How long can PE/PP granulate be stored in a big-bag?

PE/PP granulate manufacturers typically specify a 24-month shelf life from production date under correct storage conditions. Big-bags protect the material from UV, moisture and contamination. If kept dry, UV-free and below 30 degrees C, the material retains its specification for the full period.

How many big-bags can be stacked on top of each other?

Maximum stacking height depends on the manufacturer's Stack Factor declaration on the bag label. Typical values are 3–5 layers. The SMIALA terminal strictly observes the Stack Factor printed on each bag.

Should big-bags be strapped or wrapped on pallets?

Strapping or stretch-wrapping is recommended for transport stability. At the SMIALA warehouse we store big-bags directly on the concrete floor in neat stacks without pallets, allowing higher density storage.

What happens if a big-bag is damaged?

A damaged bag (broken lifting loop, torn fabric) is quarantined and reported to the client before being accepted into storage. SMIALA offers repackaging of damaged bags as an additional service.

Can different materials be stored in the same warehouse?

Yes, but with zone separation — different materials are stored in clearly labelled separate zones. Materials that are chemically reactive with each other are not stored in the same zone.

04.07.2025

Big-Bag Warehousing: Rules and Best Practices

Transloading granulate from big-bags to a silo trailer

At a Glance

Big-bags (FIBC) with PE/PP granulate can be stored safely for up to 24 months in a dry, enclosed, UV-free warehouse. Key rules: Stack Factor compliance, FIFO rotation, zone separation.

What is a big-bag and why does its storage require attention?

A big-bag (FIBC — Flexible Intermediate Bulk Container) is a flexible bulk transport container made from woven polypropylene fabric, with a capacity of 500–2000 kg. It is the standard packaging for technical granulates, fertilisers, food-grade powders and many other materials.

Despite its simple construction, improper storage can cause serious problems:

Stack collapse (workplace safety risk)
Material degradation (UV, moisture, contamination)
Loss of traceability (batch mixing)
Fabric damage (weave, lifting loops)

Key rules for safe big-bag storage

Stack Factor

Every big-bag carries a Stack Factor on its label — the maximum number of bags that can be stacked vertically. Typical values are 3–5. Exceeding the Stack Factor risks deforming lower bags and damaging lifting loops. The SMIALA terminal enforces Stack Factor compliance.

Storage conditions for PE/PP granulate

Temperature: 5–30°C (avoid freezing and overheating)
Relative humidity: below 65%
Lighting: no direct UV exposure (UV causes photodegradation in PE/PP)
No reactive chemicals nearby: some volatile substances can permeate through FIBC fabric

FIFO rotation

FIFO (First In, First Out) means the earliest-received batch is always the first dispatched. This prevents:

Material exceeding its shelf life while newer stock is dispatched ahead of it
Traceability issues in quality complaints

The SMIALA warehouse operates strict FIFO: every inbound batch is registered with its arrival date and storage location.

Zone separation

When storing multiple materials and for multiple clients, physical zone separation is essential. Zones are labelled with client codes and access is restricted per ISO 9001:2015 procedures.