Copper chrome arsenic (CCA) treated timber (Hazard Level H5&
H6)
Copper chrome arsenic (CCA) treated timber is timber that has been
treated with preservative containing copper, chrome and arsenic.
CCA treatment prolongs the life of wood, which is why CCA treated
timber has so many common uses, including in playground equipment,
fences, retaining walls and jetties. Recently concerns have been
raised regarding the potential health risks of CCA treated
timber.
The preservation process
The CCA process was pioneered in 1933 and is used worldwide. Copper
and arsenic in the preservative protect the wood from insect and
fungal attack. Chromium (chrome) locks the copper and arsenic into
the timber and reduces the risk of the chemicals leaching out. The
CCA process gives the treated wood a green tint. New Zealand, the
USA and Australia are the three highest consumers of CCA treated
timber.
Copper Azole - An Alternative to CCA
Copper Azole is a water-based bluish-colored liquid consisting
primarily of copper with a small amount of carbon-based
tebuconazole and propiconazole fungicide and insecticide. It is
wood preservative that prevents fungal decay and insect attack.
Copper azole wood preservative is used for treating a variety of
softwood species including southern pine, red pine, ponderosa pine,
hem-fir and Douglas fir.
Applications of Copper Azole
Water-based preservatives like copper azole leave wood with a
clean, paintable surface after they dry. Copper Azole is registered
for treatment of millwork, shingles & shakes, siding, plywood,
structural lumber, fence posts, building and utility poles, land
and freshwater piling, composites, and other wood products that are
used in above-ground, ground contact and fresh water as well as in
salt water splash (marine) decking applications.
Difference between CA-AG (Above Ground- Hazard Level H3) &
CA-GC (Ground Contact- Hazard Level H4) basically is the different
dosage of chemical used.
COPPER AZOLE vs CCA
Property | Copper Azole | CCA |
Formulation:
| Waterborne solution containing copper, tebuconazole and boric acid | Waterborne solution containing copper, chromium and arsenic |
Timber appearance:
| Initially pale green ageing to green/brown. Weathers to grey over
time | Initially pale yellow ageing to pale green. Weathers to grey over
time |
Environmental:
| low metals content in timber and waste
| high metals content in timber and waste |
| Disposal of treated timber: | Burial in landfill or incineration where approved | Burial in landfill only
|
