Conduits and ducts
Fire safety in high-rise buildings (IGH) - Specifications for fire prevention in air traffic control towers

Appropriate measures must be taken to prevent the passage of smoke from the affected compartment to other parts of the building.

Stairwells, elevator shafts and freight elevator shafts are constructed of non-combustible or A1 materials, with a 2-hour fire-resistance rating, EI 120 or REI 120.

All other vertical ducts are placed in ducts, unless they themselves have a penetration fire-resistance rating equal to the fire-resistance rating of the wall they pass through.