Owens Corning
Wood and Gas Fireplaces with Clean Burn Technology
Even though fireplaces are used occasionally and not as a primary heat source in a house, they still present a major source of pollution because of their sheer numbers. In western states, wood stoves and fireplaces account for over half of the particulate matter polluting the air.

Wood stoves are regulated by the Environmental Protection Agency (EPA). The law requires that only non-catalytic wood stoves that emit less than 7.5 grams of particulate matter an hour or those equipped with catalytic converters that emit less than 4.1 grams per hour can be sold.

Fireplace Technology Passes Wood Stove Requirements

Utilizing the technology developed by the stove industry, fireplace manufacturers have adapted this "clean burn" technology to create a new class of manufactured zero clearance fireplace. Although not required by law, these new fireplaces meet, and in some cases exceed, the existing EPA standards for wood stoves.

Not only are these new units cleaner burning, they are more efficient heaters. On the outside, a high tech fireplace looks the same as a standard manufactured fireplace but inside it is quite different. In order to reach and maintain the high temperatures needed to efficiently burn the smoke, the entire unit is made from a heavier gauge metal. It has a refractory brick fire box liner, high temperature ceramic insulation and ceramic glass doors to withstand high temperatures.

Instead of venting the smoke and gasses from the fire directly up the chimney, a baffle is positioned at the top of the fire box creating a secondary burn chamber above the baffle. The smoke and unburned gasses rise from the fire and are directed by the baffle toward the front of the fireplace and then around the baffle into the secondary burn chamber. Superheated air is injected into this stream which causes it to ignite and burn before it passes up the chimney. The design challenge was maintaining the high temperatures inside the secondary burn chamber needed to ignite the waste products.

Other fireplace manufacturers chose to use catalytic converters to burn the waste products before they escape up the chimney. The catalytic converter is a device similar to the one in your car. The catalyst reacts with the smoke and waste gasses causing combustion to occur at lower temperatures. Under normal conditions, it takes an 1100 degree fire to ignite the smoke and other waste products. With a catalyst present, the smoke begins to burn around 400 degrees.

Both types have better sealing doors and duct the combustion air into the fireplace from the outside. This design provides for precise burn control. And unlike masonry fireplaces, air for combustion is drawn from the outside so warm room air is not drawn up the chimney.

Realistic Burning Gas Fireplaces

Some of the new gas fired fireplaces are even cleaner burning than wood fireplaces. These units have always been a low polluter and now they're more aesthetically appealing with a natural looking flame. Improvement in burner design yields a yellow flame which appears more like the flame produced in a real wood fire.

Gas fireplaces can burn either natural or propane gas. Some can be vented directly through the wall and do not require a chimney. These units are very efficient and recover as much heat from the combustion as many standard furnaces. Options like a thermostat, multi-speed blower and electronic ignition can make these fireplaces as efficient and almost as convenient as operating a central heating system. Gas fireplaces may be the best compromise in areas of heavy air pollution.

Easier Installation and More Options

A zero-clearance, wood-burning fireplace uses a prefabricated metal chimney system and does not require a masonry chimney. The system consists of double or triple walled sections of pipe, elbows, and mounting flanges that allow the pipe to safely penetrate walls, ceilings, and other combustible areas without large clearances.. This chimney system allows for the installation of a fireplace during remodeling where the construction of a masonry chimney system would be impossible.

Both gas and wood-burning zero-clearance fireplaces have double wall construction which allows room air to circulate around the fire box. This hot air can be routed to other parts of the house through standard heating ducts. Optional blower systems boost their efficiency by increasing the air flow around the fireplace. The blowers can also be connected to external ducting.

The hot air from the fireplace can be directed into the same room where the fireplace is located through a system of built-in vents to provide local heating. The hot air can also be ducted into other areas of the house, even ducted directly into the central heating system to be distributed throughout the house. This drastically reduces the load on the central heating system when the fireplace is in operation.

This ducting system is especially useful when trying to heat a single-story house. Heat rises, to the second floor of most two-story houses naturally from the operation of a fireplace or wood stove, but natural convection does not help move heat around a single-level house.

A manufactured zero-clearance fireplace is designed for easy installation. As an engineered system, it consists of the fireplace unit, chimney system, blowers or ducting which are designed as modules that bolt together forming a safe non-masonry fireplace that can be installed anywhere. For a homeowner with carpentry experience, it's a doable project by careful planning and following directions in the installation manual.

If you are considering the project, first check with your local building department. All high tech fireplaces meet national building codes but many localities have additional codes that apply specifically to the installation of fireplaces. Before you purchase a unit, make sure it's approved by your local building department.

Zero-clearance fireplaces can be located on any structurally sound surface and enclosed with a wood and sheetrock partition. The chimney system however does require special consideration especially if you are placing the unit on the first floor of a two-story house.

Most chimney systems can take a couple of bends to accommodate the structure of the building, but there are limitations. You have to maintain all specified clearances between the chimney pipe and combustible materials along its entire run through the roof. These systems provide special chimney support flanges that maintain these clearances and provide necessary firestops and heat shielding. The flanges require a large opening so in most cases at least one floor or ceiling joist must be cut and headers installed to accommodate the chimney pipe flanges.

Since the chimney installation is most critical in order to have a fireplace with a properly drawing, safe chimney, consider having a professional install this part and you build the partitions, mantel and do the other carpentry work necessary to complete the job.

New high-tech fireplaces that meet EPA standards for wood stoves will probably be allowed in areas experiencing air-quality problems directly related to wood burning and have restrictions on new fireplace installations. Even if you don't live in such an area, air pollution from fireplaces is still a significant problem. Not only do these units burn cleaner, they are more efficient, consume less fuel, give off more heat, and should have a longer service life.

Manufacturers Source List

RSF Energy Ltd.
Box 3637
Smithers, BC VOJ 2NO
(604) 874-4301

Majestic
1000 East Market Street
Huntington, Indiana 46750-2579
(219) 356-8000

Security Chimneys Ltd.
2125 Montery
Laval, Quebec, Canada H7L 3T6
(514) 337-3387

Heat-N-Glo
6665 W. Hwy. 13
Savage, MN 55378
(612) 890-8367

Superior
4325 Artesia Ave
Fullerton, CA 92633
(714) 521-7302

Aladdin Steel Products
Quadra Fire
401 N. Wynne St.
Colville, WA 99114-2153
(509) 684-3745


Written by the editors of HouseNet.
Copyright HouseNet, Inc.

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