New Zealand Building Code Clause G7 Compliance Assessment Tool: Development and Implementation
The New Zealand Building Code Clause G7 (NZBC G7) minimum requirement for natural light is not being met in around half of New Zealand apartments post-construction. The main reasons for this are an acceptable solution that is not effective for apartment buildings and a lack of tools for Territorial Authorities to assess accurately whether an apartment will meet the minimum requirement. This report outlines the process involved in developing a simplified tool to assess quickly natural light compliance in apartments and preparing it for implementation. The tool was developed through simulation of factors that affect daylight performance at the point in the room specified in the Code: the back of habitable rooms. From these simulations statistical analysis was used to develop mathematical relationships between building features and light levels. These relationships were used to create a tool that specifies whether an apartment would require simulation to prove compliance with NZBC G7. Calibration measurements were performed, comparing simulated and real measurements in 97 apartments with the predictions of the tool. These demonstrated that the tool provides reliable results, hence determining the accuracy of the predictions provided by the tool. The final step in the research was for potential end-user groups to evaluate the usability and functionality of the tool. The conclusion of this process is that a tool has been developed that is simple and easy to use, is sufficiently accurate for application by Territorial Authorities as a decision tool and can be easily implemented.