This chimney sizing link doesn't really apply --- it's for natural draft up a chimney of a given height and diameter -- WITHOUT a fan.
(The longer the chimney the higher velocity of the draft, so a given diameter can exhaust more heat. They recommend " The velocity of air and flue gas in a smaller furnace should not exceed 2 m/s . " -- so I presume that the charts are based on this, and not the maximum 10m/s. ). I haven't put a ruler on the aerial photos of the vents on the roof ... but it looks like they could easily be 22 inches. Since a 22-inch vent WITHOUT a fan at a velocity of 2 m/s can handle 1MW, it seems likely that a vent WITH a fan could also do so. There's probably a vent/fan sizing chart somewhere, but this isn't it. From: "Jed Rothwell" <jedrothw...@gmail.com> To: "vortex-l" <vortex-l@eskimo.com> Sent: Saturday, May 21, 2016 9:16:31 AM As I said, 1 MW in this space would be like running 16 space heating furnaces continuously without thermostats. To remove that much heat, you need a 22" vent and a large fan. An expert from I.H. would have to confirm this ventilation equipment is installed and working to confirm the claim. 1 MW of heat release calls for at least at 22" vent: http://www.engineeringtoolbox.com/chimney-sizing-d_175.html
