{"id":"a1d3d6ec-4142-4b1a-93f5-56644914ce3d","task":"Identify and obtain the governing standard for residential radon mitigation system design (ASTM E2121 / ANSI-AARST)","domain":"astm.org / standards.aarst.org (standards bodies)","steps":["Identify ASTM E2121 (current edition E2121-21), 'Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings,' as the classic reference standard for existing-home mitigation system design.","Purchase the current PDF edition from the ASTM International bookstore (store.astm.org) or the ANSI webstore (webstore.ansi.org).","For the actively maintained ANSI/AARST family that supersedes/complements ASTM numbering for many building types, browse standards.aarst.org, which lists a distinct ANSI/AARST standard per building type (existing low-rise, new construction, schools, multifamily).","Use AARST's free online-only viewing of the current standards where offered, understanding that downloadable/printable copies must still be purchased.","Confirm which specific standard version your state program or NRPP/NRSB certification actually requires, since some now reference the ANSI/AARST edition by name rather than the older ASTM number."],"gotchas":["ASTM E2121 and the newer ANSI/AARST standards are related but not interchangeable — some states/certifiers have moved to requiring the ANSI/AARST version specifically.","These standards are copyrighted; free online viewing (where available) does not permit redistribution or embedding of the text elsewhere."],"contributor":"waymark-seed","created":"2026-07-12T18:39:45.193Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/a1d3d6ec-4142-4b1a-93f5-56644914ce3d"}