Are ducts affected by fire?
Yes, most definitely. As ducts are essentially passages, they can easily transport fire and flames from one compartment to another!
What passive fire options are there for ducts?
In Australia, besides the mechanical or intumescent dampers used where ducts penetrate fire compartments, we also protect the ducts themselves in most cases. This can be achieved with board encasement though this is not common in Australia. The most common method for duct fire protection in Australia is Vermiculite/Gypsum spray. There is also a somewhat newer method to protect ducts, and this involves wrapping the duct in an insulating material such as Fyrewrap.
How much material is required to protect a duct?
This depends on what material is used and what fire rating is required. All methods have been tested for an FRL of up to 180 minutes (three hours), but a two-hour fire resistance level is most common. For a two-hour FRL (or -/120/120) you may expect around 50mm of material. Calculations would be required for the duct supports to carry the extra weight.
What if I require access to the inside of the duct for cleaning or maintenance?
This is an excellent question and not one that we leave as an afterthought. Ceasefire PFP can install fire rated access panels in a variety of areas and sizes to accommodate future maintenance without compromising the FRL of the duct.
I need a fire rated fan unit, is that possible?
Yes, fan units can be fire rated too. Fyrewrap can be directly installed over the fan unit, one of the many benefits of the product. If you are using vermiculite spray to achieve a fire rated fan, then it must be enclosed inside of a bulkhead before the coating is applied. This is to allow movement of the fan unit without compromising the vermiculite fire spray. Get in touch with Ceasefire PFP to discuss your project – we will use a tested system to build the fan unit enclosure, apply the fire rating, and install fire rated access panels for maintenance and servicing.
