Adding the PA additive to CCA provides poles with benefits comparable to PCP such as preventing hardening, while retaining the advantages of a water-borne treatment, and this over the service life of the pole.
Developing a Treatment Especially for Wooden Poles
From the end of the 1930’s to the beginning of the 80’s, pentachlorophenol (PCP) was widely used in the preservative treatment of wooden poles and railway ties. However, due to health and safety concerns, public utilities were still trying to reduce the use of PCP-treated poles. In a report filed in December 2021, the United States Environmental Protection Agency (US EPA) has announced its final decision to phase out the use of the wood preservative pentachlorophenol (PCP) over the next five years, after determining that the substance poses health risks to workers. Registrants of the substance can continue to produce, sell and distribute wood preservatives containing PCP until 29 February 2024. However, wood treatment facilities can use existing stocks of PCP-containing products to produce treated wood until 28 February 2027, after which date the use of PCP will be prohibited.
Poles treated with CCA (chromated copper arsenate) and public utilities have been progressively replacing PCP-treated poles since the 80’s. Over the last decades, the popularity of CCA- treated poles has increased significantly in North America; they are now widely accepted.
Unfortunately, the CCA treatment tends to harden the wood over time, making it more difficult for the linesmen to drill and climb. This is one of the reasons why PCP usage was maintained for some applications.
Testing was undertaken to find a solution to the hardening of poles treated with CCA, including the addition of polyethylene glycol (PEG) to the preservative solution. This additive solved the hardening problem – for a while. Unfortunately, extensive laboratory and field testing has shown the effect of PEG on pole hardness to last no more than 3 years. The long-term results were less than satisfactory, as the effect waned, and the poles became too hard to safely climb.
The CCA-PA pole
In 1998 an R&D partnership initiated by Hydro-Québec with Arch Wood Protection, developed a polymer-based additive (PA), which, when injected into CCA-treated wood poles, offers the benefits of a CCA-treated pole, as well as the climbability benefits of poles treated with oil-borne wood preservatives. The result is the CCA-PA treated utility pole, approved by Hydro-Québec, Bell Canada and Group CSA (O80.207-05 standard), and already in widespread use.
CCA-PA benefits compared to PCP, CCA or CCA-PEG
Adding the PA additive to CCA provides poles with benefits comparable to PCP such as preventing hardening, while retaining the advantages of a water-borne treatment, and this over the service life of the pole. A pole treated with CCA-PA offers:
- Good climbability over the service life of the pole
- Significant increase in the service life of the pole to more than 50 years.
- CCA-PA does not affect wood’s natural low conductivity nor significantly affect its strength
- Fixation of the preservative to the wood fibre prevents it from migrating to the bottom of the pole, or from leaching out
- CCA-PA poles are non-oily, non-staining, and have no fumes
- Poles can be reused without re-treatment
- Reduced environmental impact
We have availability in poles from 25’ to 65’ in all industry recognized classes.