DSS-M.07.01 — Edge-Origin Stress Crack (chip origin)

An edge-origin stress crack is a through-thickness (or developing) crack that initiates at the edge/arris-often from a pre-existing edge chip (“origin chip”)-and propagates inward under mechanical or handling stress. Any confirmed crack is an integrity indicator and lies out of in-place restoration scope under VIS (CAT-5 by condition/location). Classification is appearance-only; methodology is out of scope. Inspect under VIS lighting/geometry after Non-Invasive Reveal; record surface numbering and worked-surface status on Forms:

• Filament-thin, continuous line emerging from the edge/arris (or from a discrete origin chip at the edge), extending into the lite; may curve with stress fields.
• No abrasive flank sparkle like a scratch; can show branching/hackle near the origin chip or at stress changes.
• Often visible at standard view once length grows; raking light and oblique sweep clarify continuity.

Surface-catch class (MSRT)

• Do not pass a stylus across any suspected crack. If needed, a single light, non-marring pass adjacent to the origin chip may be used to sense local relief from chip facets (context only). MSRT is auxiliary and is never determinative for integrity.

Visual signature

• Unbroken, hairline fissure that can pass across faint surface texture without interruption; may display branching or feathering away from an edge chip origin.
• Under oblique sweep, the line remains phase-stable (persists through small viewpoint shifts), unlike shallow surface scores.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in using normal incidence and oblique sweep (~60°-120°); include raking light to resolve origin and continuity.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). If laminate-internal or between-pane by fixed parallax, mark CAT-5 by location and refer per protocol.

Assign category by appearance + integrity:

• CAT-5 (default): Any confirmed crack (edge-origin) → Non-Repairable / Out of In-Place Scope. Document extent, apparent growth direction, and proximity to corners/hardware; refer per project protocol (e.g., replacement/manufacturer service).
• Reassign only if no crack is present:
• If examination shows no fissure and only edge micro-chips/spalls → classify under M.03.01 / M.03.02 / M.03.03 as appropriate.
• If the cue is a linear surface scratch (abrasive, chip-flank sparkle, MSRT catch) without crack characteristics → classify under M.01 Linear scoring.

CAT is governed by integrity/location for cracks; acceptance is evaluated separately under VIS §6.

• vs. Edge micro-chipping/spall: Chips have faceted, sparkly flanks and are discrete; cracks are continuous, filament-thin and lack abrasive sparkle.
• vs. Thermal stress crack (Th.03.01): Thermal cracks may show different origin cues (e.g., from localized heating or solar hot-spot) and pattern; if mechanism is uncertain, classify as crack = CAT-5 and note suspected cause in remarks.
• vs. Surface score: Scores exhibit MSRT catch and abrasive edges; cracks may pass through slight residues/texture without interruption and can show branching.
• vs. Laminate-internal line/inclusion: Use parallax and reflection tracking; a fixed, between-pane or ply-internal line is CAT-5 by location even if not structurally active on the exposed face.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique, include raking macros that show the origin (edge or origin chip) and continuous fissure. Add a context frame showing distance from edge/corner/hardware. Record distance/angle in-frame.
• MSRT note. If recorded, note adjacent SC-class only (do not cross the crack). One light, non-marring pass; polymer stylus if coating is suspected.
• Forms: Pane ID; surface numbering (#1-#4; laminate-internal); worked surface Y/N; functional coating on worked surface? (Y/N/Unknown); reveal status; lighting/time; geometry checklist; photos attached.
• Disposition. Mark CAT-5 for any confirmed crack. Note apparent stability (e.g., tip blunting vs. sharp active tip), estimated length, and proximity to support points. Refer per project protocol.

• M.07.01 Edge-Origin Stress Crack (chip origin) - Continuous fissure observed emanating from [edge/arris | origin chip] on surface #___ under VIS geometry (oblique + raking). MSRT not performed across fissure; adjacent reading SC-[ ] noted for context. Classification: CAT-5 (integrity/location). Surface numbering recorded; parallax checked. Photo set + forms attached; acceptance per VIS §6 (separate).