Technical files

Treatment

Impregnability of coniferous species

According to the hazard class the wood is used for (see technical file), each species should be treated with the right insecticide-fungicide to protect it. To carry out this treatment in the right conditions, you need to have a sufficient quantity of the product so that it penetrates into the wood and impregnates it. However, not all timber can be impregnated in the same way.

Impregnability classes of timber marketed
by Scierie Mandray

Fir tree

  • Sapwood moderately impregnable, variable.
  • Heartwood slightly to moderately impregnable.

Spruce

  • Sapwood slightly impregnable, variable.
  • Heartwood not to slightly impregnable.

Scots pine

  • Sapwood impregnable.
  • Heartwood not to slightly impregnable.

Douglas fir

  • Sapwood slightly to moderately impregnable.
  • Heartwood not impregnable.

Larch

  • Sapwood moderately impregnable, variable.
  • Heartwood not impregnable.

From all these factors, we can state that each species has a maximum life in the various classes, due to the natural durability of the heartwood and sapwood, and the treatment capacity due to its impregnability status.

Maximum hazard classes according to treatments and species

Fir tree

  • Tank treatment: Class 2 and,
    if thickness under 27 mm, Class 3a.
  • Autoclave treatment: Class 3b.
  • Untreated: none.

Spruce

  • Tank treatment: Class 2 and,
    if thickness under 27 mm, Class 3a.
  • Autoclave treatment: Class 3b.
  • Untreated: none.

Scots pine

  • Tank treatment: Class 2 and,
    if thickness under 27 mm, Class 3a.
  • Autoclave treatment: Class 4.
  • Untreated: none because sapwood is present in the cuts.

Douglas fir

  • Tank treatment: Class 2 and,
    if thickness under 27 mm, Class 3a.
  • Autoclave treatment: Class 3b.
  • Untreated: none or class 3a for sapwood-free cuts.

Larch

  • Tank treatment: Class 3a and,
  • Autoclave treatment: Class 3b.
  • Untreated: Class 3a (sapwood-free)