DSS-U.01.03 — Halo without Central Feature (Unknown Chemistry)

Halo without central feature is an appearance change presenting as a ring or oval band whose center is not visibly occupied by residue or defect. The annulus is presumed to result from edge-biased deposition during wetting/evaporation, surfactant Marangoni flow, or migration from adjacent materials, but the controlling chemistry is not yet identified. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status.

• Discrete rings/ovals (single or clustered) ranging 10-150 mm+ diameter; ring width 1-10 mm.
• Variable contrast: faint sheen shift to light-toned rim; sometimes slight dark edge against reflections.
• No obvious seed or particulate at the center; multiple halos may partially overlap.

Surface-catch class (MSRT)

• Core: generally SC-0 (no relief).
• Rim: SC-0 if purely film; SC-1 where very shallow micro-texture or fine crystalloid is present; SC-2 implies misclassification-evaluate for mineral etch (Ch.03.03) or hot particle craters if present.
• Perform one light, non-marring pass across core → rim → outside on a small revealed test patch. Use polymer stylus if a functional coating is suspected. MSRT supports classification only.

Visual signature

• Annular band with cleaner center; no chip-flank sparkle (not scoring), no fused nodules (not hot particle).
• Under raking: rim shows sheen discontinuity or fine granularity; core is optically continuous with surrounding glass.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal and oblique sweep (~60°-120°); use raking to locate rim density and to confirm feature absence at the center. Record distances/angles in-frame.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). Often on outboard (#1) (dew/droplet drying), but may occur on inboard (#4) near sprays/aerosols. Between-pane appearance on #2/#3 via parallax → CAT-5 by location.

Mechanism cue (context)

• Mist/spray usage, detergent or additive residues, nearby silicone/EPDM, roof/metal runoff atomization, or condensation cycles. Lack of drip legs favors isolated droplet history over sheet flow.

Assign CAT by visibility at acceptance geometry and MSRT after a reveal patch. Depth values are indicative-field measurement not required.

• CAT-1 (Benign / non-relief): Faint annular halo; SC-0 rim, SC-0 core; visible mainly in raking/angle; lifts on reveal patch. Indicative relief: 0-10 μm (film only).
• CAT-2 (Light): Persistent rim post-reveal with localized SC-1 (incipient micro-texture or very fine crystalloid); minimal standard-view impact. Indicative relief: ~10-40 μm at rim.
• CAT-3 (Moderate): Multiple rings/panels legible at standard distance; SC-1 consistent around rims; suggests recurrent cycles or additive-laden droplets. Indicative relief: ~40-120 μm at rim.
• Reclassify when (diagnostic cues present):
• White/grey crystalline rim, facet sparkle, or etched inner band → Ch.03 Mineral system (Deposits/Staining/Etching subtype).
• Iridescent, rainbow-thin rim tracking wipe geometry → R.04.01 Detergent/Surfactant film.
• Oily clear ring near PVC/EPDM contact → R.05.02 Plasticizer migration or R.05.01 EPDM rub if dark.
• Brown/black tonal rim below upstream materials → E.04.03 Curtain wall runoff staining.
• CAT-5 (by condition/location): Between-pane/inaccessible by parallax, integrity indicators, or confirmed functional-coating loss on the surface to be worked → CAT-5.

CAT is appearance-based; acceptance is separate under VIS-A at 12/36/72 in. Do not abrade to “force” a response during classification.

• vs. Mineral spot/etch rings (Ch.03): Mineral rings often show crystalline texture and may leave true etch (SC-1→SC-2) after reveal; U.01.03 halos can be film-only (SC-0) with no inner etch.
• vs. Surfactant islands (R.04.01): Surfactant halos show thin-film colors and align with wipe paths; U.01.03 rings are isolated droplet-like without path context.
• vs. Silicone/siloxane halos (Ch.06.01 / R.01.01 proximity): Silicone halos often adjacent to sealant lines and resist wetting conspicuously; U.01.03 may occur mid-pane and show weaker wetting anomaly.
• vs. Coating anomalies (Co): Coating patchiness is planar on coated faces and not annular; verify face identity before attribution.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; raking macros of rim segment and core; include mist/wetting test frame to show wetting response across rim vs. core where permitted. Record distance/angle in-frame.
• MSRT results: After a small reveal test patch, record SC-class at core (SC-0), rim (SC-0/SC-1), and outside control (SC-0).
• Forms: Pane ID; product family & surface numbering; worked surface Y/N; functional coating on worked surface? (Y/N/Unknown); reveal status; lighting/time; geometry checklist; photos attached.
• Acceptance split: Post-restoration acceptance per VIS-A §6; classification ≠ acceptance. Coated-face appearance rules apply per VIS §6.2.e when the worked surface is a factory functional coating.

• U.01.03 Halo without Central Feature - Isolated annular ring with clear core on surface #___; post-reveal test patch shows [rim SC-0/SC-1] / core SC-0; visible at [12/36/72 in] under VIS geometry. Morphology: annular band, no chip-flank grooves, no fused nodules. Classification: CAT-[1/2/3] by visibility and SC-class; reclassify to Ch.03 (mineral), R.04.01 (surfactant), or R.05.02 (plasticizer) if diagnostic cues present; CAT-5 if between-pane or coating-side loss on the surface to be worked. Forms + photo set attached; acceptance per VIS-A §6.