John Dirks Jr Posted March 31, 2010 Report Share Posted March 31, 2010 Hi everyone. I hope you are all doing well. I have an upcoming job that has a fireplace which appears to open on it's side as well as it's front. What are any specific concerns with a design like this? Click to Enlarge 333.35 KB Quote Link to comment Share on other sites More sharing options...
mgbinspect Posted March 31, 2010 Report Share Posted March 31, 2010 Looks kike a pre-fab unit. If it was designed for the application and has acceptable hearths as required, there should be no concerns. Quote Link to comment Share on other sites More sharing options...
John Dirks Jr Posted March 31, 2010 Author Report Share Posted March 31, 2010 I'll ckeck the total opening area. If it is greater than 6 sq ft it should have at least 20" hearth to the front and 12" to the sides. Correct? What about ratio of flue size to fire box opening area? No concerns there? Quote Link to comment Share on other sites More sharing options...
kurt Posted March 31, 2010 Report Share Posted March 31, 2010 You're going to find that it doesn't comply when applying those dimension restrictions. At least, they usually don't. The proportions are all screwed up when compared to the stuff you're referencing. Check hearth dimensions. After that, look for a UL listing label, tell the folks to have a Level II inspection on the chimney. Quote Link to comment Share on other sites More sharing options...
randynavarro Posted March 31, 2010 Report Share Posted March 31, 2010 BTW, how are you getting photos of the interior before you get there? Quote Link to comment Share on other sites More sharing options...
hausdok Posted March 31, 2010 Report Share Posted March 31, 2010 Hi, As long as the builder installs the thing according to its listing and labeling it should not be an issue. ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
Tom Raymond Posted March 31, 2010 Report Share Posted March 31, 2010 BTW, how are you getting photos of the interior before you get there? That looks like a listing pic, it's oddly composed and poorly lit but the feature is smack in the middle.[] Tom Quote Link to comment Share on other sites More sharing options...
John Dirks Jr Posted April 1, 2010 Author Report Share Posted April 1, 2010 BTW, how are you getting photos of the interior before you get there? I google addresses of pending inspections to see what I can find in advance. Sometimes it prepares me to zero in on things, such as it did in this case. The front alone is 6 sq ft. Add the side in and it's probably over 8. The hearth only extends 16" so it's sized for 6' or less. I'll be referring the matters to the chimney pro. I already explained it all to the client and they are expecting it. Thanks to all for the input. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted April 1, 2010 Report Share Posted April 1, 2010 . . . The front alone is 6 sq ft. Add the side in and it's probably over 8. The hearth only extends 16" so it's sized for 6' or less. . . Why would you add the side opening to the front opening when considering the size of the hearth extension? The point of the chimney-opening/hearth extension size ratio is to protect the floor from radiant heat. A larger opening has the capacity to throw more radiant heat at the floor so it needs a larger hearth extension. The front opening and its hearth extension should be considered as one case and the side opening as another. They're not additive. Does someone have a reference that says otherwise? - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
kurt Posted April 1, 2010 Report Share Posted April 1, 2010 Somewhat thread drift....... About 35 years ago, a mason building a fireplace in a house I was building described the opening dimensions relative to the depth of the fireplace as critical so the thing would draw. He was insistent that the opening height be 2/3 of the width and the depth. Anyone else ever heard that? Quote Link to comment Share on other sites More sharing options...
Chad Fabry Posted April 1, 2010 Report Share Posted April 1, 2010 About 35 years ago, a mason building a fireplace in a house I was building described the opening dimensions relative to the depth of the fireplace as critical so the thing would draw. He was insistent that the opening height be 2/3 of the width and the depth. Anyone else ever heard that? Rumford never heard of it. Quote Link to comment Share on other sites More sharing options...
Tom Raymond Posted April 1, 2010 Report Share Posted April 1, 2010 It's a bricky thing. The old timer who taught him to lay brick used that formula, and he probably got it from the the old timer before him. When I worked masonry every firebox was exactly the same, because they worked. Why would you expect anything different from someone content to lay brick, one after another, over and over, gazillions of times. Tom Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted April 1, 2010 Report Share Posted April 1, 2010 Somewhat thread drift....... About 35 years ago, a mason building a fireplace in a house I was building described the opening dimensions relative to the depth of the fireplace as critical so the thing would draw. He was insistent that the opening height be 2/3 of the width and the depth. Anyone else ever heard that? I haven't heard that one. But I have observed that, among the building trades, masons are the most susceptible to superstition & folklore and, without a doubt, the most resistant to change of any kind. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
Marc Posted April 1, 2010 Report Share Posted April 1, 2010 Maybe they simply know what they are doing. Long experience has it's virtues. We just can't always explain things that work, in terms of codes and existing science. I don't mean to deny the presence of superstitions. Marc Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted April 1, 2010 Report Share Posted April 1, 2010 Maybe they simply know what they are doing. Long experience has it's virtues. We just can't always explain things that work, in terms of codes and existing science. . . I think it's more likely that they believe that, because they've always done something a certain way and it's always worked, then it must be the only way that it will work. I find that mentality a lot, but especially with masons. Quote Link to comment Share on other sites More sharing options...
