How do you choose the correctly treated wood for a particular project?

The Building Act 2004 sets out the legislation on building standards and procedures. The Building legislation and regulations page of the website has detailed information on this.

Six Hazard classes are used to describe the service exposure conditions in relation to the biological hazard.  They are set out in the Hazard Classes .pdf.  More detail about the actual hazards is provided in the found on the Hazards page of the website.