[Greenbuilding] Visible Flames (Fireplaces) in Tight Houses

[Frank Tettemer]

Clarke and Eli,

I need to say that I'm extremely alarmed by the idea of filling that 2" 
space with vermiculite, Roxul, or Fiberglass insulation. Especially with 
in a chase. The rise in temperature of the steel components of the 
chimney, due to the insulation surrounding them,  would exceed safe 
levels. The chimney could fail.

I also would like to add a note that, although acceptable by code, 
planning an insulated chimney with off-sets, (45 or 90 degree) is also 
not a good idea. Off sets are an area that create 'eddy currents' within 
the chimney, and thus create cooler and hotter areas within the chimney 
liner. These eddy currents can also create landings for creosote 
deposits. This causes wear and tear on the steel components, and that is 
not desirable.

Off sets need additional structural support, to prevent the lower 
portion of the chimney from bearing the weight and load of the upper 
portion of the chimney. I have seen a situation where these components 
were not structurally supported. The weight of the upper portion of the 
chimney levered the 45 degree parts to open up, and allow a fire to start.

Off sets with in a chase also need to be surrounded by a tightly 
constructed heat shield. This is difficult to do well, and if it can't 
be done well, it needn't be done at all. Careful planning and design, so 
thata straight chimney can be installed is not mandatory; but it is the 
only acceptable idea to consider. What could possibly trump fire safety? 
Certainly not aesthetics, and certainly not budget.

Sorry for my Rant, Rant, Rant. I've witnessed too many house fires, of 
friends and neighbours, to be complacent.
I'm apologetic for my rant, but firm about fire safety,

-- 
Frank Tettemer
Living Sol ~ Building and Design
www.livingsol.com
613 756 3884


On 03/12/2014 2:32 PM, Clarke Olsen wrote:
> What is the reason for not insulating that space? Why would 
> vermiculite be a better conductor than air?
> Does this apply to metal and masonry chimneys?
> Clarke Olsen
> clarkeolsendesign.com <http://clarkeolsendesign.com>
> 373 route 203
> Spencertown, NY 12165
> USA
> 518-392-4640
> colsen at taconic.net
>
>
>
>
> On Dec 3, 2014, at 11:14 AM, Norbert Senf <norbert.senf at gmail.com 
> <mailto:norbert.senf at gmail.com>> wrote:
>
>> Under no circumstances should anything be put into the 2" air space 
>> that is specified around a UL/ULC listed factory chimney.
>>
>> If you put vermiculite in there, you are voiding the UL listing of 
>> the chimney by virtue of not installing according to "manufacturers 
>> instructions". This creates liability for you.
>>
>> This is a common misconception, and is the reason for the  "attic 
>> radiation shield" required in attics, which are required to have a 
>> storm collar on them, specifically to prevent people from putting 
>> insulation into the 2" air space. Here in Canada, a radiation shield 
>> is also required around chimneys in chases, specifically to avoid 
>> this scenario.
>>
>> This is not an issue in normal use. However, the ULC-621 listing 
>> means the chimney system (including the air space) has been tested to 
>> survive three 30 minute chimney fires at 2100F, without torching the 
>> adjacent walls. Put vermiculite into the air space, and the wall will 
>> burn. I have seen photos of where this has happened.
>>
>> Norbert
>>
>> On Wed, Dec 3, 2014 at 9:43 AM, <conservationarchitect at rockbridge.net 
>> <mailto:conservationarchitect at rockbridge.net>> wrote:
>>
>>     Alan
>>     How tight were the openings into this closed loop fireplace? 
>>     This may be acceptable to my client. .6ach at 50pa
>>     <mailto:.6ach at 50pa>is impressive with these handicaps.  What
>>     would your recommendation for interior cloths dryer be?
>>     As an alternative to the insulated chase, could you define a
>>     space up to a triple wall chimney that has the specified
>>     clearance to combustible material filled with non combustible
>>     insulation such as vermiculite.
>>     Thanks
>>     Eli
>>
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