The main challenge for this building was the Cross Laminated Timber (CLT) primary structure and how this would achieve compliance with Part B of the building regulations.
The standard method of compliance (TGD-B Ireland) could not be adopted in this case as the guidance document does not allow such a large-scale building to use timber as the main structure. The fire design of the building required careful consideration and the UK guidance document BS 9999: 2017 was successfully adopted as the method of compliance for Part B.
ORS prepared an expertly tailored application, complete with a compliance report specific to the design of the building, and carefully considered fire engineering drawings. The application successfully demonstrated to the Fire Authority that the design of the building is fully compliant with the guidance set out in BS 9999: 2017, including the specifications of the CLT itself requiring a load bearing fire resistance of at least 60 minutes.
The other challenge presented was the southwest elevation, which was almost fully glazed, and the potential of external fire spread was a concern.
An expert value engineered approach was used to avoid the need for such a substantial amount of fire rated glazing on the elevation. The solution was to provide active and passive fire safety provisions internally. Fire curtains were provided to the open stairs, and a limited amount of fire rated glazing to certain locations of the atria were specified. This resulted in the building effectively being split into two fire compartments. The provision of the fire rated curtains ensured that the building maintained it’s open connections between floors, and only forming compartmentation between floors on activation of the fire detection and alarm system.
