Re: PRV and Sampling - With Air Scrubbers On or Off

[Guest guest]

,

Don’t get me wrong, I still agitate

the air prior to sampling. Simply, I like to see the environment not under

filtration (HEPA) prior to sampling. I totally agree with agitation just not

with filtration especially hours prior to and leading up to sampling.

Bob

From: iequality [mailto:iequality ] On Behalf Of Geyer

Sent: Thursday, March 08, 2007

6:04 PM

To: iequality

Subject: PRV and

Sampling - With Air Scrubbers On or Off

This is a worthwhile tread....and

this group may do well to air-out the issues herein.

I, for one, routinely sample post-remediation with the air scrubbers operating

and creating turbulent and aggressive air currents inside containment. I

often place sample pumps near the front (but not directly in font) of the

HEPA-filtered fan units whose exhaust is pointed directly at the areas where

mold was removed/remediated. If a reservoir of fungi is still present,

and it has not been adequately cleaned and encapsulated, then it is going to be

blasted into the air and my samplers going to capture it. Bob/Ma, your

suggestion of allowing a neutral environment I feel is flawed because it allows

a truly passive environment to exit with no air currents, therefore, the biomass

will not be entrained into the air and anything that was in the air has 24 to

48 hours to settle out. Moreover, the only time I conduct a PRV in a

neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling

post-remediation, i.e., fan units on or off, and look forward to the dialog of

others.

On 3/7/07 12:18 PM, " Bob_CIEC " <BobEnvironmentalAirTechs>

wrote:

Steve,

Why would one take the air samples when the air scrubbers are on? I believe the

environment has the potential to be misrepresented if sampled when the

scrubbers are on. If the environment is clean than having the scrubbers off

would more closely represent (snap shot in time) the environments present

condition (prior to removing the containment).

If one samples the contained environment with the scrubbers on, than what you

are testing is the efficiency of the scrubbers and not necessarily if the

reservoir(s) were discovered and removed.

Keep in mind, if the scrubber’s were set up correctly than what you

should have is an AFD that should be filtering at a rate greater than the

emission rate. What you have proven is the air scrubber(s) is/are affective (sufficient

for the project intended).

Also, keep in mind, if the UFD is sufficient enough than (depending how many

ACH you required) you should get passing results while on (if you are

subscribing to the magnitude of 10 X’s greater). Consider if you sample

within the cleaned/down stream (HEPA filtered) air, again you can get skewed

results. At a minimum of even 4 ACH that is a lot of filtration going on. And

if the unit is sized correctly you should get minimal (less than a magnitude of

10) results.

I prefer allowing the environment to rest under neutral pressure, allowing

greater concentrations to seek low (nature hates an imbalance) for at least

24-48 hours (doors and windows closed) and than sample. My belief is I am (more

likely than not) getting a sample that has a greater chance of discovering or

confirming absents of a reservoir and/or its emissions.

Bob/Ma.

From: iequality

[mailto:iequality ]

On Behalf Of AirwaysEnvcs

Sent: Wednesday, March 07, 2007

1:31 PM

To: iequality

Subject: Re: Mold,

Moisture & Remediation Workshop in Cincinnati

November ...

In a message

dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652

writes:

That was the class where they taught to take post-remediation air

samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

[Guest guest]

Bob/Ma:

Good. We both agree that aggressive air movement is benefit (maybe required?) during PRV sampling. You mention “agitated,” however, when I go into a contained space, let’s say it is 1,500sqft, and there are three to four 2000cfm HEPA air scrubbers operating, the air inside that space is more than just agitated, its down-right turbulent! I often have the remediation contractor operate the air scrubbers a minimum of 12hrs post-remediation, preferably 24hrs, prior to me conducting the PRV inspection and sampling. Moreover, my PRV is done BEFORE any encapsulants are used - I specify the use of encapsulants after PRV inspection and sampling in most, but not all, projects. In my view, if there are reservoirs of biologicals present, those air scrubbers are going to do a much better job of dislodging the material, entraining the material in the air, and keeping it aerosolized during my sampling effort than I could by simple agitation alone. Yes...they are also scrubbing the air and removing the bio-mass, but it is an iterative process that does not happen quickly. Also, if there are available bio-sources present (that have not been removed) that keep adding to the concentration, 24-hrs is not sufficient time to remove it if it is significant. And if it is not significant, what is the point? If all tests come back favorable, encapsulate the area and restore it back to a pre-loss condition.

,

Don’t get me wrong, I still agitate the air prior to sampling. Simply, I like to see the environment not under filtration (HEPA) prior to sampling. I totally agree with agitation just not with filtration especially hours prior to and leading up to sampling.

Bob

From: iequality [mailto:iequality ] On Behalf Of Geyer

Sent: Thursday, March 08, 2007 6:04 PM

To: iequality

Subject: PRV and Sampling - With Air Scrubbers On or Off

This is a worthwhile tread....and this group may do well to air-out the issues herein.

I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything that was in the air has 24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others.

Steve,

Why would one take the air samples when the air scrubbers are on? I believe the environment has the potential to be misrepresented if sampled when the scrubbers are on. If the environment is clean than having the scrubbers off would more closely represent (snap shot in time) the environments present condition (prior to removing the containment).

If one samples the contained environment with the scrubbers on, than what you are testing is the efficiency of the scrubbers and not necessarily if the reservoir(s) were discovered and removed.

Keep in mind, if the scrubber’s were set up correctly than what you should have is an AFD that should be filtering at a rate greater than the emission rate. What you have proven is the air scrubber(s) is/are affective (sufficient for the project intended).

Also, keep in mind, if the UFD is sufficient enough than (depending how many ACH you required) you should get passing results while on (if you are subscribing to the magnitude of 10 X’s greater). Consider if you sample within the cleaned/down stream (HEPA filtered) air, again you can get skewed results. At a minimum of even 4 ACH that is a lot of filtration going on. And if the unit is sized correctly you should get minimal (less than a magnitude of 10) results.

I prefer allowing the environment to rest under neutral pressure, allowing greater concentrations to seek low (nature hates an imbalance) for at least 24-48 hours (doors and windows closed) and than sample. My belief is I am (more likely than not) getting a sample that has a greater chance of discovering or confirming absents of a reservoir and/or its emissions.

Bob/Ma.

From: iequality [mailto:iequality ] <mailto:iequality %5d> On Behalf Of AirwaysEnv@...

Sent: Wednesday, March 07, 2007 1:31 PM

To: iequality

Subject: Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

[Guest guest]

,

I agree with you and have been doing PRV air sampling this way, when possible, going back many years. I believe that aggressive or semi-aggressive air sampling is indirectly representative of more surface area in the containment than any reasonable amount of surface sampling would be. The only thing I would do differently from your description below is shut off the scrubber for 5 minutes or so to let the air streams and convections in the room "homogenize" so that I didn't unknowingly set up the sampler in a "clean stream" from the scrubber exhaust.

What I don't understand is why someone would wait 24 hours for spores to settle and then take an air sample inside a containment NOT using aggressive or semi-aggressive techniques.

If you wait 24 hours and then take surface samples to identify whether Condition 2 contamination (per S520) exists, that makes sense to me as well.

Steve Temes

This is a worthwhile tread....and this group may do well to air-out the issues herein.

I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything that was in the air has 24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others.

[Guest guest]

/Bob,

I agree with that this is useful thread. Here's a common problem ...

You finish the remediation of a particular wall. This gets the spore count in the house down to a low enough level that you should now be able to see other secondary problems.

