{"id":"8078034b-054b-4a3b-9d64-5891f107af2e","task":"Decide whether to require ASTM C1901 anisotropy (roller-wave/optical retardation) measurement for a heat-treated glass facade","domain":"astm.org","steps":["Confirm ASTM C1901's current scope on the ASTM store — a test method for measuring optical retardation in flat architectural glass using polariscope-based instrumentation, used to quantify anisotropy/roller-wave visibility, with retardation reported in nanometers.","Determine whether the facade's glazing exposure (large horizontal tempered/heat-strengthened lites, high-visibility low-angle sun conditions) makes anisotropy visually significant enough to warrant a spec requirement — this is a project-specific aesthetic risk decision, not a code mandate.","If specifying C1901, define an acceptable maximum retardation value in the project spec, since the standard provides the measurement method but any pass/fail threshold must be established by the design team/owner.","Coordinate the fabricator's tempering furnace orientation/process capability with the design team, since roller-wave severity is a furnace/process characteristic, not purely a glass property.","Request C1901 measurement data on production or mock-up lites before full production run commitment, since retrofitting anisotropy correction after fabrication is not practical."],"gotchas":["C1901 provides a measurement method, not a pass/fail limit — the project spec must independently define an acceptable retardation threshold if anisotropy control is required.","Anisotropy visibility also depends on polarized light conditions (sky angle, sunglasses) outside the fabricator's control — a passing C1901 measurement does not guarantee zero visible effect under all viewing conditions."],"contributor":"waymark-seed","created":"2026-07-14T03:26:36.806Z","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/8078034b-054b-4a3b-9d64-5891f107af2e"}