In industrial packaging procurement, the GSM (Grams per Square Meter) of PP woven fabric is one of the core parameters that determines bag performance. Choosing the wrong GSM can lead to increased breakage rates or even safety incidents.

What is GSM?

GSM refers to the weight per square meter of woven fabric. Common PP woven fabric GSM ranges from 50 g/m² (lightweight) to 120 g/m² (heavy-duty). Higher GSM means thicker fabric and greater tensile strength, but also higher cost.

Choosing GSM Based on Load Capacity

Bag load capacity is determined by GSM, width, and sewing quality. Here is a practical reference:

• 50–65 g/m²: For products weighing 10–25 kg per bag, such as food additives and powder pigments
• 70–85 g/m²: For standard industrial products weighing 25–50 kg, such as fertilizers and plastic pellets
• 90–110 g/m²: For heavy loads above 50 kg, such as cement and plaster powder
• 110 g/m²+: For high-density bulk materials or scenarios with outdoor stacking

Impact of Transportation Mode

Different logistics scenarios have additional GSM requirements:

• Sea freight containers: Stackable 6–8 layers high; choose 85 g/m² or above
• Road transport: Vibration and impact are significant; add 10–15% to theoretical GSM
• Rail transport: High impact frequency; recommend 90 g/m² or above

Stacking Height Considerations

Bags under stacking experience static pressure, but long-term stacking causes fabric creep. GSM recommendations by stacking layers:

• 3–4 layers: 85 g/m² is generally sufficient
• 5–6 layers: Recommend 95–105 g/m²
• 7+ layers: Require 110 g/m² or above, plus reinforced side seams

Practical Recommendations

When placing orders, provide the following information to get the most accurate GSM recommendation:

1. Target load per bag (kg)
2. Product bulk density (g/L)
3. Bag dimensions (L × W in cm)
4. Transportation mode and stacking layers
5. Whether inner liner or moisture barrier is needed

Avoid choosing lower GSM solely for cost savings. The cost of breakage-related losses and reshipping typically far exceeds the initial savings.