You have recessed lights that are the older type and not sealed. The afternoon sun heats up the attic and pushing mold spores from the attic into the house. Or the air handler which is non-ducted, sucks mold spores from the attic space due to a few openings around the coolant lines leading into the attic.

You would not see either of these problems if you ran the scrubbers while testing. Now you may not care about these additional problems as you were paid to remediate a particular wall. Or these problems will not make someone sick as they are minor unless the homeowner is sensitive (cancer, asthma, chemically sensitive etc.)

However depending on the job and the client, PRV that has the scrubbers running while you are testing may not be appropriate and may be covering up problems.

On the other hand ... in any older house with carpets and old drapes the background from these components will most likely swamp any effort to try to find subtle mold growth problems in walls, attics or around air handlers. In such cases we don't take air samples at all. Our PRV is based on pictures during and after remediation that all the problem materials have been replaced with new or brought to like new condition.

Rosen,Ph.D.

www.Green-Buildings.org

www.Mold-Books.com

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@

yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?Steve Temes

The fish are biting.

Get more visitors on your site using Yahoo! Search Marketing.

[Guest guest]

: I like your thinking. Pete Geyer wrote: Bob/Ma:Good. We both agree that aggressive air movement is benefit (maybe required?) during PRV sampling. You mention “agitated,” however, when I go into a contained space, let’s say it is 1,500sqft, and there are three to four 2000cfm HEPA air scrubbers operating, the air inside that space is

more than just agitated, its down-right turbulent! I often have the remediation contractor operate the air scrubbers a minimum of 12hrs post-remediation, preferably 24hrs, prior to me conducting the PRV inspection and sampling. Moreover, my PRV is done BEFORE any encapsulants are used - I specify the use of encapsulants after PRV inspection and sampling in most, but not all, projects. In my view, if there are reservoirs of biologicals present, those air scrubbers are going to do a much better job of dislodging the material, entraining the material in the air, and keeping it aerosolized during my sampling effort than I could by simple agitation alone. Yes...they are also scrubbing the air and removing the bio-mass, but it is an iterative process that does not happen quickly. Also, if there are available bio-sources present (that have not been removed) that keep adding to the concentration, 24-hrs is not sufficient time to remove it if it is

significant. And if it is not significant, what is the point? If all tests come back favorable, encapsulate the area and restore it back to a pre-loss condition.On 3/8/07 5:27 PM, "Bob/Ma." <BobEnvironmentalAirTechs> wrote: , Don’t get me wrong, I still agitate the air prior to sampling. Simply, I like to see the environment not under filtration (HEPA) prior to sampling. I totally agree with agitation just not with filtration especially hours prior to and leading up to sampling. Bob From: iequality [mailto:iequality ] On Behalf Of GeyerSent: Thursday, March 08, 2007 6:04 PMTo: iequality Subject: PRV and Sampling - With Air Scrubbers On or OffThis is a worthwhile tread....and this group may do well to air-out the issues herein.I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place

sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything that was in the air has 24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others.On 3/7/07 12:18 PM, "Bob_CIEC"

<BobEnvironmentalAirTechs> wrote: Steve, Why would one take the air samples when the air scrubbers are on? I believe the environment has the potential to be misrepresented if sampled when the scrubbers are on. If the environment is clean than having the scrubbers off would more closely represent (snap shot in time) the environments present condition (prior to removing the containment). If one samples the contained environment with the scrubbers on, than what you are testing is the efficiency of the scrubbers and not necessarily if the reservoir(s) were discovered and removed. Keep in mind, if the scrubber’s were set up correctly than what you should have is an AFD that should be filtering

at a rate greater than the emission rate. What you have proven is the air scrubber(s) is/are affective (sufficient for the project intended). Also, keep in mind, if the UFD is sufficient enough than (depending how many ACH you required) you should get passing results while on (if you are subscribing to the magnitude of 10 X’s greater). Consider if you sample within the cleaned/down stream (HEPA filtered) air, again you can get skewed results. At a minimum of even 4 ACH that is a lot of filtration going on. And if the unit is sized correctly you should get minimal (less than a magnitude of 10) results. I prefer allowing the environment to rest under neutral pressure, allowing greater concentrations to seek low (nature hates an imbalance) for at least 24-48 hours (doors and windows closed) and than sample. My belief is I am (more likely than not) getting a sample that has a greater chance of discovering or confirming absents of a reservoir and/or

its emissions. Bob/Ma. From: iequality [mailto:iequality ] <mailto:iequality %5d> On Behalf Of AirwaysEnvcsSent: Wednesday, March 07, 2007 1:31 PMTo: iequality Subject: Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...In a

message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652 writes: That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.What's wrong with that?Steve Temes

It's here! Your new message!Get

new email alerts with the free Yahoo! Toolbar.

[Guest guest]

,

Turbulent may be too aggressive just prior

to sampling. I want some settled out, and I want some aerosolized (if its

there). Turbulent may cause results to be a misrepresentation. ,

see below:

From: iequality

[mailto:iequality ] On Behalf

Of Geyer

Sent: Thursday, March 08, 2007

11:17 PM

To: iequality

Subject: Re: PRV and

Sampling - With Air Scrubbers On or Off

Bob/Ma:

Good. We both agree that aggressive air movement is benefit (maybe

required?) [bob/Ma.] agreed) during PRV sampling.

You mention “agitated,”

however, when I go into a contained space, let’s say it is 1,500sqft, and

there are three to four 2000cfm HEPA air scrubbers operating, the air inside

that space is more than just agitated, its down-right turbulent! [bob/Ma.]

true)

I often have the remediation

contractor operate the air scrubbers a minimum of 12hrs post-remediation,

preferably 24hrs, prior to me conducting the PRV inspection and sampling. [bob/Ma.]

ok so you

had the scrubbers potentially cleaning what may have been left behind)

Moreover, my PRV is done BEFORE any

encapsulants are used - I specify the use of encapsulants after PRV inspection

and sampling in most, but not all, projects[bob/Ma.] why encapsulate if the remediation is

successful? If the moisture issue is resolved mold should not reoccur.).

In my view, if there are reservoirs

of biologicals present, those air scrubbers are going to do a much better job

of dislodging the material, entraining the material in the air, and keeping it

aerosolized during my sampling effort than I could by simple agitation alone.

[bob/Ma.] except that the air is being scrubbed 4-8 times per

hour. What you may actually be doing is skewing your samples allowing the

scrubber(s) to run. I do agree with creating turbulence (only for a short

time) and pointing the air stream towards toe plates, etc. to loosen up what

may be hiding under them as well. Than let rest for a while and sample

thereafter. I really like the leaf blower as long as it is new. Otherwise one

may say you brought it in and contaminated the project. They are not very

expensive. If you don’t want to buy a new one each time, take it outside

and run for a while to be sure it minimally represents the outside. Even if it

has a few spores (from outside) the likely hood of it being a problem are

unlikely at best. Besides, even if the inside is representative (rank and

order) of the outside, you’re good to go.

Yes...they are also scrubbing the

air and removing the bio-mass, but it is an iterative process that does not

happen quickly[bob/Ma.] shouldn’t be scrubbing anything out of the

air stream (above background ) if remediated properly (which is my point).

Also, if there are available

bio-sources present (that have not been removed) that keep adding to the

concentration, 24-hrs is not sufficient time to remove it if it is significant.

[bob/Ma.] at 4-8 air changes per hour it surely has a great

impact potentially even to the point of giving a false acceptance.

