DSS-E.02.02 — Dust-Storm Micro-Pitting

Dust-storm micro-pitting is an appearance change on glass caused by high-velocity mineral particulate impacts during dust/sand storm events, producing peppered micro-craters and a matte scatter field. Concentrations track wind exposure, building geometry, and near-grade vortices, often forming edge blast zones and height gradients. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status.

• Dense peppering of pinpoint craters (50-300+ μm dia.) in exposed zones; more sparse toward sheltered/lee sides.
• Height gradient: strongest near lower elevations and corners, tapering with height; frame-adjacent intensification.
• Under raking: bright micro-sparkles at crater rims and non-directional matte between impacts; may overlay directional eolian frost (see E.02.01).

Surface-catch class (MSRT)

• Commonly SC-2 within peppered fields (distinct interruption over crater rims); SC-1 at transition margins; SC-0 only outside impact zones.
• Perform one light, non-marring pass on a small revealed test patch (substrate). Use a polymer stylus if a functional coating is suspected. MSRT supports classification only.

Visual signature

• Discrete, random micro-craters (not fused nodules), sometimes with raised rim/chip; no wipe arcs, no oily gloss.
• Under oblique sweep, specular highlights blink at individual pits; between pits, low-contrast frost may be present.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal and oblique sweep (~60°-120°); employ low-angle raking macros to show crater geometry and edge blast density. Record distances/angles in-frame.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). Typical on outboard (#1) faces in arid regions or after extreme wind events. Between-pane peppering by parallax on #2/#3 → CAT-5 by location.

Mechanism cue (context)

• Recent dust/sand storm, construction winds, gust fronts; accumulated grit on sills/frames; reports of abrasive blasting rain.

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

• CAT-2 (Light): Sparse micro-pits in bands or corners; SC-1 at margins, SC-2 intermittent; minimal standard-view impact. Indicative relief: ~20-60 μm (pit depth).
• CAT-3 (Moderate): Continuous pepper field legible at standard distance; SC-2 common; matte between pits. Indicative relief: ~60-150 μm typical.
• CAT-4 (Severe): High-density peppering and rough edge blast clearly visible at standard and wide-field, frequent coalesced pits; SC-2 prevalent. Indicative relief: ~150-350+ μm local maxima.
• Reclassify when: If fused metallic nodules/rust dots are observed → evaluate Th.01.02 grinder spark embed; if damage is continuous directional frost with few discrete pits → consider E.02.01 eolian abrasion; if linear incised score lines dominate → M.01 linear scoring.
• 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. Hot-particle peppering (Th.01.02): Hot particles show fused metal beads/pits (often rust-toned) and thermal halos; dust-storm pits are mineral impact craters without metallic residues.
• vs. Eolian frosting (E.02.01): Eolian presents directional micro-texture with fewer discrete pits; dust-storm micro-pitting shows random peppering superimposed (often both coexist).
• vs. Stone/seed defects (P.02.03): Factory stones are internal inclusions or polished-out craters with production context; storm pits are surface impacts with exposure mapping.
• vs. Chemical etch (Ch.01/Ch.02/Ch.03.03): Chemical etch yields modeled, non-particulate micro-texture; storm pits are discrete, rimmed craters.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; raking macros of individual pits, density maps, edge blast zones; façade context documenting windward/lee sides and site exposure. Record distance/angle in-frame.
• MSRT result (substrate): After a small reveal test patch, perform one light, non-marring pass; record SC-class (SC-1/SC-2) within pepper fields and outside as control.
• Forms: Pane ID; product family & surface numbering; worked surface Y/N; functional coating present 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.

• E.02.02 Dust-Storm Micro-Pitting - Peppered micro-craters with edge blast gradient on surface #___ (windward); post-reveal test patch shows [SC-2 in field / SC-1 at margins]; visible at [12/36/72 in] under VIS geometry. Morphology: random rimmed pits, non-directional peppering, inter-pit matte; no fused nodules. Classification: CAT-[2/3/4] by visibility and SC-class; reclassify per notes if metallic fusion or directional frost predominates; CAT-5 if between-pane or coating-side loss on the surface to be worked. Forms + photo set attached; acceptance per VIS-A §6.