concentric double skin steel flue 1

[djstone]

I am looking for design criteria for a concentric double skin steel flue that will enable the discharge of room temperature air to atmosphere without a weatherproof cowl. Typically if I remember correctly, the gap between the inner and outer flue is 25 to 50mm.
Can someone point me in the right direction?

 

[ChrisConley]

Check out:

http://www.selkirkcanada.com/products/candi/index.shtml

I'm not sure exactly what you are venting, but they carry products to vent just about anything.

They also have technical guides that might interest you.

 

[lilliput1]

Page 6-41, Fig 6-24 Stackhead Designs, of Industrial Ventilation 17th Edition shows (3) styles. You are refering to the vertical discharge style wherein the stack dia is "D" and the stackhead dia is "D+1 inch". The overall length of the stack head is "4D+6 inch". The 6 inch being the overlap betwen the stack & the stackhead which protrudes 4D above the stack. The stack head is bracketed to the stack side within the overlap. There is no additional discharge loss associated with this design. The design works with typical windblown rain falling diagonally anbd adhering to the inside of the stackhead & discharging out the gap between the stack & stackhead, not falling into the stack.