And if it is not significant, what

is the point? [bob/Ma.] see above

If all tests come back favorable[bob/Ma.]

most

likely will when it should not

, encapsulate [bob/Ma.]

what the

mold and its spores? Who could possible ever fail under those conditions

(unless they really didn’t clean very well). What I am also confirming is

the reservoir(s) have been discovered and remediated.

the area and restore it back to a

pre-loss condition.

[bob/Ma.]

On 3/8/07 5:27 PM, " Bob/Ma. " <BobEnvironmentalAirTechs>

wrote:

,

Don’t get me wrong, I still agitate the air prior to sampling. Simply, I

like to see the environment not under filtration (HEPA) prior to sampling.

I totally agree with agitation just not with filtration especially hours

prior to and leading up to sampling.

Bob

From: iequality [mailto:iequality ]

On Behalf Of Geyer

Sent: Thursday, March 08, 2007

6:04 PM

To: iequality

Subject: PRV and

Sampling - With Air Scrubbers On or Off

This is a worthwhile tread....and this group may do well to air-out the issues

herein.

I, for one, routinely sample post-remediation with the air scrubbers operating

and creating turbulent and aggressive air currents inside containment. I

often place sample pumps near the front (but not directly in font) of the

HEPA-filtered fan units whose exhaust is pointed directly at the areas where

mold was removed/remediated. If a reservoir of fungi is still present,

and it has not been adequately cleaned and encapsulated, then it is going to be

blasted into the air and my samplers going to capture it. Bob/Ma, your

suggestion of allowing a neutral environment I feel is flawed because it allows

a truly passive environment to exit with no air currents, therefore, the

biomass will not be entrained into the air and anything that was in the air has

24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in

a neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling

post-remediation, i.e., fan units on or off, and look forward to the dialog of

others.

On 3/7/07 12:18 PM, " Bob_CIEC " <BobEnvironmentalAirTechs>

wrote:

Steve,

Why would one take the air samples when the air scrubbers are on? I believe the

environment has the potential to be misrepresented if sampled when the

scrubbers are on. If the environment is clean than having the scrubbers off

would more closely represent (snap shot in time) the environments present

condition (prior to removing the containment).

If one samples the contained environment with the scrubbers on, than what you

are testing is the efficiency of the scrubbers and not necessarily if the

reservoir(s) were discovered and removed.

Keep in mind, if the scrubber’s were set up correctly than what you

should have is an AFD that should be filtering at a rate greater than the

emission rate. What you have proven is the air scrubber(s) is/are affective

(sufficient for the project intended).

Also, keep in mind, if the UFD is sufficient enough than (depending how many

ACH you required) you should get passing results while on (if you are

subscribing to the magnitude of 10 X’s greater). Consider if you sample

within the cleaned/down stream (HEPA filtered) air, again you can get skewed

results. At a minimum of even 4 ACH that is a lot of filtration going on. And

if the unit is sized correctly you should get minimal (less than a magnitude of

10) results.

I prefer allowing the environment to rest under neutral pressure, allowing

greater concentrations to seek low (nature hates an imbalance) for at least

24-48 hours (doors and windows closed) and than sample. My belief is I am (more

likely than not) getting a sample that has a greater chance of discovering or

confirming absents of a reservoir and/or its emissions.

Bob/Ma.

From:

iequality [mailto:iequality ]

<mailto:iequality %5d>

On Behalf Of AirwaysEnvcs

Sent: Wednesday, March 07, 2007

1:31 PM

To: iequality

Subject: Re: Mold,

Moisture & Remediation Workshop in Cincinnati

November ...

In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652

writes:

That was the class where they taught to take post-remediation air

samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

[Guest guest]

Steve,

If the scrubber is off when you arrive and

you choose to turn on the scrubber for only a few minutes or so (as not to

scrub the air and in place of a blower) I could agree with that. But I would

still do surface sampling. In addition I would lock around to see where the air

stream is most likely to slow down allowing particulate to settle out (good

place to conduct surface sampling). I always do surface along with air

sampling.

Down the road I may purchase a microscope

(when I get more money) to analyze the surface samples while in the field. I

would really like one that takes pictures of the slides for evidence. Anyone

have an idea of cost? If I had that tool I could avoid charging unnecessary air

samples if the surface samples fail.

Bob/Ma.

From: iequality

[mailto:iequality ] On Behalf

Of AirwaysEnv@...

Sent: Friday, March 09, 2007 10:06

AM

To: iequality

Subject: Re: PRV and

Sampling - With Air Scrubbers On or Off

,

I agree with you and have been doing PRV air sampling this way, when possible,

going back many years. I believe that aggressive or semi-aggressive air

sampling is indirectly representative of more surface area in the containment

than any reasonable amount of surface sampling would be. The only thing I

would do differently from your description below is shut off the scrubber for 5

minutes or so to let the air streams and convections in the room

" homogenize " so that I didn't unknowingly set up the sampler in a

" clean stream " from the scrubber exhaust.

What I don't understand is why someone would wait 24 hours for spores to settle

and then take an air sample inside a containment NOT using aggressive or

semi-aggressive techniques.

If you wait 24 hours and then take surface samples to identify whether

Condition 2 contamination (per S520) exists, that makes sense to me as well.

Steve Temes

In a message dated 3/8/2007 6:03:48 PM Eastern Standard Time, mgeyeratg1

writes:

This is a worthwhile tread....and this group may do well to

air-out the issues herein.

I, for one, routinely sample post-remediation with the air scrubbers operating

and creating turbulent and aggressive air currents inside containment. I

often place sample pumps near the front (but not directly in font) of the

HEPA-filtered fan units whose exhaust is pointed directly at the areas where

mold was removed/remediated. If a reservoir of fungi is still present,

and it has not been adequately cleaned and encapsulated, then it is going to be

blasted into the air and my samplers going to capture it. Bob/Ma, your

suggestion of allowing a neutral environment I feel is flawed because it allows

a truly passive environment to exit with no air currents, therefore, the biomass

will not be entrained into the air and anything that was in the air has 24 to

48 hours to settle out. Moreover, the only time I conduct a PRV in a

neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling

post-remediation, i.e., fan units on or off, and look forward to the dialog of

others.

[Guest guest]

-

If the source of moisture has been addresssed and corrected, the

remediation conducted in a way that would ensure removal, the

project has passed a visual inspection and work site is free of

dust, dirt & debris, and the lab results come back looking

acceptable -

why would you encapsulate on nearly every project?

Just curious.

Stacey Champion

Owner/Consultant

Champion Indoor Environmental Services, LLC

> >>

> >>

> >>

> >>

> >>

> >> Steve,

> >>

> >> Why would one take the air samples when the air scrubbers are

on? I believe

> >> the environment has the potential to be misrepresented if

sampled when the

> >> scrubbers are on. If the environment is clean than having the

scrubbers off

> >> would more closely represent (snap shot in time) the

environments present

> >> condition (prior to removing the containment).

> >>

> >> If one samples the contained environment with the scrubbers on,

than what you

> >> are testing is the efficiency of the scrubbers and not

necessarily if the

> >> reservoir(s) were discovered and removed.

> >>

> >> Keep in mind, if the scrubber¹s were set up correctly than what

you should

> >> have is an AFD that should be filtering at a rate greater than

the emission

> >> rate. What you have proven is the air scrubber(s) is/are

affective

> >> (sufficient for the project intended).

