Dataset · v1.0.0 · 22 rows
Radon terminology dataset
A controlled vocabulary for residential radon: term, definition, the category it belongs to, and the common misunderstanding each term attracts.
The data
| Term | Category | Definition | Common misreading |
|---|---|---|---|
| pCi/L | measurement | Picocuries per litre — the US unit for indoor radon concentration. | Treated as a linear danger scale. It is a concentration; risk rises with it, but no value is a safety boundary. |
| Action level | regulatory | The concentration at which EPA recommends taking action to reduce radon: 4 pCi/L. | Read as the point where radon becomes dangerous. It is a feasibility threshold for a national programme, and guidance also recommends considering action between 2 and 4. |
| Closed-building conditions | measurement | Windows and exterior doors kept closed except for normal entry, for 12 hours before a short-term test and throughout it, with whole-house fans and window units off. | Assumed to mean the house must be empty. Occupancy is fine; deliberate ventilation is not. |
| Lowest lived-in level | measurement | The lowest floor occupied or reasonably occupiable, where a measurement device belongs. | Read as "where we spend time". It is a conservative, comparable benchmark, which is why an unused basement still sets the number. |
| Sub-slab depressurization | mitigation | The standard active method: a fan lowers pressure beneath the slab so soil gas is drawn out and vented above the roofline instead of entering the house. | Described as "venting the basement". It works on the soil beneath the slab, not on room air. |
| Suction point | mitigation | A penetration through the slab where the system draws from the sub-slab layer. | Assumed one is always enough. How many are needed is determined by measuring how far the pressure field actually extends. |
| Pressure field extension | mitigation | The diagnostic that measures how far suction reaches across a slab, using test holes and a micromanometer. | Skipped as optional. It is the measurement that decides fan size and suction-point count; a quote without it is a guess. |
| Manometer | mitigation | The gauge on a mitigation pipe showing the pressure difference the fan is developing. | Read as a radon meter. Offset columns mean the fan is pulling; the gauge says nothing about the concentration in the room. |
| Passive system | mitigation | Radon-resistant construction piping that relies on stack effect rather than a fan. | Treated as a result. It reduces levels in many houses and is insufficient in others, which is why a new house still needs a test. |
| Activation | mitigation | Converting a passive rough-in to an active system: diagnostics, sealing, a fan sized to measured conditions, and verification. | Described as "adding a fan". The buried half was installed by someone else and has to be evaluated first. |
| Sub-membrane depressurization | mitigation | The crawl-space equivalent: a sealed membrane over exposed soil with suction drawn from beneath it. | Confused with encapsulation. Encapsulation is moisture control; without suction and a roofline discharge it is not a radon system. |
| Post-mitigation verification test | mitigation | The measurement after at least 24 hours of continuous operation that proves the indoor number fell. | Treated as a formality and dropped from cheap bids. It is the deliverable; without it you own equipment, not a result. |
| Short-term test | measurement | A measurement over a few days reporting an average under controlled conditions. | Read as a fixed property of the house. It is one sample from a distribution that moves with season and weather. |
| Long-term test | measurement | An alpha-track or similar detector exposed for 90 days or more, reporting an annual-scale average. | Expected to match a short-term result. They answer different questions and disagreeing is normal. |
| Continuous radon monitor | measurement | An instrument logging hourly concentrations, often with tamper and condition data. | The hourly graph is read as a second result. The average is the result; the log shows whether conditions held. |
| Stack effect | building-science | Warm air rising and escaping high in a building, drawing replacement air in low — including soil gas through the foundation. | Ignored when comparing seasons. It is why the same house reads higher in the heating season. |
| Radon-resistant new construction | building-science | Building provisions — aggregate layer, membrane, sealing, vent pipe — intended to limit soil-gas entry in new homes. | Read as exemption from testing. It improves odds; it does not produce a number. |
| EPA Map of Radon Zones | regulatory | A county-level classification of predicted indoor average, produced for public-health planning. | Used as an address-level prediction. Zone 1 houses test low and Zone 3 houses test high routinely. |
| Seller disclosure | transaction | The statutory or form-based obligation to report known conditions, including radon results a seller holds. | Confused with a duty to test. Disclosure attaches to what you know; no state we serve requires testing an existing home. |
| Inspection contingency | transaction | The contract period in which a buyer may investigate and respond to findings. | Assumed to be long enough. A radon test needs 12 hours of setup plus the measurement plus time for a quote. |
| Buyer credit | transaction | A negotiated sum at closing in lieu of the seller performing the work. | Sized from a national average. It should come from a written quote on the actual house. |
| NRPP / NRSB | regulatory | The two national radon proficiency programmes that certify measurement and mitigation professionals. | Treated as optional extras. In states that do not license radon work, national certification is the credential. |
Download and API
- radon-terminology.csv — 22 rows, comma separated.
- radon-terminology.json — rows plus the field schema, methodology, and version. Stable URL, same origin, no key required.
- index.json — the catalogue of every dataset, for programmatic discovery.
Licence. CC BY 4.0 — reuse with attribution to Radon Connect and a link to the dataset page.
Field schema
| Field | Type | Description |
|---|---|---|
term | string | The term as a homeowner encounters it. |
category | enum measurement · mitigation · regulatory · transaction · building-science | Domain the term belongs to. |
definition | string | Plain-language definition. |
commonMisreading | string | The mistaken understanding this term reliably produces, and why it matters. |
Methodology
The question this answers
What does each term of art in residential radon actually mean, and what does a homeowner reliably get wrong about it?
How a row comes to exist
- Terms were selected because they appear in homeowner-facing decisions on this platform and carry a recurring misreading — not because they are technically interesting.
- Definitions follow the framing used in EPA publications where those publications define the term.
- The misreading column is original editorial work drawn from the decision content across this site.
Inclusion and exclusion
- A term qualifies when a homeowner encounters it in a test report, a quote, a disclosure form, or an inspection report.
- Terms used only between professionals are excluded.
What this dataset cannot tell you
- This is a vocabulary, not a standard. Where a term has a precise regulatory definition in a specific state, that state’s definition governs.
- The misreading column is an editorial observation, not a measured frequency. We have not surveyed homeowners and do not claim to have.
Related
- Radon FAQ Corpus — 1363 hand-written question-answer pairs, structured and downloadable.
- Radon Testing Method Comparison Dataset — Which method answers which question — and which decisions each one cannot carry.
- How testing works — Devices, placement, closed-building conditions, and what invalidates a result.
- What makes a great system — Six design choices that decide whether a system performs for a decade.
- Research Center — every dataset, with its provenance and status.
- Research methodology — how this platform builds and checks content.
Sources
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
- U.S. EPA — EPA Map of Radon Zones
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