Marty's Basement Brewery

[kal]

Charcoal filter hoods that dump right back into the kitchen are for smoke and odors, not CO right?

I would assume so. I think they were only viable back when nobody had gas ranges. My mother-in-law has one in her 50+ year old house (for example).

I guess I don't see how that battles the CO produced by these monstruos ranges in todays kitchens.

Nope. I don't see how you could use a non-evacuating hood with a gas range. They're probably not even even allowed to build houses in most areas with these non-evacuating hoods anymore as it limits what sort of range the homeowner can install.

If you had to add an external intake to make up for the loss due to your ventilation shouldn't that be part of the recommendation?

Most sites that explain what CFM you need are selling you a hood. They probably don't care. But you're right. As I mentioned above it also depends on the home, the code it was built to, and so forth. Always good that the homeowner do some research into what's safe/recommended themselves and not rely on the (sometimes incorrect) opinions of others of course. Trust but verify!

Kal

 

[mprossman]

Not to change the subject as safety is always a concern. But on another note what do you think of the 2 compartment sink? Enough for all your needs or wish you had the 3rd? I am going back and forth so reason for or against is much appreciated.

Sorry for not responding guys. Work has been crazy. I will try and read through everything tonight. I appreciate everyone's responses. I say this lovingly...you are all a bunch of nerds.

FoCobrewguy...I absolutely love the 2 compartment sink. I could never go back now. I would recommend 2 things. 1.) Get a sink with big enough dimensions to fit your pots. A keggle barely fits in mine and the Blichmann won't fit and its a bit tricky. 2.) Get a sink with the biggest sideboards you can get for your space. I wish mine had larger ones, but it works. I guess I could add a third that the sprayer is a must.

 

[mprossman]

I'd be surprised if you have a carbon dioxide (CO2) detector as that's what we breath out (and plants like). It's also what yeast expels when fermenting and what we carbonate our beer with. I don't know why these sorts of detectors would even be available for sale in the first place or why you would want to have one?

Carbon Monoxide (CO) is the one you care about: It's the poisonous gas that is expelled when natural gas and propane is burnt. It's a colorless, odorless, and tasteless gas that is toxic to humans above certain levels.

If you have the CO detector in the same spots where you are working in and around the kettles and it's not going off then you're probably ok and the poisonous CO is being expelled correctly, assuming it's working correctly. There may be higher concentrations that would would normally be permitted near/in/around the kettles so you may want to try moving the detector around a bit to where you normally work. For example, it's not uncommon to have our head/face pretty close to the boil kettle when working.

Kal

Kal,

I actually have the CO2 detector because I also have my keg setup in the basement. It has a 20lb CO2 tank attached to it. If my setup has a leak and the entire CO2 tank leaks out in the basement it can also kill you. Also orderless and almost as dangerous.

In case you want to nerd out...http://www.blm.gov/style/medialib/b...A/cfodocs/howell.Par.2800.File.dat/25apxC.pdf


Thanks,
Marty

 

[FoCobrewguy]

Thanks for the tips on the table much appreciated.

 

[brewman !]

Careful with the sizing of the fan and using natural gas. That's a 452 CFM (only) fan - enoug for electric but not really for natural gas / propane.

Due to the extra heat and poisonous gases that must be removed, the ventilation requirements are considerably higher with a gas brewery as compared to electric.

John Blichmann wrote an article for the November 2012 issue of BYO magazine that summarized ventilation requirements as follows:

Electric based brewery: Divide the element size (in watts) by 17.6 to obtain the required CFM (cubic feet per minute). (Example: I use a 5500W element in our boil kettle. 5500 / 17.6 = 312 CFM).

Gas based brewery: Divide the burner’s BTU/hour rating by 30. (Because of the inefficiencies, a 80,000 BTU burner produces approximately the same amount of heat in the kettle as a 5500W element. 80,000 / 30 = 2666 CFM. You would therefore require a fan that can move 2666 CFM in order to ventilate a gas setup properly if you are running a total of 80,000 BTU in burners at once.)

Kal

I highly suspect that you do not need 2666 CFM to properly ventilate 80,000 BTUs of burner power.

Example #1) My house is heated by a 100,000 BTU natural gas boiler. Natural gas and propane are different fuels, but they aren't that different. Natural gas (CH4) has more H and less C than propane, but that is where it ends.

The boiler in my house is direct vent. That means its combustion is entirely sealed from the air in the rest of the house. All the intake air and exhaust products are piped in and out through 4" PVC ducting. You can even use 3" PVC ducting if the runs are short enough, ie under about 30 feet.