> >>

> >> Also, keep in mind, if the UFD is sufficient enough than

(depending how many

> >> ACH you required) you should get passing results while on (if

you are

> >> subscribing to the magnitude of 10 X¹s greater). Consider if

you sample

> >> within the cleaned/down stream (HEPA filtered) air, again you

can get skewed

> >> results. At a minimum of even 4 ACH that is a lot of filtration

going on. And

> >> if the unit is sized correctly you should get minimal (less

than a magnitude

> >> of 10) results.

> >>

> >> I prefer allowing the environment to rest under neutral

pressure, allowing

> >> greater concentrations to seek low (nature hates an imbalance)

for at least

> >> 24-48 hours (doors and windows closed) and than sample. My

belief is I am

> >> (more likely than not) getting a sample that has a greater

chance of

> >> discovering or confirming absents of a reservoir and/or its

emissions.

> >>

> >> Bob/Ma.

> >>

> >>

> >>

> >> From: iequality

[mailto:iequality ]

> >> <mailto:iequality %5d> On Behalf Of

AirwaysEnv@...

> >> Sent: Wednesday, March 07, 2007 1:31 PM

> >> To: iequality

> >> Subject: Re: Mold, Moisture & Remediation Workshop

in Cincinnati

> >> November ...

> >>

> >>

> >> In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time,

> >> garyrosen72652@... writes:

> >>>

> >>>

> >>> That was the class where they taught to take post-remediation

air samples

> >>> inside the containment with the air scrubbers on.

> >>

> >> What's wrong with that?

> >>

> >> Steve Temes

> >>

> >>

> >

> >

>

[Guest guest]

Hi Bob, I am usually a "lurker", but out of curiosity, who would do your analysis out in the field? Dawne"Bob/Ma." wrote: Steve, If the scrubber is off when you arrive and you choose to turn on the scrubber for only a few minutes or so (as not to scrub the air and in place of a blower) I could agree with that. But I would still do surface sampling. In addition I would lock around to see where the air stream is most likely to slow down allowing particulate to settle out (good place to conduct surface sampling). I always do surface along with air sampling. Down the road I may purchase a microscope (when I get more money) to analyze the surface

samples while in the field. I would really like one that takes pictures of the slides for evidence. Anyone have an idea of cost? If I had that tool I could avoid charging unnecessary air samples if the surface samples fail. Bob/Ma. From:

iequality [mailto:iequality ] On Behalf Of AirwaysEnvcsSent: Friday, March 09, 2007 10:06 AMTo: iequality Subject: Re: PRV and Sampling - With Air Scrubbers On or Off ,I agree with you and have been doing PRV air sampling this way, when possible, going back many years. I believe that aggressive or semi-aggressive air sampling is indirectly representative of

more surface area in the containment than any reasonable amount of surface sampling would be. The only thing I would do differently from your description below is shut off the scrubber for 5 minutes or so to let the air streams and convections in the room "homogenize" so that I didn't unknowingly set up the sampler in a "clean stream" from the scrubber exhaust.What I don't understand is why someone would wait 24 hours for spores to settle and then take an air sample inside a containment NOT using aggressive or semi-aggressive techniques.If you wait 24 hours and then take surface samples to identify whether Condition 2 contamination (per S520) exists, that makes sense to me as well.Steve TemesIn a message dated 3/8/2007 6:03:48 PM Eastern Standard Time, mgeyeratg1 writes: This is a worthwhile tread....and this group may do well to air-out the issues herein.I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and

encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything that was in the air has 24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others.

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[Guest guest]

ge

Stacey, I always wonder why people refer to coating as encapsulating. Very few products are sealants and most are coatings.

Hope you weathered the barrage of ??????? Ok

-If the source of moisture has been addresssed and corrected, the remediation conducted in a way that would ensure removal, the project has passed a visual inspection and work site is free of dust, dirt & debris, and the lab results come back looking acceptable - why would you encapsulate on nearly every project?Just curious.Stacey ChampionOwner/ConsultantChampion Indoor Environmental Services, LLC> >> > >> > >> > >> > >> > >> Steve,> >> > >> Why would one take the air samples when the air scrubbers are on? I believe> >> the environment has the potential to be misrepresented if sampled when the> >> scrubbers are on. If the environment is clean than having the scrubbers off> >> would more closely represent (snap shot in time) the environments present> >> condition (prior to removing the containment).> >> > >> If one samples the contained environment with the scrubbers on, than what you> >> are testing is the efficiency of the scrubbers and not necessarily if the> >> reservoir(s) were discovered and removed.> >> > >> Keep in mind, if the scrubber¹s were set up correctly than what you should> >> have is an AFD that should be filtering at a rate greater than the emission> >> rate. What you have proven is the air scrubber(s) is/are affective> >> (sufficient for the project intended).> >> > >> Also, keep in mind, if the UFD is sufficient enough than (depending how many> >> ACH you required) you should get passing results while on (if you are> >> subscribing to the magnitude of 10 X¹s greater). Consider if you sample> >> within the cleaned/down stream (HEPA filtered) air, again you can get skewed> >> results. At a minimum of even 4 ACH that is a lot of filtration going on. And> >> if the unit is sized correctly you should get minimal (less than a magnitude> >> of 10) results. > >> > >> I prefer allowing the environment to rest under neutral pressure, allowing> >> greater concentrations to seek low (nature hates an imbalance) for at least> >> 24-48 hours (doors and windows closed) and than sample. My belief is I am> >> (more likely than not) getting a sample that has a greater chance of> >> discovering or confirming absents of a reservoir and/or its emissions.> >> > >> Bob/Ma.> >> > >> > >> > >> From: iequality [mailto:iequality ]> >> <mailto:iequality %5d> On Behalf Of AirwaysEnv@...> >> Sent: Wednesday, March 07, 2007 1:31 PM> >> To: iequality > >> Subject: Re: Mold, Moisture & Remediation Workshop in Cincinnati> >> November ...> >> > >> > >> > >>> > >>> > >>> That was the class where they taught to take post-remediation air samples> >>> inside the containment with the air scrubbers on.> >> > >> What's wrong with that?> >> > >> Steve Temes > >> > >> > > > >>

[Guest guest]

Turbulent is fine with me. Then you don't have to do any surface sampling.

Rosen, Ph.D.

www.Green-Buildings.org

www.Mold-Books.com

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@ yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?Steve Temes

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[Guest guest]

/Bob,

Here's a common problem ...

You finish your remediation of a particular wall. This gets the spore count in the house down to a low enough level that you should now be able to see other secondary problems.

You have recessed lights that are the older type and not sealed. The afternoon sun heats up the attic and pushing mold spores from the attic into the house. Or the air handler which is non-ducted, sucks mold spores from the attic space due to a few openings around the coolant lines leading into the attic.

You would not see either of these problems if you ran the scrubbers while testing. You may not care about these additional problems as you were paid to remediate a particular wall. Or these problems will not make someone sick as they are minor unless the homeowner is sensitive (cancer, asthma, chemically sensitive etc.)

However depending on the job and the client PRV that has the scrubbers running while you are testing may not be appropriate and may be covering up problems.

On the other hand ... in any older house with carpets and old drapes the background from these components will most likely swamp any effort to try to find subtle mold growth problems in walls,attics or around air handlers. In such cases we don't take air samples at all. Our PRV is based on pictures during and after remediation that all the problem materials have been replaced with new or brought to like new condition.

Rosen,Ph.D.

Green-Buildings

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@

yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?Steve Temes

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[Guest guest]

,

Why wait to encapsulate until after you test? I always encapsulate after cleaning and before final testing. I challenge the cost/value benefit of waiting as it adds an extra step.

