Passive Fire Protection Systems for Multi-Residential Buildings

What This Requirement Covers

Passive fire protection (PFP) for multi-residential buildings covers the fixed, built-in systems and constructional measures that limit the start, growth and spread of fire and smoke so occupants can escape and fire fighters can operate safely. It focuses on fire-resisting construction, compartmentation, fire-stopping of service penetrations, protection of openings (doors, windows, ducts), and fire-protected structural elements. These measures work without activation (unlike sprinklers or alarms) and are fundamental to achieving the NCC performance requirements for structural stability, spread of fire and safe evacuation.

This requirement exists to prevent rapid fire spread between apartments, common corridors and other building parts in multi-residential buildings (for example Class 2 and Class 3 buildings), to provide separation between different uses within a building and to protect means of egress and fire-fighting access. It applies to designers, builders, certifiers, and building owners of multi-residential developments in Australia and informs specifications used by trades who install walls, ceilings, service penetrations, doors and fire-resisting linings.

Key Requirements

1. Compartmentation and fire-resisting construction: Building elements that form fire compartments or separate classifications must achieve the required Fire Resistance Level (FRL) as specified in NCC Volume One, Specification 5 - Fire-resisting construction and the Deemed-to-Satisfy provisions in Parts C2 and C3. Typical FRLs for multi-residential situations commonly referenced in the NCC include 60/60/60 and 90/90/90 for walls and floors where required by Table S5C21 series and related tables (see Specification 5 and Table references in NCC Volume One).
2. Protection of openings: Openings in external and compartment walls (doors, windows, glazed panels) must be protected in accordance with Part C4 Protection of openings and C1 objectives. Specific acceptability methods and minimum door ratings are set out in C4D5 - C4D16. Fire doorsets used in fire isolated exits or compartment boundaries typically require self-closing devices and an FRL consistent with the wall they protect (for example a door in a 60/60/60 wall must achieve the appropriate fire door rating as specified in NCC Volume One, C4D6 and Specification 5).
3. Service penetrations and fire-stopping: Openings for services in floors, walls and shafts must be protected to maintain the FRL of the separating element. See C4D13 - C4D16 for acceptable methods and requirements for sealing penetrations and construction joints. Fire-stopping systems must be installed so the assembly achieves the required FRL and resists passage of smoke and flame.
4. Fire-isolated exits and lifts: Elements enclosing fire-isolated exits, lift shafts and public corridors in Class 2 and 3 buildings are subject to specific construction and opening protection requirements in C3D15 and C4D11 - C4D12 to ensure means of egress are protected.
5. Material combustibility and linings: Combustible linings and finishes are limited by Specification 7 and other S clauses; for example combustible internal linings used on building elements requiring a non-combustible substrate must not exceed 1 mm finished thickness unless otherwise permitted (see S7C6 - S7C7). Fire-protected timber requirements are in S10C1 - S10C3 and include performance criteria and testing references to AS 1530.4.
6. Fire-protected timber: Where used, fire-protected timber systems must deliver the FRL required for the element and resist incipient spread of fire for at least 45 minutes when tested in accordance with Section 4 of AS 1530.4, or use two layers of 13 mm fire-protective plasterboard as described in S10C2.
7. Standards referenced: Common Australian Standards referenced by the NCC for passive fire protection details include AS 1530.4 (fire-resistance tests), AS 4100 and AS 1684 when structural steel and timber framing interfaces with fire-resisting construction, and AS 3700 where masonry construction forms part of compartmentation. Always cite the specific clause in NCC Volume One relevant to the element being designed (for example C2D2 Type of construction; C3D1 Deemed-to-Satisfy Provisions; C4D12 Bounding construction: Class 2 and 3 buildings and Class 4 parts).
8. Smoke control and sealing: Smoke sealing at junctions, doors and service penetrations must maintain compartmentation. Smoke control objectives are part of C1P4 and related Deemed-to-Satisfy clauses in Part C4 concerning openings in fire isolated exits and lobbies.
9. Verification and testing: Where non-standard systems or alternative solutions are proposed, verification methods in C1V1 - C1V4 are used. Fire-resistance testing must follow the referenced test methods in Specification 5 and AS 1530.4.

