View Full Version : Fermenting room

03-30-2003, 02:02 PM
I have posted a few questions earlier and got most valuable answers. thank You All.

My question of today is: I have a fermenting room with limited space. I have good ventilation with a over pressure. I also have a co2-guard which contols the ventilation (1%) system and an alarm (2%). The ventilation inlet blows just under the ceiling to avoid condensation dripping down in the open fermenters. Where (high or low) should I place the ventilation outlet due to minimize co2 level in the fermentation room. Theoretical it ought to be down at the floor but how dows it work in practice if the ventilation is good?

dick murton
03-31-2003, 04:25 AM
CO2 is heavier than air, and will therefore sink to the lowest level of the room, and form a dense layer there. CO2 extraction should therefore be at floor level to reduce risk of build up.

CO2 monitoring equipment should be set withthe sample points at low level. no more than 50 cms above the floor.

In the UK, we are only allowed to work for 8 hours in an atmosphere containing less than 0.5% by volume CO2. If the level rises to I think 1.5 % you are only allowed in the area for a maximum of ten minutes per 8 hours.

At these sorts of levels you will actually start to notice a slight shortness of breath after a short while. Having worked in a brewery where 3 guys died a few years before I went there, due to entering a vessel still containing CO2, control should be taken seriously. If you manually clean vessels, you need to ensure the level of CO2 in the bottom of the vessel is below 0.5% before entering, with no risk of increase whilst in there.

Hope this helps

03-17-2004, 07:24 PM
So, given this information, what method(s) is/are used (if any) to ensure that CO2 produced by fermentation is ventilated from the brewery. In my case, the fermenters will be located in the same shed as everything else, not in a separate room.

Do we need a floor-level forced ventilation system with a switch connected to a CO2 monitor? Or should I just calculate the max. CO2 concentration possible in the proposed space given an assumed max. fermentation rate and see if this is less than the 0.5% by volume you suggest, in which case the concentration cannot reach problem levels? I guess local codes may also advise, but what does everyone else do?

03-17-2004, 10:24 PM
When I wrote the first post I had no experience about it. Now I can follow it up and I have noticed that

With a fast fermenting of 20 hl and a ventilation of 85 litres / sec. the co2 level have not reached 0,5 % concentration (it is a small and closed fermenting room with air in at the ceiling and air out at the floor). But with a air exchange of 35 litres / sec the co2 level go far to high. A co2 monitor must be a good investment in any case.

ATB Consulting
03-17-2004, 11:30 PM
May I suggest that you invest in at least 2 CO2 monitors, a redundancy in a system can be beneficial.

Also, obtaining a CO2 meter will give you piece of mind that the monitors are alarming at the correct levels.

From experience I know that a ventilation system at floor level works well even in a cellar with 26 100bbl fermenters. However, blowing down an empty tank can create extremely high CO2 levels. It is possible to hook up a blow off system (during ferment or for blowing down empty tanks) that will pipe CO2 outside.

03-18-2004, 06:41 AM
Having worked in a brewery with 50 bbl open fermenters, I always wished we had a fan to suck CO2 out via the drains.

Practice was to empty the tank and then open all valves. This meant a 2" valve on the bottom and a 1.5" with zwickel were the only way CO2 had to exit. If a fast turn was required the tanks were hit with increasingly warmer water to help push out CO2 and yeast. Misdirect the hose and a full blast of gas left you choking for O2. Of course all cleaning was by hand.

In the other cellars we could attach a hose to vent to exterior, but no one went in closed tanks for routine cleaning. SOP was to test for O2 and CO2 concentrations before any tank entry. HIIPA and OSHA allows for establishing guidlines for timing entry into enclosed tanks based on previous O2/ CO2 testing, I guess so small businesses don't have to buy the monitors and can rent them for initial tests.

Kudos to the management for allowing funding of permanent equipment.