Flue Size when size matters?

[msylvester]

Hi All,
Ran into this situation where is was scratching my head today. My question is this. I know when there are multiple furnaces(2) and water heaters(2) sharing the same flue the vent off of the furnace is increased, OK. Now with the rule of the main flue being the same size as the largest vent plus %50 of all other flue sizes. Would you say if the flue coming off of the furnaces are I think 4" (I think some kid took my tape measure at one of yesterdays inspections and lost it) and the water heaters are 3" then the flue going into the chimney should be 8 or 9 inches. Do they even make a 9" flue. It looks like the one there now is 6" b-vent.

Your thoughts.

[William J. Decker]

Originally Posted by msylvester

Hi All,
Ran into this situation where is was scratching my head today. My question is this. I know when there are multiple furnaces(2) and water heaters(2) sharing the same flue the vent off of the furnace is increased, OK. Now with the rule of the main flue being the same size as the largest vent plus %50 of all other flue sizes. Would you say if the flue coming off of the furnaces are I think 4" (I think some kid took my tape measure at one of yesterdays inspections and lost it) and the water heaters are 3" then the flue going into the chimney should be 8 or 9 inches. Do they even make a 9" flue. It looks like the one there now is 6" b-vent.

Your thoughts.

Mark;

Where they all feeding into the main before the chimne?. Picture not really clear on that.

Was there back drafting at the water heaters. I would think so.

[Brian E. Kelly]

Someone help with the area of a circle.

[msylvester]

Hi Will,
Back drafting was experienced. Also they did all go into the main before the chimney.

[Larry D. Kage]

Originally Posted by bkelly2

Someone help with the area of a circle.

3.14 x radius x radius = area

...I believe.

[David P. Valley]

http://www2.iccsafe.org/states/seatt...pendix%20B.pdf

[Roy D. Cooke, Sr]

Originally Posted by lkage

3.14 x radius x radius = area

...I believe.

and a quick method gives an approx size you can do in your head is Diameter times diameter and take 80% of the answer.
Example 8*8=64 and 80% = 51.6
true answer is 50.24

this also works with a sphere I believe and that is much harder to figure Diameter * diameter * diameter take 80% and again 80% . great way to check your answer on an exam tells you are close or not.

How to find the area of a circle:

• The area of a circle can be found by multiplying pi ¶ (which is equal to 3.14) by the square of the radius
• If a circle has a radius of 4, its area is 3.14*4*4=50.24
• If you know the diameter, the radius is 1/2 as large.

Roy Cooke.

[Marcel R. Cyr]

That is pretty cool Roy. Thanks.

Originally Posted by rcooke

and a quick method gives an approx size you can do in your head is Diameter times diameter and take 80% of the answer.
Example 8*8=64 and 80% = 51.6
true answer is 50.24

this also works with a sphere I believe and that is much harder to figure (the volume = 4*3.14*r3
3

Surface = 4*3.14*r2

This one on your method seems to not work as well, but where would you want to apply a sphere too.?)

Diameter * diameter * diameter take 80% and again 80% . great way to check your answer on an exam tells you are close or not.

How to find the area of a circle:

• The area of a circle can be found by multiplying pi ¶ (which is equal to 3.14) by the square of the radius
• If a circle has a radius of 4, its area is 3.14*4*4=50.24
• If you know the diameter, the radius is 1/2 as large.

Roy Cooke.

Thanks Roy

Marcel

[Roy D. Cooke, Sr]

Originally Posted by mcyr

That is pretty cool Roy. Thanks.

This one on your method seems to not work as well, but where would you want to apply a sphere too.?)

Thanks Roy

Marcel

The best funnies in my openion is BC and if you are grog and are making water balls you would need to know how much water they hold to be be able to figure out the weight of each one .

