Class 9b is the National Construction Code classification for assembly buildings, meaning buildings where people gather. Gyms, studios and sporting facilities fall into it because people assemble there for recreational and sporting purposes, not because of their size. The classification is decided by a Registered Certifier, not by Council’s planners, and it brings stricter requirements for exits, fire safety, sanitary facilities and accessibility than what a shop or a warehouse carries.
Most operators meet the term for the first time in a Certifier’s email, weeks after the lease is signed and the fit-out has been drafted. That is the expensive way to meet it. This post covers what the classification is, why a gym attracts it, who applies it and when, and what it changes about the space you have committed to.
What is a Class 9b classification?
Class 9b is one of three sub-classes of Class 9, the National Construction Code’s category for buildings of a public nature. The Australian Building Codes Board describes Class 9b buildings as assembly buildings in which people may gather for social, theatrical, political, religious or civil purposes, and names sporting facilities, schools, childcare centres, pre-schools, night clubs and public transport buildings among them. The other two sub-classes are Class 9a, health-care buildings, and Class 9c, residential care buildings.
The word doing the work is “Assembly”. The NCC treats a building where a number of people gather in one space differently from one where a handful of people work or shop, because getting everyone out safely is harder. Everything Class 9b adds follows on from that.
In New South Wales the Building Code of Australia sits inside the National Construction Code, so Class 9b is not a state-specific concept, rather, a national one. The same logic applies to a gym in Gosford, a studio in Melbourne and a fitness tenancy in Brisbane, even though the planning approval around it runs under three different Acts.
Class 9b follows the use, not the building
Gyms and studios are Class 9b because people assemble in them for recreational and sporting purposes. The NCC’s guidance on building classification describes a Class 9b building as an assembly building, defined to include a building where people may assemble for entertainment, recreational or sporting purposes. A gym floor, a group fitness room, a reformer studio and a boxing gym all fit that.
This is why the classification tends to catch operators out. The building has not changed. A tenancy that was a Class 7b warehouse, or a Class 6 shop, is the same shell on the day you receive the keys. What changes is the use, and the classification follows the use. A fit-out that turns a storage unit into a room where forty people train at once has changed the building’s class, whether or not anyone has said so out loud.
Who decides the classification, and at what point?
A Registered Certifier does, at certificate stage. In New South Wales, Registered Certifiers are regulated by the Building Commission of NSW under the Building and Development Certifiers Act 2018, and they are the ones who issue Construction Certificates, Complying Development Certificates and Occupation Certificates. Determining the class of the building, and endorsing it with the certificate, is part of that job.
Prestige Town Planning is not a Registered Certifier and does not issue certificates. What it does is Construction and Occupation Certification Management: running the certification stage inside the same engagement as the Planning Approval, so the classification question is raised while the design can still absorb the answer.
The timing matters more than the technical detail. Classification is confirmed at certificate stage, however, it is decided in substance much earlier, by the use you intend and the tenancy you choose.
What Class 9b changes in a fit-out
Class 9b raises the standard across five areas at once, all driven by the number of people the space is designed to accommodate.
| Requirement | Class 6 shop or Class 7b warehouse | Class 9b assembly building |
| Basis of design | Floor area and a modest occupant load | Occupant numbers for an assembly use, which are higher for the same floor area |
| Exits and egress | Fewer exits, longer permitted travel to them | More exits, shorter travel distances, wider paths of travel |
| Fire safety measures | Baseline detection and extinguishers | Additional measures scaled to occupant numbers and building size |
| Sanitary facilities | Sized for staff and limited customers | Sized for the assembly occupancy, commonly including change and shower facilities |
| Accessibility | Access to the tenancy and basic amenities | Accessible paths, sanitary facilities and features assessed against the Premises Standards for a public assembly use |
The practical consequence is that the same floor plate either supports fewer members than the fit-out assumed, or needs more exits and amenities than the base building has. Either way it is a design constraint, not a paperwork step.
Is a Class 9b classification the same as Development Approval?
