Paper
The heavy loads involved in paper making require strong pallets and so timber pallets are widely used. However, moisture uptake by paper can be a problem and wood pallets have to be well dried before use. In Northern Europe a pallet supplied at normal moisture content (mc) is typically 20-25% but this is still far too wet for the paper industry. Their target is usually below 15% mc.
250 kg reel
Even 15% can produce paper damage or encourage paper mites during storage. Wood, kiln-dried to a low moisture content (level agreed with the customer) is essential for success in the paper industry. PalletLink have frequent enquiries arising from undried pallets being used in the paper industry.
The use of a resistance type moisture meter by the pallet maker (and papermaker) is essential and a good one can quickly measure moisture levels in sawn timber (not chipboard or mdf) down to as low as 10%, we have more on this on our MEASURING MOISTURE page.
Shrink or stretch wrapping of paper loaded onto fairly dry wood pallets can still cause water damage problems because the humidy under the stretch wrapping immediately rises above that of the outside air. To determine the values of wood moisture content that trigger this damage, we have produced a Datasheet - Equilibrium Moisture Content (see below).
After drying, pallets for paper use need to be kept in a dry building, although heating is not needed, ventilation and good overhead cover is.
Note that if polythene is used between deck and paper it is not impermeable, it transmits a small amount of water and may still cause damage. This is not a safe way of avoiding kiln drying. Our datasheets on moisture transmission on the EXPORT CASES page gives further advice.
The use of wood chipboard sheet as a pallet deck is common to ensure dry decks. This is because wood chipboard (also called composite or particleboard) is manufactured at around 2% moisture content and when delivered to a customer in good condition is rarely above 6% moisture content, a very safe level for paper. Although this can be cheaper than kiln drying softwood deckboards, wood chipboard is less than half as strong as sawn timber (thickness for thickness) so you must ensure it will support the intended loading for the pallet.
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75e Wood Equilibrium Moisture Content Table (EMC). (PDF 61kb)76b Book lice, paper mites on pallets. (PDF 107kb)76c Booklice problems draft (PDF 123kb)77e Introduction to wood moisture meters. (PDF 69kb)