Material Bulk Density for Storage Calculations

Plant area calculations for tyre recycling operations depend on knowing the bulk density of each material at each stage of the process. Bulk density (tonnes per cubic metre) converts mass-based inventory targets (e.g., 30 days of feedstock) into the actual floor area and storage height required. This five-material reference table covers the typical bulk densities from incoming whole tyres through to finished product forms.

Whole tyres have the lowest bulk density at 0.35 tonnes per cubic metre (t/m³). A tyre's irregular shape and large hollow air volume mean that stacked tyres are mostly air — a tonne of whole tyres occupies approximately 2.85 m³ of storage space. This creates a significant difference between the mass of feedstock and the storage area needed, particularly for plants planning 30-day feedstock buffers. At 10 tonnes per day input, a 30-day buffer of whole tyres requires approximately 857 m³ of storage volume — roughly 1,750 sq ft at 5 metres stacking height.

Shredded tyre chips (50–150 mm pieces) pack more efficiently at 0.45 t/m³ because the irregular shapes nest together. Crumb rubber (10–40 mesh, approximately 0.4–2 mm particle size) packs to 0.48 t/m³ — slightly denser than chips but not dramatically different because the particles are still granular, not solid. Fine rubber powder (below 80 mesh, below 0.18 mm) packs more densely at 0.55 t/m³ as the finer particles settle into a more compact bed. Reclaimed rubber sheets are the densest material at 1.10 t/m³ — approximately three times denser than crumb rubber — because the devulcanisation and sheeting process produces a semi-solid slab with no significant void space. Reclaimed rubber storage is much more compact per tonne than any granular form.