DSS-M.05.02 — Long FD Scratch Field

Pane-scale, predominantly parallel lineations caused by trapped/dragged fabrication debris during washing/handling, typically extending across large regions (often banded) rather than isolated short clusters. Classified by visual morphology and surface-catch response; methods of removal are outside scope.

• Repeating, co-directional lines that traverse much of the lite; banding may correlate to wash/transport path.
• Read strongly in raking/oblique views; individual lines may vary in intensity along a common path.
• Often coexists with short FD clusters near starts/stops or edge lands. (Family placement in DSS index confirms this damage class.)

• Surface-catch class (MSRT): SC-1 to SC-2 typical; escalate to SC-3 when bright chip flanks/pitting accompany lines. Perform one light, non-marring pass per VIS §5.5; prefer polymer stylus on suspected coated faces.
• Visual signature: Long-run, near-parallel scoring that forms fields/bands rather than a single track; localized bright “edge sparkle” under raking light indicates increasing depth. Evaluate at 12/36/72 in, normal + oblique sweep under raking light.
• Location/access: Record pane ID and surface numbering (#1-#4; laminate-internal). If fixed parallax shows the cue is between panes, classify CAT-5 (out-of-place scope).

• CAT-2 (Light): SC-1; narrow, clean-edged lines; limited impact at standard view.
• CAT-3 (Moderate): SC-2-SC-3; clear catch; minor chip flanks may appear; noticeable at standard view.
• CAT-4 (Severe): SC-3 with pronounced chip flanks, crater-pepper, or dense banding evident at wide-field views.
• CAT-5: Use only when location/condition places the defect out of in-place scope (e.g., IGU cavity). Acceptance of restored glass is governed separately by VIS §6; do not conflate classification with acceptance.

Depth ranges are illustrative, used to align with CAT and morphology (numeric measurement not required for classification):

• CAT-2: ~0.2-1 μm (shallow, clean-edged; SC-1).
• CAT-3: ~1-5 μm (clear catch; emerging chip flanks).
• CAT-4: ≥5 μm (rough chip flanks; possible pit/crater association). Use MSRT class + morphology as the primary cues; numeric depth is not required.

• vs. Cutting skid lines (factory, edge-zone): Skid lines are short, edge-confined micro-lines; FD fields are long-run, pane-face bands that may escalate in catch.
• vs. Linear tracks (M.01): Single scraper/straightedge tracks present as one or a few distinct lines with consistent direction; FD fields present as many near-parallel lines forming bands. (See DSS index family separation.)
• vs. Abrasion fields (M.02): Abrasion fields show webbing/swirls and broader texture; FD fields are dominantly linear/parallel.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique (~60°-120°); include raking-light frames. Capture a context frame showing band extent and at least one macro of line edges/chip flanks.
• MSRT result: Record SC class (one pass, non-marring; polymer stylus on suspected coated faces).
• Forms: Pane ID; surface numbering; worked-surface Y/N; “coating present on worked surface?” Y/N/Unknown; reveal status; lighting/time; geometry checklist.

Attempting spot-work across a distributed FD field can create visible transition edges; VIS disallows visible worked boundaries in acceptance (CAT-0...CAT-4). Keep classification appearance-only; acceptance is evaluated under VIS §6.

• M.05.02 Long FD Scratch Field - Pane-scale bands of near-parallel lineations observed at VIS geometry; MSRT = SC-x (record value). Long-run morphology with [chip-flank status]. Classified CAT-y by cues. Pane ID, surface #, and photo set attached; acceptance per VIS §6 (separate determination).