Re: Ocean salts and mold -- was Boric salts

[Guest guest]

I have

lived or worked within 1/4 mile of salt water most of my life, including

15 years on the oceanfront where I could hear the waves crashing at night

and everything would be covered with salt spray after high easterly

winds. I have given a lot of thought to why the many shore houses I

have seen (and their contents) have more mold. My conclusion has to

do with psychrometrics and not airborne salt absorption/adsorption.

The temperature of the humid air is lowered as it gets near, or drifts

over, the cooler water surface causing an increase in RH. In my

experience, this is the reason for the association with mold near large

bodies of water. As they say on the news every night all summer in

my area, " Temperatures cooler near the shore " . Ever see

that morning mist on the water? That's a visual of the higher

humidity that is occurring.

I tend to agree with Steve on this case. A very well-known

mold guru-expert once told me of a case that he had in a hospital located

next to the ocean. (I refrain from further details for

confidentiality.) The hospital had a problem with

immuno-compromised patients developing fungal diseases. The problem

was traced back to mold growing on the HEPA filters in the air handling

units supplying air to the patient reverse-isolation rooms.

The wise of you will ask, " How did mold get downstream of the filter

when the filter cake is trapped on the upstream side of the

filter? " The mold actually grew through the filter and

sporulated on the downstream side.

ASHRAE research has shown that it is extremely difficult to grow mold on

a filter cake that constantly has air moving across it because the mold

is desiccated. (Please note that I used the word

" constantly " intentionally. I can see where growth on

filters that only have intermittent airflow and adequate moisture is a

possibility.) In one study in which mold growth on the filter was

desired, water had to be sprayed into the air stream to get the filters

moist enough for mold to finally grow consisitently. In the

hospital case, the expert discovered heavy fog around the hospital on

many mornings. Corresponding to the timing of the fog, the air

handlers' economizer dampers were full open. After all, in many

locations, late night and morning are usually when air is coolest.

The moisture was adequate to get the filters damp enough for mold to grow

on the filter cake.

While I also agree with Steve's question about the salinity possibly

providing a hostile mold environment, for every environment and food

source, at least one species of mold seems to survive. (Just as an

example, I am amazed at a mold that is growing at just the waterline of a

not-too-often used toilet that gets flushed on-average once a day,

despite there being one of the chlorine tablets in the tank.) So,

species that can survive a saltier environment probably exist.

Furthermore, might be making a valid point because salt is

hygroscopic, meaning that it might attract moisture to surfaces that

usually are moisture resistant. Having moisture meter readings from

the material would be educational,.

Still, I am surprised that neither of you guys mentioned the insane mold

counts in the areas around shores. During trips to some of the

southern U.S. areas, I hear counts over ten thousand, which makes our one

to two thousand in the Ohio Valley pale by comparison. There has to

be a reason for those counts being so much greater in shore areas and we

all know moisture quantity is likely involved; but other reasons might be

involved. Heck, the counts alone might mean a greater probability

of spores finding favorable conditions to grow.

******************************************************

If what is written looks too stupid to be written by me, I disclaim

it. On the other hand, if it is brilliant, then I have no one to

blame but myself. Otherwise, whether you choose to accept my

opinion is up to you.

******************************************************

K. Klein, PE ME, MBA

Indoor Air Quality Solutions, Inc.

2523 SR 133

Bethel, OH 45106-0007

VOICE:

FAX: (with notice)

E-mail: mkklein68@...

*******************************************************

[Guest guest]

Some one mentioned

an economizer drawing in fog and wetting HEPA

filters sufficiently to sprout mold. Is it also possible that these

hospital HEPA filters were down stream of a cooling coil and a

blower in somewhat of a 'clean room' position?

