Why Is Everyone Talking About Sub Slab Depressurization Systems (SSD Systems) “Part 2”
What You Need to Know: Telemetry for Sub Slab Depressurization Systems
Our last SSDS blog post described vapor intrusion of volatile organic compounds (VOCs) and the role that sub slab depressurization systems (SSD systems or SSDS) are taking in maintaining safe conditions for building occupants. Vapor intrusion occurs when vapors from VOCs in soil or groundwater enter a building through cracks, holes, or other penetrations in the foundation. Inhalation of these vapors can be detrimental to the health of building occupants, sometimes even in the short term.
The Massachusetts Contingency Plan (MCP) establishes the requirements for the identification and remediation of these exposures. While the Massachusetts Department of Environmental Protection (DEP) is the agency that governs site investigations and cleanups under the MCP, the cleanups themselves are managed and implemented by individuals with specific expertise called Licensed Site Professionals (LSPs).
Under the MCP, the objective is to achieve a condition of “No Significant Risk” at contaminated sites. Satisfying this requirement (and demonstrating through an extensive risk assessment evaluation that future conditions will not alter the outcome of the findings) allows the entity responsible for the cleanup to file a Permanent Solution Statement with DEP.
The overall objective of MCP cleanups is to demonstrate that the conditions of a Permanent Solution have been achieved, thereby qualifying the site for closure. Achieving a condition of “No Significant Risk” is paramount to attaining this status. Previously disposal sites were not eligible for obtaining a Permanent Solution if operation of an active SSDS was necessary for maintaining a condition of No Significant Risk; SSD Systems are considered “active” when a blower is needed to maintain a protective indoor environment. These scenarios are known in the MCP as “active exposure pathway mitigation measures” (AEPMMs) – a mouthful of an acronym even for environmental professionals!
Changes made to the MCP, that were enacted in June 2014, allow sites with these active systems to achieve a Permanent Solution with Conditions. One of the “conditions” for sites that rely on AEPMMs to protect human health is that a telemetry unit be used to remotely monitor the operations of the AEPMM. Telemetry is required to ensure that the condition of No Significant Risk is maintained through the continuous operation of the AEPMM, which in most cases, is an SSDS.
The telemetry unit monitors the system to verify that:
- There is power to the system.
- The system is mechanically functional.
- The system is operating without significant disruption of effectiveness
If any of these conditions aren’t met, the telemetry unit must communicate this information by:
- Notifying DEP and notifying the owner/operator of the building regarding the power loss, mechanical failure or other significant disruption of system effectiveness; and also must
- Provide notification to these same parties upon the restart of the system.
Telemetry units communicate to DEP and the property owner via cellular signals or an internet connection; they incorporate a backup battery to address potential power outages; and most maintain a high level of control through a web-based interface. A good telemetry system will offer data-logging, real time monitoring, message formatting, escalation levels, and the ability to schedule shutdowns without causing an alarm, among other important features. The telemetry unit informs the person responsible for the system if it is not running properly, and is an essential tool to assist in protecting the inhabitants of a building.
Cooperstown Environmental staff have been integrally involved with DEP throughout the process of refining the state’s specific telemetry requirements. We continue to work with DEP and the LSP Association to keep up with the latest advancements in the regulations and technology, and to remain at the forefront of this emerging industry. Cooperstown is uniquely positioned to help LSPs, engineering firms, developers, real estate agencies, private companies, and individuals with any and all telemetry and SSD system needs.