BRANZ conducted field trials in Rotorua to examine how metals degrade in geothermal environments. Different metals showed very different responses. The scope of NZS 3604:2011 Timber-framed buildings requires a 50 m separation from geothermal hot spots. This will not always reduce corrosion rates to a safe range.
Wood discolouration is likely to be the result of copper sulphide forming on/in wood treated with copper-based preservatives.
This bulletin covers:
- corrosion of mild steel, zinc and copper
- corrosion of aluminium and stainless steel
- the performance of aluminium-zinc alloy-coated steel
- distance effects of corrosion in geothermal environments
- discolouration of wood.