Vapor Intrusion Mitigation System Implementation And Inspection In Palo Alto, CA

Terra-Petra has overseen the implementation of the vapor intrusion mitigation system design (a combination passive venting and sub-slab membrane system) for the Porter Drive Redevelopment in Palo Alto, CA and is now wrapping up inspections of the installation of the system.

The development consists of the following: A new one level below grade structure having two stories above grade with an approximate 11,080 SF footprint.

We followed our standard inspection process which included the following:

  • Document review prior to site visit
  • Jobsite kickoff meeting
  • Pre-installation field inspection
  • Substrate preparation field inspection
  • Application observation field inspection
  • Testing field inspection
  • Final approval

More about Terra-Petra’s vapor intrusion mitigation system design services:

Vapor Intrusion refers to the migration of Soil Gas Vapors emanating from the earth into an occupied space or structure. The particular vapors of concern are volatile organic compounds (VOCs), including chlorinated solvents, petroleum hydrocarbons, methane, hydrogen sulfide and semi volatile organic compounds (SVOCs) to name a few. Terra-Petra can prevent these vapors from intruding into your structure.

Some governing agencies will require any new structure built on a contaminated site to protect the occupants from potential soil vapor intrusion with a Subslab Building Protection System, while some developers elect to do so voluntarily because of a potential human health risk down the road. Regardless of the reason, Terra-Petra can design a 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.

Vapor Intrusion Inspection At San Fransisco Affordable Housing Development

Terra-Petra Environmental Engineering is providing inspection services for the installation of the vapor intrusion mitigation system (VIMS) design for the project located at 4840 Mission Street in San Francisco, CA.

The site will be redeveloped into a mixed use space which will include 137 units of affordable housing, a 10,000 SF space for a nonprofit health clinic, and 5,000 SF of retail space.

The footprint of the redevelopment overlays a parking garage of 40 cars and bicycles, with four at-grade residential apartments, lobby, mechanical, electrical, trash, and maintenance rooms occupying the first story. The building footprint is approximately 44,000 SF.


More about Terra-Petra’s vapor intrusion mitigation system design services:

Vapor Intrusion refers to the migration of Soil Gas Vapors emanating from the earth into an occupied space or structure. The particular vapors of concern are volatile organic compounds (VOCs), including chlorinated solvents, petroleum hydrocarbons, methane, hydrogen sulfide and semi volatile organic compounds (SVOCs) to name a few. Terra-Petra can prevent these vapors from intruding into your structure.

Some governing agencies will require any new structure built on a contaminated site to protect the occupants from potential soil vapor intrusion with a Subslab Building Protection System, while some developers elect to do so voluntarily because of a potential human health risk down the road. Regardless of the reason, Terra-Petra can design a 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.

Vapor Intrusion Mitigation System – San Francisco, CA

Terra-Petra has completed the vapor intrusion mitigation system design for a new development in San Francisco and is now performing inspections during the installation of the system. The development is comprised of an 18 Story High-Rise, with 1 Level below grade, a basement slab, and with a building footprint of 20,080 SF.

Our standard inspection process for a project like this includes:

  • Document review prior to site visit
  • Jobsite kickoff meeting,
  • Pre-installation field inspection
  • Substrate preparation field inspection
  • Application observation field inspection
  • Testing field inspection
  • Final approval

More about Terra-Petra’s vapor intrusion mitigation system design services:

Vapor Intrusion refers to the migration of Soil Gas Vapors emanating from the earth into an occupied space or structure. The particular vapors of concern are volatile organic compounds (VOCs), including chlorinated solvents, petroleum hydrocarbons, methane, hydrogen sulfide and semi volatile organic compounds (SVOCs) to name a few. Terra-Petra can prevent these vapors from intruding into your structure.

Some governing agencies will require any new structure built on a contaminated site to protect the occupants from potential soil vapor intrusion with a Subslab Building Protection System, while some developers elect to do so voluntarily because of a potential human health risk down the road. Regardless of the reason, Terra-Petra can design a 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.

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.