Hi all--
We're in construction on a new cellar that's fairly small, walled off from other parts of the brewery and packed with fermenters. We'll be installing make up air fans and exhaust fans to help ensure Co2 levels are safe for our employees, but I wanted to see if anyone could verify that I'm calculating this correctly.
The square footage of the space is 1066 s.f., and the cubic feet is 14,924 (14 ft. ceilings). The fermentation capacity of the space is 420 BBL (7 x 60 BBL FV's), and our average attenuation is 15 Plato over 5 days.
I want a "worst case scenario" design, so the assumption would be that all fermenters in this space would be at their peak of fermentation simultaneously (which will never happen since it takes 24 hours for us to fill up each tank). I came up with a maximum of 72.5 lbs. of Co2 being released per hour, which I believe equals 634 cubic feet of Co2 per hour. We'd want to keep Co2 levels to 5000 ppm or below (OSHA low end Co2 concentration safe for 40 hour work week) as there will be keg washing in this area, so it's possible that a worker would be in here for 40 hours a week.
To get the Co2 levels with 1 air change per hour, I'm multiplying the cubic square feet by 500 ppm (a bit above average for outside air-- equals 7,462,000 parts of Co2) plus 634,000,000 parts of Co2 (634 cubic feet of pure Co2 times 1,000,000 to get the ppm equivalent), for a total of 641,462,000 units of Co2, which averages to 42,981 ppm. Since I need it to be 5,000 ppm or less, there needs to be 8.6 air changes per hour (42,981 ppm / 5,000 ppm = 8.59).
Does this look reasonable? We'll get a Co2 monitor just in case, just want to see if this is how you'd all go about it.
Thanks in advance for the help!
Cheers,
Patrick Rue
The Bruery, Orange County, CA
We're in construction on a new cellar that's fairly small, walled off from other parts of the brewery and packed with fermenters. We'll be installing make up air fans and exhaust fans to help ensure Co2 levels are safe for our employees, but I wanted to see if anyone could verify that I'm calculating this correctly.
The square footage of the space is 1066 s.f., and the cubic feet is 14,924 (14 ft. ceilings). The fermentation capacity of the space is 420 BBL (7 x 60 BBL FV's), and our average attenuation is 15 Plato over 5 days.
I want a "worst case scenario" design, so the assumption would be that all fermenters in this space would be at their peak of fermentation simultaneously (which will never happen since it takes 24 hours for us to fill up each tank). I came up with a maximum of 72.5 lbs. of Co2 being released per hour, which I believe equals 634 cubic feet of Co2 per hour. We'd want to keep Co2 levels to 5000 ppm or below (OSHA low end Co2 concentration safe for 40 hour work week) as there will be keg washing in this area, so it's possible that a worker would be in here for 40 hours a week.
To get the Co2 levels with 1 air change per hour, I'm multiplying the cubic square feet by 500 ppm (a bit above average for outside air-- equals 7,462,000 parts of Co2) plus 634,000,000 parts of Co2 (634 cubic feet of pure Co2 times 1,000,000 to get the ppm equivalent), for a total of 641,462,000 units of Co2, which averages to 42,981 ppm. Since I need it to be 5,000 ppm or less, there needs to be 8.6 air changes per hour (42,981 ppm / 5,000 ppm = 8.59).
Does this look reasonable? We'll get a Co2 monitor just in case, just want to see if this is how you'd all go about it.
Thanks in advance for the help!
Cheers,
Patrick Rue
The Bruery, Orange County, CA
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