[TheForge] forge flues

[Peter Hirst]

8 Feet of stack outside the building and above the level of fhte top of the 
hood

pgh
----- Original Message ----- 
From: "Dan Brewer" <danqualman at gmail.com>
To: "'Sponsored by ABANA'" <theforge at mailman.qth.net>
Sent: Thursday, January 17, 2008 12:21 AM
Subject: RE: [TheForge] forge flues


> On the outside of your enclosure how much height do you have?  The top of
> the stack should have at least two feet of clearance from any obstruction.
> A cap on the flue is also a good Idea it keeps water out and  prevents 
> back
> draft.  A plus for a good cap that it will induce a draft no matter which
> way the breeze is blowing.  They almost always have a spark arrestor on 
> them
> and some type of screening to prevent birds and other critters making 
> there
> home in the flue.
>
> Dan in Auburn WA
>
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net
> [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Peter Hirst
> Sent: Wednesday, January 16, 2008 7:15 PM
> To: GHS at execpc.com; Sponsored by ABANA
> Subject: Re: [TheForge] forge flues
>
> Good points.  Any idea how to calculate sufficient stack size and height?
> Mine is 8" pipe eight feet high from the thimble and that is inadequate. 
> It
> draws just ok when the fire is at its hottest, but any thing less and  it
> spills smoke.   I know I have to add to it, but how much?
>
> pgh
> ----- Original Message ----- 
> From: "GRAF" <adveniam at att.net>
> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
> Sent: Wednesday, January 16, 2008 7:13 PM
> Subject: Re: [TheForge] forge flues
>
>
>> If the flue is set up with enough size and height it will draw like a
>> banshee with just the room ambient heat to make it work.
>> Kitchen vents in restaurants don't work without fans because they lack 
>> the
>
>> stack height usually and have filters which restrict the flow.
>>
>> Mike Graf
>>
>>
>> Peter Hirst wrote:
>>> One more thought if you can stand it.  Something to watch out for:
>>> "positive ventilation".  I had a fire and health inspector come by
>>> recently who asked me if my forge was positively (power) vented (it
>>> isnt).   There is no specific standard in this jusridiction for forges
>>> (as there is for coal stoves, wood stoves and everything else), and the
>>> concern was that the flue gases  are NOT HOT ENOUGH to draw well.  Just
>>> like over a stove or gas grill in a commercial kitchen, the heat from an
>>> open fire mixes with a lot of ambient air on its way toward the hood, 
>>> and
>
>>> is not very hot at all as it travels up the flue.  That's why commercial
>>> kitchen hoods are POWERFULLY positive vented.  With a coal forge,   this
>>> usually means that significant smoke escapes the hood and the least back
>>> pressure stops the draft altogether.  How many of us with coal forges
>>> have shops as smokeless as a commercial kitchen?  Or as any room with a
>>> properly vented wood stove? Anybody?  I didn't think so.
>>>
>>> So I would soft pedal the idea that the flue gases don't get very hot.
>>> This could work against you and lead your inspector to conclude that the
>>> forge should have a high powered exhaust fan.  Which it probably should,
>>> but why press it?
>>>
>>> pgh
>>>
>>>
>>>
>>>
>>> ----- Original Message ----- From: "john ortery"
>>> <bluestoneforge at gmail.com>
>>> To: <theforge at mailman.qth.net>
>>> Sent: Monday, January 14, 2008 7:36 PM
>>> Subject: [TheForge] forge flues
>>>
>>>
>>>> Thanks guys,This seems to be the thought all around.  Most of the 
>>>> people
>
>>>> I
>>>> talked to seem to think that as long as you have double wall pipe at 
>>>> the
>>>> exit point and are insulated from any combustible material all should 
>>>> be
>>>> well.
>>>> Thanks again Allen Ortery
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