Additionally, sooner rather than later is better when painting. Even if you use DP (low odor) encapsulant and not s which is high odor ... you want the stuff sprayed and dried sooner rather than later to avoid the smell which may be a problem for some sensitive occupants.

Rosen

www.Mold-Books.com

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@ yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.What's wrong with that?Steve Temes

Now that's room service! Choose from over 150,000 hotels in 45,000 destinations on Yahoo! Travel to find your fit.

[Guest guest]

Dawne,

As the consultant, I would perform such

observations as a pre-caution to avoid conducting unnecessary air sampling if

the surface samples exhibit a fail (dust, debris, etc) right at the onset. Not

everyone has 20/10 eyesight (including me).

If I see the samples are clean, continue

with air sampling. IMHO I would think it was any different than conducting a

visual? It would only be another tool in the field. I am not interpreting the

samples beyond clean or not. Besides, the more I am able to observe the more data

I am able to gather for the future. It would not be my intention nor would I

attempt to replace the labs (if that was what you may be concerned over).

EnviroBob

From: iequality [mailto:iequality ] On Behalf Of Dawne Yates

Sent: Friday, March 09, 2007 2:56

PM

To: iequality

Subject: RE: PRV and

Sampling - With Air Scrubbers On or Off

Hi Bob,

I am usually a " lurker " , but out of curiosity, who would do

your analysis out in the field?

Dawne

" Bob/Ma. "

<BobEnvironmentalAirTechs> wrote:

Steve,

If the scrubber is off when you

arrive and you choose to turn on the scrubber for only a few minutes or so (as

not to scrub the air and in place of a blower) I could agree with that. But I

would still do surface sampling. In addition I would lock around to see where

the air stream is most likely to slow down allowing particulate to settle out

(good place to conduct surface sampling). I always do surface along with air

sampling.

Down the road I may purchase a

microscope (when I get more money) to analyze the surface samples while in the

field. I would really like one that takes pictures of the slides for evidence.

Anyone have an idea of cost? If I had that tool I could avoid charging

unnecessary air samples if the surface samples fail.

Bob/Ma.

From: iequality [mailto:iequality ] On Behalf Of AirwaysEnvcs

Sent: Friday, March 09, 2007 10:06

AM

To: iequality

Subject: Re: PRV and

Sampling - With Air Scrubbers On or Off

,

I agree with you and have been doing PRV air sampling this way, when possible,

going back many years. I believe that aggressive or semi-aggressive air

sampling is indirectly representative of more surface area in the containment

than any reasonable amount of surface sampling would be. The only thing I

would do differently from your description below is shut off the scrubber for 5

minutes or so to let the air streams and convections in the room

" homogenize " so that I didn't unknowingly set up the sampler in a

" clean stream " from the scrubber exhaust.

What I don't understand is why someone would wait 24 hours for spores to settle

and then take an air sample inside a containment NOT using aggressive or

semi-aggressive techniques.

If you wait 24 hours and then take surface samples to identify whether

Condition 2 contamination (per S520) exists, that makes sense to me as well.

Steve Temes

In a message dated 3/8/2007 6:03:48 PM Eastern Standard Time, mgeyeratg1

writes:

This

is a worthwhile tread....and this group may do well to air-out the issues

herein.

I, for one, routinely sample post-remediation with the air scrubbers operating

and creating turbulent and aggressive air currents inside containment. I

often place sample pumps near the front (but not directly in font) of the

HEPA-filtered fan units whose exhaust is pointed directly at the areas where

mold was removed/remediated. If a reservoir of fungi is still present,

and it has not been adequately cleaned and encapsulated, then it is going to be

blasted into the air and my samplers going to capture it. Bob/Ma, your

suggestion of allowing a neutral environment I feel is flawed because it allows

a truly passive environment to exit with no air currents, therefore, the

biomass will not be entrained into the air and anything that was in the air has

24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in

a neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling post-remediation,

i.e., fan units on or off, and look forward to the dialog of others.

Now that's room service! Choose

from over 150,000 hotels

in 45,000 destinations on Yahoo! Travel to find your fit.

[Guest guest]

,

I would fail your project. Like another

consultant said to me I would hand them a sanding and tell them to call me when

you’re done.

What is the purpose of encapsulation if

the moisture problem is eliminated and the clean-up is complete (otherwise than

to hide what you feel you did or may have missed)? I do have to admit, you sure

can do the job quick and cheap that way.

I ask you, what is the purpose of sampling

if you encapsulated first? Why don’t you just fog the place before

testing? You’ll knock out any spores that way. IMHO I believe you are

utilizing old practices.

EnviroBob

From: iequality [mailto:iequality ] On Behalf Of gary rosen

Sent: Friday, March 09, 2007 4:44

PM

To: iequality

Subject: Re: PRV and

Sampling - With Air Scrubbers On or Off

,

Why wait to encapsulate until after you test? I

always encapsulate after cleaning and before final testing. I challenge

the cost/value benefit of waiting as it adds an extra step.

Additionally, sooner rather than later is better when

painting. Even if you use DP (low odor) encapsulant and not s which

is high odor ... you want the stuff sprayed and dried sooner rather than later

to avoid the smell which may be a problem for some sensitive occupants.

Rosen

www.Mold-Books.com

Re: Mold,

Moisture & Remediation Workshop in Cincinnati

November ...

In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@

yahoo.com writes:

That was the class where they taught to take post-remediation air

samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

Now that's room service! Choose

from over 150,000 hotels

in 45,000 destinations on Yahoo! Travel to find your fit.

[Guest guest]

Bob, No, I'm not worried--takes more than that to make me worry:) As someone who has analyzed literally thousands of samples.... its not so easy to know what you are looking at if you have not had any experience at analysis. I am a curious sort. DawneEnviroBob wrote: Dawne, As the consultant, I would perform such observations as a pre-caution to avoid conducting unnecessary air sampling if the surface samples exhibit a fail (dust, debris, etc) right at the onset. Not everyone has 20/10 eyesight (including me). If I see the samples are clean, continue with air sampling. IMHO I would think it was any

different than conducting a visual? It would only be another tool in the field. I am not interpreting the samples beyond clean or not. Besides, the more I am able to observe the more data I am able to gather for the future. It would not be my intention nor would I attempt to replace the labs (if that was what you may be concerned over). EnviroBob From: iequality [mailto:iequality ] On Behalf Of Dawne YatesSent: Friday, March 09, 2007 2:56 PMTo: iequality Subject: RE: PRV and Sampling - With Air Scrubbers On or Off Hi Bob, I am usually a "lurker", but out of curiosity, who would do your analysis out in the field? Dawne"Bob/Ma." <BobEnvironmentalAirTechs> wrote: Steve, If the scrubber is off when you arrive and you choose to turn on the scrubber for only a few minutes or so (as not to scrub the air and in place of a blower) I could agree with that. But I would still do surface sampling. In addition I would lock around to see where the air stream is most likely to slow down allowing particulate to settle out (good place to conduct surface sampling). I always do surface along with air sampling. Down the road I may purchase a microscope (when I get more money) to analyze the surface samples while in the field. I would really like one that takes pictures of the slides for evidence.

