Re: Possible Use of Heat Treatment of a Building

[Guest guest]

We have just become involved in a mold case (6 months after the fire)

where heat treatment of the building as a drying technique may be

appropriate.

The structure is unusual from an historical construction technique, but

is something we are seeing more and more of.

THis is the issue with the installation of multiple layers of drywall

to achieve specific fire ratings.

In this case, these were two story condos, but instead of being next to

each other, they were one on top of each other.

(The units are so close to each other the space between the individual

driveways is less than 6' so you can't park a car on the street without

blocking a driveway!)

Not surprisingly, the building code required TRIPLE layer drywall

ceilings, between the two units. Complicating this situation was the

additional installation of 1.5 inches of light weight concrete on the

floor of the above condo to reduce noise transfer. The ceiling/floor

was constructed by 3 layers of 5/8s, below a 2x10 structural lumber

joists, with 6 inches of FG, covered with a 5/8 OSB flooring, with 1.5

inches of concrete.

How do you dry this? Or should the question be " How do you dry this

rapidly enough to control mold growth? "

Standard drying did not work and 6 months into the rebuild the

significant mold growth was found inside the joist cavity on both the

drywall and OSB flooring.

In future water intrusions, I will be recommending raising the

temperature in these buildings to 160 for an extended period of time to

dry them without producing conditions favorable to mold growth. (Can

we instrument a ceiling cavity without ruining the fire rating to

document adequate drying? Have to convince the code officials on this

subject.)

I have also run into this same problem in multilayer dividing fire

walls. These can be fixed by removing the drywall and installing

mineral wool or other high fire rated materials to restore the fire

rating.

Bob

[Guest guest]

Bob,

If there was a previous fire in the structure then you must be wary of previous thermal degradation of combustible materials. Unpiloted Ignition can occur that much lower temperatures than one might think in materials previously subjected to high heat. There is evidence of spontaneous ignition at temperatures as low as 170ºF with a long enough exposure.

You said you would be working at 160ºF and very likely for a relatively short period of time so you may be fine. Still, this subject might be worth looking into for anyone doing heat treating on a previously fire damaged structure.

http://www.doctorfire.com/low_temp_wood1.pdf

http://www.fpl.fs.fed.us/documnts/pdf2001/white01a.pdf

Stojanik

Re: Possible Use of Heat Treatment of a Building

We have just become involved in a mold case (6 months after the fire) where heat treatment of the building as a drying technique may be appropriate.The structure is unusual from an historical construction technique, but is something we are seeing more and more of.THis is the issue with the installation of multiple layers of drywall to achieve specific fire ratings.In this case, these were two story condos, but instead of being next to each other, they were one on top of each other.(The units are so close to each other the space between the individual driveways is less than 6' so you can't park a car on the street without blocking a driveway!)Not surprisingly, the building code required TRIPLE layer drywall ceilings, between the two units. Complicating this situation was the additional installation of 1.5 inches of light weight concrete on the floor of the above condo to reduce noise transfer. The ceiling/floor was constructed by 3 layers of 5/8s, below a 2x10 structural lumber joists, with 6 inches of FG, covered with a 5/8 OSB flooring, with 1.5 inches of concrete.How do you dry this? Or should the question be "How do you dry this rapidly enough to control mold growth?"Standard drying did not work and 6 months into the rebuild the significant mold growth was found inside the joist cavity on both the drywall and OSB flooring.In future water intrusions, I will be recommending raising the temperature in these buildings to 160 for an extended period of time to dry them without producing conditions favorable to mold growth. (Can we instrument a ceiling cavity without ruining the fire rating to document adequate drying? Have to convince the code officials on this subject.)I have also run into this same problem in multilayer dividing fire walls. These can be fixed by removing the drywall and installing mineral wool or other high fire rated materials to restore the fire rating.Bob

[Guest guest]

Bob:

The situation you described is not unlike several which I have done, most successfully and some not...and Yes, the multiple layers for sheetrock combined with the thermal mass of 1.5-in of concrete, make drying floor/ceiling cavities challenging. Moreover, you need to keep the heat source going with sufficient BTU input such that ALL the floor/ceiling elements gets up to 160F and stay there. If some of it only heats to 130F, you end-up creating a nice incubator – a bad thing! However, if heated uniformly (a really critical aspect of heat treatment, i.e., distribution uniformity) and kept at the elevated temperature long enuff, the water vapor will move out of the hollow-cavity system. 12 to 24-hrs at the elevated temp may be all that’s needed.

