb | 6,482 lb |
Gross weight by product, 275 and 330 gallon
Three places this bites
- Forklifts. Capacity plates are rated at a 24-inch load centre and a tote sits at or past that. A nominal 5,000 lb truck can be near 3,800 lb in practice, which a filled 330 of caustic exceeds comfortably.
- Floors and racking. Three filled 330s in one rack bay is over 12,000 lb on four upright footprints. Suspended slabs and mezzanines frequently cannot take it, and a floor gives no warning.
- Legal load weight. At water density, 18 filled 275s is about 43,700 lb and legal. At SG 1.2 the same count is 51,900 lb and is going to be turned away at a scale.
| Product density | 275 gal units | 330 gal units |
|---|---|---|
| SG 1.0 (water) | 18 | 15 |
| SG 1.2 | 15 | 12 |
| SG 1.4 | 12 | 10 |
| SG 1.6 | 11 | 9 |
| SG 1.8 | 10 | 8 |
Units per legal load by density, ~44,000 lb payload
The fourth place: the stacking plate
Less obvious and worth knowing. The stacking rating on a specification plate is a load in kilograms, not a number of units. Three-high is a convenient shorthand that assumes water-density contents.
A plate rated for a 1,800 kg stacking load supports two filled water-density units above it. The same assembly with SG 1.5 product supports one. Nothing on the container tells you this; you have to do the arithmetic against the plate.
The counterintuitive answer for dense product
Above about SG 1.4, the right container is frequently a 120-gallon half-height rather than a 275.
It costs more per gallon stored, which is why nobody chooses it voluntarily. What it buys is staying inside the handling equipment you already own, and avoiding a floor-loading conversation entirely. A filled 120 of caustic is about 1,620 lb, which any warehouse truck handles.
| Option | Units | Gross per unit | Handling |
|---|---|---|---|
| 4 × 275 gal | 4 | 3,643 lb | Needs a derated 5,000 lb truck or better |
| 9 × 120 gal | 9 | 1,620 lb | Any warehouse truck; more handling events |
| 3 × 330 gal + 1 × 120 | 4 | up to 4,362 lb | Needs a 6,000 lb truck |
Storing 1,100 gallons of 50% caustic (SG 1.53)
The container is rarely the constraint on dense product. Your forklift is, and it will tell you by lifting its back wheels.
What to send with an enquiry
Just the liquid name. Not the specific gravity — I will look it up, and I would rather look it up than have you guess.
- The product, by name. "50% caustic" is enough. "Chemical" is not.
- The volume you need to store or ship.
- Your forklift capacity, if you know it.
- Whether it is going on a mezzanine, a suspended slab or a ground-level slab.
Four facts, and the quote comes back with unit count, gross weight per unit, total load weight and a note if your equipment is going to struggle. Full conversion tables are on capacity conversions, and the forklift derating is worked through in a 48-inch load centre will lie to your forklift.
Written by
Nina Caldwell
Trading desk
Prices grades and landed freight. Measured on used-first sourcing and repeat business, not on margin per unit.