Anyone have an idea of cost? If I had that tool I could avoid charging unnecessary air samples if the surface samples fail. Bob/Ma. From: iequality [mailto:iequality ] On Behalf Of AirwaysEnvcsSent: Friday, March 09, 2007 10:06 AMTo: iequality Subject: Re: PRV and Sampling - With Air Scrubbers On or Off ,I agree with you and have been doing PRV air sampling this way, when possible, going back many years. I believe that aggressive or semi-aggressive air sampling is indirectly representative of more surface area in the containment than any reasonable amount of surface sampling would be. The only thing I would do differently from your description below is shut off the scrubber for 5 minutes or so to let the air

streams and convections in the room "homogenize" so that I didn't unknowingly set up the sampler in a "clean stream" from the scrubber exhaust.What I don't understand is why someone would wait 24 hours for spores to settle and then take an air sample inside a containment NOT using aggressive or semi-aggressive techniques.If you wait 24 hours and then take surface samples to identify whether Condition 2 contamination (per S520) exists, that makes sense to me as well.Steve TemesIn a message dated 3/8/2007 6:03:48 PM Eastern Standard Time, mgeyeratg1 writes: This is a worthwhile tread....and this group may do well to air-out the issues herein.I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything that was in the air has 24 to 48 hours to settle out.

Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others. Now that's

room service! Choose from over 150,000 hotels in 45,000 destinations on Yahoo! Travel to find your fit.

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[Guest guest]

EnviroBob is right on the money here.

A white glove/ black glove test of surfaces (or a Swiffer) should be done before you do any air sampling. This can be done by the remediation contractor before calling in the consultant for PRV.

Rosen

www.Mold-Books.com

Re: PRV and Sampling - With Air Scrubbers On or Off

,I agree with you and have been doing PRV air sampling this way, when possible, going back many years. I believe that aggressive or semi-aggressive air sampling is indirectly representative of more surface area in the containment than any reasonable amount of surface sampling would be. The only thing I would do differently from your description below is shut off the scrubber for 5 minutes or so to let the air streams and convections in the room "homogenize" so that I didn't unknowingly set up the sampler in a "clean stream" from the scrubber exhaust.What I don't understand is why someone would wait 24 hours for spores to settle and then take an air sample inside a containment NOT using aggressive or semi-aggressive techniques.If you wait 24 hours and then take surface samples to identify whether Condition 2 contamination (per S520) exists,

that makes sense to me as well.Steve TemesIn a message dated 3/8/2007 6:03:48 PM Eastern Standard Time, mgeyeratg1 (DOT) com writes:

This is a worthwhile tread....and this group may do well to air-out the issues herein.I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything

that was in the air has 24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others.

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[Guest guest]

I see pros and cons to each way: sampling with the scrubbers/negative

air on and off. The best thing to do is sample with them on (to

prevent the perception of cross-contamination in case there is still

contamination) then perform a second test after the first test results

are back from the lab and indicate a clean environment AND at that

time the srubber (neg-air) is shut off for 24 hours prior to re-

sampleing. Most clients don't want the time and expense of both. But

that's ultimately the only senrario that allows for preventing cross-

contaminatjon and testing under normal conditions.

[Guest guest]

Bob/Ma:

I don’t understand your logic and maybe you could explain.....

What do you mean when you say – “Turbulent may be too aggressive just prior to sampling.” Huh? In my opinion, the only time turbulence skews sample results is when I am conducting isokinetic sampling in a duct or air shaft and the flow is not laminar. Within a room or contained space, I imagine that if a jet engine is operating and air velocities greater than 1000fps are present, it may be too turbulent to sample; but I have yet to encounter this phenomenon in a mold remediation project. I will stick to turbulent air flows over agitation any day....then I don’t have to rely on surface sampling.

Now why would you want to have “some” spres settle-out, and “some” spres to remain aerosolized? Is there a magic 50/50 mix you like to see? Moreover, what is in the air is what a person may reasonable be exposed to, what is on a surface does not represent an exposure issue. It will either be left behind, locked-down with an encapsulant and/or covered up. So what? I know that you are one of a total source removal advocate......it is an impractical position! Why are you going to allow some spores to settle out? Air scrubbers are an effective means of removal and serve a similar purpose as physical removal. Do you advocate leaving some moldy drywall behind so some spores can remain? If not, why turn off the air scrubbers early to allow some spores to settle-out? If spores are present in the air above an unacceptable concentration, allow the machines to do what they are designed to do, i.e., remove the aerosolized bio-mass. You also state - “(Air scrubbers) shouldn’t be scrubbing anything out of the air stream (above background ) if remediated properly (which is my point).” Excuse Me!.....Air scrubbing is a remediation method, air scrubbing is a requirement of almost all remediation projects, and air scrubbing removes bio-mass. Are you inferring that “proper” remediation, by your definition, does not involve air scrubbing?

You also state, and Stacey is right in the same barrel with you - “Why encapsulate if the remediation is successful? If the moisture issue is resolved mold should not reoccur.” For the simple fact that you cannot, never, in a million years, nada, no way, remove ALL the bio-mass. And to do so is to also state that you have sterilized the area. Not practical! Moreover, you (and Stacey) must de-couple this arcane thinking regarding encapsulation and moisture. Encapsulants are used to seal surfaces for purposes of locking-down loose particulate matter. That’s all. It has nothing to do with water issues! True encapsulants are not designed to be a water barrier or make a surface repel water. This said, some products can do both. The moisture issue, or what ever the root cause of the moisture is/was, is irrelevant to the use of an encapsulant. Moreover, many water issues are re-occurring. These are, and need to be, un-related. To directly answer you question, i.e., why encapsulate if the remediation is successful?....It is because encapsulation has been a standard industry practice when abating solid particulate material in all sorts of remediation efforts for years, it makes remediation efforts more effective and more successful, they have proven effectiveness, AND, you can never remove ALL the bio-mass that is present in a mold event, and encapsulation can be very effective at preventing what is left behind from becoming aerosolized. Is encapsulation required to make a mold remediation project successful?...some times yes, and sometimes no. It depends. On my projects, we encapsulate.

For what it is worth.......

Great dialog folks!

,

Turbulent may be too aggressive just prior to sampling. I want some settled out, and I want some aerosolized (if its there). Turbulent may cause results to be a misrepresentation. , see below:

From: iequality [mailto:iequality ] On Behalf Of Geyer

Sent: Thursday, March 08, 2007 11:17 PM

To: iequality

Subject: Re: PRV and Sampling - With Air Scrubbers On or Off

Bob/Ma:

Good. We both agree that aggressive air movement is benefit (maybe required?) [bob/Ma.] agreed) during PRV sampling.

You mention “agitated,” however, when I go into a contained space, let’s say it is 1,500sqft, and there are three to four 2000cfm HEPA air scrubbers operating, the air inside that space is more than just agitated, its down-right turbulent! [bob/Ma.] true)

I often have the remediation contractor operate the air scrubbers a minimum of 12hrs post-remediation, preferably 24hrs, prior to me conducting the PRV inspection and sampling. [bob/Ma.] ok so you had the scrubbers potentially cleaning what may have been left behind)

Moreover, my PRV is done BEFORE any encapsulants are used - I specify the use of encapsulants after PRV inspection and sampling in most, but not all, projects[bob/Ma.] why encapsulate if the remediation is successful? If the moisture issue is resolved mold should not reoccur.).

