Technical Specifications

Definition and Standards of Safety Factor

Safety factor of an FIBC (bulk bag/jumbo bag) refers to the ratio of ultimate breaking force of bag body and lifting straps to the rated working load, reflecting the safety redundancy of the packaging system.  

- Single-Use Type: Minimum 5:1 safety factor, meaning a 1-ton-rated FIBC must withstand 5 tons of tensile force without failure.  

- Reusable Type: Requires a 6:1 safety factor, with mandatory compliance for hazardous material transportation.  

Load-Bearing Calculation Methods  

The load-bearing capacity of an FIBC is calculated by integrating static loads and dynamic effects:  

1. Static Load Formula  

- Wstatic=Wbag+Wmaterial 

- Where Wbag is the self-weight of the FIBC, and Wmaterial is the net weight of the material.  

2. Dynamic Load Adjustment  

Introduce a dynamic load coefficient kd (1.2–1.5) to account for acceleration effects:  

- Wdynamic = kd x Wstatic

- Example: For a 1-ton material load:  

- Wdynamic = 1.3 x (10kg + 1000kg) = 1313kg  

3. Safety Factor Application  

The final load-bearing capacity must satisfy:  

- Wfinal ≥ SF x Wdynamic  

- Example (5:1 safety factor):  

- Wfinal ≥ 5 x 1313kg = 6565kg

Type A

Type A FIBCs, also known as standard FIBCs, lack antistatic treatment and exhibit high surface resistance (≥10¹² Ω). Prone to electrostatic accumulation, which may generate sparks or discharges.  

Primary applications include: Non-flammable, non-conductive materials (e.g., general plastic pellets, dry construction materials) in low-risk environments with controlled humidity (humidity >50%).  

Type B  

Type B FIBCs, also called specially treated FIBCs, reduce static electricity through surface coatings or structural designs but lack a defined resistance range. Antistatic performance is unstable, posing residual risks.  

Primary applications include: Scenarios without stringent antistatic requirements (e.g., short-term storage of low-risk materials). Additional antistatic measures (e.g., ionizers) must be implemented.  

Type C

Type C FIBCs, known as conductive FIBCs, incorporate conductive fibers or metal threads with surface resistance ≤10⁵ Ω. Type C FIBCs rapidly dissipate static electricity via grounding to eliminate spark risks.  

Primary applications include: High-risk flammable/explosive environments, such as volatile solvents (e.g., ethanol, acetone) or explosive dust-prone materials (e.g., metal powders, sulfur).  Note:  Type C FIBCs must be grounded, and operating environments must comply with explosion-proof standards (e.g., ATEX).  

Type D

Type D FIBCs, termed static dissipative FIBCs, utilize antistatic additives or carbon fibers to achieve surface resistance of 10⁶–10¹¹ Ω. Type D FIBCs gradually release static charges to prevent sudden discharges.  

Primary applications include: General antistatic requirements, such as mildly flammable dusts (e.g., flour, starch), low-volatility chemicals (e.g., plastic pellets, rubber compounds), or scenarios requiring humidity control (humidity >40%).  

Aging Resistance Test Duration Standards

The aging resistance of UV-resistant FIBCs is primarily evaluated through accelerated artificial aging tests. Test duration requirements under different standards are as follows:  

- Chinese National Standard: According to the new GB/T standard General Technical Requirements for Plastic Woven Bags, accelerated aging tests typically use UVB-313 lamps with a test cycle of 144 hours (alternating 8-hour UV exposure and 4-hour condensation cycles). Post-aging retained tensile strength must be ≥50%.  

- International Standards:  

• ISO 4892-3/ASTM G154 specifies a broad test duration range (hundreds to thousands of hours), depending on material type and intended usage. Plastic FIBCs generally require 2,000–4,000 hours of testing.  

• ISO 21898: For FIBC aging resistance, UVB-313 lamps are used, with retained tensile strength required to be ≥50%.  

Methods to Extend Service Life  

1. Material Optimization  

   - Add aging-resistant additives: Incorporate UV stabilizers and antioxidants (0.1%–3% by weight) into polypropylene (PP) or polyethylene (PE) raw materials to significantly enhance UV resistance.  

   - Use color masterbatches with high lightfastness ratings to prevent fading and UV degradation.  

2. Production Process – Sewing Techniques  

   - Employ heavy-duty threads with fine needles or composite stitching techniques to improve seam sealing and aging resistance.  

3. Avoid Direct UV Exposure  

   - Store FIBCs in shaded areas or cover them with UV-blocking tarps during storage to minimize sunlight exposure. 

Core Principles for Matching Base Fabric Grammage Based on Material Characteristics  

1. Matching by Material Weight & Density  

- For FIBCs containing lightweight materials (density <0.8g/cm³), such as grains (wheat, corn), cotton, synthetic fiber products, or foam pellets:  

  160g/m² base fabric is recommended. Low-density materials impose minimal load stress, allowing reduced fabric strength requirements to lower packaging costs and improve handling efficiency.  

- For FIBCs containing high-density materials (density ≥0.8g/cm³), such as polymer pellets (PE/PP), aggregates, feed, cement, or mineral powders:  

  220g/m² base fabric is required. Heavy loads (typically 1-2 tons) demand higher tensile strength and puncture resistance to prevent seam failure or bottom rupture.  

2. Matching by Material Physical Form  

- For smooth/low-abrasion materials (powders, spherical pellets, textiles):  

  160g/m² base fabric suffices due to minimal abrasion and tear propagation risks.  

- For sharp/abrasive materials (crushed ores, construction aggregates, metal chips):  

  220g/m² base fabric is critical. Tightly woven structures with enhanced tear resistance mitigate puncture risks during rough handling.  

3. Matching by Material Chemical Properties  

- For non-corrosive/neutral materials (food-grade products, dry industrial goods):  

  160g/m² base fabric applies. Optional PE coating can be added for moisture barrier requirements.  

- For hygroscopic/corrosive materials (fertilizers, salts, acidic/alkaline powders):  

  220g/m² base fabric is mandatory. Reduced inter-fiber porosity limits moisture ingress, while thicker fabric delays chemical degradation. Additives (e.g., anti-corrosion agents) or laminated fabrics may be required.  

4. Matching by Material Flowability & Filling Method  

- For free-flowing materials requiring rapid discharge (feed pellets, grains, powder coatings):  

  160g/m² base fabric offers superior flexibility for easy bag collapse and cost efficiency.  

- For viscous/blocky materials requiring manual breaking or multi-handling cycles (wet clay, sticky powders):  

  220g/m² base fabric ensures structural integrity under repeated flexing and prevents fine particle leakage through dense weaves.  

5. Matching by Operational Environment  

- Indoor/short-term storage applications:  

  160g/m² base fabric** optimizes cost-effectiveness.  

- Outdoor/long-term exposure or high-frequency reuse scenarios:  

  220g/m² base fabric is essential. Higher PP content and uniform UV stabilizer dispersion enhance weatherability and aging resistance.