My question is regarding the installation of the mineral wool for the flutes in item #7 of the Design No. N664. Does the mineral wool (Hilti CP 777, 2" Speed Plugs) have to be installed before the intumescent paint is applied to the beam or can the flutes be filled with the mineral wool after the beams are coated with intumescent to be compliant with this design? In one version, the plugs are also covered with intumescent, however in the other, they're not covered with intumescent.
Hello Ben, the system is saying for you to spray the beams with Fire Finish 120+ to the mil thickness required and then install the CP 777 speed plugs / Mineralwool. Then you are to fill any gaps in the speed plugs with the same thickness of the material.
If you have already installed it with the speed plugs first we can create an custom detail for you showing the FF120+ sprayed over the speed plugs for a rating.
I hope this helps clarify the system and our capability to provide alternatives. If you have any further questions please reach out to on Hilti Construction Platform (HCP) at Hilti.com/EJ. You can then sign in and submit a question case (or engineering judgement) on HCP.
Thank you,
Chase Hellan
Sr Fire Protection Engineer