By construction
U-Panel
Load carried on continuous fabric
One continuous panel forms two sides and the base, so the load is carried by fabric rather than by stitching.
Product description
A U-panel bag is made from one continuous piece of fabric that forms one side, the base and the opposite side, a U, with two further panels closing the remaining sides. The seam count is the same as a four-panel; what differs is where the seams are not. No seam crosses the load path, so the fabric carrying the weight runs unbroken from the lifting loops, under the base and back up.
Because the continuous underlay runs uninterrupted beneath the load and up into the lifting loops, force travels through fabric rather than stitching. All three constructions are rated over the same range, so the reason to choose U-panel is that load path and its cost, not a higher number. It is our default recommendation unless something else about the job overrides it.
Uses
- Heavy, dense material where load rating is the priority
- General bulk handling where cost per bag matters
- Applications with fewer seams needed to reduce contamination risk
Industries we supply this for: Mineral, Sand, Ingredients, Animal Nutrition
Configurable options
Everything below is specified per order. Nothing here is a fixed catalogue number.
| Static type | A, B, C or D |
|---|---|
| Top | Open, duffle, flap, spout, conical spout, double spout |
| Bottom | Flat, spout, conical spout, full bottom discharge |
| Loops | Corner (four-point), cross corner, double, tunnel, stevedore straps |
| Fabric | Coated or uncoated |
| Liner | None, loose, glued-in, antistatic, foil |
| Add-ons | Document pouch, sift-proof seams, safety bands, custom print |
Customizable options
Every option below is available on this product. They change how the bag fills, lifts and empties.
Lift loops
Corner loops
One loop sewn into each corner seam. The standard build, and the most affordable way to lift a bag.
Cross corner
Sewn into eight points across opposite corners, so the loops stand upright and the forklift operator is not fishing for four floppy straps.
Tunnel loops
A sleeve of body fabric spanning each side, corner to corner. The forks go straight through: the easiest pick where headroom is tight.
Stevedore straps
Double-layer straps across the corner loops, so the bag can be taken on one or two points instead of all four.
Double loops
Two lifting points instead of four, where that suits the load and the lift better.
Top
Spout top
A cylindrical spout sewn into the top panel. 14 in diameter by 18 in long as standard, sized to your filling head.
Spout top with flap
A spout top with a flap panel over it, tied down so the spout stays covered in transit.
Duffle top
A skirt the full width and depth of the bag, so the top opens completely and ties closed.
Flap top
A closed panel with a flap sewn along one seam, tied down over the mouth.
Open top
No panel at all. Fastest to fill where dust and weather are not a concern.
Conical spout top
A top panel that tapers up into the spout. Double spout tops are available too, specified to your filling equipment.
Bottom
Discharge spout
The standard 14 by 18 in spout, tied off. A wider spout is worth specifying for material that bridges.
Flat bottom
Closed base for product that is emptied by tipping or cutting.
Full bottom discharge
The whole base opens, for material that will not flow through a spout.
Spout protection
A flap, or a petal or iris closure, over the discharge, for when the spout must stay clean in transit.
Conical discharge spout
The base narrows into the spout, which helps product that is slow to flow empty completely. Specified to your equipment.
Add-ons
Baffles
Corner panels that hold a cube instead of a bulge: roughly 25 to 30% more volume in the same footprint, and it stacks safely.
Sift-proof seams
Filler cord sewn into the seam, for product fine enough to work through the stitching.
Document pouch
A sealed pouch for the paperwork which needs to travel with the bag.
Safety bands
A reinforcing band around the top, for added strength at the lift.
Custom print
Up to four sides, for branding and traceability on the line.
Liner
No liner
Fabric alone, where the product needs no barrier. The cleanest liner is the one you never have to specify.
Loose liner
Dropped in, not attached. Affordable insurance against fine powder finding the seams.
Glued-in liner
Bonded to the bag so it stays in place through filling and discharge, which is what a food or pharmaceutical audit expects to see.
Antistatic liner
Specify this inside a Type C or Type D bag, so the liner carries the same static classification as the fabric.
Foil liner
Designed for product that is filled hot, the foil laminate holds temperatures that would deform a polyethylene liner.
Fabric
Uncoated
Breathable, and the default build.
Coated
A thin polypropylene coat over the weave, for fine powder and moisture resistance.
How the constructions compare
| Construction | Vertical seams | Typical SWL (lb) |
|---|---|---|
| U-Panel | 4 | 2,205–3,000 |
| Four-Panel | 4 | 2,205–3,000 |
| Circular | 0 | 2,205–3,000 |
Load figures are indicative industry ranges shown for comparison. Every bag is made to order, so tell us your fill weight and we will specify to it.
Frequently Asked Questions
Why is U-panel stronger than four-panel?
Load passes through continuous fabric into the loops rather than across stitched joints, so the weight is never carried by stitching.
Will it stack?
It stacks, but it bulges when filled, so it uses container and rack space less efficiently than a four-panel or baffle bag. If cube efficiency is your constraint, look at baffle.
Does it need a liner for powders?
For fine powders, either a liner or sift-proof seams. If the material is very fine or hygroscopic, a circular bag with no vertical seams may be the better answer.
Related products
Send us the load, not a part number.
Material, fill weight, how you fill and how you discharge. That is enough for us to come back with a specification.