I mentioned that, and sorry, I cannot answer your question about

where the filters were located because it wasn't my project. The

expert who told me the story, whose project it was, seemed very sure that

it was the fog. I would say that he is likely correct. Fog is

condensed water vapor in the air. Therefore, the moisture is in

droplet form rather than gaseous form as a vapor, which is what humidity

measurements are indications of. Water droplets can be

" filtered " from the air by filters due to impaction and

probably other filtering mechanisms, while vapor is more of an absorption

by the filter cake. Filter materials usually are not hygroscopic,

making them averse to moisture absorption; but I am not knowledgeable

enough about them to say they cannot absorb any moisture. For sure,

filters could become wetter with fog than with high humidity air that

does not have condensed water in it.

That being said, air coming off the cooling coils on our hot humid days

runs around 90+%. After all, the air is being taken near the

condensation point as it passes through the coil. Still, the air

usually doesn't contain droplets. Coil contamination or design

problems could create cases of carry-over where the air actually carries

moisture off of the coil. In which case, the air could have

droplets in it; but in these cases, the droplets tend to be larger than

with condensed water vapor droplets in foggy air. The larger

droplets would settle out of the air within a distance of the coil,

depending on the carrying velocity and droplet size. If a filter

bank were placed downstream of and close enough to the coils, droplets

could land on the filters, saturating them that way. In the case of

the fog, the cooling coils would take out some of the moisture either

through condensation, if the coils are partially working, or through

impaction or other filtration mechanisms, after all, cooling coils

basically act as coarse filters.

However, filter banks are usually located upstream of the cooling coil to

help (ok, supposedly to help) keep the coil clean. If I were going

to put HEPA filters in the system downstream of the coils, such as in

reverse-isolation rooms, I would position the filters so that they are

the last thing the air sees before it enters the room. In which

case, they should be located where water from carry-over could not hit

them, and they would be seeing less moisture in foggy air than if they

were placed upstream of the cooling coils.

BTW, as I recall, another reason that the fog was also believed to be the

problem was that the economizer controls were changed so that they

remained closed during potentially foggy periods. Something that

can be done with an enthalpy economizer control system, although I am not

sure exactly what the hospital did. That fix reportedly stopped the

mold growth problem.

BTW-2, that concentric rings of mold growth pattern with various species

growing in each ring depending on growth conditions, noted in the

message, has always fascinated me too.

******************************************************

If what is written looks too stupid to be written by me, I disclaim

it. On

the other hand, if it is brilliant, then I have no one to blame but

myself.

Otherwise, whether you choose to accept my opinion is up to you.

******************************************************

K. Klein, PE ME, MBA

Indoor Air Quality Solutions, Inc.

2523 SR 133

Bethel, OH 45106-0007

VOICE:

FAX: (with notice)

E-mail: mkklein68@...

*******************************************************

Wouldn't it be nice if common sense were really common?

[Guest guest]

Matt:

Sorry for that last message - I re-read the posts and realized I

really wasn't responding to the core question. Anywho.

Pat: I had noticed conductivity differences due to salts a while ago

with urine stains. The stained areas tended to have higher readings

using a radio frequency meter. I had figured it was due to the

deposited salts. I'm glad ya'll had this discussion - very informative.

Cassidy

> >

> >

> > >I have lived or worked within 1/4 mile of salt water most of my

> > >life, including 15 years on the oceanfront where I could hear the

> > >waves crashing at night and everything would be covered with salt

> > >spray after high easterly winds. I have given a lot of thought to

> > >why the many shore houses I have seen (and their contents) have more

> > >mold. My conclusion has to do with psychrometrics and not airborne

> > >salt absorption/adsorption. The temperature of the humid air is

> > >lowered as it gets near, or drifts over, the cooler water surface

> > >causing an increase in RH. In my experience, this is the reason for

> > >the association with mold near large bodies of water. As they say

> > >on the news every night all summer in my area, " Temperatures cooler

> > >near the shore " . Ever see that morning mist on the water? That's a

> > >visual of the higher humidity that is occurring.

> >

> > I tend to agree with Steve on this case. A very well-known mold

> > guru-expert once told me of a case that he had in a hospital located

> > next to the ocean. (I refrain from further details for

> > confidentiality.) The hospital had a problem with immuno-compromised

> > patients developing fungal diseases. The problem was traced back to

> > mold growing on the HEPA filters in the air handling units supplying

> > air to the patient reverse-isolation rooms. The wise of you will

> > ask, " How did mold get downstream of the filter when the filter cake

> > is trapped on the upstream side of the filter? " The mold actually

> > grew through the filter and sporulated on the downstream side.