Residential vs Commercial

1. Class 1 and Class 10 buildings (detached houses, outbuildings) generally have simpler passive fire protection requirements under NCC Volume Two (Housing Provisions). Requirements focus on external wall performance, separation between dwellings and limits on combustible linings; specific references include NCC Volume Two, Section 3 and relevant performance provisions.
2. Class 2 and Class 3 multi-residential buildings are regulated by NCC Volume One and are subject to more stringent compartmentation, FRLs and protection of shared means of egress. Examples:
3. Class 2 flats: Internal walls separating sole-occupancy units or bounding public corridors frequently require FRLs specified in Table S5C21e/ S5C21g and protection of openings (C4D12).
4. Class 3 boarding houses or hostels: Additional requirements for smoke spread, protected corridors (C3D15) and fire-isolated exits apply due to higher occupant movement and vulnerability.
5. Commercial classes (Class 5-9) may have higher FRLs or different compartmentation strategies driven by differing hazard levels, occupancies and public access. The same Specifications and Tables in NCC Volume One apply, but the required FRLs, construction types and performance outcomes differ according to building class, rise in storeys and type of construction (see C2D2 and C2D3).

Exceptions and Exemptions

1. Alternative Solutions: Where deemed-to-satisfy provisions cannot be met, an alternative solution demonstrating at least an equivalent level of safety may be accepted under the NCC using verification methods (C1V1 - C1V4). Evidence usually requires fire engineering reports, tested assemblies, or specific fire performance data.
2. Fire-protected timber concessions: Massive timber and certain fire-protected timber systems can be used subject to S10C2 - S10C3 conditions (including interface temperature limits such as 300°C for massive timber interface temperatures where relevant).
3. Minor penetrations and small service openings may be permitted when adequately sealed with tested fire-stopping products that maintain the FRL; such allowances must reference C4D13 - C4D16 and tested product data.
4. Certain low-rise single dwellings (Class 1a) are regulated under NCC Volume Two and may be exempt from many multi-residential PFP obligations that apply to Class 2 buildings; check NCC Volume Two, Section 1 and relevant performance provisions.

State and Territory Variations

1. The NCC is national, but each state and territory may have schedules or amendments that modify national provisions. Designers must check the relevant state schedule in NCC Volume One (Schedules 4-12). For example:
2. Queensland: Schedule 7 (NCC Volume One) contains state-specific amendments that can affect fire separation and performance requirements for certain building classes.
3. New South Wales and Victoria: Both jurisdictions publish state-specific interpretations and may have additional fire safety orders or guidance relevant to egress, sprinkler requirements and fire safety statements.
4. Always verify the applicable state schedule in NCC Volume One and any local planning or fire authority requirements - for instance, some jurisdictions may mandate sprinklers in certain multi-residential buildings which changes the passive fire protection approach or influences acceptable FRLs under the Deemed-to-Satisfy path.

Practical Compliance Tips

1. Plan compartmentation early: Integrate fire compartments, fire-isolated exits and protected corridors into early schematic designs so structural, services and layout decisions support FRLs and limit penetrations.
2. Specify tested systems: Use fire-stopping and doorsets with manufacturer test evidence showing the required FRL for the actual substrate and penetration configuration; do not rely on generic product claims.
3. Treat service penetrations as critical: Coordinate mechanical, electrical and plumbing trades to route services to minimise crossings of compartment boundaries and use proprietary fire-stop systems at every penetration per C4D13 - C4D16.
4. Document FRL requirements: Put the required FRL for each separating element on drawings and schedules (eg, 60/60/60 wall between apartments) with NCC clause and table references so builders and certifiers can verify compliance.
5. Mind combustible linings and finishes: Check S7C6 - S7C7 limits on combustible linings and ensure any combustible finish attached to a required FRL element is either limited to 1 mm finished thickness on a non-combustible substrate or protected in line with NCC allowances.
6. Include smoke sealing: Seal gaps at junctions, door thresholds and service zones to maintain smoke control. Smoke can defeat compartmentation faster than flame and is often overlooked.
7. Check state schedules and sprinkler requirements: Confirm whether the relevant state schedule or local authority requires sprinklers or additional measures; a sprinkler system often affects passive design decisions and acceptable solutions.

Citations: Refer to NCC 2022 Volume One - Building Code of Australia: Parts C1, C2, C3, C4; Specification 5 - Fire-resisting construction; Specification 7 - Fire hazard properties; Specification 10 - Fire protected timber (S10C1-S10C3); and the relevant Tables in Specification 5 (Table S5C21 series) and C4D clauses for openings. Also consult AS 1530.4 for fire-resistance test methods, AS 1684 and AS 4100 where timber/steel framing interfaces with fire-resisting construction, and AS 3700 where masonry forms part of compartmentation.

Could not directly quote full clause text here; designers should refer to the NCC 2022 Volume One documents and the applicable state schedule for exact table numbers and any jurisdictional amendments.