Homestar Technical Clarification Rulings
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| Technical Question Title | Tool Version | Date Released | Credit Name | Tool Category | TC Link |
|---|---|---|---|---|---|
| TQ219 Alternative Compliance for Thermally broken window | v5 | September 2024 | HC4 - Moisture Control | HC | Link |
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Approved Ruling: The NZGBC approves the proposed alternative to meet the thermally broken window frames requirement of HC 4:mosisture control credit by demonstrating through simulation that the surface of the frame at the coldest point meets the ANSI/ASHRAE Standard 160-2021, Criteria for Moisture-Control Design Analysis in Buildings. That is the mould index is below 1 on the internal surface. This alternative approach is accepted because it fulfils the aim of the credit requirement which is to reduce condensation risk on the frames to improve IEQ, reduce risk of mould and increase durability. Also, considering that this is an existing building, there are sustainability advantages from a cost and carbon perspective for retaining the current windows, essentially while meeting the aim of the credit requirement. Please see more comments below: The project must provide evidence that: 1. Occupancy, room volume and ventilation rate for the most conservative apartments be used in the analysis; 2. Ventilation must be continuous and specified as such in the documentation; 3. Ventilation must have acoustic consideration (i.e. openings attenuated or fan noise considered) to reduce the chance occupants will turn off or block the system. We strongly recommend commissioning the mechanical system to ensure it functions as designed. |
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