Volume 5: Response activity for the VIAP
Appendix A.2 – 2.0 AVMS documentation and as-builts

2.1 Overview of AVMS

This section should include the design basis that explains how vapors are, or may, enter the structure and how the AVMS will mitigate unacceptable soil vapor concentrations from entering the building.

2.2 Design

2.2.1 Overview

This section should include the diagnostic tools that were used to develop the AVMS design. Information gaps identified in Section 1.5.4 and 1.6 should be discussed.

2.2.2 Pre-design sub-slab diagnostics (PFE) testing (required)

The section should include the PFE testing results which includes:

• An evaluation of the findings and how it relates to the AVMS.
• Known subsurface features (see Section 1.5.1, 1.5.4 and 1.6) and if/how they influenced the PFE testing.
• A discussion of any evidence of poor effectiveness (i.e., unexpectedly low vacuum at test ports associated with the tested exhaust vent pipe).
• A discussion of any inconsistencies identified (i.e., unexpected differences between vacuum at one test port compared to another test port that is associated with the same exhaust vent pipe).
• A discussion of any design consideration based on the results.

Note: The number of PFE tests and locations is dependent on multiple factors (see ANSI/AARST SGM-SF-2017 (updated in 2020). If the number of PFE tests does not align, this section should identify that what additional supporting information makes the additional testing locations unnecessary.

Key supporting information

• Figure(s) that identify where the PFE tests were completed.
• Table(s) that present the data collected.

2.2.3 Building HVAC testing (required)

The section should include the data and the analysis of the evaluation of the HVAC system(s) and any influence on the pressure gradients generated by the HVAC on the AVMS. If any natural back drafting appliance(s) are present, data that confirms that the AVMS does not influence the normal operation the results must be included.

Key supporting information

• Table(s) with the testing results.

2.2.4 Other testing (if necessary)

The section should include any other diagnostic testing that was performed and aided in the design of the mitigation system including:

• Characterization of pressure or air exchange rates between indoors and outdoors.
• Characterization of pressure or air exchange rates between floors or adjoining air spaces.
• Diagnostic radon measurements or other contaminant measurements at locations of interest.

Key supporting information

• All information should be included in a separate appendix.
• Figure(s) that identify where the tests were completed.
• Table(s) that summarize the data collected.

2.3 As-builts of the AVMS

2.3.1 Suction pit and vent lines

This section should describe the installed suction pits or the mechanism(s), such as vent lines, that produce vacuum beneath the slab, liner, or walls if necessary.

Key supporting information

• Figure that details the suction pit or piping, and vent lines beneath the slab that will produce or introduce a negative vacuum.

2.3.2 Horizontal conveyance piping

This section should describe the installed horizontal conveyance piping used to direct the vapors through the structure. In addition, any slopes that were installed to encourage drainage.

Key supporting information

• Figure that details horizontal conveyance piping layout.

2.3.3 Vertical vent risers and height of building

This section should describe the installed vertical piping to and above the roof.

Key supporting information

• Figure(s) in the plan view that depicts the vertical piping run locations (may be identified on Figures for Section 2.3.3).
• Cross section(s) that details the vertical piping runs.

2.3.4 Fans

This section should identify the fan-type that was used in the final design.

2.3.5 Exhaust vents

This section should describe the installed point(s) of exhaust for the AVMS and identify what distances are met for air intake(s), window(s), vents, structure access point(s) such as a door or patio, and HVAC components based on AARST SGM-SF-2017. This section should also provide the height above the structure or roof where the exhaust gas exits the system.

Note: All distances should be measured between the closest point of the exhaust opening and the closest point of all location requirements specified using the shortest distance.

Key supporting information

• Figure(s) in the plan view that details the where the exhaust was installed and distances for structure openings that have been met.
• Cross section(s) that provide construction details.

2.3.6 Materials and other specifications

2.3.6.1 Sealing cracks, joints, and other openings

This section should reaffirm that when sealing cracks, joints, or other openings was warranted that all sealants followed standards such as AARST SGM-SF 2017 and, in addition to assisting in the effectiveness of the system, it has been affirmed that there are no adverse effects to occupants. The documentation, including a figure that identifies the location, is either attached to this submittal or can be made available upon request by RRD.

Key supporting information

• Figure(s) in the plan view identifying the location where each sealant was applied.
• Detailed or expanded figure view showing the application and supporting photo documentation.

2.3.6.2 Component labeling

This section should reaffirm that labeling practices followed standards such as AARST SGMSF-2017 when and where labeling was warranted.

Key supporting information

• List of required labels as per SGM-SF 2017.
• Figure(s) depicting final labels and language.
• Figure(s) identifying the physical location of each label.

2.3.6.3 Other specifications (if necessary)

This section can be provided if the design firm feels there is additional information necessary warranted to establish that an AVMS is effective.

Key supporting information

Figures, tables, or appendices may be provided as appropriate.

2.3.7 Barrier membrane (if installed)

If a membrane was installed as part of the AVMS, this section should provide information on the barrier and how it was installed including any documentation of the oversight that was performed. Barrier Membranes that are installed to meet performance factors other than vacuum or flow should consult the passive mitigation system install and commissioning document for the additional information that should be included.

Key supporting information

• Figure(s) that detail the barrier installation.
• A separate appendix is warranted to provide supporting information.

2.3.8 Preferential pathways and other unique features (if necessary)

This section should describe the mitigation strategy for any preferential pathways that was required to be implemented as part of the mitigation strategy (Section 1.6), how it is documented to be effective, or identifies that one was not necessary and includes the evaluation that was completed.

Key supporting information

• Figure(s) that detail each unique mitigation approach implemented for any preferential pathways.

