Bulk bag dimensions and sizes

Footprint against the pallet

The first two numbers are the body footprint. A 35 x 35 in bag on a 40 x 40 in pallet leaves (40 - 35) / 2 = 2.5 in spare on every side. A 41 x 41 in bag on the same pallet overhangs by half an inch a side, which is why 41 in bags usually ride on 48 x 48 in pallets, leaving 3.5 in each way.

Remember that an unbaffled body bulges as it fills. A bag that fits the pallet empty can hang over it full, and overhang is where forks catch fabric and stacks lean. If your pallets are fixed, tell us their size and we'll work the footprint back from it.

Height against the fill head and the discharge frame

The third number is body height, not including loops or spouts. Your fill station has a maximum height from the floor to the nozzle, and the loops have to reach the hooks with the bag standing on the scale. Your discharge frame has its own clearance from the lifting bar to the hopper lid. Measure both before choosing a tall bag.

Common heights run from 35 in to about 72 in in our size table. Taller bags carry more light product per footprint. Shorter bags suit dense product, low doorways and operators who tie spouts by hand.

Volume against SWL

Volume and weight run out at different points depending on the product. A 35 x 35 x 50 in body holds 35 x 35 x 50 = 61,250 cubic inches, or 61,250 / 1,728 = 35.4 cubic feet. Filled with resin pellets at an assumed 34 lb per cubic foot, that is about 1,205 lb. Filled with dry sand at an assumed 100 lb per cubic foot, it would be about 3,540 lb, far past a 2,000 lb SWL.

So dense product needs a shorter bag, not a stronger one. To hold 2,000 lb of sand at 100 lb per cubic foot you need 2,000 / 100 = 20 cubic feet. In a 35 x 35 in footprint that is 20 x 1,728 / 1,225 = about 28 in of fill height. Light product goes the other way and fills the whole body well under its SWL.

These densities are working assumptions for the arithmetic. Your product's own data sheet decides, and the bag must never be filled past the SWL on its label whatever room is left at the top.

Filled bags on a 53 ft trailer

If you ship product out in the bags you buy, the footprint also sets how many fit on a truck. For the arithmetic our size pages assume a 53 ft dry van with about 630 in of usable length, 100 in of inside width and a 44,000 lb payload limit. Your carrier's actual equipment decides.

A 41 x 41 in footprint sits floor(100 / 41) = 2 across and floor(630 / 41) = 15 rows deep, so 30 bags on the floor. At 2,000 lb apiece that would be 60,000 lb, far past the cap, so weight stops the count at 44,000 / 2,000 = 22 bags. A 35 x 35 in footprint fits 2 across and floor(630 / 35) = 18 rows, 36 spots, and the same 2,000 lb fill still tops out at 22.

Light product turns that round. Thirty-six bags of resin at roughly 1,200 lb each come to 36 x 1,200 = 43,200 lb, just under the cap, so the floor sets the count instead. Empty bags travel folded in bales and take a small fraction of that room.

Measuring the bag you already use

Lay an empty bag flat on clean floor. Measure one side panel seam to seam for width, the next panel for depth, and the body from bottom seam to top seam for height. Leave out loops, spouts and any duffle skirt.

If the label gives centimetres, divide by 2.54. A 90 cm panel is 90 / 2.54 = 35.4 in, and a 105 cm panel is 105 / 2.54 = 41.3 in. A spout lying flat shows half its circumference, so double the flat width and divide by pi: a spout 22 in across flat is 44 / 3.1416, about 14 in in diameter.

The building matters as much as the bag

Check the places a full bag has to pass or rest. Pallet racking has a beam spacing, and a tall bag plus its pallet plus fork clearance must fit under the next beam up. Doorways, mezzanine edges, sprinkler heads and overhead conveyors all set ceilings of their own. Truck deck height and dock plate angle matter if filled bags leave on your own trailers.

People count as well. An operator tying a discharge spout reaches up under the bag, so a very tall body on a high frame can put the knot out of comfortable reach. Ask the crew who run the stations before switching to a taller size.

Writing a size request in one line

An example, with figures for illustration only: 35 x 35 x 50 in, 2,000 lb SWL at 5:1, spout top 14 in diameter by 18 in long, spout bottom 14 by 18, Type A, uncoated, four cross-corner loops, no liner. That single line carries every number a maker needs to price the bag.

Bags are sewn goods, and finished dimensions can differ slightly from nominal ones. If clearance on a frame or a rack is tight, ask for the maker's tolerance before you commit to a size. Fabric also stretches a touch under load, and settled product can slump sideways during a bumpy journey.