Processed Wood

Processed board or sheet materials such as plywood, strandboard, hardboard and chipboard are collectively known as panel products and are made up of wood in the form of strips, veneers, chips, strands or fibres. This material can also be made up in non-sheet form such as chipboard (sometimes known as composite) blocks particularly used as deck spacers in pallets, see figure below. Sawn wood, even when accurately machined and having been kiln dried or planed, is not defined as processed wood. Plywood was developed to provide large panels with a dimensional stability lacking in sawn timber with good strength properties along and across the sheet. A listing of relative sheet properties is here and in BS 1133: 2011. Straight well-grown logs are required for peeling the veneers for plywood manufacture. The categories usually recognised within this group that are used in packaging are:-

4.3_400
Particleboard pallet blocks
  • Plywood sheet
  • Waferboard and strandboard (OSB) sheet
  • Wood chipboard or composite wood blocks, particularly used in pallets,
  • Wood chipboard  sheet also known as wood particleboard sheet
  • Fibre building board including hardboard and medium density fibreboard (MDF)

Wood particleboard and fibre building boards were developed to provide utility sheet materials with uniform properties. They often utilise forest thinnings, lower quality trees, sawmill waste or reclaimed waste wood. The main end use in packaging is for pallet blocks with small amounts used in printers pallets where dryness is essential. Wood-based panel products are covered by a series of EN Standards but unlike previous standards, which were largely prescriptive and based on manufacturing requirements, new ENs are based on performance requirements such as the water resistance of gluelines and limiting formaldehyde gas emission. Appropriate grades of board materials for packaging are as follows:

Plywood with a water resistant glueline in the UK is historically known as WBP, but more recently by the European standard term Exterior, it is suitable for most end uses but for export to Australia there is also a need for unusual phytosanitary safeguards (see ISPM 15 web page for details). Water resistant exterior glueline plywood can be used for medium term packaging but whilst defining specification to plywood suppliers is easy, it requires considerable experience to ensure you receive this grade. The pitfalls of using interior gluelines and/or species which discolour with mould or sapstain in damp conditions are often seen in packaging.

OSB (oriented strandboard) and waferboard is classed with plywood as it is made in a similar manner, some end uses can be the same.

Wood chipboard also called composite when made as short blocks is heavier as a sheet material and is much less strong than plywood, but as short block material for pallets it is widely used but needs care when used in place of sawn timber (formaldehyde emmission see our sheet 88h) can also cause weakness issues in in racking. A problem also with block material is knowing the wet and the dry strength since most packaging gets wet and some unbranded material may delaminate in wet conditions. External appearance is little help and it must be quality assured if it goes into full perimeter (highly stressed) pallets. As sheet, wood chipboard is not a normal choice except where used for the paper printing trade where it can be ideal since it is normally supplied in a very dry state of about 2 to 4% moisture content (as are composite blocks).

Fibre building board is available in Standard or Tempered (latter has moisture resistance) Grade and is used for light packing case sheathing.

New materials such as finely chipped rubber from scrap vehicle tyres have been introduced as pallet blocks but the low percentage of wood in the mix means they are not classified as timber. Such material can be nailed as easily as timber and often has good compressive strength.

For Downloading...

Close this box This is a members only document.  Login if you are an existing member.

Click Here for information on joining PalletLink to gain access to all the benefits of a subscription.
PDF73a Pallet blocks from scrap crumb rubber. (PDF 10kb)
PDF73a Pallet blocks from scrap crumb rubber. (PDF 10kb)
PDF73c Composite chipboard blocks v plastic recyclate. (PDF 33kb)
PDF73e Composite pallet blocks v sawn wood. (PDF 123kb)
PDF73m Marine plywood to BS 1088. (PDF 109kb)
PDF74c Six types of woodbased sheet material. (PDF 76kb)
PDF77h Issues with composite chipboard blocks for high quality pallets. (PDF 10kb)
PDF85f ISPM 15 treated wood packing imported into the EU to be resused in Europe. (PDF 11kb)
PDF85g ISPM 15 - Portugal - New phytosanitary requirements 2009. (PDF 11kb)
PDF85h ISPM 15 - Australia - Phytosanitary requirement - plywood. (PDF 54kb)
PDF88m Far Eastern import measures for Zika virus prevention. (PDF 63kb)
Web Design and Hosting by Acuras Web Development
Copyright © 2007-2017 PalletLink