DSS-R.06.02 — Steel / Ferrous Rub / Black Smear

Steel / ferrous rub / black smear is an appearance change on glass caused by mechanical contact with carbon steel or ferrous components (fasteners, brackets, trowels, knives, ladders, window bars, site hardware) leaving a dark grey/black transfer. May slowly oxidize to brown at the edges if moisture is present. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status.

• Dark linear smears along hardware contact paths (e.g., ladder foot, trowel edge) or localized arcs at knock points.
• Heavier density and soot-like transfer at pressure loci; can stain cloth dark on wipe.
• In some cases, brownish haloing from surface oxidation.

Surface-catch class (MSRT)

• Typically SC-0 (transfer film on surface).
• SC-1 appears where dry abrasive wiping or grit under contact created very shallow micro-texture; SC-2 suggests misclassification-check for M.01 linear scoring or Th.01.02 hot-particle embed.
• Perform one light, non-marring pass on a small revealed test patch (substrate). Use polymer stylus if a functional coating is suspected. MSRT supports classification only.

Visual signature

• Dark grey → black smear, sometimes with brown oxidation edge; directional drag evident; no discrete pits/nodules.
• No chip-flank sparkle (not incision) under raking.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°); raking macros to show drag, oxidation halo, edge feather. Record distances/angles in-frame.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). If parallax places the smear between panes (#2/#3), classify CAT-5 by location and refer.

Mechanism cue (context)

• Steel tools/hardware used near glass, ladder rails/feet, masonry trowels, grinders (without sparks contacting) rubbing surfaces; iron fines visible on adjacent materials.

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

• CAT-1 (Benign / non-relief): Light dark smear; SC-0; mainly angle/raking visible. Indicative relief: 0-10 μm (optical film).
• CAT-2 (Light): Persistent black smear with localized SC-1 from prior dry wiping/soil; limited standard-view impact. Indicative relief: ~10-40 μm.
• CAT-3 (Moderate): Broad/high-contrast smears legible at standard distance, with scattered SC-1 and possible brown oxidation; indicates extended dwell or repeated contact. Indicative relief: ~40-120 μm.
• Reclassify when: After true residue lift, any incised lines with chip-flank sparkle or SC-2 persist → evaluate under M.01 (linear scoring). If pits/fused nodules present, evaluate Th.01.02 grinder spark embed.
• 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” removal during classification.

• vs. Aluminum rub (R.06.01): Aluminum is cool/light grey; ferrous rub is dark grey/black, can finger-stain, and may oxidize brown.
• vs. EPDM gasket rub (R.05.01): EPDM is black but follows gasket geometry; ferrous rub follows tool/hardware paths and may show oxidation halo.
• vs. Hot-particle embed (Th.01.02): Hot particle shows pit/nodule field, sometimes with rusting dots; ferrous rub is smear-film without pits.
• vs. Soot/particulate pollution (E.01.03): Soot is broad/dirty grey and dry; ferrous rub is localized, directional, and often coincident with hardware contact.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; raking macros of drag, oxidation halo, edge feather; context frames showing steel tools/hardware proximity. Record distance/angle in-frame.
• MSRT result (substrate): After a small reveal patch, perform one light, non-marring pass; record SC-class (SC-0/SC-1/SC-2).
• 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.

• R.06.02 Steel / Ferrous Rub / Black Smear - Dark grey-black directional smear along hardware/tool contact on surface #___; post-reveal test patch shows [SC-0/SC-1]; visible at [12/36/72 in] under VIS geometry. Morphology: drag path, possible brown oxidation halo, no chip-flank sparkle, no pits. Classification: CAT-[1/2/3] by visibility and SC-class; reclassify to M.01 if incisions persist, or to Th.01.02 if pits/nodules are 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.

⭐ DSS-E

Damage Specification Standards 2026

DSS-E Environmental/Weathering/Biological

Draft v1.0

E.01 Marine/Coastal & Atmospheric

• E.01.01 Salt‐spray crystals / shoreline frosting
• E.01.02 Atmospheric corrosion matte (SOx/NOx/acid rain)
• E.01.03 Soot/particulate pollution film

E.02 Eolian Abrasion

• E.02.01 Wind‐borne sand abrasion (matte/frost)
• E.02.02 Dust storm micro‐pitting

E.03 Biological & Organic Deposits

• E.03.01 Algae/biofouling film
• E.03.02 Lichens/moss (rough adhesion)
• E.03.03 Tree sap/organic exudate shadow
• E.03.04 Avian residue acid shadow

E.04 Condensation/Runoff Patterns

• E.04.01 Recurring drip/run staining pattern
• E.04.02 Thermal bridging condensation patterning
• E.04.03 Curtain wall runoff staining (adjacent materials)

E.05 Photo‐Degradation of Films

• E.05.01 UV‐induced browning/yellowing of residues
• E.05.02 Oxidation darkening of films