The phrase “fire-rated ceiling” has become a generic description, but in reality it is not commonly achieved locally. For a ceiling system to be fire-rated, there should be a complete system test performed at an accredited laboratory, within a specified period and with a test report available to substantiate the claim. All the components tested should also be non-combustible, which should not be confused with fire-rated. Materials manufacturer, Siniat, extinguishes some of the myths around this topic:
System specification
When it comes to the fire performance in ceiling systems, it is essential to understand what the client is looking to achieve, and that a suspended ceiling works as a system and not as individual components. A fire-rated ceiling grid can’t be specified alone, as the whole system is evaluated.
If a true fire rating is required, it’s important to remember that not only is it the tested system that should be used in its entirety but also the supplier’s installation specifications that must be meticulously followed on site. A particular note should be made about the actual ceiling tile used in the fire test, since “or similar” doesn’t count when it comes to supporting test reports.
A suspended ceiling works as a system and not as individual components, working together to provide as much time as possible for evacuation.
Performance criteria
When a system is tested, there are two distinct performance criteria:
Stability and integrity
- A fire-rated ceiling system with an exposed ceiling grid should provide time for occupants to evacuate an area, and for emergency personnel to enter without the ceiling collapsing and dropping ceiling tiles onto them.
- A stability and integrity test will determine whether a ceiling will stay up when exposed to heat and flames and for how long it will remain structurally stable – the generally accepted minimum time is 30 minutes.
Insulation
- A fire-rated plastered ceiling is used to protect vital services within the ceiling void, such as sprinkler systems, cabling for access control systems and other services that may play a role in the evacuation of the building.
- The insulation test is conducted to determine how long these services will be protected from a fire below the ceiling and will measure the heat within the ceiling void to the point that these systems would start to fail. Only a plastered ceiling without a visible grid will be able to provide an insulation rating.
A notch above the rest
An engineered fire notch on the main tee should be regarded as a crucial safety feature, allowing the exposed grid to expand without buckling – because when it does, tiles fall out and can injure people below.
Even in a large space with an open floor plan, the concertina effect is big enough that people can still get bombarded by falling ceiling tiles 100 metres away from the actual fire.
Safe evacuation
The fire notch in a ceiling grid, together with a suitable Fire Class-A ceiling tile, can offer some assurance that there will likely be sufficient time for a safe evacuation. Siniat deems the fire notch so important that it is included as a standard feature on the Siniat MasterGrid exposed main tees. Even in an unspecified system, this could provide a few extra minutes of safety over a grid that does not include a fire notch.
In the unthinkable event of a fire, a non-tested system that has an engineered integral fire notch included on the main tees will ensure some extra time to evacuate and help protect the safety of building occupants.
For more information, contact Siniat:
Tel: +27 11 389 4500
Email: contactus.siniat@etexgroup.com
Website: www.siniat.co.za