Description

BRANZ conducted field trials in Rotorua to examine how metals degrade in geothermal environments. Different metals showed very different responses. 

Scope

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