Fire-rated ductwork plays a vital role in modern passive fire protection (PFP) strategies. While most attention is often placed on fire-rated walls and floors, it’s important to remember that ductwork frequently passes through multiple fire compartments within a building. Without proper protection, these ducts can inadvertently become conduits for fire and smoke, compromising compartmentation and endangering occupants. Effective fire-rated duct systems are designed to maintain the required Fire Resistance Level (FRL) while still allowing essential building services—such as ventilation, smoke extraction or pressurization—to function during an emergency.
Types of Fire-Rated Ductwork
- Smoke Extract Ducts: Designed to remove smoke from fire-affected zones.
- Kitchen Exhaust Ducts: Require high-temperature resistance due to grease fires.
- Pressurization Ducts: Maintain positive pressure in escape routes.
Standards and Compliance
In Australia, fire-rated ductwork systems must meet stringent testing and installation standards in order to achieve certification:
- AS 1530.4 — Specifies the test methods for evaluating the fire resistance of building materials and systems, including ductwork. This test confirms both insulation performance and structural integrity when exposed to fire.
- AS 4254 — Applies to air-handling and ventilation duct systems, governing design and installation requirements.
- AS 4072.1 — Covers the requirements for penetration sealing and control joints when ducts pass through fire-rated elements.
Compliance with these standards ensures that duct systems will perform as intended in the event of a fire, preventing flame or smoke spread across fire compartments and protecting occupants and property.
Fire Protection Methods for Ductwork
There are several proven techniques for protecting ductwork, depending on the system’s purpose and location within the building:
- Fire-Rated Board Systems – Ducts are constructed using pre-tested board materials that deliver a high level of fire resistance without requiring additional wraps or coatings.
- Fire-Resistant Blanket Wraps – Applied around conventional steel ducts, blanket systems provide insulation and integrity protection and are suited for projects where retrofit solutions are required.
- Intumescent Coatings – Specially formulated coatings are applied to the exterior of steel ducts. When exposed to high temperatures, the coating expands and forms a protective char layer, limiting heat transfer and preventing structural failure.
Ceasefire PFP’s Approach
At Ceasefire PFP, we adopt a practical and fully compliant approach to fire-rated ductwork:
- We select duct systems based on their tested performance for the specific application (smoke, kitchen exhaust, or pressurisation).
- Our installations include correct fire-sealing at all wall and floor penetrations to preserve compartmentation.
- All works are supported with comprehensive compliance documentation and photographic records for building certifiers and facility managers.
Conclusion
Fire-rated ductwork is an essential safeguard in ensuring that ventilation systems do not become unwitting conduits for the spread of fire and smoke. By utilising fully tested systems and installing them in accordance with Australian Standards, Ceasefire PFP helps to ensure that critical airflows are maintained during an emergency—while preserving the fire-resisting integrity of the building structure.