In my view, if there are reservoirs of biologicals present, those air scrubbers are going to do a much better job of dislodging the material, entraining the material in the air, and keeping it aerosolized during my sampling effort than I could by simple agitation alone. [bob/Ma.] except that the air is being scrubbed 4-8 times per hour. What you may actually be doing is skewing your samples allowing the scrubber(s) to run. I do agree with creating turbulence (only for a short time) and pointing the air stream towards toe plates, etc. to loosen up what may be hiding under them as well. Than let rest for a while and sample thereafter. I really like the leaf blower as long as it is new. Otherwise one may say you brought it in and contaminated the project. They are not very expensive. If you don’t want to buy a new one each time, take it outside and run for a while to be sure it minimally represents the outside. Even if it has a few spores (from outside) the likely hood of it being a problem are unlikely at best. Besides, even if the inside is representative (rank and order) of the outside, you’re good to go.

Yes...they are also scrubbing the air and removing the bio-mass, but it is an iterative process that does not happen quickly[bob/Ma.] shouldn’t be scrubbing anything out of the air stream (above background ) if remediated properly (which is my point).

Also, if there are available bio-sources present (that have not been removed) that keep adding to the concentration, 24-hrs is not sufficient time to remove it if it is significant. [bob/Ma.] at 4-8 air changes per hour it surely has a great impact potentially even to the point of giving a false acceptance.

And if it is not significant, what is the point? [bob/Ma.] see above

If all tests come back favorable[bob/Ma.] most likely will when it should not

, encapsulate [bob/Ma.] what the mold and its spores? Who could possible ever fail under those conditions (unless they really didn’t clean very well). What I am also confirming is the reservoir(s) have been discovered and remediated.

the area and restore it back to a pre-loss condition.

[bob/Ma.]

,

Don’t get me wrong, I still agitate the air prior to sampling. Simply, I like to see the environment not under filtration (HEPA) prior to sampling. I totally agree with agitation just not with filtration especially hours prior to and leading up to sampling.

Bob

From: iequality [mailto:iequality ] <mailto:iequality %5d> On Behalf Of Geyer

Sent: Thursday, March 08, 2007 6:04 PM

To: iequality

Subject: PRV and Sampling - With Air Scrubbers On or Off

This is a worthwhile tread....and this group may do well to air-out the issues herein.

I, for one, routinely sample post-remediation with the air scrubbers operating and creating turbulent and aggressive air currents inside containment. I often place sample pumps near the front (but not directly in font) of the HEPA-filtered fan units whose exhaust is pointed directly at the areas where mold was removed/remediated. If a reservoir of fungi is still present, and it has not been adequately cleaned and encapsulated, then it is going to be blasted into the air and my samplers going to capture it. Bob/Ma, your suggestion of allowing a neutral environment I feel is flawed because it allows a truly passive environment to exit with no air currents, therefore, the biomass will not be entrained into the air and anything that was in the air has 24 to 48 hours to settle out. Moreover, the only time I conduct a PRV in a neutral, passive environment, is to still things up with a leaf blower.

I understand there are pros and cons with respect to this method of sampling post-remediation, i.e., fan units on or off, and look forward to the dialog of others.

Steve,

Why would one take the air samples when the air scrubbers are on? I believe the environment has the potential to be misrepresented if sampled when the scrubbers are on. If the environment is clean than having the scrubbers off would more closely represent (snap shot in time) the environments present condition (prior to removing the containment).

If one samples the contained environment with the scrubbers on, than what you are testing is the efficiency of the scrubbers and not necessarily if the reservoir(s) were discovered and removed.

Keep in mind, if the scrubber’s were set up correctly than what you should have is an AFD that should be filtering at a rate greater than the emission rate. What you have proven is the air scrubber(s) is/are affective (sufficient for the project intended).

Also, keep in mind, if the UFD is sufficient enough than (depending how many ACH you required) you should get passing results while on (if you are subscribing to the magnitude of 10 X’s greater). Consider if you sample within the cleaned/down stream (HEPA filtered) air, again you can get skewed results. At a minimum of even 4 ACH that is a lot of filtration going on. And if the unit is sized correctly you should get minimal (less than a magnitude of 10) results.

I prefer allowing the environment to rest under neutral pressure, allowing greater concentrations to seek low (nature hates an imbalance) for at least 24-48 hours (doors and windows closed) and than sample. My belief is I am (more likely than not) getting a sample that has a greater chance of discovering or confirming absents of a reservoir and/or its emissions.

Bob/Ma.

From: iequality [mailto:iequality ] <mailto:iequality %5d> <mailto:iequality %5d> On Behalf Of AirwaysEnv@...

Sent: Wednesday, March 07, 2007 1:31 PM

To: iequality

Subject: Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

[Guest guest]

:

Read my post to Bob/Ma. You and Bob need to de-couple encapsulation and moisture....they have NOTHING to do with each other and are mutually exclusive!

Moreover, no work site is “free” of dust, dirt or debris.

-

If the source of moisture has been addresssed and corrected, the

remediation conducted in a way that would ensure removal, the

project has passed a visual inspection and work site is free of

dust, dirt & debris, and the lab results come back looking

acceptable -

why would you encapsulate on nearly every project?

Just curious.

Stacey Champion

Owner/Consultant

Champion Indoor Environmental Services, LLC

> >>

> >>

> >>

> >>

> >>

> >> Steve,

> >>

> >> Why would one take the air samples when the air scrubbers are

on? I believe

> >> the environment has the potential to be misrepresented if

sampled when the

> >> scrubbers are on. If the environment is clean than having the

scrubbers off

> >> would more closely represent (snap shot in time) the

environments present

> >> condition (prior to removing the containment).

> >>

> >> If one samples the contained environment with the scrubbers on,

than what you

> >> are testing is the efficiency of the scrubbers and not

necessarily if the

> >> reservoir(s) were discovered and removed.

> >>

> >> Keep in mind, if the scrubber’s were set up correctly than what

you should

> >> have is an AFD that should be filtering at a rate greater than

the emission

> >> rate. What you have proven is the air scrubber(s) is/are

affective

> >> (sufficient for the project intended).

> >>

> >> Also, keep in mind, if the UFD is sufficient enough than

(depending how many

> >> ACH you required) you should get passing results while on (if

you are

> >> subscribing to the magnitude of 10 X’s greater). Consider if

you sample

> >> within the cleaned/down stream (HEPA filtered) air, again you

can get skewed

> >> results. At a minimum of even 4 ACH that is a lot of filtration

going on. And

> >> if the unit is sized correctly you should get minimal (less

than a magnitude

> >> of 10) results.

> >>

> >> I prefer allowing the environment to rest under neutral

pressure, allowing

> >> greater concentrations to seek low (nature hates an imbalance)

for at least

> >> 24-48 hours (doors and windows closed) and than sample. My

belief is I am

> >> (more likely than not) getting a sample that has a greater

chance of

> >> discovering or confirming absents of a reservoir and/or its

emissions.

> >>

> >> Bob/Ma.

> >>

> >>

> >>

> >> From: iequality <mailto:iequality%40yahoogroups.com>

[mailto:iequality <mailto:iequality%40yahoogroups.com> ]

> >> <mailto:iequality <mailto:iequality%40yahoogroups.com> %5d> On Behalf Of

AirwaysEnv@...

> >> Sent: Wednesday, March 07, 2007 1:31 PM

> >> To: iequality <mailto:iequality%40yahoogroups.com>

> >> Subject: Re: Mold, Moisture & Remediation Workshop

in Cincinnati

> >> November ...

> >>

> >>

> >> In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time,

> >> garyrosen72652@... writes:

> >>>

> >>>

> >>> That was the class where they taught to take post-remediation

air samples

> >>> inside the containment with the air scrubbers on.

> >>

> >> What's wrong with that?

