2.1 Overview of PVMS
This section should include a design basis that explains how vapors are entering, or may enter, the structure and how the PVMS will prevent soil vapors from entering the structure. It should include an overview of the type and function of the proposed mitigation system (e.g., vapor barrier, epoxy coating, passive sub-slab venting system, etc.).
Note: EGLE generally does not allow the individual use of a vapor barrier, epoxy coating, or venting system as a stand-alone mitigation approach. If the PVMS relies upon a vapor barrier or epoxy coating, a venting system should be incorporated into the overall PVMS design.
2.2 Passive vapor barrier selection
This section should briefly discuss why the vapor barrier or epoxy coating material(s) selected were determined to be appropriate for the intended application based on the results of chemical and physical testing data available for the material(s) and the information provided in Sections 2.2.1 through 2.2.4.
2.2.1 Diffusion coefficients
This section should indicate whether the vapor barrier or epoxy coating material(s) can provide an adequate level of protection for the building(s) proposed to be mitigated. Briefly discuss any diffusion coefficients established for those materials, which hazardous substances they address, and whether they are capable of preventing unacceptable soil gas concentrations from the vapor source(s) identified in Section 1.6.2 from entering the building(s). This section should contain an affirmative statement made by a professional engineer and liner manufacturer that attests to the liner’s ability to prevent advective and diffusive transport of the contaminants present into the structure and meet the testing requirements identified by EGLE. It should NOT be a generic statement and must be specific to the structure and the site contaminants.
Note: It is the responsibility of the person proposing the plan to ensure the PVMS is protective of public health. RRD’s approval is based on the design firm and design engineers’ evaluation and confirmation that the liner used will be successful in reducing the subslab concentrations to below acceptable indoor air values.
Key supporting information
- Figure(s) – cross section that shows the vapor barrier or epoxy coating and the sampling locations.
- Appendix – manufacturer’s product documentation that identifies established diffusion coefficients for the vapor barrier or epoxy coating material(s) used as part of the PVMS design.
2.2.2 Puncture resistance
The manufacturer of the vapor barrier product(s) should provide results of puncture resistance testing similar to ASTM D1709. This information should be assessed to determine the need to implement any precautions during the installation process, such as restricting specific types of work, and/or use of certain types of equipment on the installed vapor barrier.
Key supporting information
- Appendix – manufacturer’s product documentation that includes results of puncture resistance testing conducted for vapor barrier material(s).
Note: PVMS liners come in a wide range of puncture resistance. The easier a product can be punctured, the more oversight and QA/QC needs to be implemented, including the need to perform additional smoke testing at different phases of the installation process to ensure the integrity of the liner. The design engineer should evaluate the puncture resistance and assess how that relates to on-site building and construction activities so that it can be properly reflected in the installation process of the liner.
2.2.3 Tensile strength
The manufacturer of the vapor barrier or epoxy coating material(s) should provide results of tensile strength testing similar to ASTM D882. This information should be used to assess the potential for a vapor barrier to resist settling of the structure during and after the installation process.
Key supporting information
- Appendix – Manufacturer’s product documentation that includes results of tensile strength testing for vapor barrier or epoxy coating material(s).
Note: PVMS liners come in a wide range of tensile strengths that may impact the effectiveness of a liner if exceeded during the installation process. The design engineer should evaluate the tensile strength and assess how that relates to on-site building and construction activities so that it can be properly reflected in the installation of the liner.
2.2.4 Other material characteristics and tests
This section should briefly identify any other material testing data that the PVMS designer assessed as part of the vapor barrier or epoxy coating material(s) selection process and why the material(s) selected is appropriate for the intended application.
Key supporting information
- Appendix – Manufacturer’s product documentation that includes results of any other relevant material testing data.
2.3 Plan of proposed PVMS
This section should include the preliminary design that depicts the PVMS. It should include a description of the system, and the specific components and elements described in Sections 2.3.1 through Section 2.3.12 below. Figures identified below may be combined when appropriate.
2.3.1 Liner
This section should include a general description of the preliminary design of the liner and a figure that depicts the PVMS.
Key supporting information
- Figure(s) – cross-section(s) depicting the liner portion of the PVMS.
- Figure – depicting the PVMS location, if a PVMS is to be installed in only a portion of the structure.
2.3.2 Terminations and penetrations
This section should include a depiction of how the liner will be terminated against vertical surfaces and where there are vertical features such as pipes or other penetrations and how they will be completed.
Key supporting information
- Figure(s) – cross-section(s) or callouts that depict the termination of the liner against vertical surfaces.
- Figure(s) – cross-section(s) or callouts that depict how piping or other penetrations will be completed.
2.3.3 Liner overlap, joining, and seaming (if necessary)
If the liner, as provided from the manufacturer, will need to be joined or seamed to allow for coverage of the entire floor space, this section should include a description of how that occurs, how it is verified to be successful, and how it will be documented to be completed appropriately.
Key supporting information
- Figure(s) – cross-section(s) or callouts that depict how two liners will be joined or seamed.
