NASH Standard: Steel Framed Construction in Bushfire Areas
The NASH bushfire standard (NS300) is an NCC H7D4 deemed-to-satisfy path for steel-framed homes in bushfire areas, an alternative to AS 3959, covering BAL-12.5 to BAL-FZ.
Ask Chalkline about this →The NASH Standard for Steel Framed Construction in Bushfire Areas (current edition NS300, 2021) is the deemed-to-satisfy pathway for building steel-framed homes in bushfire-prone areas. It is the steel-frame alternative to AS 3959, and the NCC names both as acceptable: under NCC 2022 Volume Two H7D4, the bushfire Performance Requirement H7P5 is satisfied for a Class 1 building (or an associated Class 10a building or deck) if it is built in accordance with either AS 3959 or the NASH Standard (verified 2026-05-25, ABCB NCC 2022, NASH NS300).
Why a separate standard for steel
AS 3959 is the general bushfire construction standard and is written largely around timber and mixed construction. The NASH bushfire standard is purpose-built for non-combustible construction: steel framing, steel roof cladding, and non-combustible wall systems. It was developed from full-scale bushfire simulation and small-scale testing combined with fire-engineering analysis (verified 2026-05-25, NASH). For a steel-frame builder, detailing to the NASH standard is often a cleaner fit than working a steel frame into AS 3959’s provisions.
What BAL levels it covers
The standard is built around the same Bushfire Attack Level (BAL) definitions as AS 3959, and gives two solution sets (verified 2026-05-25, NASH):
- Lower BALs: a solution covering BAL-12.5, BAL-19, BAL-29, and BAL-40.
- Flame zone: a separate solution for BAL-FZ, the most severe exposure.
Covering BAL-FZ matters, because flame zone is the hardest level to satisfy and the one where a purpose-designed non-combustible system earns its place.
How it sits with AS 3959
The two are parallel DTS paths, not a hierarchy:
| AS 3959 | NASH bushfire standard | |
|---|---|---|
| Scope | General construction in bushfire areas | Steel-framed (non-combustible) construction |
| NCC status | DTS under H7D4 | DTS under H7D4 |
| BAL range | BAL-LOW to BAL-FZ | BAL-12.5 to BAL-FZ (two solution sets) |
| Publisher | Standards Australia | NASH (industry body) |
You pick one path for the bushfire compliance of the build. A steel-frame home can be detailed to the NASH standard; the BAL rating itself is still established by an AS 3959 site assessment.
Accessing it
The NASH standard is industry-published by the National Association of Steel-Framed Housing, not Standards Australia, so it is obtained through nash.asn.au rather than the Standards store. NASH publishes amendments separately, so confirm you are working from the current NS300 (2021) edition before specifying. For the wider NASH framing standards (Parts 1 and 2 for general steel framing), see NASH Standard.
For a builder
- It is a genuine alternative, not a supplement. If you are building a steel frame in a BAL zone, you can use the NASH bushfire standard as your DTS path instead of detailing the frame to AS 3959.
- Establish the BAL first. The BAL rating comes from an AS 3959 site assessment; the NASH standard then tells you how to build to it in steel.
- It reaches flame zone. BAL-FZ has a dedicated NASH solution, which is useful on the most exposed sites.
- Check the edition. NS300 (2021) is current; confirm before you specify or price.
Related
- NCC bushfire BAL ratings
- AS 3959: construction in bushfire-prone areas
- NASH Standard (general steel framing)
- Steel framing basics
- Light gauge steel (LGS)
See also
Last updated: 2026-05-25. Verified: 2026-05-25. Quarterly review for currency.