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gas range,no vent?

jonny88 Member Posts: 1,139
I lived in many apartments in Bklyn and didnt have vent on stove.I have a customer who wants me to install one but I am hesitant to do it as he does not want to vent appliance.Stupid ? ,how critical is it to vent the appliance,Town codes aside,my town doesnt require it.


  • icesailor
    icesailor Member Posts: 7,265
    edited May 2014
    In theory:

    In theory, residential gas ranges aren't supposed to emit enough CO to be a problem with "normal" air infiltration. What is "Normal" air infiltration in a building that has undergone heat loss modification?

    Some of us who have checked it because we are curious, find gas ranges to be really big CO emitters. But unless it says that it is required for the listing of the appliance, I don't believe it is an enforceable requirement. No one runs a range fan/hood when using the oven. The highest emitter of CO. IMO

    Some Jurisdictions like the entire State of Massachusetts require CO detectors installed with any gas appliance replacement. Not all CO detectors are created equal.

    Its also my experience that a vented to the outside range hood can and will suck large amounts of heat to the outside in cold weather, causing a rise in heating cost. The same/opposite is true in the Summer with AC.

    Personally, for me, in anything I have done for myself, I always install a microwave hood over a stove and don't vent it or get a non-vented one. O don't have any heat loss and I/we hardly ever use the stove top. Boiling potatoes for mashed potatoes or scrambling eggs is about the limit. I never use the fan but I use the light. Warm up the coffee in the cup? 30 seconds on high. 60 seconds if it's really cold.

    Tim's the expert. Whatever he says, is the rule. What I say is just my experience where I worked.
  • jonny88
    jonny88 Member Posts: 1,139
    thanks Icesailor

    i think you should write a book,you have a great way with words and your posts are always entertaining.Thanks again for your time
  • Bob Harper
    Bob Harper Member Posts: 1,034
    codes can get you killed

    The ANSI standards allow for 800 ppm of CO from a gas oven. The rationale for this is that ovens usually don't fire at more than about 3hrs. At that rate, in a typical building with a minimum ventilation rate of 0.35 Air Changes per Hour (ASHRAE 62.2), theoretically, the ambient CO would not reach levels that would cause a UL listed CO alarm to alert. That's a lot of ASSumptions but it gets worse. They base this off the UL 2034 listing of those crummy CO alarms. The way their sensors are set up they will not alert until your blood has reached a carboxyhemoglobin level of 10%. In other words, the UL standard is designed to protect against CO death only--not CO poisoning. Therefore, your gas oven can legally poison you daily as long as the dose is not immediately fatal and keep on doing it year after year. Now, do gas ovens burn cleanly or produce more CO than the standard allows? Try this test: zero your combustion analyzer and place the probe at the back of the range top where the combustion fumes exhaust and leave it sampling. Light the broiler with the door closed and let it warm up. Note the fluctuations in CO levels. Now, open the door so the cooler room air rushes in on that overhead spreader plate and watch the CO levels jump! What about a gas range? Set up your analyzer running then place a pot of cold water over a burner and watch it jump. Now, breathe deeply and tell yourself this is all approved by code. The tests are with just the bare burners and no with pots of cold water on them or with an oven door ajar as commonly used. It is not run with tin foil lining the floor of the oven either.

    Note that microwave ovens listed for use over ranges typically must be 66" above the floor, which provides only about 13-16" of clearance from the burners. Combustible cabinets, however, must be at least 30" above range top burners. These numbers are based upon a maximum input of 68,000 BTU/hr. Large "professional" cook tops may require higher clearances. "Commercial" cook tops are not allowed in residential applications hence the cheating on naming them to get by the code. Some of these flamethrowers get waay too hot for residential applications and typically have stated clearances to combustibles with requirements for noncombustible materials in proximity.

    Gas ranges do not require exhaust fans in residential applications.

    UL listed CO alarms protect fire departments from responding to so many alerts. They provide a false sense of security. Get unlisted CO monitors instead.
  • icesailor
    icesailor Member Posts: 7,265
    I'm SHOCKED, I say. I'm just shocked.

    "What do you mean that your instrument says that the new stove is dumping out large amounts of CO. They told me at the Kitchen Design Center where I bought the whole kitchen that this is a commercial design rated for residential/domestic use and I just LOVE how it looks with the great big burners on the top."

    Later, "I talked to the Kitchen Design Palace and they told me that YOU were absolutely wrong, the factory said so and the guy that usually does their gas stove installations says you are too. So we're going to have HIM finish the job. He says that he doesn't need any instruments and that they aren't any good anyway. Highly unreliable".

