[Greenbuilding] Visible Flames (Fireplaces) in Tight Houses

[Norbert Senf]

In an insulated wall, the temperature in the middle is halfway between the
temperature on the inside and on the outside.
If you put insulation between an insulated chimney and a cavity wall
(insulated or not), you have no way of predicting in perpetuity how thick
the insulation in the wall will be. If the wall gets a retrofit with say
12" of insulation, and the chimney has 1", then the temperature 3" from the
hot face will be 80% towards the hot face, and will ignite your wall.

If there is a 2" air space, convection allows heat to be transferred away
from any hot spots in the chimney. If you have even just one really hot
spot, the insulation will not allow the convection to happen.

On Wed, Dec 3, 2014 at 2:32 PM, Clarke Olsen <colsen at fairpoint.net> 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
> 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> 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>
> wrote:
>
>>   Alan
>>
>> How tight were the openings into this closed loop fireplace?  This may be
>> acceptable to my client.   .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
>>
>>
>>
>  _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>
>
>
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>



-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20141203/f3e42790/attachment.html>