Of course a maladroit can not pick up Grogs water Balls
A long time ago before Calculators I was on a job and we had a round tank.
The engineer wanted to know how many gallons it held .
He went with his pencil and paper and Tape measure .
I went with my tape measure and did it in my head using the above formula.
I was done in about two minutes and wrote my answer on a piece of paper folded it and put it on the top with my Name date and time .
About 10 minutes later he had the answer and I handed him my paper .
I forget the actual figures but it was about 200 + Gallons and I was with in 3 or 4.
Well I sure gained a lot of respect from him .
He thought I was the prety good and never ever doubted any thing I said .

Roy Cooke

[Marcel R. Cyr]

Originally Posted by rcooke

The best funnies in my openion is BC and if you are grog and are making water balls you would need to know how much water they hold to be be able to figure out the weight of each one .

Of course a maladroit can not pick up Grogs water Balls
A long time ago before Calculators I was on a job and we had a round tank.
The engineer wanted to know how many gallons it held .
He went with his pencil and paper and Tape measure .
I went with my tape measure and did it in my head using the above formula.
I was done in about two minutes and wrote my answer on a piece of paper folded it and put it on the top with my Name date and time .
About 10 minutes later he had the answer and I handed him my paper .
I forget the actual figures but it was about 200 + Gallons and I was with in 3 or 4.
Well I sure gained a lot of respect from him .
He thought I was the prety good and never ever doubted any thing I said .

Roy Cooke

Maladroit.
Man, I haven't seen or heard this word since the 1960's when working with my father. He used to call me that quite a bit. ha. ha.

Marcel

[Roy D. Cooke, Sr]

Originally Posted by mcyr

Maladroit.
Man, I haven't seen or heard this word since the 1960's when working with my father. He used to call me that quite a bit. ha. ha.

Marcel

Very Good now in Dad's eyes you have made it and he is the one who counts .
Now do you have any of your offspring following in your shadows.
</IMG></IMG>.
Roy Cooke

[Marcel R. Cyr]

[quote=rcooke]Very Good now in Dad's eyes you have made it and he is the one who counts .
Now do you have any of your offspring following in your shadows.
</IMG></IMG>.
Roy Cooke[/quote

Actually, I did the same thing my old man did to me, start them at age 13. Man, don't they learn quick at that age.
I made sure my son would not have to work hard as me and his grandfather and sent him to school. He is now a Physical Therapist.

He told me more than once working with me during the summers that he did not like to push a broom.
I usually responded as, well I hope that all the $800 books I bought you this semester, you can learn and proceed to accomplish your Masters program and pass, for if you do not, what your doing right now is going to be your source of living. Do you believe that it worked???

Well, I'll be darn, he passed with a 3.4 GPA.
Where he got the medical stuff, is beyond me.

Marcel


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[Roy D. Cooke, Sr]

[quote=mcyr][quote=rcooke]Very Good now in Dad's eyes you have made it and he is the one who counts .
Now do you have any of your offspring following in your shadows.
</IMG></IMG>.
Roy Cooke[/quote

Actually, I did the same thing my old man did to me, start them at age 13. Man, don't they learn quick at that age.
I made sure my son would not have to work hard as me and his grandfather and sent him to school. He is now a Physical Therapist.

He told me more than once working with me during the summers that he did not like to push a broom.
I usually responded as, well I hope that all the $800 books I bought you this semester, you can learn and proceed to accomplish your Masters program and pass, for if you do not, what your doing right now is going to be your source of living. Do you believe that it worked???

Well, I'll be darn, he passed with a 3.4 GPA.
Where he got the medical stuff, is beyond me.

Marcel



Smooth Move who cares he is going and doing what he wants and knowing you will be great at it ,and you did not get the Chance to cal him a maladroit.
Life is great and the rewards are wonderfull .
Glad for you and your Family.
Remember Grog.
Roy Cooke A Happy NACHI member
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[msylvester]

Dave thank you!

Roy very nice.

[Gary Reecher]

Check NFPA62 for the correct sizing.