Referring to NFPA 90 A – Standard for the installation of Air-Conditioning and Ventilating Systems – at point 18.104.22.168 it is specified that “approved fire dampers shall be provided in all air transfer openings in partitions that are required to have a fire resistance rating and in which other opening are required to be protected”.
Trying to understand the requirement exactly, I looked at figure A.5.3 – Application of Penetration Requirements – but no answer to my query was found.
The case I’m facing concerns a transition opening on a 120 h fire rated external wall, where fresh air intakes are placed (refer to attachment 1.1).
In my understanding the external wall is not a “partition wall”, so it is not necessary to provide a fire damper, even if the wall is fire rated and also considering that it faces outdoors (refers to attachment 1.1 & 1.2).
Someone can please confirm the requirements for that specific application?