Bay Area Vapor Intrusion Mitigation System Design

Terra-Petra Environmental Engineering is providing environmental engineering services for the design of the vapor intrusion mitigation system (VIMS) for a development of affordable Senior Housing in downtown San Rafael, CA. The development consists of the construction of a new six-story building. The building footprint is approximately 14,000 SF.

The site served as a Manufactured Gas Plant prior to the proposed improvements. Site assessment work was completed at the site prior to Terra-Petra’s involvement. A Human Heath Risk Assessment (HHRA) and a Site Conceptual Model (SCM) were carried out to determine the potential risk exposure posed to future construction workers, future commercial occupants and future residential occupants of the building based on VOC’s at the site. It was determined that the calculated risks for all potential receptors were less than the bench marks set forth for the property. The bench marks for this site were HI = 1 and ILCR = 1E-6. Results of the evaluation suggest that soil vapor intrusion mitigation systems may not be required to protect future occupants on this parcel.

The Department of Toxic Substances Control (DTSC) was engaged to serve as the lead regulatory agency at the site. Terra-Petra was directed to design a VIMS system in compliance with DTSC’s published guidelines, which we are in the process of completing.

It will be up to the DTSC to determine if the submitted VIMS design package meets DTSC guidelines and the soil vapor mitigation system provides for adequate human health assurance per the terms of the Land Use Covenant (LUC). If so, the DTSC can formally approve this project. Terra-Petra is confident that our VIMS design will satisfy the mitigation requirements as we have a vast amount of experience designing such systems that have been reviewed/approved by the DTSC.

Aside from the design work, Terra-Petra will be assisting our client in soliciting bids form qualified and experienced vapor intrusion contractors in the Bay Area. We will also be reviewing submittal packages and providing support throughout the Construction Administration Phase of the project. Our inspection crew is slatted to inspect and document the installation of the system using our state of the art field reporting system.

Vapor Intrusion Mitigation System Design & Installation – San Jose, CA

Terra-Petra Environmental Engineering is pleased to provide environmental engineering services for the design of the vapor intrusion mitigation system (VIMS) being proposed for a new affordable housing development in the Diridon Station Area in San Jose, CA.

The project consists of a multi-family residential building having 130 units with 5 stories above grade (no below grade elements). The lowest level will consist of parking with lobby, offices and a community room. The building footprint is approximately 23,400 SF on 1.02 acres.

The site where the proposed building is to be constructed did contain an Underground Storage Tank (UST) potentially containing PCE which was considered to be a Recognized Environmental Condition (REC). As such, soil vapor data was collected from the site during both wet and dry seasons approximately 9 months apart. The data showed that no on-Site sources of PCE have been identified at the Site. Further, no VOCs were detected at concentrations above residential DTSC-AF SLs for future buildings, and no further investigation, evaluation or consideration of exposures associated with VOCs in soil vapor is proposed. Additionally, no residential units were being proposed on the ground floor of the new development. However, the regulatory oversight agency for this site is still requiring that passive Vapor Intrusion Mitigation System (VIMS) be designed and installed at this building.

Terra-Petra was engaged to design a pragmatic code compliant VIMS system that would take into consideration the lack of site-specific risk. As such, we were able to design a creative membrane system that limited the more protective mitigation measures to areas of higher residential occupancy/risk of exposure. These areas included the community room and elevator lobby. While areas of lower risk such as the trash enclosure rooms and parking garage we were able to design a system that would be protective of VI, but also reduce overall cost impacts on the project’s budget.

Terra-Petra will also be providing Construction Administration services and Construction Quality Assurance/Quality Control Services.

Vapor Intrusion Mitigation System – Reno, NV

Terra-Petra is continuing to provide environmental engineering services for the design of the vapor intrusion mitigation system (VIMS) design for the Urology Nevada project located in Reno, NV.

The project will consist of a new slab on grade structure having a footprint of 8,700 SF. Terra-Petra designed the vapor intrusion mitigation system for Phase I of Urology Nevada which consisted of a new slab on grade structure having a footprint of 16,624 SF. The entire site was over-excavated a minimum of 5 feet below finish grade.

Terra-Petra is licensed to perform work in all 50 states!

Although our company started its operations over 20 years ago in Los Angeles to address methane concerns in the region, Terra-Petra has since evolved to become a well-known Environmental Engineering firm throughout the United States, and is certified to work in all 50 states.

No matter where you’re project is located, Terra-Petra’s expertise is available to you.  Learn more about our services, approach and philosophy on our company overview page, or contact us today to get started.

Vapor Intrusion Mitigation System Design And Installation – Santa Fe Springs, CA

Terra-Petra’s Environmental Engineering Division has partnered with a Los Angeles REOC and investment management firm to design a comprehensive Vapor Intrusion Mitigation System (VIMS).

The new development, located in Santa Fe Springs, CA, will consist of a tilt-up industrial warehouse building, on grade, with an approximate building footprint of 150,500 SF. The gas vapor mitigation system shall be designed in accordance with a site specific Phase II Environmental Site Assessment report, and in accordance with the Vapor Intrusion Mitigation Advisory published by the C.A. EPA Department of Toxic Substances Control (DTSC) dated October 2011 (Cal/EPA 2011a, 2011b).

Vapor Intrusion Consulting, Testing And Monitoring – San Diego

Terra-Petra has been performing continuous inspections in San Diego at the Witt Mission Valley Apartments project since early this year. Terra-Petra observed the installation of a VI-20 geo-membrane and Liquid Boot Vapor Barrier application with smoke and thickness testing most recently.

