The following is an alternative compliance path to EQc3.2 for the testing procedure for the detection of 4-PCH: BACKGROUND: The project is a small 1-storey office building. An indoor air quality testing procedure was conducted prior to occupancy in compliance with the EPA referenced standard. The report indicated that all levels were below the required limits except 4-PCH. Unfortunately, the detection limit of the equipment used for 4-PCH was 18-23ug/m3. The maximum 4-PCH level required by the IAQ testing protocol for LEED is 6.5ug/m3, based on the precendent from CIR ruling 11/29/2004. 4-PCH is a contaminant almost exclusively found in carpet backing using Styrene-butadiene latex rubber (SBR). The carpet installed has SBR backing but also complies with the requirements of EQc4.3, which limit the level of 4-PCH to less than 0.05 ug/m2/h, in keeping with the Carpet and Rug Institute\'s Green Label specifications. The project cannot retest for 4-PCH with more sensitive equipment because the building has been occupied for some time now, so the results would be meaningless at this point. We believe we can demonstate compliance to the 4-PCH level requirements through an alternative path, which involves calculating the maximum emissions possible and comparing this with the LEED requirement: Although the carpet contains SBR backing, it does meet the Carpet and Rug Institute\'s Green Label specifications for 4-PCH, which are 0.05 ug/m^2/h. Given that the gross square footage of the building is 9,000 SF (836.4 m^2) and the average ceiling height is 15 FT, the volume is therefore 135,000 FT^3 (3,823 m^3). If we assume the carpet emits 4-PCH at a rate of 0.05 ug/m^2/h (maximum possible emission factor for compliance), then the maximum emission rate the whole carpet could have, if applied to the entire floor area, is: (0.05 ug/m^2/h) x (836.4 m^2) = 41.8 ug/h. Therefore, the maximum 4-PCH emissions that could possibly contaminate the indoor air (without even considering the introduction of outdoor air) is: (41.8 ug/h) / (3,823 m^3) = 0.011 ug/m^3/h Since the maximum 4-PCH level required by the IAQ testing protocol for LEED is 6.5 ug/m^3, it would take 590 hours (25 days) for the 4-PCH to reach this level, if the carpet were inside a sealed box with the same inside volume as the building. Since the carpet is not in a sealed box, and since there will be at worst case conditions at least 25% outdoor air mixed into the air stream, it is reasonable to assume that the 4-PCH levels will never reach 6.5 ug/m^3. We believe this calculation method demonstrates compliance with the credit requirements for 4-PCH levels.
Your proposed calculation method, in combination with the air quality testing, is acceptable to demonstrate achievement of this credit - with two qualifications. First, you state that, "all levels were below the required limits except 4-PCH". From your proposal, we assume that the results for 4-PCH were "non-detect", but you do not specifically state that this is the case. Clearly, your proposed method only works if your test results indicated "non-detect" for 4-PCH. Second, in order to solidify your approach: instead of making a final assumption, complete the calculation by estimating the 4-PCH steady state. Employ a simple calculation for the building as a whole. Applicable Internationally.