> >

> > ASHRAE research has shown that it is extremely difficult to grow mold

> > on a filter cake that constantly has air moving across it because the

> > mold is desiccated. (Please note that I used the word " constantly "

> > intentionally. I can see where growth on filters that only have

> > intermittent airflow and adequate moisture is a possibility.) In one

> > study in which mold growth on the filter was desired, water had to be

> > sprayed into the air stream to get the filters moist enough for mold

> > to finally grow consisitently. In the hospital case, the expert

> > discovered heavy fog around the hospital on many

> > mornings. Corresponding to the timing of the fog, the air handlers'

> > economizer dampers were full open. After all, in many locations,

> > late night and morning are usually when air is coolest. The moisture

> > was adequate to get the filters damp enough for mold to grow on the

> > filter cake.

> >

> > While I also agree with Steve's question about the salinity possibly

> > providing a hostile mold environment, for every environment and food

> > source, at least one species of mold seems to survive. (Just as an

> > example, I am amazed at a mold that is growing at just the waterline

> > of a not-too-often used toilet that gets flushed on-average once a

> > day, despite there being one of the chlorine tablets in the

> > tank.) So, species that can survive a saltier environment probably

> > exist. Furthermore, might be making a valid point because

> > salt is hygroscopic, meaning that it might attract moisture to

> > surfaces that usually are moisture resistant. Having moisture meter

> > readings from the material would be educational,.

> >

> > Still, I am surprised that neither of you guys mentioned the insane

> > mold counts in the areas around shores. During trips to some of the

> > southern U.S. areas, I hear counts over ten thousand, which makes our

> > one to two thousand in the Ohio Valley pale by comparison. There has

> > to be a reason for those counts being so much greater in shore areas

> > and we all know moisture quantity is likely involved; but other

> > reasons might be involved. Heck, the counts alone might mean a

> > greater probability of spores finding favorable conditions to grow.

> >

> >

> > ******************************************************

> > If what is written looks too stupid to be written by me, I disclaim

> > it. On the other hand, if it is brilliant, then I have no one to

> > blame but myself. Otherwise, whether you choose to accept my opinion

> > is up to you.

> > ******************************************************

> > K. Klein, PE ME, MBA

> > Indoor Air Quality Solutions, Inc.

> > 2523 SR 133

> > Bethel, OH 45106-0007

> > VOICE:

> > FAX: (with notice)

> > E-mail: mkklein68@

> > *******************************************************

> >

>

[Guest guest]

1. They will be higher. I see this a lot of this down in Florida - relatively

dry drywall (misnomer) with elevated readings due to saltation. The saltation

beats the crap out of the cooling coils there as well; and over time the

concrete patios and the like.

I generally add the following phrase as a footnote in my secifications for

clearance criteria of moisture content in materials of the space for mold

remediation:

" * Presuming no salts present (adjustment higher if Contractor can show salts

present [such as

through a filter paper salt test at >19 WME on a protimeter]) or can utilize dry

oven testing as an alternative at Contractor's cost) "

This paper salt test is outlined in the Protimeter manual (yeh - I read those

things - keeps me out of trouble).

2. On a related issue, I have some photomicrographs of drywall after several

cycles of wet-dry. This produces recrystallization (including twinning) of the

gypsum and the hysteris-like effect of changes in sizes and relative position of

crystals that will result in expansion (similar to corrosion in iron). This

will then make it appear sponge-like as there will be air spaces where the new

larger crystal packing results in gaps. Seen this in Indiana well as Florida

and Georgia.

3. As for Boric Acid, This Old House (magazine) did a nice piece on its use a

few years ago. I'll try to dig it out when I can. The Forest Products Lab has

some data as well but I don't recall where I put mine at. Leaching out is a

problem. I don't recall the mechanism, but I believe that the boric acid or

salt product does resist Wood decay. This fungal attach is usually from

basidiomyces or ascomyces, but can be from bacteria.