Contact me off-post if you want to chat about this more.

Regards,

--

Geyer, PE, CIH, CSP

President

KERNTEC Industries, Inc.

Bakersfield, California

www.kerntecindustries.com

We have just become involved in a mold case (6 months after the fire)

where heat treatment of the building as a drying technique may be

appropriate.

The structure is unusual from an historical construction technique, but

is something we are seeing more and more of.

THis is the issue with the installation of multiple layers of drywall

to achieve specific fire ratings.

In this case, these were two story condos, but instead of being next to

each other, they were one on top of each other.

(The units are so close to each other the space between the individual

driveways is less than 6' so you can't park a car on the street without

blocking a driveway!)

Not surprisingly, the building code required TRIPLE layer drywall

ceilings, between the two units. Complicating this situation was the

additional installation of 1.5 inches of light weight concrete on the

floor of the above condo to reduce noise transfer. The ceiling/floor

was constructed by 3 layers of 5/8s, below a 2x10 structural lumber

joists, with 6 inches of FG, covered with a 5/8 OSB flooring, with 1.5

inches of concrete.

How do you dry this? Or should the question be " How do you dry this

rapidly enough to control mold growth? "

Standard drying did not work and 6 months into the rebuild the

significant mold growth was found inside the joist cavity on both the

drywall and OSB flooring.

In future water intrusions, I will be recommending raising the

temperature in these buildings to 160 for an extended period of time to

dry them without producing conditions favorable to mold growth. (Can

we instrument a ceiling cavity without ruining the fire rating to

document adequate drying? Have to convince the code officials on this

subject.)

I have also run into this same problem in multilayer dividing fire

walls. These can be fixed by removing the drywall and installing

mineral wool or other high fire rated materials to restore the fire

rating.

Bob

[Guest guest]

If the drywall on the firewall is Denshield which is covered with fiberglass and not water, you probably can't dry out the fire walls even with heat.

Certainly if you make a hole in the fire wall it needs to be repaired with fire rated caulking or other fire rated sealant.

Rosen, Ph.D.

www.Mold-Free.org

Re: Possible Use of Heat Treatment of a Building

We have just become involved in a mold case (6 months after the fire) where heat treatment of the building as a drying technique may be appropriate.The structure is unusual from an historical construction technique, but is something we are seeing more and more of.THis is the issue with the installation of multiple layers of drywall to achieve specific fire ratings.In this case, these were two story condos, but instead of being next to each other, they were one on top of each other.(The units are so close to each other the space between the individual driveways is less than 6' so you can't park a car on the street without blocking a driveway!)Not surprisingly, the building code required TRIPLE layer drywall ceilings, between the two units. Complicating this situation was the additional installation of 1.5 inches of light weight concrete on the floor of the above condo to reduce noise transfer. The

ceiling/floor was constructed by 3 layers of 5/8s, below a 2x10 structural lumber joists, with 6 inches of FG, covered with a 5/8 OSB flooring, with 1.5 inches of concrete.How do you dry this? Or should the question be "How do you dry this rapidly enough to control mold growth?"Standard drying did not work and 6 months into the rebuild the significant mold growth was found inside the joist cavity on both the drywall and OSB flooring.In future water intrusions, I will be recommending raising the temperature in these buildings to 160 for an extended period of time to dry them without producing conditions favorable to mold growth. (Can we instrument a ceiling cavity without ruining the fire rating to document adequate drying? Have to convince the code officials on this subject.)I have also run into this same problem in multilayer dividing fire walls. These can be fixed by removing the drywall and

installing mineral wool or other high fire rated materials to restore the fire rating.Bob

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[Guest guest]

:

I disagree! Moreover, I feel you are purely speculating and not speaking from experience.

