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Originally published in the December 2014 issue of Sweeping Magazine

Question: I am relining a flue with a stainless steel liner for a client because the existing clay liner is now over sized for the new appliance. Do I really need to perform an internal camera inspection of this flue if I already know that I'm fixing it?


by Mike Segerstrom 

Answer: Yes. There are several reasons why, and we will take a look at each.

The first reason we will discuss is the NFPA 211, and the Levels of Inspection found in Chapter 15. Whether we are certified or not, these Levels of Inspection have become the “Standard of Care”, or “Industry Standard”. It's not possible to cover all of the NFPA 211 inspection requirements here, but we will look at one. In the level 2 Inspection section of Chapter 15, the 211 states that “internal surfaces of all flue liners” will be examined by “video scanning or other means”, “prior to relining or replacement of flue lining”. If there is only 6 feet of clay liner, we can probably evaluate all of the internal surfaces of the liner without an internal camera inspection. But if the chimney flue height is more than that, and especially if the flue contains offsets, performing an internal camera inspection is likely the only way to meet that Level 2 Inspection requirement. We may not see anything that affects relining, but we are following the requirements of the industry standard. And by following the industry standard, we are not only providing a better service to our clients, but we are helping to protect ourselves and our companies if we ever find ourselves in a legal situation.

Next let's look at some of things we may find, during this internal camera inspection, which could affect flue relining. One of the common things that we could see in a clay tile lined flue, is excess mortar at the joints. If this is in an offset area, we may not have seen it with a visual evaluation from the top and the bottom. Then the only time we would know about it, is when the stainless steel liner is halfway down and won't go any further, or even gets stuck. If we would have scanned the flue first, we would have seen it, taken the steps to remove it, and saved ourselves what can sometimes be big headaches! And like excess mortar at the joints, clay tile liners can sometimes be severely misaligned at the joints, especially in offset areas. This can also result in stopping our liner from passing through, or even getting it stuck!

Excess mortar seems obvious, but there are many things that can be less obvious. Often these things can be latent or original construction defects that were never known about until we scanned the flue. One good example is combustible materials being incorporated in the chimney construction, and exposed in the flue passageway. Though rare, it does happen. If we install on liner and it is in contact with these combustible materials, realining the flue could actually result in a fire! In some cases it may be possible to remove these combustible materials, but in other cases they are so incorporated into the chimney structure, that they are not suitable for removal. In those cases, relining the chimney flue is not an option.

Other things that can show up in a flue passageway include gas piping and electrical wiring. If we don't see these things and address them beforehand, installing the liner could cause problems and even result in hazardous conditions if damage to the wiring or gas piping occurs. Again, these types of things are rare, but they are out there, and we need to spot them first, before we reline the flue.

Another hidden defect that can be more common in older homes, is an unsealed or improperly sealed thimble or breach, usually found on the first floor. Sweeps have seen these thimbles/breaches partially sealed, sealed with combustible materials, are not sealed at all. In one case, the thimble was sealed in the kitchen, by the side wall of a combustible kitchen cabinet! Installing a metal liner in this flue, would have resulted in a metal pipe that gets hot, being only inches away from an already highly combustible kitchen cabinet! Scanning the flue first gives us the opportunity to catch these things, and address them beforehand. In the case of a thimble, installing a stainless steel liner could have taken a bad situation, and made it even worse!

In addition to knowing about hidden or not so obvious defects in advance, it can also make communicating with the Client more comfortable. None of us likes to have to go to our client and explain that we ran in to an unexpected problem! None of us wants to have to explain that it’s going to cost more, or absorb the extra cost ourselves, because we didn’t tell them in advance. It’s much easier if we tell our clients ahead of time, that we may have to remove excess mortar or properly seal a thimble, and here are the additional costs if necessary.

Another thing to look at is appliance manufacturer requirements. Whether it's a wood stove or a boiler or furnace, many appliances manufacturers are starting to specifically require completion of a level 2 inspection prior to installation of their appliance. One of the Northeast’s bestselling woodstove inserts, that is actually made in Europe, states in the manual that the chimney “must meet NFPA 211 Level 2 inspection requirements”. And as stated before, a Level 2 Inspection will require an internal camera inspection of the flue. So technically, if we don't do this, we wouldn't be installing that woodstove according to its installation instructions.

Another thing to consider is that a Level 2 Inspection requires us to look at “all enclosed flues”. So if we are relining for a woodstove and there is a 2nd flue in the chimney, typically for heating equipment (boiler, furnace, waterheater), Level 2 Inspection standards require us to scan that flue too. Or vice versa, if we are relining for a furnace, we would have to also look at the fireplace and its flue. Some of us may see that as an inconvenience or even something that may put off our client. “Why do you have to look at my fireplace? I thought you were relining my furnace flue?” But for many of us, this becomes an opportunity. By following the inspection standards that have become our standard of care, we have the opportunity to perform a better and more complete service, an opportunity to discover otherwise undetected hazards, and of course, an opportunity to increase our profits.

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