Here is the thing about this boiler. The fan that pulls the air in and pushes the exhaust products out is a tiny 4" squirrel cage. That is all the air that is required to burn 100,000 BTU per hour cleanly. This boiler is certified at 92% efficient. It was tested for a proper air fuel mixture with a mixture analyzer when it was installed. With that air flow there was no CO in the exhaust products, ie its getting enough air.

Example #2) My house came with a big 5 burner natural gas cook top. I guesstimate the total heat output to be over 50,000 BTU. It had a hood and fan over it. The hood was NOT connected to the cooktop in any way, ie it didn't automatically run when you fired up the burner. The fan in it was a low performance 8 inch centrifugal on a variable speed circuit. Often the fan was not running at all when the cook top was being used, often for hours on end.

Example #3) My RV has a 4 burner propane oven/stove combo. Total heat output is probably 25,000 BTUs. Nothing vents to the outside of the trailer. There is a fume hood, but it only runs when the trailer is plugged into 120VAC. There is a CO detector on the wall adjacent to the oven. Trailers are much smaller inside than houses.

I fully agree that one need to have adequate ventilation when burning natgas and propane indoors. People are killed doing this every year. However, if one truly needed 2700 CFM for that 80,000 BTU burner, people would have been killed or as least displayed some form of poisoning in each of these situations.

The actual amount of ventilation needed is much lower than that.

I could calculate how much air it takes to burn propane at a given rate, but its late and I have better things to do.

FWIW,

- we removed the the natgas cooktop and replaced it with an induction model.

- my home brewery in the basement is powered by electricity, not gas, even though I initially designed and ordered parts for a natgas brewstand.

- this web page compares the efficiencies of heating water by various methods.
http://physics.ucsd.edu/do-the-math/2012/05/burning-desire-for-efficiency/

Pot over a flame = 16 to 25%. For reference, 5.5 Kwhr = 18,766 BTU. 18,766 / 80,000 = 23.4% <--- if 5.5 Kw element was as fast as a pot over a flame, this is what the relative efficiencies are.

 

[kal]

My gut feel is that it's on the high side as well. I'm curious where John Blichmann got the info and what the BYO editorial review board had to say about it. (I'm actually board of that board now so maybe I'll poke around a bit and ask).

The pessimist in me would say that Blichmann says this to promote their new electric setups but the article was written well before they were selling electric stuff - back when they only had propane burners so you'd think that if they wanted to help market their own products he would have tried lowering that CFM number for gas as much as possible.

My kitchen range has 6 gas burners in the rangetop (and electric oven below). The range produces 84200 BTU total if I had all 6 running at once (15K BTU each plus one 9.2K simmer burner). So pretty close to a 80,000 BTU propane burner.

The recommendation that comes into play the most from what I can find for calculating BTUs for rangetops by the Home Ventilating Institute (HVI) is to divide the BTU rating of your stove by 100 to arrive at a minimum guideline for CFM rating. That's 842CFM for me. Then you're supposed to add 9 CFM per foot of ductwork (we have about 20 feet) plus 25 CFM per elbow (we have 3). So 1097 CFM total. Our range hood is a 900 CFM model which is sold/matched to the range itself. So pretty close. We've never run all 6 at once.

Important to note too that larger fans will often require a makeup air system. We have a dedicated one in the basement with heater and automatically opening damper just because of this large kitchen range hood fan (the builder was required to install it by code). The silly thing cost more than the hood fan! (Sheesh)

Kal

 

[brewman !]

The ductwork additions are to up the CFM of the fan to counteract the flow losses due to higher pressure the ductwork will present. Applicable for the whimpy fans they put in most hoods, but not applicable for the inline fans that most homebrewers are using.

850 CFM sounds better for 80,000 BTU, but probably still a bit high. That probably accounts for steam boil off, etc while cooking.

I'll leave you guys to work out what the appropriate air flow should be. I'm building an electric powered brewery !

FWIW, I lost a lot of faith in JB for writing that. I thought he was an ex Cat engineer. 2600 CFM is a huge, huge amount of air ! Its a complete air change in a 2 story (basement + mainfloor) 1000 ft^2 house with 8 foot ceilings (16,000 ft^3) every 6 minutes ! For the whole house !

Like I said, our 100K BTU water heater moves everything though 4" PVC with a small, squirrel cage fan. I mean small !

As far as make up air, you are exactly right, especially given how air tight modern houses are. Over a certain CFM the makeup air needs to be brought in with a fan. And modern building code actually requires that the make up air gets preheated in some jurisdictions.

And make sure that the exhaust vent isn't close to any intakes ! You don't want to expel a bunch of combustion products and then draw them right back in.

There are a lot of reasons to like electric brewing for indoors.