I have dried-out multiple (2 and 3) layers of 5/8” FX and 1” FX sheetrock systems with heat. What makes you think that multiple layers of sheetrock cannot be dried with heat-treatment? Also, what do you mean when you say: “... Denshield which is covered with fiberglass and not water,...”? Water-covered sheetrock??? Now that’s interesting!

--

Geyer, PE, CIH, CSP

President

KERNTEC Industries, Inc.

Bakersfield, California

www.kerntecindustries.com

If the drywall on the firewall is Denshield which is covered with fiberglass and not water, you probably can't dry out the fire walls even with heat.

Certainly if you make a hole in the fire wall it needs to be repaired with fire rated caulking or other fire rated sealant.

Rosen, Ph.D.

www.Mold-Free.org

[Guest guest]

Please check out the Denshield wall board. It is a gypsum core with fiberglass mat cover in place of cellulose cover. The fiberglass material is water proof and once there is water between layers of sheetrock that is covered with fiberglass it does not dry like normal sheet rock that is permeable to moisture.

Rosen

Re: Possible Use of Heat Treatment of a Building

:I disagree! Moreover, I feel you are purely speculating and not speaking from experience.I have dried-out multiple (2 and 3) layers of 5/8” FX and 1” FX sheetrock systems with heat. What makes you think that multiple layers of sheetrock cannot be dried with heat-treatment? Also, what do you mean when you say: “... Denshield which is covered with fiberglass and not water,...”? Water-covered sheetrock??? Now that’s interesting!-- Geyer, PE, CIH, CSPPresidentKERNTEC Industries, Inc.Bakersfield, Californiawww.kerntecindustri es.comOn 11/25/06 2:30 AM, "gary rosen" <garyrosen72652@ yahoo.com> wrote:

If the drywall on the firewall is Denshield which is covered with fiberglass and not water, you probably can't dry out the fire walls even with heat. Certainly if you make a hole in the fire wall it needs to be repaired with fire rated caulking or other fire rated sealant. Rosen, Ph.D.www.Mold-Free. org

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[Guest guest]

:

another fine example -- thank you. that's great. just marvelous.

wonderful...... <gasp>

the fibrous glass layer is NOT " water proof " . where do you get these

ideas? it's just NOT PAPER.

would you PLEASE take a bit more time to get your facts straight

before posting more MISINFOMATION to this group? PLEASE?

Wane

<><><><><><><><><><><>

Wane A. Baker, P.E., CIH

Division Manager, Indoor Air Quality

MICHAELS ENGINEERING

" Real Professionals. Real Solutions. "

Phone , ext. 484

Cell

Fax

mailto:wab@...

On the web at: http://www.michaelsengineering.com

" To love what you do and feel that it matters - how could anything be

more fun? "

- Graham

>

>

>

>

>

>

> If the drywall on the firewall is Denshield which is covered with

fiberglass and not water, you probably can't dry out the fire walls

even with heat.

>

> Certainly if you make a hole in the fire wall it needs to be

repaired with fire rated caulking or other fire rated sealant.

>

> Rosen, Ph.D.

> www.Mold-Free. org

>

>

>

>

>

>

>

______________________________________________________________________

______________

> Cheap talk?

> Check out Yahoo! Messenger's low PC-to-Phone call rates.

> http://voice.yahoo.com

>

[Guest guest]

Thank you Wane!

I held off criticizing for his errors because I have been accused (by others) of being overly-critical. You are correct.....DensSheild is not “waterproof” and to use the tem is wholly incorrect! Moreover, DensShiled is used as a tile-backer, it comes in a variety of sizes, and it has a PERM rating of 1.5 – not exactly waterproof, but it is designed to be water resistant as a tile backer. It is not a sheetrock substitute; except maybe green-broad applications. DensGlass Gold, on the other hand, it a sheetrock substitute, or as GP likes to call it, a Peperless Sheetrock. DensGalss Gold has a PERM rating of 23 or 12; depending if it is 1/2” or 5/8”. Great stuff when used with mechanical fasteners, though some architects still specify adhesives.....which blows my mind. Have they not learned the mistakes of early EFIS systems? Maybe they too still don’t know the difference between waterproof, water resistant, and plain-old poor choice of materials.

