Gaps above 60 mins FD

[Davo]

Above two new 60 min fire doors being used to separate for PHE/Distance of Travel is a 450mm or so space above metal ceiling grid.
In the space is  ventilation ductwork.
To ensure full 60 min what would be recommended, please?
My preference is for intumescent block

cheers

davo

Prof you might recognise the premises I think

[kurnal]

No Davo never been anywhere near it. It must have been the other chap.
Ventilation ducts crossing compartment boundaries would require a fire damper in the duct work on the line of the compartment wall. There is probably a need for smoke control as well. But if it is steel duct work and it is not a compartment wall (Why 1 hour?) and if there are no openings to the duct  such as vents in close vicinity and if the system shuts down on operation of the fire alarm and / or if there is smoke detection in the ducts then there may not be a need smoke protection in the duct. As it is for PHE  then I think a honeycomb is the minimm standard.

If you PM me with a few more details I will be happy to give a definitive answer based on the other chaps notes.