Jumbo bags by safe working load

SWL and safety factor are two different numbers

The SWL is a working limit. You fill to it and lift at it, never past it. The safety factor is the margin the design was tested to above that limit, and it is never spent on heavier fills.

Multi-trip standard-duty bags must reach six times their SWL in the final destruction test, so a 1,000 kg SWL bag has to hold 6,000 kg, and they also pass a 4,000 kg, six-hour compression test. Single-trip bags are tested to five times SWL, and the maker's handling guidelines (2023) recommend they not be reused. That single fact decides whether a bag can ever come back round.

Kilograms, pounds and the word ton

Many bags are designed in kilograms and relabelled in pounds. One kilogram is 2.20462 lb, so a 1,000 kg bag is 2,204.6 lb and is sold as 2,200 lb. A 1,500 kg bag works out to 3,307 lb and is sold as 3,300 lb. A 2,000 kg bag is 4,409 lb, sold as 4,400 lb.

A 1-ton bag can mean either 2,000 lb, the US short ton, or 1,000 kg, the metric tonne, which is about 205 lb more. When a request says one ton, we confirm which one before quoting. Read the SWL printed on the label, not the nickname on the invoice.

Weight capacity is only half the fit

Bulk bag weight capacity tells you how much a bag may carry. It does not tell you whether that weight fits inside. Light product fills the body by volume first: 2,000 lb of pellets at 34 lb per cubic foot needs 2,000 / 34 = about 58.8 cubic feet. Heavy product hits the weight first: 2,000 lb of sand at 100 lb per cubic foot needs only 20.

That is why each rating page pairs the SWL with the volume it takes for several typical products. Choose the SWL from your target weight, then choose the dimensions that hold that weight at your density.

Worked picks from three products

Resin pellets at an assumed 34 lb per cubic foot in a 41 x 41 x 72 in body: 41 x 41 x 72 = 121,032 cubic inches, or 70.0 cubic feet, times 34 gives about 2,381 lb. The lowest rating in our list that covers it is 2,500 lb.

Seed corn at an assumed 45 lb per cubic foot in a 41 x 41 x 60 in body: 100,860 cubic inches is 58.4 cubic feet, times 45 gives about 2,627 lb, so the pick is 3,000 lb. Portland cement at an assumed 90 lb per cubic foot, aiming for a 3,300 lb fill: 3,300 / 90 = 36.7 cubic feet, which in a 35 x 35 in footprint needs 36.7 x 1,728 / 1,225 = about 52 in of fill height.

Swap in the density from your own data sheet and the same steps give your answer. If the result lands just over a rating, either step up one rating or shorten the body so the fill comes in under the lower one.

Handling the heavier ratings

A 4,400 lb bag puts real demands on the plant. Check that your forklift's rated capacity at its load centre covers the full bag plus any lifting frame, that the tines pass fully through every loop, and that the discharge frame and hoist are rated for the weight.

Stacking is a separate question from lifting. Multi-trip standard-duty bags pass a long compression test, but whether you stack, and how high, depends on the bag maker's guidance, the product and how square the lower bags stand. Inspect every bag before each use, and don't lift one that has sat out in the sun.

Low, middle and high ratings in practice

Light ratings, around 1,000 to 1,500 lb, suit small batches: a mixer charged one bag at a time, a pigment or additive dosed by hand, a pilot line, or a product so light it can't reach more weight in a normal body. They are also easier on smaller hoists and older forklifts.

The middle of the range, 2,000 to 2,500 lb, covers a great many everyday jobs. Pellets, seed, feed, fertilizer and many powders land here in standard footprints.

Heavy ratings, 3,000 to 4,400 lb, belong to dense material: sand, ore concentrates, cement, metal powders. They need stronger loops, heavier fabric and handling equipment that can take the weight with margin. A crane or overhead hoist used with them must be rated for the full load, and the lifting bar or frame too.