ALUMINUM RELINING PIPE: Aluminum used as a relining pipe when used with a low efficiency gas furnace. Can only be used with devices that produce neither enough heat or enough moisture to constitute the need for a more durable relining system.

CARBON MONOXIDE: (CO) A colorless, odorless, produced by burning material containing carbon.

CHIMNEY: A vertical system for venting hot flue gases or smoke from a boiler, stove, fireplace or furnace to the outside atmosphere.

CHIMNEY CAP: A protective covering for the top of a chimney. Designed to protect the chimney lining and mortar crown.

CREOSOTE: Combustible deposit that originates from condensed wood smoke. A natural by product from burning wood.

DAMPER: A retractable device inside a chimney flue which regulates air flow and smoke.

DRAFT: The force or pressure that causes gases to flow up and out of a chimney.

RIGID LINING PIPE: Non-flexible stainless steel pipe used for relining masonry chimneys. Used primarily in chimneys that do not have offsets.

STAINLESS STEEL CHIMNEY LINER: Stainless steel pipe, either rigid or flexible, made for relining flues of masonry chimneys when the original clay liner has cracked or broken. May also be used to create a lining in a masonry chimney that was made without a liner.

STOVE PIPE: Metal pipe used to vent a wood or coal stove into a masonry chimney.

Although chimneys are designed to withstand nearly anything, it would seem, the truth is they aren’t quit as indestructible as we might think they are. The liners in particular could easily lose their former stability and be a factor in a fire or carbon monoxide poisoning by permitting the escape of gases and/or burning embers.

If you do, indeed, find that you need to have new liners installed, there are a number of different options open to you. The fireplaces of today are not the fireplaces of old – which is a good thing for homeowners. The fireplaces of today are not necessarily simply made of brick. Many are made of a variety of more supple materials. This allows you to replace the liners without essentially rebuilding the entire chimney.

But first, of course you will need to find out if you actually need a new liner. To do that it is best to have your chimney inspected by someone who knows what they’re looking for. And where would you go for such a service? Well, to a chimney sweep. Though many may have the idea that chimney sweeps don’t actually exist anymore, the truth is they are as popular as ever. As more and more homeowners are putting fireplaces into their homes, the business of chimney sweeping as become an important element in making sure we keep our homes safe. A chimney sweep will install, clean and maintain your chimney so as to keep it in working order and safe to use.

One of the chimney sweep’s main jobs is to look for potential fire hazards, as well as blockages in your chimney. This is especially important for those who have a gas fireplace. If a homeowner with a gas fireplace has blockage in their chimney, the fumes can easily build up inside the home. A chimney sweep may do an initial inspection of your chimney, and then depending on what they find, they may suggest a more in-depth inspection.

Although there are chimney sweeps who do this type of inspection for a living, you should keep in mind in most localities there is no government oversight or industry regulators. In addition to asking friends and neighbors for suggestions of someone they trust, you might also call your local fire department or even the appropriate local government office to see what they recommend.

There can be many problems with primarily ornamental type fireplaces that can put your home and family at risk. For occasional use these fireplaces may be safe enough, but continual heavy use can cause design and material problems to put your safety on the line.

Building functional, relatively safe masonry fireplaces or to a lesser degree, installing factory made fireboxes and stacks has become a lost art. Not every mason knows how to do it properly or for other reasons it is just not done properly.

Most experts agree that a fireplace wastes more energy that it supplies. A roaring fire can draw three to four hundred cubic feet of air per minute; this air has to come from outside the home to feed the fire. It may be warm in front of the fire but cold air entering the home through cracks or around door seals will more than offset any gain produced by the heat from the fireplace.

Continual or even occasional use of a fireplace builds up creosote on the chimney liner. This is especially true with a chimney built with commonly used clay flue liner tiles. Creosote comes out of the burning wood as a gas and then condenses on the relatively cool flue tiles as a tar like substance.

Over a period of time, quite a bit of creosote can build up coating the inside of the chimney with a combustible material. This combustible material only has to reach ignition temperature to become a roaring un-controllable blowtorch. A pro-longed fire in a fireplace may bring the flue temperature up enough to cause ignition, and let me tell you, I speak from personal experience, that chimney fires are no fun and will scare the ever-loving daylights out of you and possibly burn your house down.

