Ashrae Journal - October 2008 - 82

Blame It on Star Trek: Solving IAQ Problems Saying you should never start with air testing gets you nowhere with civilians. I never win this argument. There is always henever there is a complaint about air quality in a some “expert” that comes in and does a bunch of air tests. I am building, what folks want to do first is test the air. the one usually stuck with having to explain what they mean. That is absolutely the worst thing to do. You do not More precisely, I have to explain what they don’t mean. start with air testing. Let’s start with some of the tests that are run and what they mean. I blame “Star Trek.” We grew up watching Spock go into a shuttle Then, we will get into other tests and what they don’t mean. bay, do a tricorder scan and figure out that a tachyon field was I don’t have a problem with measuring CO2. It is sometimes, causing the dilithium crystals to break down and that’s the reason but not always, a pretty good surrogate for ventilation rates. I prewhy Uhura had a headache. In “Star Trek” you could measure fer to determine ventilation rates more directly, but I am a geek. everything and anything. That’s not What hypothesis are you testing the way the real world works. with a CO2 test? Is the ventilation Civilians seem to think we have rate too low or too high according the technology to go into a space, to Standard 62.1? do a test, and determine what is in I also don’t have a problem the air. As simple as that sounds, with measuring temperature and we can’t do it. We don’t have the relative humidity. I can tell a lot technology.* You cannot go into from measuring temperature and a space and ask a simple quesrelative humidity. Again, what is tion such as “What is in the air?” the hypothesis? Do I have a partThere could be a million things in load humidity control problem the air—literally. You have to ask that could lead to mold? a narrow question such as “Is this At this point, I typically stop the Photo 1: Jewelry store on Newbury Street. No odor problems in the air?” or “Is that in the air?” testing. Why? Almost everything in neighboring retail spaces above, below or on either side. The trick is to know what to ask. else is pretty much a waste of time. † For that you need a hypothesis. The most popular waste of time is tests for volatile organic To be certain about what is in the air, you have to ask about compounds (VOCs). everything. That, of course, is impractical, because of the gazilVOC testing. I love the name. It sounds so technical, so “Star lion things that you could test for. When someone says “We Trek”-ish. How does it work? You suck on air for about a minute tested the air, and there was nothing in the air,” they are being and draw the air through “magic powder” (the sorbent) and send less than forthcoming. What they are really saying is “We didn’t it off to a lab. The idea is that the powder absorbs “stuff ” in find what we tested for within the limits of accuracy of the test the air. You then desorb the “stuff ” and run it through a mass procedure we used.” That is much different than saying there spectrometer/gas chromatograph to get a spectral “fingerprint.”‡ is nothing in the air. The only people who like air testing are You then compare the spectra of the “stuff ” to a library of people who make money doing air testing. available spectra. By Joseph W. Lstiburek, Ph.D., P.Eng., Fellow ASHRAE W *This is not “The Six Million Dollar Man.” Where is Lee Majors when you need him? †Hypothesis is engineering code language for “guess.” ‡The fingerprint analogy attracts the “CSI” junkies. “CSI” is the current societal source of science information since “Star Trek” went off the air. It’s certainly not the educational system. We no longer teach anything useful in school like science or basic physics. But we do teach the kids how to feel good about themselves, while they are unable to function in the modern world. §According to whom? It’s usually whatever 40 spectra the lab has handy, or 30 or 20. That really annoys me—the list is usually completely arbitrary and capricious. Now, some folks are a little bit more logical and look at the 40 VOCs that were sampled by the EPA in their BASE study a decade ago to at least look at some kind of a benchmark. That sounds fairly reasonable, except for the next part. Who decided on the stuff the EPA tested for? Well, the best I can figure is that the EPA tested for stuff you would expect to find. So, they looked for stuff that they expected to find and, yes, you guessed it, they found it. What about stuff that you wouldn’t expect to find? Nobody looked. With respect to air testing you have to already know what you are looking for before you find it. If you don’t already know, the odds of finding something useful are against you. 82 ASHRAE Journal ashrae.org October 2008

Ashrae Journal - October 2008

Table of Contents for the Digital Edition of Ashrae Journal - October 2008

Ashrae Journal - October 2008

Contents

Commentary
Industry News
Letters
ASHRAE HQ Dedication Booklet
ASHRAE Rebuilds HQ to Reflect Mission
Feature Articles
ASHRAE's Living Lab
Meetings and Shows
Sizing Pipe Using Life-Cycle Costs
Feature Articles
Energy-Efficient Data Centers: A Close-Coupled Row Solution
The Future of 90.1
Ventilation Standard for Health Care Facilities
Grosvenor Humidity Chart
ASHRAE Research Report
ASHRAE Honor Roll
Building Sciences
Special Products
Emerging Technologies
Product Showplace
Classified Advertisting
Advertising Index
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Contents