Our team decided to perform air quality testing before occupancy on a recently completed building. We have had some question over which method is required for tVOC testing and for what compounds. The manual states that the testing protocols should follow the guidelines in the EPA Compendium of Methods for the Determination of Indoor Air Pollutants. This guide references methods IP-1A and IP-1B for tVOCs, however when we got the results back from the lab, they referenced method TO-15 and included a separate list of compounds called Tentatively Identified Compounds (TICs). The TO-15 method comes from a much later EPA publication, the Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air. So now we have two VOC totals - one tVOC without TICs and another tVOC with TICs included. The list of VOC compounds in the TO-15 method contain the same compounds as listed in the IP-1A and IP-1B methods. None of the three methods talk about or list the TIC compounds. Are TICs required to be included in tVOC?
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Dale Walsh
30 thumbs up
November 15, 2013 - 8:23 pm
This is an unfortunate consequence of the USGBC's IEQ TAG not consulting with those professionals who have been doing this air testing in the field for decades (e.g., industrial hygienists) though help has been offered for more than a decade. The main problem is that there is no consensus definition for TVOCs or a consensus method for determining TVOCs. Each lab does it differently.
The IP methods that have been specified by LEED for years are not the methods IHs and IAQ Professionals use. Industrial Hygienists use the EPA TO methods, NIOSH methods, OSHA methods, and direct reading instruments (based on my 27+ years of IAQ consulting experience). The USGBC finally realized this and started referencing methods other than the IP methods in LEED v.4 though many of those newly referenced methods are also not used by the field practitioners.
None of the methods identified previously are for identifying TVOCs. They are for identifying the presence and quantity of specific compounds on a limited list of common airborne VOCs. The Tentatively Identified Compounds (TICs) are an added analysis for which many labs charge extra. Most labs do not just add up the listed compound amounts and the TIC amounts and call that number TVOCs. They take the total area of a gas chromatograph of the air sample and normalize it to toluene, hexane, or another internal standard depending on the lab. The added list/TIC total and normalized chromatograph total are often very different. Also, whether toluene or hexane or some other standard is used can make the difference between LEED pass and fail for TVOCs. I did a mini-study of this about five years ago comparing different methods and collection media and found data to be all over the place (presented at the American Industrial Hygiene Association [AIHA] conference in Denver 2010 – PO128).
Now that I have thoroughly confused you with gobbledygook (you must be because I am confused) I’ll try to answer your question. The answer is “adult diapers” (e.g., Depends). It depends on whoever reviews you submittal for the credit and whether they have an opinion on TICs or not or simply want a TVOC number without the listed compounds plus TICs or the listed compounds without TICs. If you ask your lab strictly for a TVOC result and nothing else you will likely get a number that exceeds both the listed/TIC total. If you just ask the lab for the analytical report for the listed compounds only and then add them up yourself you would likely get a lower number. Since there is no standardized method for identifying TVOCs and the USGBC or GBCI has not clarified what it is looking for (as far as I know) presenting the total of just the listed VOCs and ignoring the TICs would be just as valid as any other method. However, in my opinion, the chromatograph area total normalized to toluene will eventually become the norm. That is what I use for my LEED air testing projects.
The main point of my whole discussion is that TVOCs are not a good parameter to be using to determine whether the indoor air quality is good or will be good in a newly built LEED building. I know many of my fellow Certified Industrial Hygienist colleagues agree with this statement. Also, in my opinion, the addition of the “target chemicals listed in CDPH Standard Method v1.1, Table 4-1” found in LEED v.4 will not improve the current air testing requirements but will make them even more onerous and difficult to achieve with the same lack of value. Besides, the CDPH target chemicals are for chamber testing of building materials regarding their off-gassing of VOCs. They have little to do with the potential health impacts of VOCs in the occupied environment. Members, including myself, of the AIHA (www.aiha.org) have just begun writing a White Paper on VOCs in Construction that will address the issues brought up here and offer reasonable alternatives for evaluating a building to help assure good indoor air quality for the occupants both in the short and long terms.