Sprinkler System Requirements for Residential Buildings

What This Requirement Covers

This requirement covers the design, installation, commissioning and monitoring of automatic fire sprinkler systems in buildings in Australia as required by the National Construction Code (NCC) / Building Code of Australia (BCA) and referenced Australian Standards. Sprinkler provisions exist to limit fire growth, protect life and property, and in some cases to permit alternative building design concessions (for example, reduced compartment sizes or altered egress provisions) where sprinklers provide an acceptable level of fire safety. The requirement applies where the NCC or a state or territory schedule specifically requires sprinklers for a building class, storey height, or particular use (for example, residential care buildings, certain multi-storey Class 2/3 buildings and some carparks).

Who this applies to includes designers, builders, certifiers and homeowners involved with buildings where the NCC requires or permits sprinkler protection. It also applies when designers choose sprinkler systems as an alternative solution under Performance Requirements of the NCC; in those cases the system must comply with the relevant Deemed-to-Satisfy Specifications or approved Australian Standards cited by the NCC.

Key Requirements

1. Sprinkler systems must be designed and installed in accordance with the NCC Specification for fire sprinkler systems and the applicable Australian Standards, primarily AS 2118.1 (general requirements for sprinkler systems) and AS 2118.4 (residential and domestic-type occupancies) where nominated. See NCC Volume One, Specification 17 and Specification 18 for Class 2 and 3 concessions (e.g., S17C1, S18C1, S18C3).
2. For most building classifications the NCC requires compliance with AS 2118.1 unless the NCC or a state schedule specifies otherwise (see S17C2 - Application of automatic fire sprinkler standards).
3. For Class 2 and 3 buildings with an effective height not more than 25 m and a rise in storeys of 4 or more, the required system must comply with AS 2118.1 or AS 2118.4 or the FPAA documents listed in Specification 18 (S18C3).
4. For Class 2 or 3 buildings with a rise in storeys of not more than 3, AS 2118.4 may apply (S17C2(e)).
5. Residential care buildings (Class 3 used as residential care, Class 9a used as residential care, and some Class 9c) require additional measures: sprinkler systems must have a monitored main stop valve and be permanently connected to a fire station or approved monitoring system (S17C12(1)-(2)).
6. Carparks protected by sprinklers and forming part of a multi-class building must be either independent from other building sprinkler sections or designed so the non-carpark section can be isolated without interrupting the carpark protection (S17C11).
7. Where sprinklers are installed in lift machine rooms, sheave rooms or spaces housing lift control equipment, heads must be guarded against accidental damage and must be able to be isolated and drained without affecting other sprinklers (S17C13). Valves must be installed per S17C10(2).
8. Where NCC or a State schedule allows concessions (for example reduced passive fire-resistance or egress provisions) when sprinklers are installed, the sprinkler system must meet the specific clause conditions including sprinkler head type, coverage and monitoring (see S18C3(2)(a)-
9. (c) for additional requirements where concessions apply). For example, when a Class 2 or 3 building not more than 25 m in effective height with 4 or more storeys uses a sprinkler system to obtain concessions, the system may need permanent connection to fire alarm monitoring if it has more than 100 sprinkler heads or, for residential care, will accommodate more than 32 residents (S18C3(2)(a)).
10. Sprinkler system components, spacing and location must comply with the quoted Australian Standards clauses such as AS 2118.1 (general design, hydraulics, pipe sizing, system water supplies), AS 2118.4 (residential applications, bedroom protection, clause references e.g., clauses 4.4, 4.5 and 5.5.2 for bedroom sprinklers where relevant), and other related standards for monitoring and alarms where cited in the NCC. Cite exact clauses when designing or certifying (for example, S18C3(2)
11. (b) references clauses 4.4, 4.5 and 5.5.2 of AS 2118.4 for bedroom sprinklers).
12. Specific dimensional/operational values are set by the Australian Standards referenced by the NCC rather than the NCC text itself. Important measurable requirements you will encounter in the standards include:
13. Hydraulic design pressures and flow rates as calculated per AS 2118.1 (system-specific and determined by hazard classification and number of heads operating) - refer to AS 2118.1 clauses on hydraulic calculation and minimum system pressures.
14. Maximum spacing and minimum coverage per sprinkler head determined by sprinkler type and occupancy per AS 2118 series (spacing expressed in metres; see AS 2118.1/4 for tabulated values).
15. Number of heads operating for design (design area / number of heads) and density (mm/min) required by hazard type in AS 2118.1/4 tables.
16. Monitoring and valve supervision requirements (monitored main stop valves and permanent connections to approved monitoring or fire station when specified in NCC clauses such as S17C12 and S18C3(2)(a)).
17. Always cite the NCC clause or Specification used: e.g., “as specified in NCC Volume One, Specification 17 (S17C1-S17C14)” or “as specified in NCC Volume One, Specification 18, S18C3.”

