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combustion air calc

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Unknown
Unknown
in THE MAIN WALL
Some of my local towns now require combustion air calculations when submiting permits for new or replacement boiler instalations. They have a form to fill in the blanks but it is a little confusing and not standardized. The local inspector said he heard of a computer program that makes it easy and you just fill in the boxes and print out a report. They also have another form that sizes the chimney, also confusing, they are concerned about the new high efficency boilers and furnaces that leave the hot water heater the only applance left on the exiting chimney. This would make the chimney over sized and the flue gasses would cool and cause problems in the chimney, so it forces you to use a liner in the chimney.
This is all well and fine am all for protecting the public and doing the right thing but am looking for a easier method of doing the calculations.

Thanks Don

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  • Unknown
    Unknown
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    Don if you get a copy of the forms

    I will look them over and see if my guide will work for filling them out.

    I am also working on something (requested by Dave Yates) to resolve the removal of appliances from chimneys and possible subsequent inability to vent by the smaller appliance.

    We must keep in mind however that water heaters typically work all summer in chimneys without the heating equipment. So the issue is possible outdoor temps in the winter and what kind of chimney (inside or outside).

    I commend your local towns for being in the forefront and addressing this problem.

    One of the things they may want to address is the removal of the draft hood from the water heater and using a barometric for automatic draft control.

    My FAX number is 401-270-1893
  • Mark Hunt
    Mark Hunt Member Posts: 4,909
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    Was in a home today


    Customer is remodeling an old brownstone. There were 3 old fireplaces in it. He'll be adding three gas logs where the old fireplaces used to be. Fireplace company ran 3 SS liners as per manufacturers instructions. Today I watched the air blowing OUT of those SS liners. Wait!! It gets better. On the other side of the room was another old chimney. Same size and heighth as the other. Air was being sucked through that one. Nothing attached to it. Nothing. Yet it was drafting.

    Anyone want to tell me why this was happening? One chimney system was spilling air while the chimney 15 feet away was drawing air.

    Did you ever think this could happen?

    What say you?

    Mark H

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Weezbo
    Weezbo Member Posts: 6,232
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    Supposedly 1 sq \" per 4000 btu input or table 2...Nat Gas

    1 sq " per 6000 btu input or table 701....oil....i just hate the frick out of reference to tables on a test....that supposedly is closed book and that seems more like lets see what we can do to get the guys to Flunk it rather than to simply inform as should be the case when taking an administrative test....i need to find my reference materials .
  • Weezbo
    Weezbo Member Posts: 6,232
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    I'd like to tell you Mark , excepts its too good for words :)...

    it is much like building a set of fulcrum points and havinga bunch of boards laid out precariously balanced on one each of the points then running over the "surface" of them to get from point A to point B. different things happen, basically because ,one fraction one way or the other begins a balancing act... see the balance is oki dokie over the fulcrum points however the further one moves away from the stability of the points the more quickly and more out of balance the system becomes...
    thats a bout as clear an analogy as i can come up with ...no there isnt a ghost on the teeter totter that is just an imbalance caused by moving air....:)
  • Robert O'Connor_7
    Robert O'Connor_7 Member Posts: 688
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    Goldie Locks Saves the Three Bears from Certain Asphyxiation!

    Goldie Locks Saves the 3 Bears from Certain Asphyxiation: The last time we saw Goldie Locks, she was a mere child being chased around by 3 bears. But alas, Goldie has grown up and is now an appliance installer. As we peek in on Goldie Locks, she is attempting to connect a furnace to one of three vent pipes in the three bears house. The first vent pipe was toooooo small, the second vent pipe was toooooo big, but the third vent pipe was just right. At one point we were simply worried about vent pipes being big enough but as technology has progressed, we are now worried about vents being too big. Vent pipes for new Federally mandated mid-efficiency appliances have to be "just right" When a vent pipe is too small there isn't sufficient area to vent the products of combustion. When a vent pipe is too big it will be subject to excessive condensation. The corrosive nature of this condensate will cause the vent pipe to deteriorate. This issue, as well as the dangers associated with vents and chimneys that don't funtion properly have led to incresed concern about using existing chimneys and vents when appliances are being replaced. You have probably seen some articles on the subject. An article called "Carbon Monoxide--The Silent Killer" , "Danger Lurks in Local Neighborhoods: Dangers of Carbon Monoxide," written by George E. Lucia and Trica Branley of Hillsboro, NJ and it appeared in the Feburary 1994 issue of New Jersey Municipalities Magizine. Both of these articles are worth reading. Some questions I ask as a aplicant who is proposing to use an existing chimney or vent with a replacement appliance are: 1. Is the chimney/vent clear and free of obstructions? 2. Is the chimney lined, and is the liner in good condition? 3. Is the chimney/vent size appropriate for the new appliance? Often it is not possible for an inspector to see the inside of the flue or chimney. In most cases, an inspection is done after the new appliance is installed. For this reason getting some certification about existing conditions from the installer probably makes sense and is in fact code in the great state of New Jersey (counter form: F370). In addition, a spill test performed by the contractor should be performed. If possible, this spill test should be witnessed. We now return to Goldie Locks, who has just completed the furnace installation in the 3 bears house. The 3 bears are so happy with the installation that they don't chase Goldie Locks out of the house, but rather, invite her to sit down and have some porridge with them. And they all lived happily ever after--untill the bears got the bill. Papa Bear thinks Goldie Locks' prices are toooooo high! The End.............Robert O'Connor/NJ
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