When a radon professional says they follow “AARST standards,” they are referring to a specific set of American National Standards developed by the American Association of Radon Scientists and Technologists (AARST) and approved by the American National Standards Institute (ANSI). These standards are the technical backbone of professional radon practice in the United States — governing how systems are installed, how measurements are conducted, and what constitutes acceptable post-mitigation performance. Understanding what these standards require helps you evaluate whether a contractor is following best practice or cutting corners.
What Is AARST?
The American Association of Radon Scientists and Technologists (AARST) is the primary professional organization for radon professionals in the United States. Founded in 1988 — the same year as the Indoor Radon Abatement Act — AARST administers the National Radon Proficiency Program (NRPP), develops technical standards through a consensus process, and advocates for radon-related policy. AARST’s standards are developed collaboratively by measurement professionals, mitigators, researchers, regulators, and public health specialists.
What Is ANSI Approval?
The American National Standards Institute (ANSI) is a private nonprofit organization that oversees the development of voluntary consensus standards for products, services, processes, and systems in the United States. ANSI accreditation ensures that standards are developed through a documented, consensus-based process with balanced stakeholder representation and opportunities for public comment. AARST’s key radon standards are ANSI-approved, meaning they carry the authority of the U.S. voluntary consensus standards system — the same system that produces ASTM, ASHRAE, and ASME standards used throughout U.S. construction and engineering.
The Core AARST-ANSI Radon Standards
ANSI/AARST SGM-SF: Mitigation Standard for Single-Family Homes
Standard of Practice for Mitigation of Radon in Schools and Large Buildings — Single-Family (SGM-SF) is the governing standard for radon mitigation system design and installation in single-family residential buildings. This is the standard that determines:
- Required pre-installation diagnostic testing procedures
- Fan placement requirements (unconditioned space only)
- Pipe sizing, routing, and joint cementing requirements
- Slab sealing requirements
- System performance indicator (manometer) requirements
- Required labeling on installed systems
- Post-installation testing timing and protocol
- Documentation requirements for installed systems
SGM-SF is referenced in NRPP certification requirements and is the standard against which certified Radon Mitigation Specialists are tested. Many state radon programs and contractor licensing requirements specifically cite SGM-SF compliance as a requirement for licensed work.
ANSI/AARST RMS-LB: Mitigation Standard for Large Buildings
The Radon Mitigation Standard for Large Buildings (RMS-LB) covers radon mitigation in schools, commercial buildings, multifamily housing, and other large structures. It addresses the additional complexity of large-building mitigation: multiple foundation zones, complex HVAC integration, sub-membrane depressurization for large crawl spaces, and the heightened documentation and verification requirements appropriate for public-use buildings.
ANSI/AARST MAMF: Measurement Standard for Multi-Family and Large Buildings
The Measurement and Mitigation Protocol for Large Buildings (MAMF) governs radon measurement in commercial and multifamily residential settings. For real estate professionals, the most relevant application is its guidance on certified measurement for real estate transactions — particularly in multifamily and commercial properties where residential measurement standards (which address single-family protocol) may not directly apply.
ANSI/AARST RRNC-2022: Radon-Resistant New Construction Standard
The Radon-Resistant New Construction standard (RRNC-2022) defines the technical requirements for incorporating radon-resistant features into new residential construction. It is the most current and comprehensive technical document governing RRNC — superseding earlier EPA guidance documents on the topic. Key content includes:
- Gas-permeable layer specifications (aggregate type, depth, coverage)
- Vapor barrier specifications (minimum thickness, seam overlap, sealing requirements)
- Vent pipe specifications (diameter, schedule, routing, termination)
- Electrical outlet requirements for future fan activation
- Crawl space-specific RRNC provisions
- Quality verification requirements
ANSI/AARST Series SSDS: Soil Suction Depressurization Standards
The SSDS series covers specific mitigation methods including sub-slab depressurization, sub-membrane depressurization, drain-tile depressurization, and block-wall depressurization — providing technical specifications for each method type that exceed the general requirements in SGM-SF.
How Standards Are Used in Practice
AARST-ANSI standards function as the technical reference layer for radon professional practice in several ways:
- Certification examinations: NRPP and NRSB certification exams test knowledge of AARST-ANSI standards — a certified professional is expected to know and follow these requirements
- State licensing requirements: States with radon contractor licensing often cite AARST-ANSI standards as the technical basis for licensed work — contractors must demonstrate compliance
- Workmanship warranty basis: When a mitigator’s workmanship warranty specifies what they will and will not do on a callback, the underlying technical obligation is typically SGM-SF compliance
- Litigation reference: In disputes about radon mitigation quality or post-mitigation testing results, AARST-ANSI standards provide the objective technical benchmark against which contractor work is evaluated
- Real estate due diligence: Buyers and home inspectors can reference AARST-ANSI standards to evaluate whether an existing mitigation system was installed to professional standards
Frequently Asked Questions
Are AARST-ANSI radon standards legally binding?
AARST-ANSI standards are voluntary consensus standards — they are not automatically law. However, they become legally operative when incorporated by reference into state licensing requirements, building codes, or contract specifications. When a state radon licensing law requires compliance with SGM-SF, that standard becomes legally binding in that state. When a contractor’s contract specifies AARST-ANSI standard compliance, violation becomes a breach of contract. Courts also routinely treat industry consensus standards as evidence of the duty of care applicable to professionals in negligence cases.
How do I know if my mitigation contractor followed AARST standards?
Key SGM-SF compliance indicators to check: fan is in unconditioned space (attic, exterior, or garage — not a finished basement or utility room); all PVC joints are cemented (not dry-fitted); a U-tube manometer is installed and visible; required warning label is on the pipe; slab core hole is sealed with hydraulic cement (not just foam); and the contractor provided written documentation of pre-mitigation radon level, system specifications, and post-mitigation test results. A system missing any of these elements is likely not fully SGM-SF compliant.
Where can I get copies of AARST-ANSI radon standards?
AARST-ANSI standards are available for purchase through the AARST website (aarst.org) and through the ANSI standards store (ansi.org). Some standards are available for free download from AARST as part of their public education mission. State radon programs sometimes make the most relevant standard (typically SGM-SF) available as a reference document.
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