Draft. These pages were imported from the ARC Technical Criteria document (16 April 2026) and have not yet been reviewed in this format. Several thresholds are still being settled and are flagged on the pages concerned.

Zone 2 - the communal heat refuge

A communal heat refuge, large enough to accommodate all building occupants, for use during extreme heatwaves - and which must keep working during power cuts.

Performance requirements

A "Communal Heat Refuge", designed to stay comfortable during heatwaves using natural ventilation and adaptive comfort cooling measures.

Large enough to accommodate all building occupants - a dedicated room or zone for use during extreme heatwaves.

This space may include some mechanical cooling. If it relies on mechanical cooling, this needs to continue to operate during power cuts, so battery backup, ideally solar fed. External planting for shading, and anything else to help.

How to design it

The passive measures - orientation, shading, reflective surfaces, heat-shedding roofs, window openings and draughtproofing - and the temperature limits that apply are set out in designing a heat refuge.

Temperature criteria

Zone 2 spaces are subject to the same everyday criteria as zone 1: they should remain below the upper range of the comfort model's humidity-adjusted temperature thresholds for ≥ 90% of the time. Separate thresholds apply during heatwave conditions - see success criteria.

Incomplete in the source

The source sentence reads "designed to stay comfortable during using natural ventilation, adaptive comfort cooling measures" - a word appears to be missing after "during". The substance above is faithful; the exact wording needs confirming with ARC.

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Source: ARC Technical Criteria - Zone 2
Pattern · confidence medium · Imported 2026-08-29, not yet reviewed · next review 2026-11-29
Tags: zones, heat-refuge, heatwaves, passive-design
Citation key: zone-2-heat-refuge