Dielectric heat treatment process kills the fungus blue strained wood and other types of fungi.
The heattreatment kill fungus hypher, (i.e. the growing cells) as well as fungus spores inside the wood as well as on the surface
If the wood will be resurrected after treatment it only can take place by re-contamination with spores from outside.
It is typical spores that spread, fungus hypher spread usually not very good.
Q: We currently heat treat pallets via ISPM 15 standards. What does this Dielectric process entail in addition to regular heat treatment. Occasionally if our pallets do not dry properly after heat treatment they will mold. It doesn't happen often and we are diligent about letting them dry but does this process eliminate the need for extra drying time? Just gathering some information for my reference.
A: ISPM 15 heat treatment does not inactivate the fungi due to too low temperature.
When the pallet is dried the fungi are still in the wood, but it will stop growing.
If the moister contend increase again the fungi are growing again.
Drying only makes sense if the wood equilibrium moisture in the open air is less than the moister that gets fungus to grow. If the equilibrium moisture is higher the fungus are growing again.
ISPM 15 heat treatment by dielectric heating inactivates fungus hypher, (i.e. the growing cells) but not the fungus spores which will start to grow if the moister contend in the wood is high enough.
If the heat treatment is performed by dielectric heating at higher temperature than ISPM 15 heat treatment requires, becomes fungal spores inactivated as well.
This means that there are no fungi in the wood to grow even if the moisture content is high.
If the fungus will be resurrected after dielectric treatment it only can take place by re-contamination with spores from outside.
Processing time for wood pallets are 8-10 minute and the energy consumption are less than 50 % of the consumption when drying.