Overview: This CIR applies to Option 2- Air Quality Testing. With regards to the process to demonstrate that the maximum TVOC concentrations are below 500 micrograms/cubic meter, this CIR is requesting the acceptance of an alternate unit of measure based on a volumetric reading from an instantaneous, direct reading photoionization detector instrument (PID) using a 10.6 eVolt lamp. This reading would be recorded in a ppb (parts per billion) measurement and then converted to the designated unit of measure called out in the requirements (micrograms/cubic meter) using a conversion factor. This direct reading approach for TVOC will offer a more economical solution for IAQ testing by a factor of approximately two for our ~480,000 SF project. Methodology A conversion factor has been developed (by EH&E in Newton, MA) and is based on a TVOC "fingerprint" of 33 individual volatile organic compounds grouped by chemical category, resulting from a technical evaluation of the Building Assessment Survey Evaluation (BASE) data, the EPA TO-15 list of VOC\'s, and other relevant technical data. The EH&E team examined three lists of indoor VOC\'s to develop the TVOC "fingerprint." These lists originated the following sources: BASE dataset for commercial buildings, PID-readable chemical compounds, and an EPA approved list of indoor VOC\'s. Seven individual VOC\'s from the BASE data the had the highest reported concentrations and could be measured by a PID formed an initial, preliminary fingerprint. These individual VOC\'s were chemically regrouped (i.e. alcohols, halogenated hydrocarbon, aliphatics, etc.) and the relative group proportions in the fingerprint were compared with the BASE dataset. Based on the EPA guidance and a review of indoor VOC literature, additional VOC\'s not measured in the BASE dataset were considered for inclusion. By mapping additional pollutants from the EPA TO-15 list of VOC\'s, EH&E modified the fingerprint to represent new or existing buildings. The expanded list of compounds included all BASE compounds that were both on the EPA TO-15 list and measurable by the PID. This "fingerprint" is based on the following list of chemicals, sorted by their group, their average group molecular weight (AGMV), the % in BASE data, and specific compounds in fingerprint: Format given in following order: Group/AGMW/% in BASE/Compounds in Fingerprint Aldehydes/44.06/12%/Acetaldehyde Alkanes & alkenes/113.6/8%/n-undecane; n-decane; Nonane; Octane; n-hexane; 1,3 butadiene Aromatics/110.5/14%/d-limonene; a-pinene; Naphthalene; o-xylene; m- & p-xylenes; Ethylbenzene; Styrene; Toluene; Benzene Halogenated Hydrocarbons/130/15%/1,2 -dbromoethane; 1,2, 4-trichlorobenzene; 1, 2, -dichlorobenzene; Trichlorobenzene; 1,3,5 -trimethylbenzene; Chlorobenzene; 1,1 -dichloroethene; Vinyl chloride Alcohols/78.5/31%/2 -butoxyethanol; Phenol; 1 -butanol Ketones/58.1/15%/Acetone Other(e.g. acetates,sulfides, ethers, etc.)/92.55/5%/Butyl acetate; Dimethyl disulfide; Ethyl acetate; Carbon disulfide; t-butyl methyl ether Conversion Factor In order to convert a PID reading from part per billion (ppb) to a mass-based equivalent in micrograms/cubic meter, the PID value is multiplied by a derived conversion factor, MCF, defined below as the product of two correction factors, CF-1 and CF-2. For the TVOC fingerprint listed above, the formula is MCF = CF1 * CF2, where MCF = 2.70 Mass Conversion Factor CF1 = 0.88 Correction for predicted ppb PID reading to "actual" ppb reading, based on isobutylene equivalents, and CF2 = 3.07 Correction for "actual" ppb to micrograms/cubic meter equivalent, based on the chemical distribution of the mixture and the average molecular weight. Summary The acceptance of this CIR would provide a lower cost test for TVOCs, including the use of both hand held PID-TVOC direct read instruments and permanently installed PID-TVOC direct read instruments.
The applicant is requesting approval for use of a photoionization detector instrument (PID) to measure TVOC concentrations during air quality testing. The proposed alternative for testing of TVOC using a PID is not an approved method in the United States Environmental Protection Agency Compendium of Methods for the Determination of Air Pollutants in Indoor Air which are the methods required for this credit. The IAQ testing must be conducted according to the test procedure outlined in the referenced standard using an approved indoor TVOC measurement device, which is either Method IP-1A, Stainless Steel Canister, or IP-1B, Solid Adsorbent Tubes. Both of these methods utilize GC/MS analyses to determine the concentrations of the collected VOC\'s. Most laboratories will calculate the total concentration of VOC\'s (TVOC) according to a toluene equivalent mass from the Total Ion Chromatogram (not just the peaks of EPA TO-15 compounds, but the integrated area of the peaks from all compounds). This method is discussed in the California Department of Health Services (CDHS) Standard Practice. http://www.ciwmb.ca.gov/greenbuilding/Specs/Section01350 First of all PID analyses miss many of the common indoor VOC\'s such as aldehydes and aliphatics and has a poor response factor (i.e. and thus large uncertainty) for common indoor VOC\'s such as alcohols. The "fingerprint" method proposed for calibration of the PID is fundamentally flawed in that it uses a calibration based upon an assumed fixed percentage of mass of VOC\'s from seven different groups of VOC\'s while the actual mass percentage of VOC\'s can vary widely from building to building. The errors associated with the "fingerprint" method could be easily demonstrated by simultaneously measuring the TVOC concentration with a PID and either method IP-1A or IP-1B in a number of buildings. Such a comparison was conspicuously missing from the EH&E report "Development of a Method to Convert Total Volatile Organic Compound Measurements in Buildings to Equivalent Mass Based Units", although the report did contain numerous caveats regarding the accuracy of the "fingerprint method" including limitations related to the "Representativeness of TVOC List" and the "Variability by Building Type". Additionally, the LEED-NC v2.2 Reference Guide states that samples must be collected over a minimum 4-hour period; instantaneous TVOC measurements do not satisfy this requirement.