What kinds of testing are available to check for mold?
can use a swab or tape lift to gather a visible sample from a surface to find out if indeed it is mold and to identify the
genus. Air samples can also be taken to check for mold.
How reliable are the "do it yourself" mold test kits?
If you want to take a swab of what is growing on your wall to make sure that it is mold, go
right ahead. But avoid buying test kits that claim they can test your air for mold. Most likely these kits have a Petri
Dish that you place in a suspect area for a period of time and then send it off to the lab. You will get a report back
saying you have mold. Save your money, no matter how clean you are every single house has mold spores in it. The
problem isn't if you have mold spores in your house, the real issue is how much do you have in relation to your outdoor environment.
The test kit cannot tell you how many mold spores you have in the air of your house. If it could then mold inspectors
wouldn't go to the expense of buying professional testing equipment.
What do viable and non-viable testing mean?
A viable sample uses cultures to grow the mold spores to see if it is alive (Active). It will also give you
the genus of each mold found. A non-viable sample will only give you the
genus and spore count of each mold that was found. It may collect viable spores but it is not meant to make that determination.
Which is better, viable or non-viable?
Procedures that use cultures to identify "viable" spores may omit high levels of non-viable spores which
nonetheless remain highly toxic. Methods that rely on culturing have a high risk of identifying a mold which is present but
is not the dominant or even the most problematic mold in the building, while completely failing to disclose a problem mold
which is present but which simply does not grow in the culture media used, or is overgrown by another species in that media.
Viable sampling takes up to 10 days to get results and is more expensive than non-viable sampling.
Some labs are able to process non-viable samples within 24 hours. This is very helpful when trying to plan a remediation
project, because the longer you wait the worse the project can get.
if mold is viable or non-viable you should still have it removed.
non-viable sampling makes the most sense.
What does LOD mean?It stands for limit
of detection. The limit of detection is the lowest spore count detectable with reasonable
certainty, and it is calculated this way using a raw count of one. Keep in mind there are 1,000 liters in a cubic meter.
- 1 x (1,000 / Total Volume in Liters)
This equation converts the total volume of air pulled through the
cassette from liters into one cubic meter.
The limit of detection for some common total volume amounts:
liters is 6.66 (6 is repeating)
75 liters is 13.33 (3 is repeating)
is 16.66 (6 is repeating)
25 liters is 40.00
The information above is provided to help you choose not only the
right inspector, but also the right lab. The reason this is important is because some labs don't read the whole sample. If
your inspector collected 75 liters of air and your LOD isn't 13 per each raw spore found then they are not reading the entire
sample. Some labs only read 25% of the sample then extraplate that number to 100%. (Basically multiple by 4.)
The LOD for 1 raw count would be 52 for a lab that only counted 25% of the sample. When it comes to sampling the more
information the better. It is obvious that it is better to count the entire sample than only 25%.
What are the typical procedures in conducting an in-wall cavity air test?
After an inspector locates an area in question he will need to place a thin tube through a
hole in your wall in order to extract air for his sample. The hole is either drilled by the inspector or he may elect
to go through an electric outlet. If the inspector has to drill a hole, he must wait an extended period of time before
testing the area. (Although wait times vary with each inspector, it is widely held that the wait time should be 24 hours.)
Why must he wait before he takes the sample? The drilling will have created a great amount of dust and debris in the
air so much so that it will difficult to get a readable sample. Even if you get a readable sample the results will be
flawed. The better option is to go through an electric outlet. Regardless of either option chosen by your inspector
another issue to contend with is if there is insulation behind the wall. Because you will have to poke the tube through
or past the insulation creating an air disturbance with fiberglass that can cloud the sample. Most inspectors will limit
air tests behind walls to 1 or 2 minutes because of these circumstances, which further diminishes the accuracy of the results.
(Typical duration times for air samples is 5 minutes.)
Are in-wall cavity air tests worth it? No...Why?
If you or your inspector suspects that mold maybe behind a wall then the best course of action
is the simplest. Have a professional mold inspector/remediator open this wall area to "discover" the extent
of the damage. As previously mentioned there are several factors involving in-wall cavity testing that call into question
the validity of the results. It will cost more than doing a test, but it can save you from an unfortunate surprise months
down the road.
What are biocides?
A biocide is a chemical substance capable of killing living organisms,
usually in a selective way.
What are enzymes?
Enzymes are biomolecules that catalyze (increase the rate of)
chemical reactions. Almost all enzymes are proteins.
What should I use, a biocide cleaner or enzyme cleaner?
Page 15 in the EPA's mold guideline states "The use of a chemical or biocide that
kills living organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup."
There are alternatives to these cleaners now. It is no longer necessary to use harsh chemicals when cleaning.
Be careful there are some products on the market that claim to have "enzymes", but they also have harsh chemicals
in them. Ask your remediator what he uses and request an MSDS (Material Safety Data Sheet).
What is an MSDS?
A material safety data sheet (MSDS) is a form containing data regarding
the properties of a particular substance. An important component of product stewardship and workplace safety, it is intended to provide workers and emergency personnel with procedures for handling
or working with that substance in a safe manner, and includes information such as physical data (melting point, boiling point, flash point, etc.), toxicity, health effects, first aid, reactivity, storage, disposal, protective equipment, and spill handling procedures.