For what it is worth....

--

Geyer, PE, CIH, CSP

President

KERNTEC Industries, Inc.

Bakersfield, California

www.kerntecindustries.com

:

another fine example -- thank you. that's great. just marvelous.

wonderful...... <gasp>

the fibrous glass layer is NOT " water proof " . where do you get these

ideas? it's just NOT PAPER.

would you PLEASE take a bit more time to get your facts straight

before posting more MISINFOMATION to this group? PLEASE?

Wane

<><><><><><><><><><><>

Wane A. Baker, P.E., CIH

Division Manager, Indoor Air Quality

MICHAELS ENGINEERING

" Real Professionals. Real Solutions. "

Phone , ext. 484

Cell

Fax

mailto:wab@... <mailto:wab%40michaelsengineering.com>

On the web at: http://www.michaelsengineering.com

" To love what you do and feel that it matters - how could anything be

more fun? "

- Graham

>

>

>

>

>

>

> If the drywall on the firewall is Denshield which is covered with

fiberglass and not water, you probably can't dry out the fire walls

even with heat.

>

> Certainly if you make a hole in the fire wall it needs to be

repaired with fire rated caulking or other fire rated sealant.

>

> Rosen, Ph.D.

> www.Mold-Free. org

>

>

>

>

>

>

>

__________________________________________________________

______________

> Cheap talk?

> Check out Yahoo! Messenger's low PC-to-Phone call rates.

> http://voice.yahoo.com

>

[Guest guest]

Philip:

While I agree that some materials, given special circumstances will auto-oxidate (the technically correct term for spontaneous ignition) at temperatures below 100F, and there are many materials that will auto-oxidate at 130F and 140F, these are not typical building materials or building assemblies, nor can typical building materials auto-oxidate at 170F – even if fire damaged! Therefore, I also ask, is your information practical or even relevant to Bob’s situation? Moreover, I have a lot of research that shows wood materials having minimum unpiloted ignition temps of 210C to 270C (500F). I have NEVER heard of an unpiloted ignition temp as low as 170F...at least not in any common and typical building material. The reference you cited (shown below in your email) speculates a fire in OSB sheeting heated to 170F for months/years. Given that this is an engineered-wooden material, I would tend to speculate that the long-duration (i.e., months/years) heating of the adhesive caused internal auto-oxidation of the adhesive, not the wood, and the subsequent ignition sequence in the sheeting (adhesive and wood).

Bottom line...This is not relevant to structural pasteurization where elevated heat is typically applied for no more than 12 to 24 hours, and at most, 5 days in extreme cases with materials of high thermal mass; usually not wood.

For what it is worth....

--

Geyer, PE, CIH, CSP

President

KERNTEC Industries, Inc.

Bakersfield, California

www.kerntecindustries.com

Bob,

If there was a previous fire in the structure then you must be wary of previous thermal degradation of combustible materials. Unpiloted Ignition can occur that much lower temperatures than one might think in materials previously subjected to high heat. There is evidence of spontaneous ignition at temperatures as low as 170ºF with a long enough exposure.

You said you would be working at 160ºF and very likely for a relatively short period of time so you may be fine. Still, this subject might be worth looking into for anyone doing heat treating on a previously fire damaged structure.

http://www.doctorfire.com/low_temp_wood1.pdf

http://www.fpl.fs.fed.us/documnts/pdf2001/white01a.pdf

Stojanik

Re: Possible Use of Heat Treatment of a Building

We have just become involved in a mold case (6 months after the fire)

where heat treatment of the building as a drying technique may be

appropriate.

The structure is unusual from an historical construction technique, but

is something we are seeing more and more of.

