Passive fire requirements above IT Walls

I have been asked for advice on the following
What is the solution for treating a gap above the IT wall on the top floor i.e. to the underside of the roof. The architect wants this gap to maintain air flows to prevent condensation and dampness, similar to a Façade cavity.
I see two issues

  1. The IT wall forms the Property separation therefore we need to have a full separation for both fire and smoke, not sure how this is achieved if a cavity is required.
  2. The gap is only 20mm therefore very difficult to install a suitable system. I don’t think products like Rainbar or Tenmat CB systems are tested for this arrangement


Hi Biswadeep,

I haven’t come across such a request before, and am not aware of a fire product tested for that arrangement. Can the ventilation instead be achieved with isolated penetrations through the wall in the roof space, such that fire dampers can be applied?
The linear gap could then be conventionally sealed.