mr x said:
If you maintain good air flow in your area, you will not encounter issues with O2 depletion or CO. An equivalent BTU propane burner will not use more O2 than an indoor range of the same rating. CO production should not be appreciably high either, and accumulation should be negligable so long as you ventilate.
Respectfully, you are just wrong.
CO is heavier than air and will collect appreciably in low points. Cracking a vent window that's 3-8ft off the floor and affixing a fan will not fix that as it only circulates the upper air layers.
As for the stove, you are correct that it will not use more O2 than an
equivalent stove. But, a stove burner is 9-12k BTU. A propane cooker is 55-210k BTU. So, unless you plan on firing up all the burners on multiple stoves you will consume much more O2 than a stove.... High gas consumption stoves (like a restaurant) have HUGE vent a hoods (1500-5000CFM) that draw in outside air.
You said "CO production should not be appreciably high either". Not correct. It is very high. CO production from a typical 9-12k propane burner ranges from 2-15000 cc/hr. At 55-210k, that is approximately 12k (min)-640k (max) cc/hr. In a 10x20 basement, that equates to 180-9600 PPM in just one hour. OSHA defines 35 ppm as unsafe for long term exposure (8 hrs) and 200ppm as an unsafe for any period. Above 2500 ppm can cause unconsciousness and above 4000ppm can be fatal within minutes. Cut all those in half if you smoke. Now that you know the hazardous levels, ask yourself this. Is your burner the 180ppm one, or the 6180ppm one?
Now that we have a lot of theory, let's talk real world at bit. You're cooking away in your basement HAHB. The fire is hot, the beer is cold, and CO levels at head hight are minimal. All is well. BUT, down near the floor, CO levels are high. 4000+ ppm and climbing. You squat down to do a little bottling, mop up a spill, or find that airlock you just dropped. Almost immediately, you feel a little dizzy. Before you can realize that the dizziness wasn't just from getting up to fast, you black out. Now, you are laying on the floor sucking in raw CO. Your wort boils over, but you don't care. You are already dead. The fire continues to burn. Levels in the whole basement rise above 4000ppm. The wife comes home. When you don't answer, she comes down to check on you....
You can try and make yourself feel better about your procedures, but carbon monoxide poisoning is a very real problem that kills hundreds of people every year. I just checked Google news for the last 30 days, and there were new 285 stories that matched "Carbon Monoxide poisoning"