What is Passive Fire Protection?
Most of us are familiar with sprinkler systems and fire extinguishers, but what about the parts of the building you cannot readily see? Passive Fire Protection involves creating physical barriers which are designed to stop fire from spreading from one building to another, or from one area of a building to another. Passive Fire Protection includes fire barriers in the ceiling, floor, and walls.
Passive Fire Barriers Criteria and Testing
The passive fire barriers are required to have a proven fire rating known as a Fire Resistance Level (FRL). An FRL is the ability for a building element to withstand a fire under test conditions as defined by the Building Code of Australia (BCA) as the grading period in minutes for three criteria including: structural adequacy, integrity, and insulation.
Let us look at these three criteria further, structural adequacy is the ability of a structure (i.e. brick wall supporting a concrete floor slab above) to maintain loadbearing capacity and stability. Integrity is the ability of a structure (i.e. a plasterboard wall) to resist the passage of hot gases and flames. Finally, insulation is the ability of an element (i.e. a bundle of cables) to maintain a temperature below specified limits on the surface not exposed to fire.
For example, an FRL requirement for a wall to be rated 90/60/30 means the structural adequacy needs to be maintained for 90 minutes. The integrity needs to hold for 60 minutes and the insulation for 30 minutes. It would need to be tested as per Australian Standards, AS 1530.4: “Methods of fire tests on building materials, components and structures – Fire-resistance test of elements of building construction” and AS4072.1: “Components for the protection of openings in fire-resistant separating elements, service penetrations and control joints”.
It’s important to note, when it comes to non-load bearing (or non-structural elements) such as fire doors, fire dampers and service penetrations, the criteria for structural adequacy does not apply.
Know The Legal Requirements For Passive Fire Protection
Furthermore, it is important to know the legal requirements within the National Construction Code (NCC) and the BCA when it comes to passive fire protection. Let’s say you have a fire barrier with an FRL and you need to put a hole in it so services can pass through to the other side, you need to make sure the hole is filled to stop fire from spreading from one side of the barrier to the other.
The NCC covers the requirements of fire protection services in Clause C3.15, “Openings for Service Installations.”
What is a building certifiers role in Passive Fire Protection of buildings?
A building certifier needs to receive evidence of compliance such as a NATA Accredited Laboratory report to meet the NCC C3.15a requirements in order to sign-off on a fire rated building. Even if you make changes to any component of an existing fire rated building or fire tested system, you may alter the performance of the system and potentially breach the fire barriers. It is very important to contact a certifier if any changes are made.