Many fireplace potential problems are not visible and can’t be found no matter who inspects it. So take my advice and consider your fireplace un-safe for prolonged use. It is just not worth the risk.

The best time to clean an oil chimney should be done after the heating season such as spring time or right before the heating season begins. A lot of homeowners are unaware of chimney problems. Most find out after the chimney clogs or the interior of the clay liner or brick has cracked or collapsed. It is usually too late for routine cleaning.

One of the biggest misconceptions by a homeowner is the belief that the oil service company takes care of the chimney. They may clean out the venting system such as the connector pipes, or even clean out the base of the chimney, but will not clean the chimney itself or inspect it.

What if I have a gas furnace?

The chimney should be inspected by qualified technicians and a thorough examination of the external structure should also be done to look for signs of deterioration and weaknesses. Staining due to flue gas seeping through the chimney walls may be visible. Broken bricks or crumbling mortar joints are signs for repair. Internal inspections should be done by a video inspection device to check for cracks in clay liner or chimney walls. The video equipment will show problems that can’t be seen from the top of the chimney.

The chimney should be cleaned to remove any soot or creosote that might be present. Check to be sure a chimney cap is there and in good condition. The condition of the appliance pipes by a visual check should also be done.

The by-products of pyrolysis are gases and solid compounds. It takes on many different appearances. It can be sooty or ash like, sticky, tacky and runny tar glaze, dry honeycombs or curly flakes. It can also be dense, hard and shiny black tar glaze. Several variables that affect the amount of build-up deposited in the wood heating system are smoke density, flue gas temperature, and residence time.

The smokiest fires and the coolest chimneys produce the greatest amount of build-up. In addition over-sized equipment usually causes more build-up. Contrary to popular belief, burning seasoned hardwood does not eliminate build-up. Wood can actually be too dry.

Proper operation of the wood heating system is the single, most important contributing factor in minimizing build-up. Burning smaller fuel loads, refueling more frequently and avoiding slow, smoldering burns is also important.

Tools for cleaning chimney creosote

The Height Of The Chimney

There is an appropriate measurement rule that must be followed for every chimney. If the measurement is followed you should not have any problems with your chimney, however, there can be exceptions. To determine if the rule has been followed you should measure ten feet from the chimney to the closest object. This object can be the line of the roof, where an addition starts, or the peak. Once you find the ten foot mark measure up two feet and that is the height that you chimney should be.

The chimney must be at the proper height to catch wind. It is not necessary for the chimney to be higher than the peak of your roof. If the peak is in the ten foot clearance area then it should. This is because the wind will blow across the roof and it should make an updraft and pull the smoke up with it.

It is sometimes necessary to raise the height of your chimney if a certain situation in pressure happens. There have been some products introduced in the market that can help with the price of raising your chimney.

You can use a flue extender to raise your chimney up to three feet. They are usually made of copper or stainless steel and have been proven to eliminate the draft problem. It is much less expensive to use one of these than it is to have your chimney raised.

Chimney pots are another method to eliminate the draft problems on your chimney. They have been around for centuries and were originally made from clay.

The newer chimney pots are made from copper. They are more expensive than the clay variety of pot, but they are very beautiful and can add to the look of your home. When copper ages it will turn a green color that is quite beautiful.

For those fireplaces that are metal zero clearance it will be necessary for you to get the manufacturers model number and the name of the manufacturer so that you can get the size of pipe you will need to raise your chimney. There may be a regulation in your city that requires you to enclose the pipe in a chase. This might cause you to have to build the chase to the new height.

This may solve some of your problems with smoke entering your home, but if it does not there may be more problems with your chimney.

Chimney caps like the Vacu-Stack or the Windbeater are another solution for your draft problems. They are specifically made to create an updraft when the wind blows across your roof and chimney. The cap will stay put and the wind will circle around the cap and make an updraft. This works fairly well with masonry chimneys, solid pack chimney pipe and metal chimneys. You can find a variety of sizes and adapters that will work on most masonry chimneys.

