You should see mine. In a two story house 37 ft. of flue.
THE MISSOURI DESIGNED MASONRY STOVE - Free Download PDF (zbook.org) 520 fire brick alone. Probably weighs close to 9 tons. Took 3 of us 5 months to build. 6 hrs a day. Had to ski in.
THE MISSOURI DESIGNED MASONRY STOVE
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THE MISSOURI DESIGNEDMASONRY STOVEFUEL EFFICIENTHOME HEATING. . .
This publication was prepared with the support of funds from the United States Department of Energy(U.S.DOE), under Grant #G-87-23-EOO-22 and was compiled and edited by the Missouri Department 0Natural Resources' Division of Energy (MO DNR/DE). However, any opinions, findings, conclusions, or recommendations expressed herein under the individual organizational entries are those of the organization! and do not necessarily reflect those of either the U.S. DOE or MO DNR/DE.
IntroductionThe Missouri Designed Mason y Stove booklet was published with funds supplied by the US. Department of Energy. Special recognition is to be given Norman Lenhardt of the Missouri Department o f Natural Resources’ Division of Energy for his extensive research, drafting, and editing of the content. Art Foell, Industrial Technology senior at Southwest Missouri State University (SMSU), refined many of the graphics in the Harris Computer Center at SMSU. Linn Sunderland, of Southeast Community College, Beatrice, Nebraska, also supplied information. The manual was conceived in response t o a slow but steady increase o f requests for information about masonry stoves (“Russian” fireplaces). General information and conceptual information has been available for the past few years in popular magazines. However, there seemed to be only a limited amount of in-depth information o n how t o build and operate a masonry stove, even though a few organizations have supplied information t o their members. Many o f these information sources have been reviewed. While these sources were helpful, they all seemed to be incomplete within themselves, also most of the stoves (as described) were too large for most homes. For this reason, it was decided to try to publish a more comprehensive write-up with suggested drawings and construction details. PHONE: (314)751-4000
The Missouri Designed Masonry Stove At last there is an energy efficient replacement for the popular, but energy inefficient English style fireplace. This style fireplace or masonry stove is based on the very simple concept of storing heat in a series of brick baffles for longer, slower release as opposed to sending heat up the chimney of the standard fireplace. With imagination, these masonry stoves, sometimes referred to as “Russian” fireplaces, can be very attractive and functional. Progressive home buyers and builders may want to consider one of these efficient units as a substitute for the older inefficient open-style fireplaces. Innovative crafters can devise many ways to make these units just as decorative as other heating units. Considering the long-term world energy situation, it makes sense to utilize the best possible heating devices in your home.The masonry stove is a highly efficient heating unit which has been used in Eastern Europe for hundreds ofyears. Once widely used in the western and northern parts of the mid-west, lower cost heating units and moreconvenient fuels ultimately resulted in the decline, and finally abandonment of these masonry stoves. High cost fuels and the impending scarcity of oil and natural gas, have stimulated a renewed interest because of the lower cost of operation compared to other types of fireplaces or fireplace inserts. This ninety (90) percent efficient stove design was reintroduced by a Russian immigrant which accounts for the commonly used name of “Russian ”fireplace. This masonry stove is based on the use of flue baffles made of brick, stone or adobe, that direct the hot flue gases in an “S” shaped pattern. The serpentine pattern slows down the air speed and also increases the length of the flow. Each additional square foot of masonry surface absorbs some of the heat from the flue gas until maximum available temperature is reached. As the fire itself is allowed to bum out, the hot bricks slowly pass their stored heat through the wall and into the living space as radiant heat. Each pound of brick will store 2/10BTU of energy for each degree (Fahrenheit) rise in temperature. This is the reason a masonry stove is so efficient and retains heat for long periods. This slow, steady, low-level heat is very comfortable, much more so than a fan-driven, central heated, hot air furnace. The appearance of this type fireplace is controlled mostly by the designer’s imagination, time and skill in constructing the unit. It is possible to design one of these units to resemble an English style fireplace, but it adds greatly to the time, cost and complexity, and serves to perpetuate an appearance of an outdated fireplace that was never well designed for home heating. On a cold day, the standard wide mouth deep firebox, English style, masonry fireplace will lose more furnace heated air up the chimney than it generates from the fuel it bums. Under the best of conditions, the English fireplace will waste ninety (90) percent of the fuel that it burns on a season long basis. By contrast the masonry stove has been tested and found to deliver to the room, about ninety (90) percent of the heat generated from the fuel that is consumed. Even the least efficient masonry stove designs have resulted in eighty (80) percent of the heat delivered to the living space, compared to sixty (60) to sixty-five (65) percent for many of the airtight modem wood stove designs. The Missouri designed masonry stove, as shown in the drawings, will cost about the same amount as the standard English fireplace, but will have a lower life cycle cost because it uses fuel so efficiently. One full loading of the firebox of a masonry stove will keep the stove at comfortable temperatures for 24 to 36 hours. These massive brick or masonry units work very well as part of the heat storage mass for passive solar heated homes. The units can also be used as room dividers. Masonry stoves are very well adapted to new homes where floor plans allow for the required extra space. They can be adapted to many existing homes by locating the unit in an insulated basement or in the living room bythe use of reinforced masonry piers. In some cases, a slab on grade floor may carry the weight if properly reinforced. These adaptations will increase the cost of the unit, but generally will be cost effective over time, because of the fuel cost savings that result.