4. I also have an article on the anti-fungal properties of TSP around here.

Thus I like to recommend 5% TSP as a detergent, despite the limited threat to

the environment at these quantities.

Tony

...........................................................................

" Tony " Havics, CHMM, CIH, PE

pH2, LLC

PO Box 34140

Indianapolis, IN 46234

cell

90% of Risk Management is knowing where to place the decimal point...any

consultant can give you the other 10%â„ 

This message is from pH2. This message and any attachments may contain legally

privileged or confidential information, and are intended only for the individual

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this message has been addressed to you in error, you are not authorized to read,

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not be copied or distributed without this statement.

Re: Ocean salts and mold -- was Boric salts

If salts are entering the building materials by the ocean, then will that change

the surface conductivity?

And since moisture meters really measure conductivity and report it as water,

how would readings be affected?

Henry Slack

FAIR USE NOTICE:

This site contains copyrighted material the use of which has not always been

specifically authorized by the copyright owner. We are making such material

available in our efforts to advance understanding of environmental, political,

human rights, economic, democracy, scientific, and social justice issues, etc.

We believe this constitutes a 'fair use' of any such copyrighted material as

provided for in section 107 of the US Copyright Law. In accordance with Title 17

U.S.C. Section 107, the material on this site is distributed without profit to

those who have expressed a prior interest in receiving the included information

for research and educational purposes. For more information go to:

http://www.law.cornell.edu/uscode/17/107.shtml. If you wish to use copyrighted

material from this site for purposes of your own that go beyond 'fair use', you

must obtain permission from the copyright owner.

[Guest guest]

2. On a related issue, I have some

photomicrographs of drywall after several cycles of wet-dry. This

produces recrystallization (including twinning) of the gypsum and the

hysteris-like effect of changes in sizes and relative position of

crystals that will result in expansion (similar to corrosion in

iron). This will then make it appear sponge-like as there will be

air spaces where the new larger crystal packing results in gaps.

Seen this in Indiana well as Florida and Georgia.

Ohio too. Now, tthat brings up another question. Is

the change due to mechanical breakdown of the cystalline structure from

the plasterboard material expanding, from it expanding and then

contracting or from contaminants in the water? I have seen the

breakdown in plasterboard that has been continuously or repeatedly

exposed to moisture, but not in plasterboard that has been wetted and

then dried right away. I have not been as observant about

plasterboard exposed to rainwater wetting versus flooding from say a

sewer backflow. I guess I'm usually more tuned into the

contamination rather than the water source. Just curious.

******************************************************

If what is written looks too stupid to be written by me, I disclaim

it. On

the other hand, if it is brilliant, then I have no one to blame but

myself.

Otherwise, whether you choose to accept my opinion is up to you.

******************************************************

K. Klein, PE ME, MBA

Indoor Air Quality Solutions, Inc.

2523 SR 133

Bethel, OH 45106-0007

VOICE:

FAX: (with notice)

E-mail: mkklein68@...

*******************************************************

Wouldn't it be nice if common sense were really common?

[Guest guest]

I would think that all or part of the answer might lie in the Vant Hoff equations for osmosis. Though I believe the equations were originally developed related to cellular biology I have seen some variant applied to explain the destruction of concrete by osmotic crystalline pressure.

Since gypsum is a sulfate salt of calcium one would expect rearrangement of the crystalline structures when a solvent like water is added. Such osmotic crystalline pressures can easily rupture concrete so gypsum would not stand a chance if enough water is present over a long enough period of time or the gypsum is subjected to numerous repeated wettings.

Of course if the gypsum is allowed to get thoroughly saturated with water (as a solvent) it very quickly turn back into the Paleozoic mush from which it came. The destruction caused by numerous wetting with intervening drying cycles however is a much slower process of destructively rearranging the crystalline structures rather than complete destabilization of its matrix.

