Quick Answer
An FIBC specification sheet should describe the contents, capacity, dimensions, safe working load, safety factor, construction, openings, loops, barrier, electrostatic classification, testing, labeling, and delivery requirements. With more than 350 active specs under management, we start with the application and give suppliers enough information to recommend the right package without guessing.
A Good Spec Prevents the Wrong Bag from Reaching the Line
Two bulk bags can look identical and behave differently. Excess width changes stacking. A mismatched fill spout slows production. The wrong fabric, seams, or electrostatic classification can create larger problems.
That is why the spec sheet matters.
We bring more than 70 years of combined experience to this work. Our team starts with the application, then works through each field until the bag fits the contents, machinery, handling method, and delivery plan.
| Specification field | What it describes | Why it matters |
|---|---|---|
| Contents and bulk density | What goes in the bag and how much space it occupies | Drives sizing and construction choices |
| SWL and safety factor | Rated capacity and intended-use category | Sets the operating boundary |
| Body construction | Panel style, fabric, coating, seams | Affects shape, strength, sift resistance |
| Top and bottom | How packed goods enter and leave | Must match filling and discharge machinery |
| Lifting system | Loop style, length, and attachment | Must fit the pickup method |
| Liner or barrier | Added protection inside the bag | Helps manage moisture, contamination, or flow |
| Static type | Type A, B, C, or D requirements | Must match the contents and operating environment |
| Testing and marks | Required validation, certification, and label content | Supports safe use and traceability |
This table is a map. The process below fills in the operating details.
Start With the Contents, Not the Bag
The request should explain what the customer needs to pack. Beyond the product name, we may need bulk density, particle size, flow, moisture sensitivity, fill temperature, contamination controls, and relevant hazards. The FIBCA Design Guide follows the same application-first approach.
A light, fluffy powder can fill the available volume before it reaches the target weight. A dense mineral may reach its SWL with room left at the top. Those two applications do not need the same sizing, even if the requested shipped mass is identical.
Describe the Entire Operating Cycle
We also need to know how the filled bag will move:
- What machinery fills it?
- How is it closed after filling?
- Will it be stacked in a warehouse?
- How will a forklift or hoist engage the loops?
- Does it discharge into a hopper, mixer, or manual process?
- Will it travel by truck, rail, container, or more than one mode?
The right build connects those steps. A single field on the order form cannot replace the application conversation.
Set Capacity, Size, and Ratings Together
Measurements are usually written as width by length by height. Those numbers describe the unfilled bag, but the filled footprint depends on body construction, flow behavior, and how the contents settle.
The safe working load (SWL) states the maximum rated weight. The safety factor identifies the test relationship and intended-use category. Most standard applications call for 5:1-rated bags for common single-trip applications, while other uses may call for different construction and validation.
Do not copy these fields from an old purchase order without checking the use case. If the contents, machinery, route, or handling method changed, the old document may no longer fit.
Check the Filled Bag Against the Warehouse
The FIBC has to work after leaving the filler. Confirm pallet size, rack or floor arrangement, trailer and container clearance, stacking plan, and available headroom. Those downstream constraints may change the ideal height or body style.
One of our chemical industry customers had been receiving oversized bags that were under-specified for their application by another FIBC supplier. The old build did not support efficient stacking and consumed unnecessary warehouse and shipping space.
We corrected the sizing, increased the fabric weight, and reinforced the seams. The new build took up less than half of the previous storage and shipping space. The customer estimated average savings of $280 per truckload. Optimizing the bag spec/design around your application can make for not only a better bag, but also create efficiencies in the economics around it
A Copyable Technical-Sheet Template
The example below shows the level of detail an RFQ needs. The sample values are illustrative and are not a recommendation for a particular application.
| Field | Illustrative entry | Verification question |
|---|---|---|
| Contents and bulk density | Dry mineral powder; density supplied by buyer | Does the description match the actual production product? |
| Capacity | Target net quantity; volume confirmed from density | Does the filled bag remain at or below SWL? |
| Size | Width × length × height; ID or OD stated; tolerance listed | Will the filled footprint fit the line, pallet, rack, and trailer? |
| Rating | SWL and design-use factor shown separately | Does the rating match the intended use category? |
| Body and fabric | Panel style, fabric weight, coating, color, seams | Which performance need does each detail solve? |
| Top and bottom | Opening type plus diameter, length, ties, and flap | Do both openings match the production line? |
| Lifting system | Loop style, length, color, and attachment | Will forks, hooks, or a hoist engage it as intended? |
| Protection | Liner or barrier, static type, contamination controls | What operating condition requires protection? |
| Control data | Revision, approver, tests, label, artwork, pack out, delivery | Can purchasing and receiving verify the exact version? |
Our team uses the use-case conversation to fill out the template. The finished document should let a qualified supplier ask targeted questions rather than guess at missing conditions.
