# Medical gas Questions



## Rhitchcock (Aug 25, 2009)

Does anybody have experience with medical gas that i could bounce some questions off of them ????? it has to with sizing of vent lines for the manifolds.


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## Protech (Sep 22, 2008)

Oh dear, the dreaded nfpa 99 book..........
Lay it on me. I don't do med gas but perfcthair4ever does. I'll call and ask him. What's your question? Be detailed.


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## Rhitchcock (Aug 25, 2009)

the NFPA says:

"where two or more vent lines discharge into a common vent line, its internal cross-sectional area shall be no less than the aggregate cross-sectional area of all discharge lines served."

I have 3 manifolds in my med gas room each has a 1/2" NPT outlet for the vent. I am trying to tie these together and run out one line outside. I can't decipher this to figure out what i means. What i get out of it is that as long as the line is large enough to handle the volume of all three lines discharging at the same time all is good. so if i tied all three together and installed a 1" line outside i would be fine.


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## SlickRick (Sep 3, 2009)

Rhitchcock said:


> the NFPA says:
> 
> "where two or more vent lines discharge into a common vent line, its internal cross-sectional area shall be no less than the aggregate cross-sectional area of all discharge lines served."
> 
> I have 3 manifolds in my med gas room each has a 1/2" NPT outlet for the vent. I am trying to tie these together and run out one line outside. I can't decipher this to figure out what i means. What i get out of it is that as long as the line is large enough to handle the volume of all three lines discharging at the same time all is good. so if i tied all three together and installed a 1" line outside i would be fine.


 ..


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## ILPlumber (Jun 17, 2008)

3.14 x radius squared gets you the area of the 1/2" pipe x 3 = .60 
3/4" pipe - the area is .45

1" pipe the area is .79 
you can see above that a 1" line is what you need


Class dismissed!


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## SlickRick (Sep 3, 2009)

I stand corrected, my 23 yr old corrected me also.


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## ILPlumber (Jun 17, 2008)

Who'da thunk we would ever use geometry.:laughing:


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## SlickRick (Sep 3, 2009)

ILPlumber said:


> Who'da thunk we would ever use geometry.:laughing:


Use it or lose it... I thought it was a trick question..:whistling2:


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## TheMaster (Jun 12, 2009)

ILPlumber said:


> 3.14 x radius squared gets you the area of the 1/2" pipe x 3 = 2.36
> 
> 3/4" pipe - the area is 1.77
> 
> ...


Your decimals are in the wrong place Mr. professor.:laughing: All of the answers are wrong if they are suppose to be in sq in. after review. You did the diameter x diameter instead of the radius x the radius.


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## ILPlumber (Jun 17, 2008)

TheMaster said:


> Your decimals are in the wrong place Mr. professor.:laughing:


 
Do tell grasshopper.


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## TheMaster (Jun 12, 2009)

ILPlumber said:


> Do tell grasshopper.


 How are your answers expressed? sq in.?


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## ILPlumber (Jun 17, 2008)

yes


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## ILPlumber (Jun 17, 2008)

take 1" for example. That's an easy one. .5 x .5 x 3.14 = .79 sq. inches


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## TheMaster (Jun 12, 2009)

ILPlumber said:


> take 1" for example. That's an easy one. 1 x 1 x 3.14 = 3.14 sq. inches


 That would be correct for 2" pipe. 1" is the radius which is half the diameter.


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## TheMaster (Jun 12, 2009)

1/2" pipe area. .25x.25=.0625x3.14=.19625x3=.58875 sq in.


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## ILPlumber (Jun 17, 2008)

:laughingammit man!:laughing::laughing:

I HATE it when I forget shtuff.

At least it was no harm done. I would rather screw up here than anywhere else. Just for the entertainment value for you folks.

The gentleman from Alabama is correct. :thumbup:

What does radius mean again? Duh..........

I am going to edit my post to reflect the correct answers now.:whistling2:


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## Protech (Sep 22, 2008)

Everyone makes a goof sometime. At least you were man enough to admit it:thumbsup:


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## ILPlumber (Jun 17, 2008)

All fixed. Except TM's.

I didn't edit it. 

He gets grumpy when I edit him.:laughing:


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## Rhitchcock (Aug 25, 2009)

Thanks for all the help fellas. That was exactly what i was looking for.


:thumbup::thumbup::thumbup:


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