If you have a metal chimney you will not need an adapter. You can measure the inner pipe if you have an air cooled chimney pipe with two or three pipes inside. A collar for the outer pipes comes with the Vacu-Stack for these types of chimneys. If you have a drafting problem with your furnace or water heater you can generally find smaller sizes to fit these.

When chimneys get old or are not maintained properly they can deteriorate and create hazardous conditions. Cracked tiles and deteriorating masonry can allow hazardous gases or even fire to enter your house.

In order to remedy these situations there are two things that can be done. The entire existing chimney can be torn down and rebuilt, or you can reline the chimney with a stainless steel or aluminum flexible chimney liner insert.

What is a flexible chimney liner?
A flexible chimney liner is just that, flexible, as opposed to rigid. The wall thickness ranges from .005 in. to .019 in. All stainless steel liners have some form of ribbed construction and are supplied in continuous lengths. Flexible liners allow for both top and bottom support because any expansion due to heating is absorbed by the liners flexible ribbing. Some flexible liners can be bent by hand while others are less flexible and require special tools for bending. The use of rain caps are recommended.

Most liners offer a strong 7-ply seam which is air and water tight. The flex liner has ten corrugations between each reinforced seam offering greater flexibility. These unique alloys are designed specifically to resist acids in the flue and extreme stresses of hot and cold cycles.

The chimney liner is the ultimate solution to the problems that plague most chimneys. Modern stainless steel provides air tight and water tight barrier that seals in gases and creosote. Underwriters Laboratory declared that flex systems excel standards for chimney safety and can even withstand a chimney fire and still maintain structural integrity.

This system is to be installed in all new or existing masonry chimneys that are used for the natural draft venting of gas, liquid, and solid fuel fired residential type appliances and masonry fireplaces. While extreme care has been taken to make the system as safe as possible, proper installation, operation and maintenance should be followed.

Are all Chimney Liners the same?
Most flexible stainless steel liners are the same from manufacturer to manufacturer. They may vary slightly in their steel makeup, some leaving out the Titanium. They are are very closely related in their design. Some manufacturers make the “hills and valleys” of the liner a little steeper claiming greater flexibility and strength.

What kind of metal chimney liner should I use?

Most people are impressed with the strength of the leading manufacturer’s liner. Does the liner need to withstand the weight of a 300lb man? No, it doesn’t. When the liner is placed in your chimney there is no weight pushing on it’s sides. So this is something that is not really necessary, however, it may give people some added peace of mind.

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This article was reprinted with permission from Chimney-Liner-Central

The seam running down the length of each liner sections is factory sealed. Individual liner sections are joined together with the crimped, male end facing down. Stainless steel pop rivets and stainless steel screws secure the joints.

Pop rivets are recommended by most manufacturers since screws may work themselves loose from the expansion and contraction of the liner. Usually rigid relining jobs are supported at the bottom of the chimney or at the thimble area.

Stainless steel tee sections are used at the thimble and clean out areas. Rigid stainless steel liners can expand several inches during heating. To accommodate for this expansion the liner moves up and down in a sleeve at the top of the chimney.

A storm collar over the sleeve prevents moisture from entering the chimney along the outside of the liner. The area around the sleeve at the top of the chimney is sealed with either a stainless steel plate or a concrete pad.

The use of rain caps are recommended for use on chimneys with stainless steel liners. It can be very important to have the most efficient venting possible.

A smooth walled rigid liner offers the most efficient venting due to the decreased turbulence. You can shape it to take full advantage of every cubic inch and offer maximum draft. It can be shaped into rectangular, square or oval.

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There are several factors that would influence draft and flow, thus affecting chimney performance.

Two of the major factors for draft are:

• Temperature difference between the average flue gas temperature and the temperature of the outside air.
• The height of the chimney.

Three major factors that influence flow:

• Draft
• The amount of flow resistance and flue cross sectional area. Flow is usually the capacity of a venting system and is determined by the way draft and the amount of flow resistance and flue area all balance out in operation.
• The size of the venting passage ways. This is the most critical variable influencing the amount of flow which affects chimney performance. The larger the flue, the greater to volume of gases that will be able to flow through the system in a given time and at a given draft and flow resistance. Measuring the cross sectional area of each flue can compare flow capacities of different flues.