This seems to match well enough with Matt's observations; i.e. if you can eliminate the water source quickly and dry the product out properly the gypsum structure will remain substantially intact. That has always been my personal experience as well by the way.

Stojanik

RE: Re: Ocean salts and mold -- was Boric salts

2. On a related issue, I have some photomicrographs of drywall after several cycles of wet-dry. This produces recrystallization (including twinning) of the gypsum and the hysteris-like effect of changes in sizes and relative position of crystals that will result in expansion (similar to corrosion in iron). This will then make it appear sponge-like as there will be air spaces where the new larger crystal packing results in gaps. Seen this in Indiana well as Florida and Georgia.Ohio too. Now, tthat brings up another question. Is the change due to mechanical breakdown of the cystalline structure from the plasterboard material expanding, from it expanding and then contracting or from contaminants in the water? I have seen the breakdown in plasterboard that has been continuously or repeatedly exposed to moisture, but not in plasterboard that has been wetted and then dried right away. I have not been as observant about plasterboard exposed to rainwater wetting versus flooding from say a sewer backflow. I guess I'm usually more tuned into the contamination rather than the water source. Just curious.

******************************************************If what is written looks too stupid to be written by me, I disclaim it. Onthe other hand, if it is brilliant, then I have no one to blame but myself. Otherwise, whether you choose to accept my opinion is up to you.****************************************************** K. Klein, PE ME, MBAIndoor Air Quality Solutions, Inc.2523 SR 133Bethel, OH 45106-0007VOICE: FAX: (with notice)E-mail: mkklein68@...*******************************************************Wouldn't it be nice if common sense were really common?

[Guest guest]

Mike,

I brought this fact up to the gypsum

industry about two years ago. After inspection of a project, they felt the

gypsum drywall having the same characteristics you mentioned, was still within

manufacturer tolerance of being acceptable.

I have not seen an ASTM standard on this

subject and I too am curious of when drywall after being affected by moisture

conditions (other than mold growth) the product is no longer acceptable to the

manufacturing industry or ASTM.

Moffett

From: iequality [mailto:iequality ] On Behalf Of Matt Klein

Sent: Friday, May 12, 2006 2:21 PM

To: IEQ List

Subject: RE: Re: Ocean

salts and mold -- was Boric salts

2. On a related issue, I have some

photomicrographs of drywall after several cycles of wet-dry. This

produces recrystallization (including twinning) of the gypsum and the

hysteris-like effect of changes in sizes and relative position of crystals that

will result in expansion (similar to corrosion in iron). This will then

make it appear sponge-like as there will be air spaces where the new larger

crystal packing results in gaps. Seen this in Indiana

well as Florida and Georgia.

Ohio

too. Now, tthat brings up another question. Is the change due to

mechanical breakdown of the cystalline structure from the plasterboard material

expanding, from it expanding and then contracting or from contaminants in the

water? I have seen the breakdown in plasterboard that has been

continuously or repeatedly exposed to moisture, but not in plasterboard that

has been wetted and then dried right away. I have not been as observant

about plasterboard exposed to rainwater wetting versus flooding from say a

sewer backflow. I guess I'm usually more tuned into the contamination

rather than the water source. Just curious.

******************************************************

If what is written looks too stupid to be written by me, I disclaim it.

On

the other hand, if it is brilliant, then I have no one to blame but

myself.

Otherwise, whether you choose to accept my opinion is up to you.

******************************************************

K. Klein, PE ME, MBA

Indoor Air Quality Solutions, Inc.

2523 SR 133

Bethel, OH

45106-0007

VOICE:

FAX: (with notice)

E-mail: mkklein68@...

*******************************************************

Wouldn't it be nice if common sense were really common?

[Guest guest]

Matt:

What you are describing appears to be more often attributed to the movement of electrons due to the presence of dissolved solids, e.g., corrosion, hydrolysis, salt migrations (efflorescence), ettringite formation, etc. Periodic or prolonged moisture can also cause migration of water-soluble platicizers, and dehydrohalogenation of additives/sealants and other manufactured products. Bottom line...yes, there are “mechanical” breakdowns” in the body of the material in question. This breakdown is attributed to many factors. However, I believe the breakdown in gyp-board is less from “contaminants” in the water, and more attributed to the solubilization of stuff (salts, minerals, and associate electron movement) due to the presence of water. Let it be known, water is the “universal” solvent.

