Forge venting questions

[Aaron J. Cergol]

Hi all,

I'm just about finished with my masonry style forge. I salvaged some old cream city bricks, made a frame (covering cinder blocks) and made several large arches and added some decorative features. I put in a 1/4" thick plate for the table, cut three holes for firepots (it's a triple forge as I do a lot of teaching) and am hooking up some blowers now.

my question is this, how do I best go about venting? in my old shop, which happened to be an old barn, I simply made a chimney all the way to the top and 10' above the roof line. in my new shop, this is not possible. it has 10' tall ceilings, but it will not be possible to go 10' above the roof line. I would like to utilize some 8" double walled pipe I was given as it's very expensive to buy new. My shop is in an old factory building, complete with an ancient sprinkler system; ya know the kind that has the little pewter or lead pins in them...with ancient water too...

anyways, I was planning on a large hood, but I don't know if this will be effective enough. I can go 4 to maybe 8' above the roof line. will this be enough draw? Will I need a fan, and if so, what kind would work for this application without breaking the bank? I am very paranoid about setting the sprinklers off. I realize they are single units that need to be provoked and it would take a lot to do so, but I cannot risk that, so I need the draw to be as good as it can get.

Thank you for your time and help.

Aaron

edit-I forgot to mention, these forges are for coal and coke. the actual table is 4'X6' with three "stations" on it.

[eric sprado]

Aaron: This question has come up before. Here is site that,if you search around,has a VERY comprehensive article on chimney building....http://www.beautifuliron.com/forge.htm

[John B]

Hi all,

I'm just about finished with my masonry style forge. I salvaged some old cream city bricks, made a frame (covering cinder blocks) and made several large arches and added some decorative features. I put in a 1/4" thick plate for the table, cut three holes for firepots (it's a triple forge as I do a lot of teaching) and am hooking up some blowers now.

my question is this, how do I best go about venting? in my old shop, which happened to be an old barn, I simply made a chimney all the way to the top and 10' above the roof line. in my new shop, this is not possible. it has 10' tall ceilings, but it will not be possible to go 10' above the roof line. I would like to utilize some 8" double walled pipe I was given as it's very expensive to buy new. My shop is in an old factory building, complete with an ancient sprinkler system; ya know the kind that has the little pewter or lead pins in them...with ancient water too...

anyways, I was planning on a large hood, but I don't know if this will be effective enough. I can go 4 to maybe 8' above the roof line. will this be enough draw? Will I need a fan, and if so, what kind would work for this application without breaking the bank? I am very paranoid about setting the sprinklers off. I realize they are single units that need to be provoked and it would take a lot to do so, but I cannot risk that, so I need the draw to be as good as it can get.

Thank you for your time and help.

Aaron

edit-I forgot to mention, these forges are for coal and coke. the actual table is 4'X6' with three "stations" on it.

For three station forging you will be struggling with one 8" diameter chimney, and I would think you will still get smoke in the room when starting your fire(s) even when the chimney is initially pre heated. One blower should be adequate to feed them all, we have 12 forges fed from 1 blower and they all can be worked at maximum at the same time, and yet be individually adjusted on slide valves for the air blast without altering the other forge's performance.

All these forges (mostly doubles) have individual chimneys, and at least 12" diameter plus cross sectional area.

An air blast injected up the chimney may assist but my experience would be to go for a much larger diameter /cross sectional area chimney for starters