New ventilation rules take effect in NZ

G4 Ventilation Acceptable Solution G4/AS1 Fifth Edition provides a compliance pathway for meeting the ventilation performance requirements of Clause G4 of the New Zealand Building Code, specifically for the ventilation of buildings and gas-fuel appliances.

The transition from the Fourth Edition ended on July 31, 2026, and as of August 1 building consent applications can no longer rely on that edition.

The NZ government says the Fifth Edition, which has been published in standalone format, has improved clarity, consistent structure, and updated terminology.

The updated document covers natural, mechanical, and combined ventilation systems for spaces within buildings, as well as specific provisions for gas-fuel appliances and flue locations. The changes provide greater clarity for designers and contractors.

The Ministry of Business, Innovation and Employment (MBIE) has been progressively updating Aotearoa’s building regulatory framework. As awareness around indoor air quality (IAQ) has grown, the standards and regulations surrounding the ventilation sector have also grown.

Mechanical ventilation systems must now deal with multiple competing objectives – such as providing sufficient outdoor air to increasingly airtight buildings, and managing moisture and contaminant issues while also minimising energy consumption.

• Access the documents here.

Image by MH Rhee from Pixabay.

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