Residential vs Commercial

1. Residential (primarily Class 1 and 10) dwellings are generally outside the NCC provisions that mandate sprinklers. However, multi-unit residential buildings (Class 2 - apartments and Class 3 - boarding houses) are treated differently: where the NCC requires or permits sprinklers for multi-storey residential buildings the applicable standards are AS 2118.1 or AS 2118.4 depending on storey rise and concession use (see S17C2, S18C3).
2. Class 1 (detached houses): Sprinklers are not commonly required by the NCC as a Deemed-to-Satisfy requirement; AS 2118.4 provides guidance for residential-style systems if voluntarily installed or required by a state/local authority. Where installed as an alternative solution they must meet the referenced standard.
3. Class 2/3 (apartments, boarding houses): The NCC explicitly deals with these classes in Specification 18 where sprinklers may be required for buildings with effective height up to 25 m and multiple storeys. Concessions (e.g., reduced compartmentation or egress adjustments) are conditioned on sprinkler compliance and monitoring (S18C3 and S18C4 references).
4. Commercial (Class 5-9): These classes are normally required to comply with AS 2118.1 where sprinklers are mandated. Certain parts of multi-class buildings that include Class 2/3 areas may follow the Class 2/3 provisions if the parts are within size/storey limits (see S17C2(c)). Specific occupancies such as health-care buildings (Class 9a used as residential care) are required to use AS 2118.4 where specified (S17C2(e), S17C12).

Exceptions and Exemptions

1. The NCC text and state schedules set particular exceptions and alternative compliance paths. Common exemptions or special cases include:
2. Where a state schedule substitutes or modifies Specification 17 or Specification 18 (for example, Victoria’s variant provisions in the NCC Volume One Schedule replacing S17C2 and S18C3) - these can change which standard or additional requirements apply (see VIC S17C2 and VIC S18C3).
3. Small domestic Class 1 dwellings are typically not required to be sprinklered under the NCC Deemed-to-Satisfy provisions; however, local councils, developers or insurance conditions can require sprinklers as a condition of approval or contract.
4. Functional or equipment spaces (lift machine rooms, plant rooms) may have special installation requirements (guards, isolation and draining arrangements) rather than being exempt; see S17C13.
5. Where an alternative solution is proposed under the NCC Performance Requirements, the sprinkler design may differ from the Deemed-to-Satisfy Specification but must demonstrate equivalence and reference the appropriate standards.

State and Territory Variations

1. State and territory schedules within NCC Volume One may amend or replace national sprinkler provisions. Always check the relevant state schedule in NCC 2022 Volume One (Schedules 4-12). Examples:
2. Victoria: Replaces S17C2 and S18C3 with VIC S17C2 and VIC S18C3 which, among other changes, specifically require that covered balconies be sprinkler protected where clause modifications apply and set application differences for Class 2/3 and other classes (see “VIC S17C2” and “VIC S18C3” in NCC Volume One).
3. Other jurisdictions may have local amendments, exemptions or additional monitoring/connection requirements; the NCC text notes that state or territory schedules may modify national provisions. Always verify the relevant state schedule before final design or certification.

Practical Compliance Tips

1. Check the correct NCC specification first - identify whether Specification 17 or Specification 18 applies and whether any state schedule overrides are in force for your jurisdiction (e.g., Victoria’s VIC S17C2).
2. Confirm building class and effective height early - whether the building is Class 1, 2, 3 or Class 5-9 and whether effective height is above or below 25 m determines which standard and clauses apply (S17C2, S18C3).
3. Follow the referenced AS 2118 parts exactly for hydraulic calculations, head spacing and design densities - the NCC delegates the technical numeric values to the Standards. Refer to AS 2118.1 for general systems and AS 2118.4 for residential-type systems where specified.
4. Include monitoring and valve supervision where required - residential care and some concessioned designs require a monitored main stop valve and permanent connection to fire station monitoring (S17C12, S18C3(2)(a)). Test monitoring at handover.
5. Plan for isolation and maintenance - design sprinkler zones so areas like lift machine rooms or carparks can be isolated and drained without affecting required protection (S17C11, S17C13). Provide labeled valves and isolation procedures in the O&M manual.
6. Document concessions and clause references - when using sprinklers to obtain NCC concessions, record the exact NCC clauses and relevant AS clauses relied on (for example, S18C3(2)
7. (b) referencing clauses 4.4/4.5/5.5.2 of AS 2118.4). Certifiers will expect precise citation.
8. Engage a fire protection designer early - sprinkler hydraulics, water supply sizing and zoning are commonly reworked late in design; an accredited fire protection designer familiar with AS 2118 series and state schedules will reduce rework and compliance risk.

References cited inline in the article: NCC 2022 Volume One - Specification 17 (S17C1-S17C14), Specification 18 (S18C1-S18C3), VIC S17C2 and VIC S18C3, AS 2118.1 and AS 2118.4.

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