For what it is worth....

--

Geyer, PE, CIH, CSP

President

KENTEC Industries, Inc.

Bakersfield, California

www.kerntecindustries.com

2. On a related issue, I have some photomicrographs of drywall after several cycles of wet-dry. This produces recrystallization (including twinning) of the gypsum and the hysteris-like effect of changes in sizes and relative position of crystals that will result in expansion (similar to corrosion in iron). This will then make it appear sponge-like as there will be air spaces where the new larger crystal packing results in gaps. Seen this in Indiana well as Florida and Georgia.

Ohio too. Now, tthat brings up another question. Is the change due to mechanical breakdown of the cystalline structure from the plasterboard material expanding, from it expanding and then contracting or from contaminants in the water? I have seen the breakdown in plasterboard that has been continuously or repeatedly exposed to moisture, but not in plasterboard that has been wetted and then dried right away. I have not been as observant about plasterboard exposed to rainwater wetting versus flooding from say a sewer backflow. I guess I'm usually more tuned into the contamination rather than the water source. Just curious.

******************************************************

If what is written looks too stupid to be written by me, I disclaim it. On

the other hand, if it is brilliant, then I have no one to blame but myself.

Otherwise, whether you choose to accept my opinion is up to you.

******************************************************

K. Klein, PE ME, MBA

Indoor Air Quality Solutions, Inc.

2523 SR 133

Bethel, OH 45106-0007

VOICE:

FAX: (with notice)

E-mail: mkklein68@...

*******************************************************

Wouldn't it be nice if common sense were really common?

FAIR USE NOTICE:

This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. For more information go to: http://www.law.cornell.edu/uscode/17/107.shtml. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner.

[Guest guest]

I would think that all or part of the answer might lie in the Vant Hoff equations for osmosis

1. I'd be interested in getting some more info on this?

2. Is this in addition to boundary migration? as seen in DDT, TNT, quartz, etc.

Tony

........................................................................... "Tony" Havics, CHMM, CIH, PEpH2, LLCPO Box 34140Indianapolis, IN 46234 cell90% of Risk Management is knowing where to place the decimal point...any consultant can give you the other 10%â„ This message is from pH2. This message and any attachments may contain legally privileged or confidential information, and are intended only for the individual or entity identified above as the addressee. If you are not the addressee, or if this message has been addressed to you in error, you are not authorized to read, copy, or distribute this message and any attachments, and we ask that you please delete this message and attachments (including all copies) and notify the sender by return e-mail or by phone at . Delivery of this message and any attachments to any person other than the intended recipient(s) is not intended in any way to waive confidentiality or a privilege. All personal messages express views only of the sender, which are not to be attributed to pH2 and may not be copied or distributed without this statement.

-----Original Message-----From: iequality [mailto:iequality ] On Behalf Of Talk2PSSent: Saturday, May 13, 2006 2:42 PMTo: iequality Subject: Re: Re: Ocean salts and mold -- was Boric salts

I would think that all or part of the answer might lie in the Vant Hoff equations for osmosis. Though I believe the equations were originally developed related to cellular biology I have seen some variant applied to explain the destruction of concrete by osmotic crystalline pressure.

Since gypsum is a sulfate salt of calcium one would expect rearrangement of the crystalline structures when a solvent like water is added. Such osmotic crystalline pressures can easily rupture concrete so gypsum would not stand a chance if enough water is present over a long enough period of time or the gypsum is subjected to numerous repeated wettings.

Of course if the gypsum is allowed to get thoroughly saturated with water (as a solvent) it very quickly turn back into the Paleozoic mush from which it came. The destruction caused by numerous wetting with intervening drying cycles however is a much slower process of destructively rearranging the crystalline structures rather than complete destabilization of its matrix.

