A brief history of Ducts with Fire Resistant Enclosing Construction, AES wraps and AS1530.4

Changes in the 2022 NCC that required all construction elements where FRL is determined by AS 1530.4, are to have been tested and / or assessed to the current standard – AS1530.4: 2014. For manufactures with tests and assessments based on older versions of AS 1530.4, if there were insignificant changes between say the 2005 and 2014 versions, then retesting is not needed. However, the older test report needed to be updated by assessment from the laboratory to confirm the FRL if tested to AS1530.4 (2014). There were many elements and configurations that saw significant changes between 2005 and 2014 versions in AS 1530.4. In particular, Fire Doors, Dampers and notably Ducts (Section 9) . Fortunately, service penetrations in section 10 did not have any significant changes – and tests conducted to the 2005 version would have the same outcome for FRL, if tested to the 2014 version, and therefore the assessment report to AS 4072.1 :2005 and AS1530.4: 2014 would have the same reports FRL as reports to AS 1530.4 2005.

Ducts in section 9 were impacted - the reporting of FRL changed significantly, such that in most cases, assessment of a 2005 test against a 2014 method is either not possible, or the assessment would see a very large reduction in FRL for External Exposure, Insulation.

Why?

Alkaline Earth Silicate (AES) wraps for Ducts have existed globally for more than 20 years, but prior to the 2005 version of AS1530.4, the reported FRL’s meant that such wraps required too many layers for passage through 120/120/120 walls and floors to be economically viable - compared to traditional sprays and Mineral wool Batts.

Cue AS 1530.4:2005, and suddenly half as much wrap can achieve FRL’s of 120/120/120 - so it’s off to the races for 10 years for AES wraps.

Since the adoption of the NCC 2022, systems for Fire resistant Enclosing Construction of ducts per AS 1668.1: 2018 have or should have reverted back to be at least double the thickness compared to the halcyon days of single layer AES wraps.  Take care when specifying - you don't want end up being Hounded for complyance 😉.