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ASTM D8408/D8408M-21

Standard Guide for Development of Long-Term Monitoring Plans for Vapor Mitigation Systems

Standard Guide for Development of Long-Term Monitoring Plans for Vapor Mitigation Systems D8408_D8408M-21 ASTM|D8408_D8408M-21|en-US Standard Guide for Development of Long-Term Monitoring Plans for Vapor Mitigation Systems Standard new BOS Vol. 04.09 Committee D18
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Significance and Use

5.1 There are two primary types of vapor mitigation systems: Active and Passive (Table 1). Active vapor mitigation systems include: Sub-Slab Depressurization (SSD), Sub-Membrane Depressurization (SMD), Sub-Membrane Pressurization, Block-Wall Depressurization, Drain-tile Depressurization, Building Pressurization, Heat-Exchange Systems, and Indoor Air Treatment. Passive vapor mitigation systems include: Passive Venting, Floor Sealants, Vapor Barriers, and Increased Ventilation. Vapor mitigation systems may also consist of a combination of active and passive technologies.

5.2 Development and implementation of a LTM Plan is important for ensuring the long-term protectiveness of the mitigation systems.

5.3 The approach presented in this guide is a practical and streamlined process for establishing long-term monitoring requirements, monitoring time frames, and factors needed to determine when the use of a vapor mitigation system is no longer needed.

5.4 This guide is intended to be used by environmental professionals including: consultants, building managers, local or regional governing or regulatory agencies, that are installing vapor mitigation systems, conducting monitoring of the vapor barriers, or developing LTM Plans for vapor mitigation systems. Vapor mitigation system installation and LTM activities should only be carried out by environmental professionals who are trained in the proper application of vapor mitigation systems and experienced in the monitoring described in this guide, as applicable.

Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

(A) Initial Verification (System Startup)—Period of time immediately following system startup.
(B) Operational Monitoring—Period of time needed to verify that the system is operating within requirements through typically expected annual conditions.
(C) Long-Term Monitoring—Period of time following operational monitoring through system decommissioning.
(D) Additional testing—These are actions that may need to be taken if there is a problem with the system or there is a change to the building/system.


1.1 This guide presents factors to consider when developing Long-Term Monitoring (LTM) Plans for monitoring the performance of both active and passive vapor mitigation systems in buildings. This guide will also assist in developing appropriate performance standards to make sure that vapor mitigation systems remain protective of human health. Active and passive vapor mitigation systems have been used for a number of years on contaminated properties where residual volatile contaminants remain in the ground. This guide discusses a variety of vapor mitigations systems; however, its focus is on the development of long-term monitoring plans for vapor mitigation systems that are designed to remain in place for multiple years.

1.2 A LTM Plan provides clear performance goals for a vapor mitigation system which help to reduce potential confusion and ineffective project management. The LTM Plan also defines performance monitoring time frames to efficiently test the vapor mitigation systems’ effectiveness without unnecessary and costly over-testing. This will also promote consistent monitoring. Vapor mitigation systems are often installed without adequate consideration of the long-term monitoring requirements necessary to make sure that they remain protective of human health for as long as the system remains in place. This guidance addresses the requirements of the LTM Plan to monitor a vapor mitigation system’s continued effectiveness. Installation verification that the vapor mitigation system was installed correctly is typically addressed in the Remedial Design stage of a contaminated Property Management and is not covered in this document.

1.3 LTM Plan limitations, constraints and potential sources of error are discussed in this standard. This guide does not endorse a mitigation system vendor or testing of vapor mitigation systems. However, this guide does provide a reference for the common procedures for testing vapor mitigation systems and related terms, as appropriate.

1.4 Units—The values stated in either International System (SI) units or English units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. The values given in parentheses are provided for informational purposes only and are not considered standard.

1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026. For purposes of comparing a measured or calculated value(s) with specified limits, the measured or calculated value(s) shall be rounded to the nearest decimal of significant digits in the specified limit.

1.6 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied with consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Book of Standards Volume: 04.09
Developed by Subcommittee: D18.21
Pages: 9
DOI: 10.1520/D8408_D8408M-21
ICS Code: 27.040