There is often confusion over the differences between heat treated and kiln dried wood. Damaged wood can be a costly problem, and with ISPN15 regulations requiring all wooden forms of packaging are heat treated before they are used for export, it is important to understand the differences. Read on to find out more about heat treating and kiln drying pallets as we answer your most asked questions about these crucial services.

What is heat treating and what is kiln drying?

The clue is in the name. ‘Kiln dried’ refers to timber that has been dried in a kiln to reduce moisture content. Notice that there is no mention of temperature. The term ‘heat treated’ refers to wood that has been heated to a specific temperature. Note that there is no mention of drying or moisture content.

But what exactly is the difference between heat treated and kiln dried?

The key to understanding the difference is to understand the main aim of each one. Kiln drying is used to reduce the moisture content of timber. By extracting the moisture in a kiln to below 15%, the wood is lighter (and cheaper to transport) and reduces any possible blue stain or discolouration later. The goal of heat treatment is to eliminate any living organisms in the wood, to ensure pests and diseases are not introduced to other countries during shipping.

Heat Treating

What is a heat treated pallet?

Wooden pallets are used to transport millions of items every day. They are essential for international shipments and national deliveries. However, since they are made from organic materials (trees), they can also be a hotbed for pests and diseases, which can be easily transported from one area of the world to another. Heat treating pallets is a necessary step to ensure pests and diseases are not introduced to places they did not originate and do not belong.

How do you heat treat a wooden pallet?

Wooden pallets must be heat treated in accordance with ISPM 15 guidelines that lay out the specific temperature and duration. Our wood packaging is heated in our specialist on-site kiln for approximately 3 hours ensuring the wood core temperature reaches a minimum of 56°C for at least 30 minutes.

What are the benefits of heat treatment?

Although less moisture is removed during the heat treatment process than kiln drying, moisture is still removed, making the pallets lighter and cheaper to transport. Parasites in the wood are removed, reducing the spread between countries, and decreasing the risk of cross-contaminated goods. By helping to preserve the wood, you will also benefit from increased durability and pallets that can be recycled and reused, helping to reduce waste.

What is ISPM 15?

ISPM 15 stands for International Standards for Phytosanitary Measures No. 15 and is the industry standard regarding wooden pallets, created to avoid the risk of spreading pests and diseases around the world. It requires that all wooden forms of packaging, including wood pallets, are heat treated before they are used for shipping. The standard has been adopted by all members of the European Union and 14 other countries globally.

How do you know if a pallet has been heat treated?

Visually, timber that has been heat treated can sometimes look darker and more worn. But do not be deceived! A darkened stained appearance occurs when the sap in the timber reacts to the heat process. In addition, to show that pallets have been through the heat treatment process, they will be stamped with an authentication mark that is recognised worldwide. This consists of the IPPC logo and a two-letter International Standards Organisation country code e.g. GB for pallets from Great Britain. This proves that the wood has been heat-treated appropriately and is free from pest infestations.

How long do heat treated pallets last?

ISPM 15 will last the lifetime of the pallet so, once it has been heat treated to ISPM 15 standards, the pallet can be reused to ship and transport goods globally without the need for re-treatment. A heat-treated pallet is designed to have a long life, not just free from pests and decay, but also hardened by the heat treating process. How long a pallet will last will depend on how well it is looked after. They can last for up to 10 years in their primary function or recycled into furniture and other home projects can see this doubled or even tripled.

Can heat treated pallets be reused?

Pallets which have been heat treated are safe to reuse, as a heat treated pallet has simply been heated to a specific temperature for a certain time to kill insects and larvae. ISPM 15 will last the lifetime of the pallet so once it has been heat treated to ISPM 15 standards, it can be reused to ship and transport goods globally without the need for re-treatment. You can also reuse heat treated pallets for DIY projects around the home. However, some woods may have had additional treatments, such as Methyl Bromide, which can be harmful and should therefore be avoided for home projects.

Can you burn wood pallets?

If your pallets haven’t been treated with any chemicals, they are most likely safe to burn. Do take care when burning your pallets as the they are normally very dry and thin and tend to burn with a hot flame.

Kiln Drying

What is kiln drying?

Kiln-dried wood is timber that has been dried in a kiln to reduce the moisture content. Moisture in timber can cause a whole host of problems, including twisting, cracking, warping and shrinking. These issues cost millions of pounds in damages each year so kiln drying serves to bring moisture levels down to a workable range.

Does kiln drying kill termites, woodworm, and other bugs?

Kiln drying is not a reliable way to kill insects in wood, owing to the cooler temperatures used during the kiln drying process compared to the more intensive heat treatment process. The dryness may eradicate some of them, but the lethal temperature required to kill woodboring insects varies considerably among families and even genera.

What are the benefits of kiln drying pallets?

Kiln drying pallets limits splits and movement associated with wet timber that has air dried. When pallets are kiln dried, the reduction in moisture means the weight is also reduced. This makes them better for export as the transportation cost, which is charged by weight, is reduced. The dryer surface is also better for moisture-sensitive products, such as paper and cardboard. The reduced moisture also decreases any blue stain or discolouration.

How is timber kiln dried?

Just like heat treated timber, wood is heated in a kiln. However, kiln drying is a much longer process with a gentler heat. The timber stays in the kiln for upwards of 3 days, where the moisture is extracted into the air, lowering the moisture content of the wood to below 15%.

We can make packing cases, pallet collars and supply any form of wooden packaging. Please get in touch to let us know your requirements.