    Then, there's a 6' Garland 6 burner, double oven with top griddle/broiler that someone got a deal on from a restaurant that was doing a remodel/upgrade. (All pilots are standing pilots) It was already converted to LP, and it just fits in between our nice wood cabinets and wooden countertops. Its on an inside wall. We're not going to put in a hood because venting the hood will spoil the outside lines of the house.

    "Do you need a permit to hook it up? Because the guy I bought it from said I didn't because I am replacing a 30" electric range".

    Go figure.
  • ChrisJ
    ChrisJ Member Posts: 15,658
    edited June 2014
    Same question

    I had the same question years ago as everyone kept telling me how dangerous water heaters are and how they must be vented properly.   My stove produces a lot more output than my water heater and oven runs for longer periods especially if the oven is going so why must the water heater be vented, but not the stove?

    My conclusion is, the water heater is dangerous, and so is the stove so a vented exhaust fan is a must and should be run on low at an absolute minimum anytime the stove or oven is in use.  I installed a 400cfm variable speed fan that moves 200cfm on low extremely quietly and it's always on whenever a burner is list.

    Besides CO and the fact the burner is consuming oxygen anyone that has seen what a self cleaning oven can do or even just frying something hot in a pan would come to the conclusion a decent vent is required.  After installing the 400cfm fan we can actually use the self cleaning oven without putting fans in several windows and the place doesn't fill up with smoke.

    I'm a homeowner, not a pro and I don't even play one on tv.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • icesailor
    icesailor Member Posts: 7,265

    Gas water heaters when running, on average are 35,000 BTU's per hour. Gas range top burners are 3,000 to 5,000 BTU's when full in high. Combining all burners on a 4 burner top stove and the oven or broiler running together won't come to 30,000 BTU's. Usually.

    But whenever a 30-50 gallon gas water heater is running, it is wide open and burning 35,000 BTU's per hour. It needs to be vented.
  • ChrisJ
    ChrisJ Member Posts: 15,658
    edited June 2014
    My stove

    My stove is 54,000 btus for the 5 top burners (17,000, 12,000, 9000, 9000, 7,000). The oven is 16,500 and the broiler is 10,000.  That means oven + all 5 burners could peak at 70,500 btus especially while preheating the oven.  If I do self clean AND run all 5 burners that's 80,500 btu.  Just because "you don't usually" doesn't mean it will never happen.

    On self clean for hours and hours you're talking 26,500 btu run nearly continuously.

    My 40,000 btu water heater may always run wide open, but its almost always for short periods.

    I stand by my previous statement. Gas stoves and ovens should always be vented outdoors.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jonny88
    jonny88 Member Posts: 1,139
    thankyou gents

    You all confirmed what I was thinking.Even though not required by code where I live I had to turn down the job.Customer does not want to open a wall to vent appliance.

    Again thanks for your time and input.
  • icesailor
    icesailor Member Posts: 7,265
    Re-branded Stoves:

    You have a re-branded commercial stove. They paid for a UL listing to make it meet "residential" specifications. I've seen these re-branded stoves that don't meet combustible clearances and burn counter tops and cabinets. Compare your "residential" stove to the normal gas domestic 4 top ranges and they aren't even in the same league.

    Its one of the many reasons that Massachusetts passed a code regulation requiring hard wired CO detectors when a gas appliance is replace or a new installation is done. If GE pays for  AGA and UL listing on a stove that they (GE) certifies meets standards, then it has to be allowed. Until there is a problem.

    Because some people will use a gas stove for heating during a power outage, there is a serious danger of CO poisoning.

    Those granite countertops that are all the rage? You don't need to put heat shields in the top/sides to keep the top from catching on fire if you have a big pan on the top and you want to sauté or boil water for corn or lobsters.
  • Jack
    Jack Member Posts: 1,047
    "The oven runs a max of 3 hrs"

    Everyone thinks it is eating the turkey that makes you sleepy on Thanksgiving. Actually it may be the CO levels.

    I just remodeled the house with a new kitchen and I put in a Zephyr hood. 6' pipe up thru the roof. I've never had one vented outside. I like being able to cook bacon without it smelling up the kitchen all day. My biggest problem with it is when it rains (which it never does here. The neighbor across the street lost their well last week and it is happening to many others in the area as well) the flat cap on the roof is like a drum. I went up and glues a piece of rubber roofing on the cap to quiet it down. I also have a damper in the exhaust.
  • ChrisJ
    ChrisJ Member Posts: 15,658
    Oven times

    There has been times where my wife has baked cakes nonstop from 6AM to 12AM and the oven runs nonstop. Well, the burner cycles, but it's in use nonstop for that time.

    I was using a deep fryer over the weekend and once again was glad to have a decent fan exhausting to the outside. Even though it was a tiny electric deep fryer with a lid I still sat it on the stove under the hood and was glad to exhaust the stink and moisture outside.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment