Why 2 Outdoor Samples?

[Linas I. Dapkus]

Planet Mold recommends 4 exterior samples.

[Nick Gromicko]

Michael asks:

Other than wind velocity, why would two samples taken within, say 80 feet of each other produce different results.

It really doesn't matter why they produce different results, what matters is that they do enough of the time to warrant taking two.

Linas writes:

Planet Mold recommends 4 exterior samples.

[Ben J. Gromicko]

Just as in a residential home inspection, financial or time constraints may alter the mold inspection.

Alterations or adjustments to the inspection should be agreed to by the Client and Inspector prior to the inspection process.

Alterations or adjustments to the normal procedure or locations of taking air pump samples, particularly for the control sample, must be recorded in a Chain-of-Custody.

If zero, one, two or ten outdoor samples are taken, the Inspector and Client should agree to that prior to the inspection.

In general for all Standards of Practice (be it Residential, Commercial, Radon Mitigation or Mold), the scope of the inspection should be agreed to by all parties prior to the inspection. Changes, alterations, adjustments can be easily made to any Standard of Practice if understood and agreed to by all parties. Where the Standards are silent or where the Standards do not address a particular issue or concern, that also should be agreed to prior to the inspection.

For example: According to the InterNACHI Res SoP:
Electrical I. The inspector shall inspect:

K. and report on any tested receptacles ... where the receptacle is not grounded

An inspector may have their Client understand and agree prior to the inspection that the inspection will actually NOT require the Inspector to "inspect and report on any tested receptacles where the receptacle is not grounded." (which is not a defect in all instances considering 2-prong receptacles)

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In summary...
If an inspector and client agree prior to the inspection on "taking only one outdoor air sample" - I see no problem with that, as long as both parties agree and understand that the Inspector is scientifically positive that two outdoor samples will always produce similar results.

[Nick Gromicko]

Also, compliance with IAC2's Mold Inspection SOP is not an IAC2 membership requirement and is not an InterNACHI membership requirement.

[Rick Maday]

Originally Posted by gromicko

The reason 2 outdoor samples is preferred over 1 is quite simple: They will often produce very different results.

Yes, it is is true that I and others are able to make a scientific argument that most mold inspections do not require sampling at all.

However, the argument for 2 outdoor samples need not resort to a scientific one, but rather a matter of simple logic.

Follow me:

If you believe that an outdoor sample is necessary then it MUST be because you believe the results of that outdoor sample mean something. Otherwise there is no need to take it at all.

Keep following me:

And if you believe that the results of that one outdoor sample mean something and so is necessary, then you MUST also believe that a different result on the outside of the other side of the building would also mean something. Basic logic forces you to assign the two different results equal weight in terms of meaning. They either both mean nothing or they both mean something.

The ONLY counter to this logic is if you believe that the two results will always be similar and so only 1 outdoor sample need ever be taken.

Simple logic has brought us to the key question. And the key question isn't "Do I take one outdoor sample or two?" The key question is "Am I scientifically positive outdoor samples will always produce similar results?"

If your answer to the key question is "yes", feel free to always take 1 outdoor sample only.

So if the reason for taking two is that they will produce different results, and you must give them equal weight - how do you compare two different, but equally weighted, control samples to the samples taken indoors?

Also why is 2 the magic number? Why not 4 (a house has 4 sides)? Why not 5, 8 or 10?

This is an interesting thread - thanks for the education.

[Larry F. Rollins]

Originally Posted by gromicko

The reason 2 outdoor samples is preferred over 1 is quite simple: They will often produce very different results.

Yes, it is is true that I and others are able to make a scientific argument that most mold inspections do not require sampling at all.

However, the argument for 2 outdoor samples need not resort to a scientific one, but rather a matter of simple logic.

Please pardon the comment Nick but I have never found "logic" to be simple. The truth to writing logic is to write a scenario that has no logic "breaks" in it. Not simple!

Follow me:

If you believe that an outdoor sample is necessary then it MUST be because you believe the results of that outdoor sample mean something. Otherwise there is no need to take it at all.

Keep following me:

And if you believe that the results of that one outdoor sample mean something and so is necessary, then you MUST also believe that a different result on the outside of the other side of the building would also mean something. Basic logic forces you to assign the two different results equal weight in terms of meaning. They either both mean nothing or they both mean something.

There is a break in the logic here Nick. You are assuming a static enviroment here. An inspection takes place in a dynamic environment. Most all parameters (air currents, amounts of spore per liter, pretty much everything) is in a constant state of change at any particular moment in time.
If you believe that a different result outside is important you will also have to believe that a different result inside is at least as important. Therefore, if your logic is valid for the outside sample(s) then it is also just as valid for the inside sample(s). Should we also be taking two of every indoor sample?

The ONLY counter to this logic is if you believe that the two results will always be similar and so only 1 outdoor sample need ever be taken.

There is, in fact, a reasonable counter to the above logic. It is... that one sample is more (or less) important than the other. If the outside weather has an effect on the inside mold spore level and the conditions of the weather are different on different sides of the home, it is a break in logic to assume that the effect on one side is equivelant to the effect on all sides. I believe that further scientific study is needed to find which side of the home "most" effects the inside mold spore level so that we can sample that side to get a reasonable baseline level.


Simple logic has brought us to the key question. And the key question isn't "Do I take one outdoor sample or two?" The key question is "Am I scientifically positive outdoor samples will always produce similar results?"

If your answer to the key question is "yes", feel free to always take 1 outdoor sample only.

As I said previously, logic is seldom "simple" and I believe your above question is a long jump from the logic you laid out. As you already know, there is only one way to be scientifically positive that two outdoor samples will give the same result, and that is to take the two samples. So it seems that you are saying to us... "If you want to take one outdoor sample then you must first take two outdoor samples in order to be positive that it is ok to take only one sample." This type of circular logic sometimes sounds good at first perusal as it does above, yet falls flat upon second read.
This is a confusing and convaluted subject and I for one am no closer to a definitive answer than I was when I started the thread. I am sure however, that I am closer to the answer now than I was before.
I believe that the answer lies not in "simple logic" as Nick suggests, but in further scientific study and understanding of the effects of outside levels on inside levels. It is very possible that as long as we have no definitive scientific answers to these questions then the solution lies in setting a maximum indoor spore level similar to the EPA indoor radon gas levels.
Food for thought... setting a max level would make only one sample necessary. This would drop the cost to the homeowner so that we could be sampling more and arguing less. How many more homes would get tested if the cost of a complete inspection was a few hundred dollars instead of a thousand dollars or more?

[Ben J. Gromicko]

The easy solution is:
Simply agree with your client prior to the inspection that only one outdoor sample will be taken - done.

Financial and time constraints influence every inspection (mold, residential, commercial, radon, water, septic, roof, energy, etc). And there are no reasons to consider an SOP as a restriction to providing a service.

The inspector should abide by the standard unless otherwise agreed to in writing by the inspector and client.

A standard is typically designed as a baseline from which the inspector and client can develop and agree to a scope of work that may deviate from this standard depending on budget, time constraints, purpose of the inspection, condition of the subject property, and risk tolerance of the client. The level of due diligence should be set where the cost, in time and money, of acquiring information about the subject property will not likely exceed the value of that information.

In short, you wanna do just one outdoor sample - go ahead - just have you and your client agree to it.

The IAC2 SoP requires the inspector to inspect the roof covering - You don't want to do that? Fine - just have you and your client agree to it.

The IAC2 SoP requires an inspection of the exterior cladding, flashing, trim, decks, eaves, gutters, grading, and much more. You don't want to do all that either? Fine - just have you and your client agree to it.

The IAC2 SoP requires an inspection of the condensate pump, humidifier, air handler, water lines, sewer lines, hot water source, toilets and showers, framing and sheathing in the attic, moisture, humidity and temperature in rooms and even more. You don't want to do all that either? Fine - just have you and your client agree to it.

The actual "sampling" is just a small part of an IAC2 Mold Inspection. I wouldn't get so hung up on it. The inspection is mostly directed by the client's needs anyways.

[Larry F. Rollins]

Originally Posted by bgromicko

The easy solution is:
Simply agree with your client prior to the inspection that only one outdoor sample will be taken - done.

Financial and time constraints influence every inspection (mold, residential, commercial, radon, water, septic, roof, energy, etc). And there are no reasons to consider an SOP as a restriction to providing a service.

The inspector should abide by the standard unless otherwise agreed to in writing by the inspector and client.

A standard is typically designed as a baseline from which the inspector and client can develop and agree to a scope of work that may deviate from this standard depending on budget, time constraints, purpose of the inspection, condition of the subject property, and risk tolerance of the client. The level of due diligence should be set where the cost, in time and money, of acquiring information about the subject property will not likely exceed the value of that information.

In short, you wanna do just one outdoor sample - go ahead - just have you and your client agree to it.

The IAC2 SoP requires the inspector to inspect the roof covering - You don't want to do that? Fine - just have you and your client agree to it.

The IAC2 SoP requires an inspection of the exterior cladding, flashing, trim, decks, eaves, gutters, grading, and much more. You don't want to do all that either? Fine - just have you and your client agree to it.

The IAC2 SoP requires an inspection of the condensate pump, humidifier, air handler, water lines, sewer lines, hot water source, toilets and showers, framing and sheathing in the attic, moisture, humidity and temperature in rooms and even more. You don't want to do all that either? Fine - just have you and your client agree to it.

The actual "sampling" is just a small part of an IAC2 Mold Inspection. I wouldn't get so hung up on it. The inspection is mostly directed by the client's needs anyways.

This may be the answer that I can work with. It seemingly will work in a theoretical sense, but will it work in the real world. One question, are you saying that I should print out the SOP's and go through them one line at a time with my client and get his/her "yea or nea" on every line... in writing? How do you handle this?

[William J. Decker]

Originally Posted by sgilligan1

There is nothing in there about diagraming a room and visible mold growth.

EPA states that if there is visable mold growth, sampling is not required or justified.

I, regularly, tell clients that they do not not need a mold test if there is visable mold growth. And, I lose about 35 mold sampling inspections a month.