THis is the issue with the installation of multiple layers of drywall

to achieve specific fire ratings.

In this case, these were two story condos, but instead of being next to

each other, they were one on top of each other.

(The units are so close to each other the space between the individual

driveways is less than 6' so you can't park a car on the street without

blocking a driveway!)

Not surprisingly, the building code required TRIPLE layer drywall

ceilings, between the two units. Complicating this situation was the

additional installation of 1.5 inches of light weight concrete on the

floor of the above condo to reduce noise transfer. The ceiling/floor

was constructed by 3 layers of 5/8s, below a 2x10 structural lumber

joists, with 6 inches of FG, covered with a 5/8 OSB flooring, with 1.5

inches of concrete.

How do you dry this? Or should the question be " How do you dry this

rapidly enough to control mold growth? "

Standard drying did not work and 6 months into the rebuild the

significant mold growth was found inside the joist cavity on both the

drywall and OSB flooring.

In future water intrusions, I will be recommending raising the

temperature in these buildings to 160 for an extended period of time to

dry them without producing conditions favorable to mold growth. (Can

we instrument a ceiling cavity without ruining the fire rating to

document adequate drying? Have to convince the code officials on this

subject.)

I have also run into this same problem in multilayer dividing fire

walls. These can be fixed by removing the drywall and installing

mineral wool or other high fire rated materials to restore the fire

rating.

Bob

[Guest guest]

Then substitute DensGlass for DensShield in my comment. You are not going to dry out a shaft made with DensGlass on the outside and paper faced drywall on the inside by cooking the building for a short period of time.

Re: Re: Possible Use of Heat Treatment of a Building

Thank you Wane!I held off criticizing for his errors because I have been accused (by others) of being overly-critical. You are correct..... DensSheild is not “waterproof” and to use the tem is wholly incorrect! Moreover, DensShiled is used as a tile-backer, it comes in a variety of sizes, and it has a PERM rating of 1.5 – not exactly waterproof, but it is designed to be water resistant as a tile backer. It is not a sheetrock substitute; except maybe green-broad applications. DensGlass Gold, on the other hand, it a sheetrock substitute, or as GP likes to call it, a Peperless Sheetrock. DensGalss Gold has a PERM rating of 23 or 12; depending if it is 1/2” or 5/8”. Great stuff when used with mechanical fasteners, though some architects still specify adhesives... ..which blows my mind. Have they not learned the mistakes of early EFIS systems?

Maybe they too still don’t know the difference between waterproof, water resistant, and plain-old poor choice of materials.For what it is worth....-- Geyer, PE, CIH, CSPPresidentKERNTEC Industries, Inc.Bakersfield, Californiawww.kerntecindustri es.comOn 11/27/06 8:43 PM, "Wane A. Baker" <wab@michaelsenginee ring.com> wrote:

:another fine example -- thank you. that's great. just marvelous. wonderful... ... <gasp>the fibrous glass layer is NOT "water proof". where do you get these ideas? it's just NOT PAPER.would you PLEASE take a bit more time to get your facts straight before posting more MISINFOMATION to this group? PLEASE?Wane<><><><><><><><><><><> Wane A. Baker, P.E., CIH Division Manager, Indoor Air Quality MICHAELS ENGINEERING"Real Professionals. Real Solutions." Phone , ext. 484 Cell Fax mailto:wab@michaels engineering. com <mailto:wab%40michae lsengineering. com> On the web at: http://www.michaels engineering. com "To love what you do and feel that it matters - how could anything be more fun?" - Graham > > > > > > > If the drywall on the firewall is Denshield which is covered with fiberglass and not water, you probably can't dry out the fire walls even with heat.> > Certainly if you make a hole in the fire wall it needs to be repaired with fire rated caulking or other fire rated sealant.> > Rosen, Ph.D.> www.Mold-Free. org> > > > > > > ____________ _________ _________ _________ _________ _________ _____________ __> Cheap talk?> Check out Yahoo! Messenger's low PC-to-Phone call rates.> http://voice. yahoo.com>

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