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Mike Vivas, P.E. <br /> City of Lodi's City Hall Annex <br /> May 17, 2002 <br /> Page 4 of 4 <br /> 3. There are no ventilation rates calculated or any confirmation of the rates <br /> provided. <br /> 4. The need to comply with Title 8 CCR Sections 3328, 5142, 5143, and 5155 as <br /> well as Title 24 CCR. This may require an independent review by the <br /> appropriate technical advisor or registered professional engineer. <br /> The Magellan Environmental Inc., letter dated March 13, 2002 RE: HVAC Modifications <br /> and Confirmation Indoor Air Sampling at City of Lodi's City Hall Annex, states that <br /> additional indoor air sampling is to be performed in the Computer Area. No locations or <br /> the number of samples to be collected was specified. Additionally, the sampling times <br /> and durations were not specified. <br /> To further reduce intrusion of soil gas/vapors into the City Hall Annex ESU recommends <br /> that any and all penetrations through the concrete slab be sealed. The seals should be <br /> provided at the termination of all electrical, cable television, telephone, sewer, and other <br /> utility conduits. Conduit seals can be created through the injection of a closed cell <br /> expanding polyurethane foam sealant into the conduit after all wiring/lines have been <br /> installed. The polyurethane foam shall be injected such that it forms a positive, gas <br /> tight seal and extends a minimum of 6 conduit diameters or 6 inches, which ever is <br /> greater, into the conduit. <br /> Finally, ESU strongly recommends that a pilot study for Soil Vapor Extraction (SVE) <br /> Assessment be performed without delay. The pilot study should determine the <br /> aerospirometry of the soils. The information collected from this study should be applied <br /> to designing an SVE system which will provide capture of the soil gas/vapors beneath <br /> the Annex's foundation. This system could eliminate the need for HVAC controls or <br /> operate in conjunction with the instituted HVAC modifications to prevent soil gas/vapor <br /> from intruding into the building's envelope. We believe that the HVAC modifications are <br /> a short term solution to the VOC vapor intrusion at the Annex. An SVE system and a <br /> groundwater treatment system and possibly some limited soil excavation could be <br /> components of an overall long term solution to the present indoor air contamination. <br /> Should you have any questions or require any additional information, please do not <br /> hesitate to call me. <br />