4,000 lb SWL bulk bags

Two tons in one lift

4,000 lb is two short tons in one bag. The users are the ones whose product is dense and whose handling is built for it: cement and mineral terminals, industrial and frac sand suppliers, aggregate plants. At our assumed densities, portland cement at 90 lb per cubic foot fills a baffled 37 x 37 x 52 at 3,708 lb, a 35 x 35 x 60 at 3,825 lb and a 39 x 39 x 50 at 3,960 lb. Gravel at 95 lb fills the 37 x 37 x 52 at 3,914 lb; sand at 100 lb fills a 35 x 35 x 50 at 3,540 lb.

Lighter products reach this weight only in the largest bags, and then only just: granular fertilizer at 60 lb fills a 41 x 41 x 60 at 3,504 lb, and sugar at 50 lb fills a 41 x 41 x 72 at 3,500 lb.

Frac sand is the classic dense, uniform product for this rating: dry, rounded grains that pour freely and fill a bag square to its label with little slack. Industrial sands for glass, foundry and filtration work behave much the same way.

Twenty thousand at 5:1

4,000 x 5 = 20,000 lb is the type-test load for a single-trip bag; 4,000 x 6 = 24,000 lb for a multi-trip bag. Fabric, loop and seam weights rise with the rating, and the bag maker's test records for that design are what stand behind the label.

Metric: 4,000 / 2.20462 = 1,814 kg. The nearest round metric ratings are 1,500 kg and 2,000 kg, or 3,307 lb and 4,409 lb, so a metric spec will not match this label. Convert, and order the rating the spec names.

At this weight the inspection before each fill matters more, not less. Cut or abraded fabric, a pulled loop stitch or a sun-softened panel fails sooner under 4,000 lb. Damaged bags come out of service; they are not repaired on site.

Volume per 4,000 lb

At our assumed densities: pellets at 34 lb per cubic foot, 117.6 cubic feet; flour at 36 lb, 111.1; seed corn at 45 lb, 88.9; sugar at 50 lb, 80.0; fertilizer at 60 lb, 66.7; cement at 90 lb, 44.4; gravel at 95 lb, 42.1; sand at 100 lb, 40.0.

Pellets, flour, seed and sugar need more than the 70.3 cubic feet of the biggest box here, so none of them reaches 4,000 lb in a standard size. Fertilizer at 66.7 fits a 41 x 41 x 72 or a 45 x 45 x 60. The dense three sit between 40.0 and 44.4: a 35 x 35 x 60 at 42.5 takes the sand and the gravel, a 39 x 39 x 50 at 44.0 just misses the cement and fills at 3,960 lb, and a 41 x 41 x 48 at 46.7 takes the cement with room.

Because 4,000 lb of sand fills only 40.0 cubic feet, a 4,000 lb bag is compact: a 35 x 35 x 60 holding it is filled to about 94 percent of its box, since 40.0 / 42.5 = 0.94.

Lifting two tons

Check the forklift's capacity plate at the load centre the bag puts on the tines; a 39 in bag carries its weight farther out than a pallet of cartons. Tines through all four loops, loops vertical, mast tilted as the truck's instructions say, travel low, and no one near or under the bag. For crane lifts, all loops go on one hook or on a spreader bar rated for the load.

On the assumed 44,000 lb payload, 44,000 / 4,000 = 11 bags. A 35 in floor has 36 spots, so the load is 11 heavy points on a big floor, and the carrier will want it spread over the axles and secured so nothing slides under braking.

Crane lifts at this weight call for a lift plan on most industrial sites: rigging rated for the load, a tag line where the bag might spin, and a cleared drop zone. Bags are never lifted over people, whatever their rating.

• Sizes: 35 x 35 x 50, 35 x 35 x 60, 37 x 37 x 52, 39 x 39 x 50, 41 x 41 x 48
• Duffle or spout top; spout or flat bottom
• Type A for sand, gravel and cement where no flammable dust or vapour is present
• 5:1 single trip unless the bag runs in a managed multi-trip loop