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 3 - transient and buffer spaces

Naturally ventilated spaces which, because of their transitory functions, can accommodate higher temperatures than the ARC limits for zones 1 and 2 - and which can be used to shade other rooms.

Performance requirements

A space that is naturally ventilated, using adaptive-comfort cooling measures as zone 2 areas, but which - due to the transitory functions of these spaces (corridors, washrooms, storage rooms, showers and so on) - is able to accommodate higher temperatures than the ARC temperature limits for zones 1 and 2.

How they are cooled

Cooling comes mainly from effective cross-ventilation, or heat shedding via openings in ceilings, which creates air movement, with electric ceiling or wall fans used when extra cooling is needed.

Where they go

These rooms will tend to be positioned adjacent to the areas of the building most exposed to sun, where shading can be difficult or costly to achieve - east and west elevations are good examples of this, where low angle sun makes shading of walls difficult.

These 'buffer' spaces can be used to shade other rooms. See the three-zone strategy.

Temperature limits

Zone 3 spaces are still subject to a limit - see temperatures of transient spaces during heatwaves.

---

Source: ARC Technical Criteria - Zone 3
Pattern · confidence high · Imported 2026-08-29, not yet reviewed · next review 2026-11-29
Tags: zones, ventilation, passive-design, shading
Citation key: zone-3-transient-spaces