2Some Reasons for Building a Masonry .13.The cost is similar to the English style fireplace. Masonry stoves use much less fuel; sometimes up to thirty (30) percent less than the best steel stoves. The units may be used as part of the mass heat storage for passive solar systems. Masonry stoves provide more comfortable heat than hot air or baseboard heat. Masonry stove owners report greater personal comfort at lower room temperatures. When properly operated, these units have reduced creosote buildup. Masonry stoves generate less pollution, by sending less fly ash and unburned gases up the chimney and into the atmosphere. The unit can be adapted for the heating of domestic hot water. The unit can contain a built-in oven. Masonry stoves can be designed to load fuel from either side or either end. Residential floor plans may be designed to permit loading the unit from an isolated hall or mud room. Masonry stoves costs only slightly more than a high quality stove and chimney. Masonry stoves can be designed and situated to occupy less space than some of the larger radiant style steel stoves because they can be set closer to walls, etc. (do not neglect safety clearances).Disadvantages01.02.03.04.Masonry stoves take up more room than most stoves or wall mounted fireplaces. However, by using specialized firebrick or castable fire clay it may be possible to have a masonry stove with a 25” x 25”exterior ornamental wall dimension. The units may be difficult to retrofit to an existing residence. Masonry stoves warm up slowly, unless a hot water radiator or oven has been designed into the unit. Specialized masonry materials are difficult to find in some locales. Construction of a Masonry Stove The following pages will include years of accumulated construction and design ideas. The construction procedure will be illustrated, starting with the reinforcement of the hearth pad. Hearth Pad The hearth pad is the lowest part of the fireplace on which the firebox is constructed. The pad should be reinforced with 3/8 inch reinforcement rods (rebar or rerods) on 18 inch centers in both directions. The rods should be centered under the firebox (firebrick) and the ornamental brick safety wall to avoid cracking the structure due to slight shifts in the substructure. Hairline cracking of the pad can be reduced by the use of 2”x 4” welded wire fence mesh, wired to the reinforcement rod with soft steel wire or baling wire. The pad should always rest on well tamped ballast for new construction. The base must be of sufficient size to carry the load of the masonry stove as determined by soil type at the construction site. The load is approximately 7 to 8 pounds per square inch or 1008 to 1152 pounds per square foot. The size of masonry stove featured in this publication, including the pad, will weigh about 11,000 pounds and contains approximately 400 fire brick and 550 ornamental bricks plus the mortar. Tile or additional ornamentation will increase this weight. This amount of material is adequate to build a masonry stove for a small single story residence with eight foot ceilings and a five foot attic to gable. Note: a pad is not necessary if the stove is set on a reinforced slab on grade. Firebrick must protect the pad or the slab floor. A pad does add to the decor, making the unit easier to load and/or clean the masonry stove, and also simplifies the intake air ducting, unless a new floor slab, including air ducting, is being poured.
3In the concrete hearth pad, use 1/2 inch diameter clean silicon gravel and clean silicon sand, drinking clarity water and enough type A1 portland cement (available at lumber yards) to handle the weight of the structure. Do not use limestone aggregate in the hearth pad, because it expands from heat and pops out of the slab. Five or six bags of cement per cubic yard of concrete mixture is more than ample for strength. Use the concrete mix as dry as it possibly can be worked; excess water reduces concrete strength. Tamp or work the mixture well to remove voids and air pockets. Tap against the side of the pad forms to remove voids in the side wall.
