Sprinkler Omission via Performance Solution: What’s Actually Required
Direct answer: Omitting a required sprinkler system through a performance solution is achievable, but it isn’t a simple exemption. It requires demonstrating that the fire safety outcome the sprinkler system would have provided (suppression, occupant tenability, structural protection) is achieved through an equivalent combination of alternative measures, assessed against AS 2118.5 (in the case of domestic sprinklers) and the relevant NCC Performance Requirements. This is common on projects without reticulated water supply or where sprinkler infrastructure is genuinely impractical, but it typically means adding measures elsewhere, not simply removing the system with nothing in its place.
Why Sprinkler Omission Comes Up So Often
Sprinkler systems are one of the most common Deemed-to-Satisfy requirements that projects can’t meet as drawn, usually because there’s no reticulated water supply to feed them, particularly on rural, regional, or acreage sites, or because retrofitting a sprinkler system into an existing building is disproportionately expensive relative to the risk it addresses. This is especially common on Class 3 buildings (short-term and long-term accommodation) in regional Queensland, where town water simply isn’t available.
What AS 2118.5 Actually Covers
AS 2118.5 sets out requirements for sprinkler systems in domestic residential buildings where the standard AS 2118.1 provisions may not directly apply, and is the reference point most fire engineers work from when developing sprinkler-related performance solutions for the relevant building classes.
What “Omission” Actually Requires
A sprinkler system in the NCC’s Deemed-to-Satisfy framework isn’t just one fire safety measure among many. It typically underpins the assumptions behind several other DTS provisions (travel distances, compartment sizes, fire resistance levels). Removing it via a performance solution means the fire engineer has to demonstrate the same overall level of safety is maintained without it, which usually involves a combination of:
- Alternative water supply – a static water tank and pump system sized to the fire load, sometimes with a dedicated fire pump, in place of reticulated town water.
- Enhanced passive fire protection – increased fire resistance levels on structure and compartmentation to compensate for the loss of active suppression.
- Improved detection and alarm systems – earlier warning to occupants, offsetting the loss of automatic suppression.
- Reduced travel distances or additional egress paths – where the sprinkler system’s absence affects assumptions about available safe egress time.
- Management and procedural measures – particularly relevant for short-term accommodation, where staff response procedures can form part of the overall fire safety strategy.
Which combination is appropriate depends entirely on the specific building, its occupant load, fire load, egress arrangement, and site constraints.
The No-Reticulated-Water Scenario
This is one of the most common contexts we see sprinkler omission requested in: a Class 3 short-term accommodation project on a site with no town water supply. Rather than a straight omission, the more common (and more readily accepted) approach is substituting reticulated supply with a static water source. A tank sized against the required fire flow and duration, connected via a fire pump set, combined with whatever additional passive or detection measures the specific project needs. This achieves the underlying Performance Requirement (adequate water for fire fighting and/or suppression) through a different supply arrangement, rather than removing the requirement altogether.
What Certifiers and Fire Authorities Look For
A sprinkler omission or substitution performance solution needs to clearly demonstrate:
1. Exactly what DTS requirement isn’t being met, and why (no reticulated supply, retrofit impracticality, etc.).
2. What alternative measures are proposed to maintain the same fire safety outcome.
3. Sizing and design justification for any substitute system (tank capacity, pump specification, detection coverage).
4. How the solution interacts with other fire safety systems already in the building.
Because sprinkler-related performance solutions often affect life safety assumptions directly, they’re more likely than some other performance solution types to require fire authority consultation that is worth factoring into your project timeline early.
Getting It Right the First Time
Sprinkler omission/substitution is one of the more technically involved performance solution categories, and it’s an area where under-scoping the alternative measures can lead to a certifier or fire authority pushing back, adding time to the project. The projects that move through fastest are the ones where the alternative water supply and compensating measures are sized and justified properly from the first submission, not added piecemeal after a review comment.
Frequently Asked Questions
Can a sprinkler system be omitted entirely with no alternative measures?
Generally, No. Omission via performance solution requires demonstrating the same fire safety outcome is achieved another way, which almost always means adding alternative measures rather than simply removing the requirement.
What’s the most common alternative to reticulated water for sprinklers?
A static water tank sized to the required fire flow and duration, combined with a dedicated fire pump, is the most common substitute on sites without town water supply.
Does sprinkler omission always require fire authority consultation?
Not always, but it’s more likely than many other performance solution types, given the direct link between sprinkler systems and life safety outcomes. This should be factored into your project timeline.
Is sprinkler omission common for regional Queensland projects?
Yes. It’s one of the most frequent performance solution requests for Class 3 accommodation projects in regional and rural areas without reticulated water supply.
Working on a project without reticulated water supply? Fyrewise regularly develops sprinkler substitution performance solutions for exactly this scenario. Call +61 492 943 682 or email admin@fyrewise.com.au.