2.3.4 Permeable sub-slab layer
A venting system should be incorporated into the overall design of a PVMS that utilizes a vapor barrier or coating. This section should provide a brief description of the materials used to create, maintain, or document the permeable sub-slab layer. The information for the permeable sub-slab layer (i.e., gravel or sand) should include the material, the thickness of the permeable sub-slab layer, and specify the material(s) (i.e., perforated piping or vent matting) installed within the permeable sub-slab layer to collect vapors.
Key supporting information
- Figure(s) – cross-section(s) that show the type of permeable sub-slab layer material(s), the thickness of the layer, and any vapor collection piping installed within the permeable sub-slab layer.
2.3.5 Horizontal conveyance piping (if installed or proposed)
This section should include a general description of the horizontal conveyance piping used to direct the vapors through the structure or beneath the subsurface. In addition, any slopes that need to be maintained should be described.
Key supporting information
- Figure that depicts horizontal conveyance piping layout of the PVMS.
2.3.6 Vertical vent risers
This section should include a general description including any limitations that must be addressed when routing the vertical piping through the building and above the roof (see Sections 1.5.2 and 1.5.5).
Key supporting information
- Figure(s) – cross-section of structure that details the vertical piping runs.
2.3.7 Exhaust vents
This section should include a general description of the proposed PVMS exhaust point location(s). This section should identify any distance(s) that must be achieved between each exhaust point location and building features including height above structure or roof, other air intake(s), window(s), structure access point(s) such as a door or patio, and HVAC components based on AARST SGM-SF-2017 (with 12/20 revisions).
Note: All distances should be measured between the closest point of the exhaust opening and the closest point of all location requirements specified.
Key supporting information
- Figure(s) – plan view that depicts the piping roofing locations and any other vents or air intakes that influences the location of the exhaust.
- Figure(s) – cross-section of structure that details the exhaust vents height above the structure.
2.3.8 Materials and other specifications
2.3.8.1 Component labeling
This section should include the proposed labeling, example wording, and locations consistent with standards similar to AARST SGM-SF-2017. Alternatively, a person may use the statement: “Labels for the system will be developed and utilized as identified in AARST standards such as SGM SF 2017.”
Key supporting information
- Figure(s) – depicting example labels and wording.
- Figure(s) – identifying the proposed physical location of each label.
2.3.8.2 Other specifications (if necessary)
Additional information can be provided in this section if the design firm believes that the information is critical to the success of the PVMS design and has not been included elsewhere in this document.
Key supporting information
- Figures, tables, or appendix may be provided as appropriate.
2.3.9 Preferential pathways and other unique features (if necessary)
This section should describe the mitigation strategy for any preferential pathways identified in Section 1.7 that need mitigation or additional considerations.
Key supporting information
- Figure(s) – detailing each unique mitigation strategy for preferential pathways.
2.3.10 Elevators and below grade pits or tunnels (if necessary)
This section should describe the mitigation strategy and how it will be effective for each elevator shaft, pit, sump, or tunnel that are part of the structure.
Key supporting information
- Figure(s) – detailing each unique mitigation strategy for any elevator shafts, pits, or tunnels.
2.3.11 Vertical/sidewalls below grade (if necessary)
This section should describe the mitigation strategy for any vertical sidewall below grade where mitigation is necessary.
Key supporting information
- Figure(s) – detailing the mitigation strategy for the vertical wall(s) below grade.
- Appendix – if necessary, to provide additional supporting information.
2.3.12 Groundwater in contact (if necessary)
If groundwater is in contact or may come into contact with the structure (see Section 1.4), this section should describe how the shallow groundwater will be addressed to allow for the proper function of the PVMS. If the PVMS will not include any mechanism to address groundwater that may come into contact with the lowest part of the structure (e.g. slab or basement floor), and there is not sufficient data from a nearby monitoring well to confirm that groundwater will not come into contact with the structure, then the monitoring that will be performed to confirm that the PVMS will remain effective should be described.
Key supporting information
- Figure(s) – detailing the mitigation strategy for shallow groundwater.
- Appendix – providing additional supporting information.
2.4 Monitoring points and test ports
Monitoring points, sometimes referred to as vapor pins, vapor monitoring points, or test ports, can be used to assess numerous aspects of a PVMS such as the integrity of a barrier or coating, breakthrough of contaminant vapors or tracer gases (if necessary), and communication between two points within the venting system. This section should describe the intended purpose(s) and location of all monitoring or test points used for any of the purposes described above.
Key supporting information
- Figure(s) – plan view depicting the location of each monitoring point in relation to any subsurface PVMS venting system components.
- Figure(s) – depicting how each type of monitoring or test point will be installed.
2.5 Installation weather and temperature limitations
Product manufacturers may specify conditions necessary to allow for the proper installation of their products. This includes a range of temperatures and/or weather conditions necessary during product application or installation. The design firm should identify any conditions that would prevent proper installation and determine what measures are necessary to ensure the vapor barrier or epoxy coating is installed in accordance with all manufacturer instructions and recommendations.
Key supporting information
- Appendix – Manufacturer’s product installation instructions, recommendations, and/or requirements.
2.6 Building codes and permits
This section should clearly state that other permits necessary for the installation of the PVMS that are not regulated by RRD shall be obtained, met, and complied with (e.g., building codes) through an affirmative statement similar to: “The system will be installed and operated in accordance with all local, state, and federal laws and rules.“