2.3.9 Elevators and below grade pits or tunnels (if necessary)

This section should describe the mitigation strategy and how it is documented to be effective for each elevator shaft, pit, or tunnel that is part of the structure, if required.

Key supporting information

• Figure(s) that detail each unique mitigation strategy for any elevator shafts, pits, or tunnels.

2.3.10 Vertical/Sidewalls below grade (if necessary)

This section should describe the mitigation strategy if there is a source of vapors (Section 1.6.2) that is adjacent (i.e., lateral) to the structure and there are vertical walls below grade that are associated with a basement, elevator shaft, pit, or tunnel.

Key supporting information

• Figure(s) that detail the mitigation strategy for the walls of the vertical wall(s) below grade as identified above.
• A separate appendix may be warranted to provide additional supporting information.

2.3.11 Groundwater in contact (if necessary)

If groundwater is in contact or may become in contact with the structure (Section 1.3), this section should describe how the shallow groundwater was addressed to allow the proper function of AVMS. If the AVMS will not contain any mechanism for addressing groundwater that may be in contact with the lowest part of the structure, the data analysis that supports that it is unwarranted is described.

Key supporting information

• Figure(s) that detail the mitigation strategy for shallow groundwater
• Data tables that support the strategy.
• A separate appendix may be warranted to provide additional supporting information.

2.4 Alarm and performance indicator (if installed)

This section describes any monitoring system(s) installed as part of the AVMS and describes the function of the alarm or performance indicator, what it measures, and how it relates to the system function. The section should be specific about any warnings that are relayed, if and how data is stored, how any alarms that are identified are documented, and what documentation (if any) is produced.

Note: Alarms and monitoring systems can provide immediate feedback on system operation and can be useful tools if high concentrations are present or where acute contaminants are located and are highly recommended by RRD. Telemetric alarms allow the most freedom as most telemetric systems provide immediate feedback to an operator and record the data of the system operation, which is a critical component of a party’s due care obligations. Visual alarms require a party to physical observe some type of indicator and record if the VIMS is operating. Audible alarms may not require a person to physically observe the operation but must be placed in a location that will be heard by building occupants.

Key supporting information

• Figure(s) that detail where the alarms are located.
• Table that identifies any alarms that have been triggered to date and the response.

2.5 Building codes and permits

This section should clearly state that other permits necessary for the installation of the AVMS that are not regulated by RRD have been met and are complied with (e.g., building codes and air quality permits) through an affirmative statement similar to: “The system was installed and is operating in accordance with all local, state, and federal laws and rules, including but not limited to, building codes and air quality regulations.”

2.6 Monitoring points and test ports

This section should describe the locations that are proposed to facilitate future confirmation of PFE effectiveness, system operation, and/or soil gas concentrations. Additional information on the locations of the test ports can be found in ANSI/AARST SGM-SF-4 2017.

Note: Special consideration should be paid to placement of monitoring points within and around areas that may inhibit vacuum or flow due to features that extend beneath the floor slab, such as building footers, floor drains, trenches, elevator pits, collection pits, and utilities.

Key supporting information

• Figure in the plan view depicting the location of each monitoring point in relation to any suction point or subsurface AVMS component.
• Table that provides detail on how each monitoring or test point will be installed. 

2.7 Performance objectives

2.7.1 System performance metrics

This section should identify and establish the performance metrics that are met at each monitoring point identified in Section 2.6 above. It also describes how each performance metric is measured and obtained. It presents why the proposed performance metrics are appropriate to evaluate the efficacy of the AVMS.

Key supporting information

• Table, if more than one performance metric is required or selected, identify the location and the specific performance metric(s) that are being measured and/or achieved.
• Figure identifying the location that the performance metric is being evaluated.

2.7.2. AVMS downtime

This section should identify how and when a party becomes aware the system is down, the response time that is appropriate to bring the system back to full operation (if it is greater than two (2) weeks), and how that was the response time was determined. This section should also include any alarms identified in Section 2.4 above and how it fits into the response time.

2.7.3. Proposed system installation oversight performed

This section should include a description of the oversight that was performed and a summary of the construction quality assurance measures that were documented throughout the installation process. Justification of the level of oversight and that the oversight was performed must be included.

Key supporting information

• It is not anticipated that any figure is warranted, though daily field logs are appropriate.

2.8 System commissioning documentation

This section should provide a general description of commissioning monitoring program that was implemented and is being used to confirm the AVMS meets the proposed performance metrics identified in Section 2.7 at the locations identified in Section 2.6. In addition to the data collected during the commissioning monitoring program, this section should include an analysis of the data, whether the data met the performance metrics or not, and why it should be considered to be commissioned.

Generally, the recommended time frames for system commissioning provided on Table 1, should be complied with, except when the following conditions are present, then Table 2 should be followed:

1. Groundwater within three feet of the lowest subsurface feature of the structure that can transmit vapor such as a basement or elevator shaft;
2. Documented indoor air concentrations near or above the acceptable indoor air concentrations of acute compounds;
3. Structure being mitigated is a school, daycare, or medical facility; or
4. Acute compounds greater than 10x the SSTLs or criteria in the sub slab soil gas.

Alternate proposals based on site specific consideration can always be made for EGLE review. If continuous tracking through telemetry is incorporated into the monitoring program at points of compliance as well as in exhaust stacks and the response time will be less than one week, a reduction in monitoring frequency may be acceptable with appropriate justification (i.e., appropriate monitoring data and frequency of data collection).

Key supporting information

• Appendix with all supporting commissioning data.
• Table that identifies the performance specifications, the locations monitored, and the associated reading.

Table 1: Recommended time frames – system commissioning

Table 2: Recommended time frames – system commissioning