4Combustion Air: Whenever possible, outside combustion air should be delivered directly into the firebox by insulated air ducts that have full flow valves which will totally block air flow when the masonry stove is not in use. Any combustion heat device will consume oxygen, which normally comes from outside air. If the outside air is not supplied by ducting, the air must be drawn through the house by way of air infiltration around doors, windows, reverse flow in other vents and any other cracks that exist in a house. Air infiltration is especially high where the walls meet the floors. In the winter, any air moving through the house will be colder and dryer than normal house air and since it is moving air, it will cool body temperatures faster than calm air and one feels uncomfortably cooler, even at a warmer inside temperature. A primary reason that the English style fireplace is so inefficient, is because it consumes 7 to 10 times more air than is necessary for maximum combustion. Combustion Air Intake Combustion air can be supplied using three 1 1/4 to 1 1/2% inch galvanized water pipes. Water pipes have been used in a fireplace for two heating seasons without visible problems. Lighter duty pipe could probably be used. While this small water pipe has worked, the air volume supplied is not adequate for the size masonry stove that is dictated by the use of standard 41/2% x 9 x 2 1/2 inch firebrick which results in a firebox of 18 x 27 x 12%inches. Two 3 x 3 inch square metal downspouts total 18 square inches and should provide adequate intake air. The downspout metal projecting into the firebox will eventually corrode out. The extension of the metal spout into the firebox serves to help keep ashes from entering the air tube. Short insert nipples could be adapted later for replacement if proven desirable. Electric conduit tube could be used for air ducting and also costs less than water pipe. Cross-Sectional Area of Selected Size Pipe and Ducts: Maximum suggested air intake area is 18 square inches via outside ducting. Each duct should be ten feet or less in length, longer lengths produce friction of the air flow reducing air volume in the firebox. If a longer run is required, increase the duct size from outside up to the air distribution box referred to in the next section. During the fire start-up period, the air damper on the fire door can be left open so that some inside (house) air can supplement the combustion until the fire dies down to a level that can be supplied by the outside air tubes. This time span is an experience factor and depends on fuel moisture, outside air temperature and volume of fuel in the firebox but usually takes less than one hour.
5Combustion Air Valve or Distribution Box The valves inside the house for the combustion air tubes can be regular full flow gate valves when using standard size galvanized pipe. Caution: Do not use globe valves because they greatly restrict the air flow. Intake pipes or tubes should be insulated from the outside house wall up to the valve inside the house to reduce heat exchange between inside and the outside. Where 3 x 3 inch down spouting or other type tubes are used the builder/crafter will have to design an insulated guillotine or insert valve substitute. Provisions should be made for partial valve closure, as opposed to only fully opened or fully closed positions. Use of a valve distribution box will enable one valve to control the air flow as opposed to a valve for each tube. Insect screen (1/8 x 1/8 inch hardware cloth) should be installed over the outside openings to avoid entry by rodents, insects, animals or trash. Buy enough wire for the insect screen and screening of the sand for the ornamental brick mortar mix. The screen on the air duct should be removable to aid in duct clean-out if something accidentally falls into the air tube. The surface area of the wire screen should be twice the area of the tube. Avoid water entry into the air tubes by down turns or by reverse angle cuts. Brick and Mortar Suggestions Brick and mortar should be selected both for ornamental value and resistance to high temperature. Use fireplace brick must be carried throughout the firebox structure, including the oven and first flue run. After the first flue run, standard face brick or common brick and sand mortar has been used with no apparent problems. Standard brick and sand mortar is lower in cost than firebrick and firebrick mortar but will add some difficulty to construction details. For this reason our drawings are based on firebrick throughout the firebox, the oven, the flue runs and into the first few inner (filler) bricks of the chimney. Caution: consult your supplier on details for handling the mortar and avoiding air bubbles between bricks or possible freezing when using air setting high temperature mortar. Firebrick mortar is normally applied as a very thin coat with a paintbrush and each brick slides (scrubs) into place to eliminate air bubbles.
7For the exterior (safety) ornamental wall, any type brick or stone will be satisfactory. Only a very limited area of this exterior wall will rise above 140 degrees Fahrenheit (the area near the primary flue exit at the rear of the firebox may be hotter). Select masonry materials which can withstand the temperature without cracking. Since the outside wall will be viewed by the home owner, your own imagination and preference will be a primary factor in choosing materials. These exterior walls have been constructed of ornamental stone, common brick, adobe, face brick, concrete with ceramic tile, or any combination of materials. Regardless of the base materials selected, the mortar should be mixed from clean sand screened through an 8 x 8 inch mesh screen. Do not use sand screened through 1/16 of an inch or smaller mesh. Do not use more than ten (10) percent lime in the mortar and avoid Missouri river sand because it usually contains carbon impurities from coal. Ten (10)percent by volume, of fly ash in addition to ten (10) percent lime added to the cement sand mortar will help to make a smoother easier to handle mortar. A bag of cement weighs 94 pounds, ten (10) percent by volume of fly ash is about 10 pounds per bag. Anti-mortar setting materials are available at some concrete ready-mixplants to retard mortar
stove design was reintroduced by a Russian immigrant which accounts for the commonly used name of “Russian” fireplace. This masonry stove is based on the use of flue baffles made of brick, stone or adobe, that direct the hot flue . water and enough type A1 portland cement (available at lumber yards) to handle the weight of the structure.
