Outside Control Sample

I was wondering what the proper location was for taking an outside control sample when inspecting say a hi or low rise apartment building. Where is the control sample taken? Is it taken at the outside of the main entry door to the building (outside air), outside the apartment’s entry door (common hall inside the building), or outside air from the balcony or window? Thanks.

37 Views and No Replies? Wow.:mad:

Outside air. Far from the building. Other things to avoid, high wind, recent rain, etc. You may need to take the NACHI course.

Apartment buildings can be fun, I just did one. You not only have to worry about the individual dwelling but all the others that surround it as well.

I would also recommend you take 2 outside samples on opposite sides of the building since it is a commercial job. Some can run over 5000 per side wich could make or break an indoor test.

Joe, I have always understood that OUTSIDE/OUTDOOR samples needed to be taken and I completely understand the reasoning for it. The reason for my original question was because I was told by an “expert” that protocol was to take the “outside” sample at the “nearest entry point to the home” and as this expert explained to me that would mean the apartment entry door - even if it was located in an interior common hallway. I questioned him on this statement several times to be clear I understood him correctly. I’m not mentioning where I received this direction but it has certainly made me question this particular organization’s credibility.

PS: I’m working through the NACHI course now.:slight_smile:

Agreed. I think two outdoor samples are called for on this job.

John I take my samples on the ground level about 20-25 feet away from the building and not near any doors, not under any trees and in an open area as I can find where free flow of air can be obtained.

What standard are you using? that should tell you

If this “expert” is referring to IAC2 standard than he is right but you need to take two samples outside.

As far as I know, the rest of the mold industry requires only one outside sample at least 20 feet away from any buildings. If you do like Russ says you will be okay.

Just make sure you use some kind of standard when testing.

5,000 what? If it is total or Asp/Pen?

Clad had been that way on a couple. I will send you one if you want…:smiley:

Apartments are different and you must consider the stack effect. Some mold problems with IAQ come from the hallway. That being said you would need Five samples to get it right. Two Outside as close to the apartment level as possible. This requires coordination with the Owner. Two inside samples in bedroom and living room along with a sample at the entrainment area of the door. The reason is that most apartments are designed with negative pressure not positive. If mold exists in the hallway it will affect the apartment and sensitive occupant. I always recommend an air exchange system installed in the closet with Hepa filtration set at a positive pressure as a more cost effective remedy than spending x amount of dollars on testing.
Carpets removed and no voc laminate flooring can be added with minimal cost along with a no smoke policy on balconies.:smiley:
You will not find a owner care very often but sometimes they do not want the problem to elevate and scare people from the property.:frowning:

Yes go ahead. I seldom see Clad at 5,000 let alone 5,000 higher.

The standard I follow requires only one outside sample.

When you say two outside samples, do you mean one at the apartment entry door and one outside at ground level. Or both samples in the same location, at the entry door or at ground level?

just take 2 samples. One on each side of the building. Its an apartment so it should have plenty of parking space and open areas. If nothing else it will give you some good learning info.

Even if they are fairly close they will always be different. One sample works just fine but if you want to learn then eat one and take 2

You need to take it at least 20 feet away from the building at ground level, preferably up wind from the building. If you are down wind or too close you can catch mold that is growing on the building. The reason I believe IAC2 requires two because they are testing too close and are allowing testing downwind from the building. If you do that you better take two samples because they will most likely read different.](*,)

Keep in mind you are trying to take as clean of a sample as possible under the most normal conditions that can be achieved as possible (inside or out). If you do mess up and your particulate level (junk in the air) is moderate to high or high then you may consider on retaking the sample (it all depends on what you are wanting to know) because that much particulate will cause the lab not to see all of the area on the slide. If the lab technician can not see everything, he could easily miss something.

If you every need some guidance on reading a lab report, you can email it to me at jbraun@mo.nachi.org .
That includes you too, Sean. :mrgreen: