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.