Terra-Petra is one of the foremost experts on Vapor Intrusion consulting, inspecting, testing, monitoring and mitigation design in Southern California.  We are conversant with the many laws, codes and regulations at the city, state, county and national level. We understand the testing, design, monitoring and reporting procedures for many different regulatory agencies.

#vaporinstrution #inspection  #CETCOliquidboot #CETCOVI-20 #smoketest

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Vapor Intrusion Mitigation System Design – San Francisco

Terra-Petra’s Environmental Engineering Division has partnered with a leading environmental consulting firm in the Bay Area to design a comprehensive Vapor Intrusion Mitigation System (VIMS) for a new high-rise residential-rental mixed-use building located in San Francisco, CA.

We will be following the Department of Toxic Substances Control (DTSC) Vapor Intrusion Mitigation Advisory to design a combination passive venting and sub-slab membrane VIMS system as a means of mitigating human health risks associated with PCE in subsurface soil vapor. Our services will also include providing the necessary Quality Assurance/Quality Control Oversight during the installation of the system. This is a process and a role that we feel very comfortable carrying out.

Regardless of the reason, Terra-Petra can design a vapor intrusion mitigation system for you. We routinely design these passive and active Building Protection Systems across numerous cities and counties governed by many different agencies.

A typical Building Protection Systems consists of an impermeable soil vapor membrane and a pressure relief system. Where deemed appropriate, Terra-Petra can design mechanical vapor extraction systems, electronic gas detection and alarm systems; employing the latest technologies.

Among our many capabilities, Terra-Petra offers:

  • A Civil Engineer, Registered Environmental Assessor, Registered Geologist and Certified Engineering Geologist on staff.
  • Years of experience designing code compliant Building Protection Systems for numerous governing agencies.
  • Easy to read comprehensive plans including project specific details and specifications.
  • Passive and Active Design Capabilities.
  • Plan coordination with project Architect, Civil, Structural, Plumbing, HVAC as well as the Landscape Architect.
  • CAD Draftsmen on staff carry an Associates of Science Degree in Computer Aided Drafting Technology and Certificates in Architecture and Design for Drafting.

Vapor Intrusion Mitigation System – Fontana, CA

Terra-Petra has been chosen to provide environmental engineering services for the design of the vapor intrusion mitigation system (VIMS) design for a new logistics center in Fontana, CA.

Over the last couple of years, we have seen an increased demand for vapor intrusion mitigation systems to be designed and installed at large commercial warehouse type buildings. The main driving force appears to be the environmental personality of the property in which the buildings are being constructed. The site history will vary, but a history of industrial or commercial use where the site was subject to a chemical release of some sorts is the commonality.

Whether it be a petroleum hydrocarbon (TPH) impact from a former oil field/oil well or a Volatile Organic Compound (VOC) release from a dry cleaner or manufacturing facility the potential impacts on the health and safety of the future occupants of the building is what needs to be addressed.

Terra-Petra is well equipped at designing these systems for the current conditions, as well as building in contingency design features for potential future changes. Essentially, we design passive venting systems that are easily upgradable to active subslab depressurization systems (with remote telemetry and remote system monitoring and maintenance built into it if such a conversion is warranted in the future).

The proposed development in Fontana will consist of the construction of a new warehouse building having an approximate 260,650 SF footprint. The vapor mitigation measures will specifically include a “passive” vapor barrier beneath the office areas of the planned warehouse building, and the installation of  a passive ventilation layer beneath the vapor barrier. Inclusion of a ventilation layer beneath the vapor barrier would enable it to be made “active” at a later date by adding in-line fans, such as those used for radon mitigation, to the vertical riser pipes inside the warehouse.

Vapor Intrusion Mitigation Design – Hayward, CA

Terra- Petra is pleased to continue partnering with a major property developer to provide Vapor Intrusion Mitigation System (VIMS) Design Assistance in Hayward, CA. The scope of work involves mitigation of VOCs that could pose a potential vapor intrusion concern into a future occupied structure at the site.

This includes document review, conducting a Human Health Risk Assessment (HHRA) and submission of a Basis of Design report complete with Construction Quality Control procedures and an Operation, Maintenance and Monitoring plan (OM&M).

The vapor intrusion mitigation system will be designed in accordance with the Alameda County Department of Environmental Health’s Local Oversight Program (ACDEH) and in general accordance with the Vapor Intrusion Mitigation Advisory published by the C.A. EPA Department of Toxic Substances Control (DTSC) dated October 2011 (Cal/EPA 2011a, 2011b).

Vapor Intrusion Mitigation System Design – Pomona, CA

Terra Petra is currently working with a client to provide full scope vapor intrusion mitigation system design (VIMS), inspection, and monitoring services for their development in Pomona, CA.

The proposed development will consist of two new slab on grade, 3-story multi-family affordable apartment buildings with a combined footprint of 26,330 SF.

Terra-Petra will work with the City of Pomona (permitting agency) and with The Los Angeles County Department of Public Works (LACoDPW), Environmental Programs Division (EPD) which prescribes means and methods of protecting structures from vapor intrusion.

Vapor Intrusion Mitigation System – Palo Alto, CA

Terra-Petra’s Environmental Engineering Division has partnered with a significant environmental consulting firm in the Bay Area to prepare a comprehensive Vapor Intrusion Mitigation System (VIMS) for a new development located in Palo Alto, CA.

Terra-Petra designed the passive mitigation system with the ability to convert it to an active system in the future if deemed necessary. The VIMS System was reviewed and approved by the Department of Toxic Substances Control (DTSC).

Having completed the VIMS design we have moved on to the construction administration phase which includes submittal review and RFI responses, as well as the QA/QC inspections. We are currently on-site overseeing the smoke testing of the subslab membrane system.

For more on this project visit the City of Palo Alto Website

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