Sawn Timber

For problems arising with the quality of pallet and packaging timber such as bluestain or white moulds, go to the page TREATMENTS/MOISTURE

There is no single wood quality grading system in Europe, a surprising fact that frustrates those new to the industry and makes understanding timber supply that much more difficult. If buying from British or Irish mills there is less of a problem, due to fewer species and no language problem but packaging timber buyers requiring large volumes from overseas are obliged to make their own ad-hoc arrangements with individual sawmills for future supply. They will need to agree acceptable visual quality including - amount of wane, knots, inclusion of weak species, dimensions, accuracy of sawing, surface finish, moisture content and if the use of chemical antistain solutions is permitted.

French maritime pine pallet boards

Wood is a natural material and where quality grading systems for wood exist they were locally developed and widely used long before the advantages of international standardisation were recognised. This is quite unlike the wide ranging ISO agreement on pallet plan sizes where the advantages of international standardisation are well recognised – they either fit freight containers or they don’t. Even outside of packaging there is no international system for specifying wood grades for end use. There are well understood commercial systems that have been in use for many years, but they are only national, or at best used by only a handful of countries, such as Scandinavia. More recently in Europe it has become commonplace to specify ‘mixed grade’ which means a mix of 1st class (square material) with an agreed amount of 2nd class (material with some wane). This appears to be happening with both softwood and hardwood purchases and is leading to considerable debate as to what is the acceptable mix eg. 80/20 (wane free/wane) and what is the acceptable amount of wane on a permitted piece, etc.

The Baltic area is important for timber used in pallets and packaging, but the term widely used by the pallet industry of ‘Baltic mixed’ can create confusion because of the increasing use of the supply industries new ‘mixed grade’ term. ‘Baltic mixed’ a term long used by the pallet industry refers to a mix of hardwood and softwood species. This can create quite different problems, for example one of safety. What is ‘Baltic mixed’ as so often quoted? It is in fact a random mix of strong species mixed with weak species and a pallet designer/specifier can hardly work with that, since the weakest in the mix have only half the strength of the strongest. However, alongside this, much commercial Baltic softwood is highly sought after for top grade pallets and packaging, such as 5th grade red/whitewood.

Adding to the weaknesses in such a species mix (apart from high quality rental or exchange pallets) white pallets (non-rental) are usually built with a small safety factor. It is therefore difficult to have any confidence in a pallet’s strength if Baltic mixed has been used. For safety, the manufacturer must assume that it includes random amounts of weak species and adjust pallet board thickness upwards to compensate. The Baltic area produces some of the highest quality, strongest softwoods anywhere but unfortunately if these are randomly mixed with the weakest, the perceived and actual value of Baltic timber for heavy-duty pallets is much less than it could be.

In 1999 a grading system for European packaging wood was published as EN 12246: Quality classification of timber used in pallets & packaging which contains a new system specifying two packaging qualities, BS EN P1 and BS EN P2. To fully understand EN 12246 it needs to be read alongside companion document EN 1310: 1997: Round and sawn timber - Method of measurement of features. However, in reality EN 12246 has had hardly had any effect on European packaging timber markets, agents or buyers. The older, all different, occasionally used, Scandinavian, Canadian, Russian and USA visual appearance grading systems all remain in use.

There has always been a market for strength graded timber for house building in the UK, Germany and Scandinavia. Strength grading has now grown and includes most EU states. However this applies to high quality timber for house building and is above the prices pallet and packaging markets expect to pay, so is of little interest. A further problem is that strength graded timber is not available in thicknesses below 35mm.

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PDF31e Weathering of pallets stored outside. (PDF 140kb)
PDF71d Imported wood species suitable for packaging. (PDF 141kb)
PDF71h Baltic hardwoods and softwoods in pallets. (PDF 11kb)
PDF75b Kilned Sitka spruce may twist on kilning. (PDF 11kb)
PDF75c Moisture content and wood fibre saturation point. (PDF 65kb)
PDF75g Frozen packs of pallet timber. (PDF 61kb)
PDF77e Introduction to wood moisture meters. (PDF 69kb)
PDF78b Natural Durability of Timber used in packaging. (PDF 27kb)
PDF79a Permissible bark and wane in pallets and packaging. (PDF 141kb)
PDF79e Wood quality grades for pallets and packaging EN 12246 summary. (PDF 20kb)
PDF79f CP Chemical industry pallets wood quality requirements. (PDF 53kb)
PDF79h Species with the worst resin pockets. (PDF 22kb)
PDF79i High temperature kilning may reduce resin exudation. (PDF 22kb)
PDF79k Bending strength properties of hardwoods. (PDF 69kb)
PDF79m Live and dead knots or knot free. (PDF 112kb)
PDF80a1 Positional and timber tolerances - International. (PDF 56kb)
PDF80b1 Positional and timber tolerances - Commercial. (PDF 54kb)
PDF86e Sustainable and recovered timber sources for pallets and packaging. (PDF 14kb)
PDF86g Environment - Pallets per tree - average spruce conifer. (PDF 87kb)
PDF89g Pallets & Packaging used in sub-zero temperatures. (PDF 12kb)
PDF93a UK Wood packaging volumes and woodwaste reuse study (PDF 1954kb)
PDF98d Timber embrittlement through unusually high kiln temperatures. (PDF 49kb)
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