Abatement notices, applications for enforcement orders, interim enforcement orders and infringement notices can be used to enforce noise emission controls within a national environmental standard, a plan and in resource consent conditions. It is important to check the controls, rules or consent conditions are enforceable. While national environmental standard controls plan rules and consent conditions are often clear and concise (and can be enforced by law), some controls/rules/conditions have minor omissions or wording problems that can lead to difficulties.
Noise levels are typically determined by taking samples and arranging the results in order from loudest to quietest. The number that is 10% below the loudest measured level becomes the L10, often called the average maximum. Similarly, the L95, often called background level, is 95% below the loudest measured level (i.e. nearly the quietest).
Sound energy is measured in decibels (dB) with most measurements being undertaken on the A-weighted (dBA) scale as this most closely matches the human ear. The scale is logarithmic rather than linear so noise increases tenfold for every additional one decibel unit recorded.
Guidance on noise management, including the preparation of plan rules for controlling noise and the setting of conditions can be found in the guidance notes on noise in mixed-use environments and land transport noise.