The same principals of draft and flow apply to fireplace flues and flues servicing stoves or other heaters. There are differences in the way draft and flow balance in various chimney systems.

Chimney performance problems can be divided into three categories.

• Wind induced down drafts
• Flow reversals
• Inadequate flow

Wind induced down drafts and flow reversals cause smoke to flow backwards down the chimney. Inadequate flow indicates that the flow volume is insufficient to handle the amount of flue gases even though the direction of flow is correct.

The solution to wind induced down drafts is to extend the chimney above the turbulence or high pressure zone that is causing the problem. Usually chimney caps, especially those designed to take advantage of the wind, are often the more economical solution to wind induced downdraft problems.

There are several causes for flow reversal problems.

• Interaction between the chimney and the home.
• Another chimney in the home.
• Operating exhaust fans in airtight homes.
• Improperly connected appliance ducting systems.

Solving flow reversal problems
Most of the time, flow reversal problems can be solved by repairs or by supplying the appliance with an alternative source of combustion air. Inadequate flow problems can be the result of insufficient draft or of insufficient flow capacity.

Draft Problems
Inadequate flue gas temperatures cause most draft problems. Anything that decreases the velocity of gases also increases their cooling. The size of the flue and other passageways in the system and the amount of resistance offered by obstacles, bends or debris in the system determine flow capacity. Other flow related problems could be due to air leaks in a chimney. Using a single flue to vent more than one appliance and airtight homes are other obsticals.

Back Puffing
Back puffing can be distinguished from smoking problems caused by wind induced down drafts by the sharpness and force of the puffs of smoke. In back puffing, the stove emits intermittent puffs of smoke due to small explosions in the stove or venting systems. Back puffing is not a true chimney performance problem but is usually mistaken for one when it occurs. Allowing more air to enter the appliance will stop back puffing. Its prevention is entirely dependent on proper operation of the stove.

If your existing terra-cotta flue liner doesn’t have much space left after the liner is installed you may opt to use a poor down insulation. The most common choice for insulation is the wrap if clearances allow for it. Insulation wraps commonly come in .25 and .5 inch thicknesses.

Instructions chimney liner insulation installation:

Using Insulating Blanket Wrap

1. Make sure the bottom termination connector is installed. The liner must be insulated all the way to the bottom of the connector.

2. Determine the length of insulation needed and cut.

3. The insulating wrap must overlap along its length by a minimum of 1 inch. To ensure you have the proper    width of insulating wrap, multiply the liner diameter by 3.14 plus one inch for overlap. You may trim the width of the insulation to this amount but is not necessary. If the overlap is more than one inch you may have difficulties with clearance.

4. With the foil side of the insulation facing down, lay it out on a flat surface.

5. Set the liner in the center of the insulation.

6. Begin wrapping the insulation around the liner, leaving at least a one inch overlap on the seam. You can use the spray adhesive to help keep the insulation in place. Use the foil tape to secure the seam at one foot increments.

7. Once the insulation is in place, lay one continuous vertical length of tape on the entire seam.

8. Unroll the wire mesh and encapsulate the full length of liner including the bottom connector. Use one hose clamp to secure the mesh to one end of the liner. Now on the other end of the liner, pull the wire mesh until it retracts and fits tightly on the liner. Use another hose clamp to secure the mesh on the pulling end. Cut away excess mesh. You may take the stainless steel locking wire and spiral wrap the wire mesh to help keep it in place during installation .

9. The liner is now ready to install.

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Using Insulating Mix

Note: Insulation mix is poured down the chimney after the liner is installed.

1. Empty insulation into a wheelbarrow or mixing box. Add the appropriate amount of water per bag of insulation mix. When the material is damp, but still granular you have achieved proper consistency.

2. Distribute the insulation mix evenly around the liner. Make sure to center the liner in the flue.

3. Vibrate the liner as you continue to pour the insulation down the flue around the liner.

4. All heating appliances or fireplaces can be used after insulation process is complete. You do not have to let the insulation set. Make sure to keep flue gas temperatures below 700 degrees F for a period of three weeks.

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