TREATED POLE INDUSTRY

introduction

The growth of the wood preservation industry has been one of the most important technical developments within the forestry industry. Pole sales achieved in 1999 was an all time record figure of 526 000m3 - an increase of 13% over 1998.

The previous best was 501 000m3 in 1995. The value of these sales in 1999 was R335 million, also a record figure. According to SAWPA (South African Wood Preservers Association) treated pole sales have reached an estimated figure of 65% of total pole sales in 1999, up from 62% in 1998.

treatment of poles

Wood preservation promotes the conservation of indigenous forests by making plantation grown timber effective substitutes for durable timber from indigenous forests. It also reduces the volume of wood used by prolonging the service life of wood for up to 40 years.

Treatment of wood involves the placement, within the wood micro structure, of preservative chemicals which are antagonistic to wood destroying agencies. The major factors which bear on the effectiveness of biological preservation systems are:


  • The biological hazards to which the wood will be subjected in service.
  • The toxicity of the preservative chemical to the particular wood destroying organisms which will be encountered.
  • The penetration and retention of the preservative chemical.

Because timber in service meets different degrees of hazard, the industry has developed a Hazard Classification. This specifies the amount of chemical required as well as the depth of chemical penetration needed in each piece of timber. The more hazardous the application, the more and deeper the chemical.

  • H0 Internal i.e. moldings, ceilings, etc.
  • H2 Internal i.e. roof trusses, flooring, etc.
  • H3 Exterior above ground i.e. outdoor decking, cladding, etc.
  • H4 Exterior in ground i.e. agricultural posts, bridges, carports, etc.
  • H5 Freshwater i.e. retaining walls, jetties, drains, walkways, etc.
  • H6 Marine i.e. jetties, piles, walk ways, etc.

POLE MARKING

Each piece of properly treated timber is required to have the following information permanently applied:

  • the identity of the treater
  • the year that the pole was treated in
  • the SANAS approved quality mark
  • the SANS specification number
  • the hazard classification

The SABS, UPC and SATAS are currently the inspecting bodies that ensure adherence to certain specified requirements. Their mark of compliance means that the product is fit for the intended end use. See the page on SANS standards for more information about marking according to SANS 1288 or SANS 457 / 753 / 754 (previously SABS 1288 or SABS 457 / 753 / 754).

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