Define the Body and Construction Requirements
The document may identify a U-panel, four-panel, tubular, or baffle body; woven-fabric weight; coating; color; ultraviolet stabilization; and seam treatment. Our bag-features page shows the available construction choices.
Use a performance requirement where possible. Telling us to “prevent visible sifting at the seam under our normal filling and operating conditions” gives us a real problem to solve. For weight conversions, our GSM-to-ounce converter keeps units consistent across facilities and suppliers.
Match the Top and Bottom to the Line
The openings are where the bag meets the line. We list the top and bottom style, diameter, length, closure, ties, and flaps, then compare them with the filler and receiver. An open or duffle top solves a different problem from a fill spout; a flat bottom behaves differently from a controlled discharge or full-open bottom. If the customer uses more than one line, we verify whether one configuration fits all of them or whether separate documents are cleaner.
Specify Lifting Loops from the Handling Method
Loop style and length must fit the pickup method. The FlexSack bag features list includes corner, cross-corner, fully belted, stevedore, and one- or two-loop options. We document the handling gear, fork size, hook or hoist arrangement, and height limits. Color can aid identification, but the written rating and label remain the controlled source.
Add Liners, Coatings, and Static Protection Only When the Application Calls for Them
A coating or liner can help with moisture, contamination, sift control, or compatibility, but it can also change filling, discharge, venting, and recycling. Our liner selection guide covers the main decisions. We document the performance needs, attachment, construction, and required behavior during filling and emptying.
State the Electrostatic Environment Clearly
Type A, B, C, and D classifications address different electrostatic conditions. We evaluate the contents, dust or vapor environment, ignition sensitivity, and grounding capability rather than treating the letter as a catalog option. Our static-protection guide provides a deeper reference.
Document Testing, Compliance, Marking, and Traceability
Regulated or high-consequence applications may require specific testing, certifications, manufacturing controls, and marks. Food, pharmaceutical, chemical, and dangerous-goods use each bring their own questions.
For UN-marked FIBCs, the UNECE ADR 2025 requirements specify durable, legible markings that identify the approved type, packing group designation, manufacture date, authorizing state, manufacturer identification, stacking test load, and maximum permissible gross mass. The required details depend on the applicable packaging category and transport rules.
Our compliance review treats tests, marks, labels, and traceability as a release gate, not a note added after production. The order file should identify:
- applicable certification or regulatory requirement
- test reports or certificates required with the order
- lot, batch, or manufacturer traceability fields
- label layout and language
- product, use, and warning information
- artwork and print requirements
The label is part of the package; therefore, it’s important to review it with the same care as the fabric and hardware.
Turn the Spec into a Controlled Purchasing Document
A clean request for quotation gives every supplier the same information. It should carry a revision number, approval owner, target quantity, delivery location, packaging method, sampling requirements, and any first-article or pre-production approval step.
We worked with one customer to create bags around their dimensions and operating needs. The new package removed a distributor middleman, saved $4 to $6 per bag, and arrived within a week of the new relationship starting. We also built a pipeline system that lets the customer adjust orders as forecasts changed.
The technical design and the supply plan belong together. A package can be correct on paper and still fail the customer if inventory arrives late, or the revision is not controlled.
Technical Specification Checklist
Before releasing the order, we use this checklist to confirm that the document answers these questions:
- What product will be filled, and what are its handling characteristics?
- What net weight, volume, SWL, and design-use rating are required?
- What filled footprint must work in storage and transport?
- Which body style, fabric, coating, seams, and color are needed?
- What top and bottom match the production equipment?
- How will the package be lifted and moved?
- Is a liner or other barrier required?
- What electrostatic conditions apply?
- Which tests, certifications, and marks must appear?
- How will revisions, approvals, and delivery requirements be controlled?
That list turns a vague request for “the same bulk bag” into a usable technical brief.
Frequently Asked Questions
Include product details, target capacity, dimensions, SWL, safety factor, body and fabric construction, top and bottom configuration, lifting loops, liner or coating, electrostatic type, testing, certifications, labels, printing, packaging, and delivery requirements.
SWL is the maximum rated capacity for the package. The factor describes the tested relationship and intended-use category. Both fields matter, and neither should be changed without confirming the complete application.
Only after reviewing product density, flow, hazards, equipment, storage, and transport conditions. A design that worked for one product may fit poorly or create risk with another.
The buyer, operations team, or quality owner when relevant, and the qualified supplier should agree on the controlled version. Regulated applications may need additional compliance review.
Yes. We work with customers to translate product, equipment, handling, and supply-chain needs into a complete package design. Contact FlexSack to review a new application or an existing specification.