John Dirks Jr Posted April 4, 2010 Author Report Share Posted April 4, 2010 Sorry I didn't respond sooner but I've been fighting a stomach flu bug. Nasty it was but i got it beat now. In the case of this fireplace, the heart extension from the side portion was too short even if you apply the < 6' rule. It extended 16" out which is fine but the side portion where it intersects with the dining room wall extended only 6" from the firebox opening. Quote Link to comment Share on other sites More sharing options...
wilsonlee Posted July 20, 2010 Report Share Posted July 20, 2010 Just imagine for a moment, you have an open fireplace in your home and you always look forward to those wonderful cosy evenings relaxing in front of the crackling flames.Thanks. Quote Link to comment Share on other sites More sharing options...
mgbinspect Posted July 20, 2010 Report Share Posted July 20, 2010 Maybe they simply know what they are doing. Long experience has it's virtues. We just can't always explain things that work, in terms of codes and existing science. . . I think it's more likely that they believe that, because they've always done something a certain way and it's always worked, then it must be the only way that it will work. I find that mentality a lot, but especially with masons. Boy, is there some truth to that. I remember the first time I constructed a true Rumford fireplace around 1976, according to all of his original dimension ratios (without asking the company owner). He had heart failure swearing it would never work and that I'd have to tear it down. The home owner loved it and said later that it would "run you out of the room" it works so well. Then there was the time I raised the smoke shelf to meet the height of the open damper door to reduce turbulence, which was met with equal panic, but worked perfectly. Masons are much like track home builders - a little variation here and a little design drift there and soon you don't have the original at all, but it remains the gospel as if no changes had occurred - kinda like that whispered phrase that is passed around a circle of people and arrives at the other end nothing like it began. Quote Link to comment Share on other sites More sharing options...
mgbinspect Posted July 20, 2010 Report Share Posted July 20, 2010 BTW, if you locate a book about the modifications to fireplaces performed by Count Rumford, all of the dimensions are relative to the height and width of the fireplace opening. I'll try to locate my copy of the book and scan and post the formulas. Codes, no doubt, have made masonry fireplaces safer, but they are the worst thing that ever happened to their aerodynamics and heating performance. Rumford was way ahead of his time and had the fireplace as tweaked as it's ever been. The newer metal double-walled construction fireplaces introduced a new dimension to convection in a fireplace - an option not available in Rumford's time. But, he capitalized upon the ventura effect to keep the most heat possible within the firebox while just skimming off the smoke, and maximized that heat through radiation with his extreme reflecting walls - all quit brilliant. Quote Link to comment Share on other sites More sharing options...
Marc Posted July 20, 2010 Report Share Posted July 20, 2010 I checked on the Rumford. That might explain a style I see on nearly all 100+ year old fireplaces in my area. They're shallower. Not that they are stock Rumfords but that a feature or two may have got carried over. Marc Quote Link to comment Share on other sites More sharing options...
Erby Posted July 20, 2010 Report Share Posted July 20, 2010 The largest majority of 100 plus year old fireplaces I see around Kentucky are coal burning fireplaces. Way shallow with metal grate to hold the coal off the floor and a metal cover to radiate the heat into the room. Sometimes the cover is still there. Sometimes not. In any case, they're mostly useless nowadays, though I've seen a few with funky gas logs installed in them. Click to Enlarge 44.97 KB Click to Enlarge 40.6 KB - Quote Link to comment Share on other sites More sharing options...
mgbinspect Posted July 20, 2010 Report Share Posted July 20, 2010 Many of the very old fireplaces in the downtown parts of Richmond are very shallow for another reason. tHey were designed to burn coal within a cast iron coal basket. The Copperclad cook stove I used in one of my 100+ year homes had in ter-changeable cast iron grates for the firebox - one for wood and one for coal. Quote Link to comment Share on other sites More sharing options...
mgbinspect Posted July 20, 2010 Report Share Posted July 20, 2010 The largest majority of 100 plus year old fireplaces I see around Kentucky are coal burning fireplaces. Way shallow with metal grate to hold the coal off the floor and a metal cover to radiate the heat into the room. Sometimes the cover is still there. Sometimes not. In any case, they're mostly useless nowadays, though I've seen a few with funky gas logs installed in them. Click to Enlarge 44.97 KB Click to Enlarge 40.6 KB - [:-thumbd] I think the gas burninng coal basket replicas are a nice touch. If I had such a fireplace, I'd install them. Quote Link to comment Share on other sites More sharing options...
Hearthman Posted August 8, 2010 Report Share Posted August 8, 2010 If it is a factory built fireplace then you go by the clearances in the listed instructions---not the clearances in the building code, which are for masonry site built fireplaces. Don't assume. Quote Link to comment Share on other sites More sharing options...
Rob Amaral Posted August 9, 2010 Report Share Posted August 9, 2010 The newer metal double-walled construction fireplaces introduced a new dimension to convection in a fireplace - an option not available in Rumford's time. But, he capitalized upon the ventura effect to keep the most heat possible within the firebox while just skimming off the smoke, and maximized that heat through radiation with his extreme reflecting walls - all quit brilliant.You do mean "Venturi" effect (not "ventura" as in "Ace")? [] Quote Link to comment Share on other sites More sharing options...
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