> >>

> >> Steve Temes

> >>

> >>

> >

> >

>

[Guest guest]

:

Based on your example......If the attic space is in communication with the house via recessed ceiling light fixtures or a non-ducted air handler, then yes, the attic space will influence the air quality of the house. However, what I believe we were discussing was conducting PRV inspections and sampling of a contained space where mold remediation occurred, not an uncontained space. While not all mold remediation efforts take place under contained conditions, sampling in uncontained areas is a crap shoot.

For what it is worth...

/Bob,

Here's a common problem ...

You finish your remediation of a particular wall. This gets the spore count in the house down to a low enough level that you should now be able to see other secondary problems.

You have recessed lights that are the older type and not sealed. The afternoon sun heats up the attic and pushing mold spores from the attic into the house. Or the air handler which is non-ducted, sucks mold spores from the attic space due to a few openings around the coolant lines leading into the attic.

You would not see either of these problems if you ran the scrubbers while testing. You may not care about these additional problems as you were paid to remediate a particular wall. Or these problems will not make someone sick as they are minor unless the homeowner is sensitive (cancer, asthma, chemically sensitive etc.)

However depending on the job and the client PRV that has the scrubbers running while you are testing may not be appropriate and may be covering up problems.

On the other hand ... in any older house with carpets and old drapes the background from these components will most likely swamp any effort to try to find subtle mold growth problems in walls,attics or around air handlers. In such cases we don't take air samples at all. Our PRV is based on pictures during and after remediation that all the problem materials have been replaced with new or brought to like new condition.

Rosen,Ph.D.

Green-Buildings

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...

In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@ yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

[Guest guest]

:

Respectfully disagree. There is no extra step, although your comments regarding odor have merit.

In most instances, applying the encapsulant before, or after, the PRV inspection and sampling does not involve any additional steps. It is, more often than not, just a scheduling issue. Encapsulating after the PRV and just before teardown can be done, albeit, there may be a time delay to allow the product to dry; which does not take long if it is not over-applied. Moreover, often the building materials have had time to dry during the air scrubbing phase and the time it takes waiting for sample results; therefore, the encapsulant dries quicker and the delay is not much from my experience. Also, applying encapsulants after I conduct my PRV and collect samples, ensures to me that the job was performed and excuted well (assuming the samples results are favorable) and not covered-up with an over-application of encapsulant in an otherwise dirty environment. It also means that the air scrubbers have been effective at removing aerosolized bio-mass without have a bunch of encapsulant sucked into their filters thereby reducing their air flow, and I avoid getting any encapsulant in my sampling apparatus or sample media; which make both me and the lab happy.

,

Why wait to encapsulate until after you test? I always encapsulate after cleaning and before final testing. I challenge the cost/value benefit of waiting as it adds an extra step.

Additionally, sooner rather than later is better when painting. Even if you use DP (low odor) encapsulant and not s which is high odor ... you want the stuff sprayed and dried sooner rather than later to avoid the smell which may be a problem for some sensitive occupants.

Rosen

www.Mold-Books.com <http://www.Mold-Books.com>

Re: PRV and Sampling - With Air Scrubbers On or Off

Bob/Ma:

Good. We both agree that aggressive air movement is benefit (maybe required?) during PRV sampling. You mention “agitated,” however, when I go into a contained space, let’s say it is 1,500sqft, and there are three to four 2000cfm HEPA air scrubbers operating, the air inside that space is more than just agitated, its down-right turbulent! I often have the remediation contractor operate the air scrubbers a minimum of 12hrs post-remediation, preferably 24hrs, prior to me conducting the PRV inspection and sampling. Moreover, my PRV is done BEFORE any encapsulants are used - I specify the use of encapsulants after PRV inspection and sampling in most, but not all, projects. In my view, if there are reservoirs of biologicals present, those air scrubbers are going to do a much better job of dislodging the material, entraining the material in the air, and keeping it aerosolized during my sampling effort than I could by simple agitation alone. Yes...they are also scrubbing the air and removing the bio-mass, but it is an iterative process that does not happen quickly. Also, if there are available bio-sources present (that have not been removed) that keep adding to the concentration, 24-hrs is not sufficient time to remove it if it is significant. And if it is not significant, what is the point? If all tests come back favorable, encapsulate the area and restore it back to a pre-loss condition.

On 3/8/07 5:27 PM, " Bob/Ma. " <Bob@EnvironmentalAi rTechs.com> wrote:

,

Don’t get me wrong, I still agitate the air prior to sampling. Simply, I like to see the environment not under filtration (HEPA) prior to sampling. I totally agree with agitation just not with filtration especially hours prior to and leading up to sampling.

Bob

[Guest guest]

EnviroBob:

You are another one of those folks that couple encapsulation with the moisture issues. Don’t! They are unrelated.

,

I would fail your project. Like another consultant said to me I would hand them a sanding and tell them to call me when you’re done.

What is the purpose of encapsulation if the moisture problem is eliminated and the clean-up is complete (otherwise than to hide what you feel you did or may have missed)? I do have to admit, you sure can do the job quick and cheap that way.

I ask you, what is the purpose of sampling if you encapsulated first? Why don’t you just fog the place before testing? You’ll knock out any spores that way. IMHO I believe you are utilizing old practices.

EnviroBob

From: iequality [mailto:iequality ] On Behalf Of gary rosen

Sent: Friday, March 09, 2007 4:44 PM

To: iequality

Subject: Re: PRV and Sampling - With Air Scrubbers On or Off

,

Why wait to encapsulate until after you test? I always encapsulate after cleaning and before final testing. I challenge the cost/value benefit of waiting as it adds an extra step.

Additionally, sooner rather than later is better when painting. Even if you use DP (low odor) encapsulant and not s which is high odor ... you want the stuff sprayed and dried sooner rather than later to avoid the smell which may be a problem for some sensitive occupants.

Rosen

www.Mold-Books.com <http://www.Mold-Books.com>

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...

In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@ yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?

Steve Temes

[Guest guest]

Good points, Dan. That would be the perception or REAL POSSIBILITY of cross-contamination in the case of shutting your negative air before you know if the containment is clean.

There are also issues with shutting off the negative air. Once the fan is off, air can be sucked or blown OUT of the machine, carrying contaminants off of the filter and back into the room and out of the containment if the filter isn't appropriately sealed and communication with the outdoors eliminated.

I also like that you distinguish between sampling for PRV purposes and sampling under normal conditions. The results should be interpreted differently as they are much different hypotheses being tested in each.

Steve Temes

I see pros and cons to each way: sampling with the scrubbers/negative

air on and off. The best thing to do is sample with them on (to

prevent the perception of cross-contamination in case there is still

contamination) then perform a second test after the first test results

are back from the lab and indicate a clean environment AND at that

time the srubber (neg-air) is shut off for 24 hours prior to re-

sampleing. Most clients don't want the time and expense of both. But

that's ultimately the only senrario that allows for preventing cross-

contaminatjon and testing under normal conditions.

[Guest guest]

Bob,

Most likely no consultant would be called in since when the client sees that the problem dyrwall is now replaced with new ...and all the structural wood encapsulated with white paint they will save their money and not do PRV sampling. Seeing is believing.

You should read the article on encapsulation in the latest IE Connections.

Rosen, Ph.D.

www.Green-Buildings.org

Re: Mold, Moisture & Remediation Workshop in Cincinnati November ...In a message dated 3/7/2007 12:39:12 PM Eastern Standard Time, garyrosen72652@ yahoo.com writes:

That was the class where they taught to take post-remediation air samples inside the containment with the air scrubbers on.

What's wrong with that?Steve Temes

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