But, I am being honest with the client and following the EPA standards.

Just my opinion.

[James E. Braun, CMI]

The EPA is wrong, just my opinion.

[William J. Decker]

Originally Posted by jbraun

The EPA is wrong, just my opinion.

Even if the EPA is wrong, it is still the EPA and the only AHJ with a protocol.

In my opinion, if you see visable mold, there is no reason to sample it. Testing it will only tell you what type of mold it is, which is irrelevant to the need for remediation. If there is mold, stop the cause (water intrusion) and remediate the mold, then clearance test. Knowing the type of mold does not change this.

Hope this helps;

[James E. Braun, CMI]

Then why according to the most recognized guide in the remediation of mold, ANSI/IICRC S520 (Second Edition), an Indoor Environmental Professional is required to assess the conditions if it is a Condition 2 or 3. Why not just remove the mold without testing, as the EPA states it is just mold? There are several answers to that question. You can find the answers in posts from previous threads.
Why then when the EPA building flooded back in 2006 at Washington D.C. did the EPA have a private indoor environmental professional pull air tests? Hypocrisy at its best.
Why is the EPA requesting bids from mold organizations on writing guidelines for mold?
If they know all about mold why do they need outside help? Mold is beyond narrow minds.

[James E. Braun, CMI]

If it is not a considered toxic mold than the mold can be removed at less cost. Testing also determines: How much area needs to be cleaned? Does the furnace and duct work need cleaning? Does just the horizontal surfaces or everything inside boxes, cabinets, drawers and closets need to be cleaned? Does cloth items such as carpeting, drapes, and furniture need to be replaced or can they be cleaned?
If a remediator removes mold without any testing, it just proves the remediator does not have the slightest idea what he is doing.

[Douglas Wall]

In my opinion, if you see visable mold, there is no reason to sample it. Testing it will only tell you what type of mold it is, which is irrelevant to the need for remediation. If there is mold, stop the cause (water intrusion) and remediate the mold, then clearance test. Knowing the type of mold does not change this.

Let’s say you have a visible mold problem in a back bedroom. Do you contain that area and clean up the mold problem or do you clean the whole house? Did the HVAC pickup airborne spores and spread them through out the home? You are concerned about mold “growth” in a home but many people react to “dead” mold spores just like live ones. Mold air sampling is not an inspection, only a part of an inspection. Every situation is different, sample or not sample, how many samples and where. Type of sampling, where to sample and how many samples is the “mold professionals” job. Everyone wants simple, easy answers which is just not right.

If it where easy, Arkansas would not require CIEC certification to get a mold inspectors license(Jan. 2010); this requires proof of 8 years experience, and we are not talking about just collecting air samples.
Florida will not allow remediation companies to do assessment on same job within 12 months beginning next year (July 2010). Inspections should be done by mold inspector not cleanup company.
Identifying the problem, extent of problem and what should be done about it is an inspector’s job.

PS
Clearance is more than just collecting air samples.
Mold sampling is not an inspection ( just part of inspection)
How many samples and where is the inspectors job to decide.

tides coming in time to go fishin, have a good week ya'll

[Ben J. Gromicko]

According to the Environmental Protection Agency (EPA), “in most cases, if visible mold is present, sampling is unnecessary.” An inspector may object to that statement, because of the assumption that what is present is actually mold. There may be many inspectors who are comfortable in making that assumption.

“That which is visible is mold” is a statement based upon assumption. Apparent mold growth cannot be confirmed as actual mold growth by visual examination only.

The only way to actually know that what is visible is actually mold is through sampling. If neither you nor your client need to confirm that what you see is actually mold, you need not sample. However, there may be others (affected by the findings of the inspector’s report) who will request proof or validation of the visual findings.

The term “visible mold” applies to what appears only on the surface, not to what is borne out by professional examination, scientific sampling, and confirmation by laboratory analysis.

The use of the term “visible mold” should not be used in reference to actual mold growth. The term “visible apparent mold” is accurate.

Don’t guess for your client. It is an inspector’s due diligence to act or perform with care and accuracy. Reporting “the presence of visible mold” for a professional inspector should be based upon fact or evidence rather than possibly inaccurate assumptions about surface appearances.

Not everything that looks like mold is mold. Paint on the backside of drywall or wood may look like mold growth. Alkaline crystals on soil or concrete walls may look like mold, but, unlike mold, they are usually water-soluble. Carpet stains also may look like mold. Spider webs, fine dust, paint spray, dried mud, and water stains may all give the appearance of mold growth. The inspector whom reports the existence of mold growth based upon the discovery of something that appears to look moldy may be in error. It may be mold; it may not. Error comes with guessing.

Most microbiology laboratories need only a little of the suspected mold on a clear strip of sticky tape to determine, using a microscope, whether it is actually mold or something that looks like mold. Sampling may help locate the source of the mold contamination, identify some of the mold species present, and differentiate between mold and soot or dirt.

What's involved in an IAC2 Limited Mold Inspection? Find out. http://iac2.org/sop.php
IAC2 Membership is free.