cable tunnel ventilation
cable tunnel ventilation
(OP)
I have a cable tunnel which is 500m long and 2m x 2m cross-section. What's the air changes per hour to be considered for ventilation in normal mode and in smoke mode ?
HVAC68
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RE: cable tunnel ventilation
For the smoke purge a velocity of 2.5 m/s is recommended across the tunnel cross section.Anything greater may impede escape from the tunnel.
I came across these figures while bidding for a cable tunnel project.
You would need to consult your local fire authority whether these figures can be used
RE: cable tunnel ventilation
Please check the above link which will give you some helpful guidelines.Looks like the figure I gave in previous post is wrong!
Arup recommends 5 m/s for smoke purge mode.
Also note that a cable cooling system is to be used(which is done with the help of a cooling tower circuit).These pipes are buried next to the cables in a sand trench.Therefore the ventilation system needs to remove only a portion of the heat generated by the cables.I can not remember what percentage I had apportioned for the cooling system .
A CFD model is required for the detailed design.
This could prove to be a lot trickier than you would have imagined!