No. They are two separate approvals answering two different questions, and a project needs both.
Development Approval answers whether the use is permitted on that land: whether a recreation facility is allowed in the zone, and whether the parking, hours, waste and amenity impacts are acceptable. That is the Development Application services side of the job, and in New South Wales it is generally Council’s decision.
Class 9b answers whether the building can be built and occupied safely for that use, and that is the Registered Certifier’s decision under the NCC. A consent permitting a gym does not certify that the tenancy can be built as one, and a tenancy that can meet Class 9b is worthless if the use is not permissible. Testing both before the lease is signed is what Planning Advice and Strategy is for.
Four failures that come from finding Class 9b too late
These four failures show up repeatedly on fitness fit-outs, and all of them are cheaper to avoid than to fix:
- A tenancy that cannot achieve egress. A single-exit unit at the back of a complex may not support the occupant numbers the business plan assumes. This is usually discovered after the lease, not before it.
- Base building upgrades the landlord did not price. Additional exits, fire measures or accessible facilities become the tenant’s problem when the lease says the fit-out is the tenant’s responsibility.
- Redrawn documentation. Fit-out drawings prepared against a Class 6 assumption have to be re-issued, and the consultants have to be paid twice.
- An Occupation Certificate that cannot be issued. Trading cannot start, rent is being paid, and the fix is construction rather than paperwork.
Prestige Town Planning has worked on fitness and gym approvals for over a decade. Studio P Architecture and Interiors, a practice the firm has partnered with on more than fifty projects, credits it with a deep understanding of Class 9b gymnasium planning requirements, which provides real value in sequencing and knowing which questions to answer before a design is fixed.
Does every studio need a Class 9b classification?
Not automatically, although most do. Classification follows the actual use and the way people assemble in the space, and the Registered Certifier makes that judgement on the facts of the tenancy. A personal training space running one or two clients at a time sits differently from a forty-person group fitness room, even where the sign on the door is similar. Where the business model involves classes, group sessions or a growing membership training at once, assembly is the reasonable planning assumption, and designing for it from the start costs less than discovering it later.
What a tenancy needs to physically support Class 9b
Enough exits in the right places, paths to them that meet the required widths and travel distances, base building fire measures that can be extended to suit the occupancy, room for sanitary and change facilities sized to an assembly use, and accessible access that does not depend on works the landlord will not fund. None of that requires a technical background to check. It requires asking early enough that the answer can still change which tenancy you take.
Frequently asked questions
What is the difference between Class 9a, 9b and 9c?
They are the three sub-classes of Class 9, the National Construction Code’s category for buildings of a public nature. Class 9a covers health-care buildings, Class 9b assembly buildings, and Class 9c residential care buildings.
Who pays for Class 9b upgrade works, the landlord or the tenant?
It depends on the lease. Fit-out obligations commonly sit with the tenant under a commercial lease, which is why the question is worth raising before signing rather than after.
Can a building be Class 9b and another class at the same time?
Yes. Buildings are commonly multi-classified, with different parts carrying different classifications. A reception or retail area within a gym tenancy may be treated differently from the training floor.
Is a yoga or pilates studio Class 9b?
Usually, where people assemble for group sessions. The Registered Certifier decides on the specific use and occupant numbers rather than on the style of training offered.
Does Class 9b apply outside New South Wales?
Yes. The National Construction Code applies nationally, so the classification logic is the same in Victoria, Queensland and all other states and territories. The planning approval that sits alongside it is not.
Raise Class 9b before the design is fixed
The cheapest version of this conversation happens at the tenancy stage, while you are still choosing between sites. Class 9b is a constraint on the building, not a document you can revise later, so the answer is far more useful before a lease is signed than after a Registered Certifier raises it.
Our planning team manages approvals for gyms, studios, and commercial fit-outs nationally, from Suite 4, 101 Victoria Street, East Gosford. If a site cannot support what you are trying to build, you will hear it on the first call. Ask us about a tenancy you are considering or call (02) 4308 7305.