This seems to match well enough with Matt's observations; i.e. if you can eliminate the water source quickly and dry the product out properly the gypsum structure will remain substantially intact. That has always been my personal experience as well by the way.

Stojanik

RE: Re: Ocean salts and mold -- was Boric salts

2. On a related issue, I have some photomicrographs of drywall after several cycles of wet-dry. This produces recrystallization (including twinning) of the gypsum and the hysteris-like effect of changes in sizes and relative position of crystals that will result in expansion (similar to corrosion in iron). This will then make it appear sponge-like as there will be air spaces where the new larger crystal packing results in gaps. Seen this in Indiana well as Florida and Georgia.Ohio too. Now, tthat brings up another question. Is the change due to mechanical breakdown of the cystalline structure from the plasterboard material expanding, from it expanding and then contracting or from contaminants in the water? I have seen the breakdown in plasterboard that has been continuously or repeatedly exposed to moisture, but not in plasterboard that has been wetted and then dried right away. I have not been as observant about plasterboard exposed to rainwater wetting versus flooding from say a sewer backflow. I guess I'm usually more tuned into the contamination rather than the water source. Just curious.

******************************************************If what is written looks too stupid to be written by me, I disclaim it. Onthe other hand, if it is brilliant, then I have no one to blame but myself. Otherwise, whether you choose to accept my opinion is up to you.****************************************************** K. Klein, PE ME, MBAIndoor Air Quality Solutions, Inc.2523 SR 133Bethel, OH 45106-0007VOICE: FAX: (with notice)E-mail: mkklein68@...*******************************************************Wouldn't it be nice if common sense were really common?

[Guest guest]

I think (aka my Opinion) it is the length of drying time - the longer the cycle the more likely the recrystallization. This is based on my knowledge of polymorphic crystallization, phases diagrams and crystal growth (particularily with pharmaceuticals and explosives).

Tony

........................................................................... "Tony" Havics, CHMM, CIH, PEpH2, LLCPO Box 34140Indianapolis, IN 46234 cell90% of Risk Management is knowing where to place the decimal point...any consultant can give you the other 10%â„ This message is from pH2. This message and any attachments may contain legally privileged or confidential information, and are intended only for the individual or entity identified above as the addressee. If you are not the addressee, or if this message has been addressed to you in error, you are not authorized to read, copy, or distribute this message and any attachments, and we ask that you please delete this message and attachments (including all copies) and notify the sender by return e-mail or by phone at . Delivery of this message and any attachments to any person other than the intended recipient(s) is not intended in any way to waive confidentiality or a privilege. All personal messages express views only of the sender, which are not to be attributed to pH2 and may not be copied or distributed without this statement.

RE: Re: Ocean salts and mold -- was Boric salts

2. On a related issue, I have some photomicrographs of drywall after several cycles of wet-dry. This produces recrystallization (including twinning) of the gypsum and the hysteris-like effect of changes in sizes and relative position of crystals that will result in expansion (similar to corrosion in iron). This will then make it appear sponge-like as there will be air spaces where the new larger crystal packing results in gaps. Seen this in Indiana well as Florida and Georgia.Ohio too. Now, tthat brings up another question. Is the change due to mechanical breakdown of the cystalline structure from the plasterboard material expanding, from it expanding and then contracting or from contaminants in the water? I have seen the breakdown in plasterboard that has been continuously or repeatedly exposed to moisture, but not in plasterboard that has been wetted and then dried right away. I have not been as observant about plasterboard exposed to rainwater wetting versus flooding from say a sewer backflow. I guess I'm usually more tuned into the contamination rather than the water source. Just curious.

******************************************************If what is written looks too stupid to be written by me, I disclaim it. Onthe other hand, if it is brilliant, then I have no one to blame but myself. Otherwise, whether you choose to accept my opinion is up to you.****************************************************** K. Klein, PE ME, MBAIndoor Air Quality Solutions, Inc.2523 SR 133Bethel, OH 45106-0007VOICE: FAX: (with notice)E-mail: mkklein68@...*******************************************************Wouldn't it be nice if common sense were really common?