The big bag with skirt top and flat bottom solves a specific problem of outdoor bulk handling: it needs the wide opening of an open-mouth bag but also the ability to close the container against rain, wind, or environmental dust once filled. This guide explains how to unfold the skirt, fill the bag with wide shovels or hoppers, tie it correctly, and transport the load with the operational safety that its 5:1 factor guarantees.
The described procedure applies to the only available product presentation, 1500 kg and dimensions 90 × 90 × 100 cm. Read it in its entirety before the first load: the critical point of this format is not filling or lifting, but the correct closure of the skirt, a one-minute operation that determines whether your bag withstands rain or not.
Product Specifications
The big bag with skirt top and flat bottom is offered in a single presentation. The following table contains the full technical specifications for the only available variant:
| Specification | Value |
|---|---|
| SKU | 532346 |
| Material | Woven Virgin Polypropylene |
| Dimensions | 90 × 90 × 100 cm (3 × 3 × 3.3 ft) |
| Load Capacity | 1500 kg (3300 lb) |
| Safety Factor | 5:1 |
| Inner Liner | No |
| Filling Spout | Skirt top (extendable top panel) |
| Base Shape | Flat bottom |
| Lifting Loops | 4 reinforced corner loops |
| Treatment | UV resistance |
| Presentation | Pack of 30 big bags |
If you work with several big bag formats at once, the sister guides might be of interest to you: the one for the open-mouth and flat-bottom big bag (the version without a skirt) and the one for the big bag with filling spout and flat bottom (format for closed plant processes).
Step-by-step guide for use
The following procedure covers the complete cycle from initial inspection to lifting the filled and closed load. The critical step is the fourth: the correct closing of the skirt is what determines whether this bag actually protects the contents or whether it becomes an expensive open-mouth bag.
Inspection of seams and skirt attachment
Check the four loops, the bottom seams, and, with special attention, the connection between the bag body and the top skirt. This is the area of greatest tension when filling in bulk and the first to fail in economical bags. Confirm that there are no loose threads or stitched points that yield under hand pressure. If you detect any defect in the skirt, do not use that bag for maximum useful load.
Positioning on pallet with skirt unfolded
Place the bag on a 1.0 × 1.2 m pallet with the four loops extended upwards. Unfold the skirt by pushing it completely outwards to create a wide and rigid opening. If you are going to fill with shovels or bulky material, it is advisable to temporarily tie the ends of the skirt to the loops so that it does not fall during filling.
Bulk filling through the full opening
Load the bag with shovels, conveyor belts, or wide-mouth hoppers. The skirt allows the passage of bulky, irregular, or high-discharge-rate material without clogging. Fill until the contents reach the bottom line of the skirt, leaving between 15 and 25 cm of free fabric to be able to close it. Do not fill to the top: you need that slack for the final knot.
Closing the skirt against rain and dust
Gather the skirt inwards by pinching the fabric at four opposite points, forming a cross of folds. Tie with industrial rope in a double knot at the top of the skirt, tightening well so that the closure is airtight against dust and surface water. A well-tied skirt protects the contents for several days of outdoor exposure in Caribbean climates.
When tying the skirt, always leave an excess of 30 to 40 cm of free rope after the knot. In export operations or agricultural yards, it is common to have to open and close the bag again to inspect contents, add samples, or balance weight between batches. A short rope forces you to cut and replace it every time; a rope with slack saves you time and allows you to reuse the same tie throughout the bag's cycle.
Lifting and transport with the four loops
Pass the crane hooks, boom arms, or forklift forks through all four loops simultaneously. Lift plumb, avoiding lateral tugs that concentrate tension on a single seam. For yard storage, stack a maximum of two full bags per column; the flat bottom allows it, but exceeding two compromises stability under wind or rain.
Do not fill the bag to completely cover the skirt. If the contents rise to the height of the skirt, there will not be enough free fabric to tie the knot, and a forced closure or knot tied flush with the material will eventually unravel during the first lift. Always leave between 15 and 25 cm of free skirt above the load level.
Do you need an inner liner or is this format sufficient?
If your material is sensitive to humidity but the main risk is occasional environmental rain, this big bag with a skirt is probably sufficient. If the material is very fine, dusty, or critical (cement, hygroscopic fertilizers, chemicals), consider a format with a liner. Ask the virtual assistant with the exact reference of your material and we will guide you to the correct solution without overinvesting.
Complementary Products
To complement the use of the big bag with a skirt, the following products cover the most common adjacent needs in outdoor operations and in agricultural or construction yards:
The open-top big bag is the sibling format without a skirt: use it when the bag will not remain outdoors and you need maximum filling speed. The big bag with a discharge spout is the closed alternative for in-plant processes where rain is not a factor but packaging cleanliness is. The transparent manual stretch film adds an additional layer of protection if the filled bag will travel for several days or be transported on an open platform. Plastic edge protectors protect the corners of the pallet in export operations where the entire unit is secured with strapping.
Maintenance and Care
The big bag with a skirt can be reused several times if handled with care. After emptying the bag, shake out any remaining material through the skirt opening, fold the bag with the skirt inwards, and store it in a dry, ventilated place away from prolonged direct sunlight. The UV-treated polypropylene resists Caribbean radiation, but prolonged sun exposure shortens the lifespan of even the most resistant fabric.
Before each new load, repeat the inspection from step 1: the skirt-body joint is the area of greatest wear due to repeated folding and tying. If you detect loose stitching at that joint, discard the bag for maximum load and reassign it to less demanding uses (e.g., static storage instead of crane transport).
Frequently Asked Questions (FAQ)
What is the real difference between this format with a skirt and the normal open-top big bag?
The big bag with a skirt allows the bag to be closed once filled, which protects the contents from rain, wind, and environmental dust. The open-top one does not close: the contents remain exposed. If your bag will remain outdoors for hours or days, or if the material is sensitive to surface moisture, the skirt makes a difference. If the bag is filled, loaded, and unloaded in a matter of minutes within the same facility, the open-top one is faster and more economical.
Does the rope for tying the skirt come with the bag?
This detail often varies depending on the batch and origin. It is advisable to have industrial polypropylene or nylon rope of at least 6 mm in your warehouse before the first use. A rope that is too thin digs into the fabric when tightened and does not guarantee a tight seal; one that is excessively thick makes it difficult to tie a double knot in the limited space of the skirt.
Can it withstand heavy tropical rain once properly closed?
A well-tied skirt closure resists ambient rain and brief downpours. In prolonged tropical storms, water can seep in by capillarity through the polypropylene weave—which is not waterproof, but woven. For these scenarios, add an additional layer of stretch film or a tarp over the entire pallet. If prolonged exposure to intense rain is common, consider a big bag with an inner liner directly.