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High-risk field starter

Corrosive duct hardware check.

Use this when duct, hangers, rods, straps, clamps, anchors, screws, nuts, bolts, or washers are in pool/natatorium air, chemical air, high humidity, coastal air, kitchen/special exhaust, or any environment where corrosion is possible.

Ask TinnerFlowSupport routeCorrosion route

Stop-and-check rule

If overhead duct support hardware shows rust, pitting, staining, white powder, loose clamps, failed coating, or eaten hardware, treat it as a stop-and-report condition. This is not cosmetic when heavy duct is overhead.

What to verify

  • Duct material: galvanized, aluminum, stainless, coated, fabric, PVC/plastic-coated, or other specified system.
  • Hanger rods, straps, clamps, cables, trapeze, anchors, screws, nuts, bolts, and washers.
  • Fastener grade/type and whether stainless hardware is actually specified.
  • Coating, isolation pad, gasket, washer, sealant, or dissimilar-metal detail.
  • Anti-seize/thread lubricant requirement for stainless fasteners.
  • Access for future inspection and maintenance.

Stainless hardware note

Stainless hardware may be required on some jobs, but the grade/type and environment matter. Stainless fasteners can gall or seize during tightening, so use approved anti-seize/thread lubricant when directed.

Anti-seize helps with thread galling/seizing. It does not magically make the entire support corrosion-proof.

Dissimilar metals

If stainless touches aluminum, galvanized steel, coated duct, or other metals, verify the isolation/coating/washer/gasket/detail. Moisture plus corrosive air plus dissimilar metals can create galvanic corrosion risk.

Do not

  • Do not swap hardware material without checking the spec.
  • Do not assume zinc/galvanized/plain steel is acceptable in a corrosive area.
  • Do not assume all stainless is the same.
  • Do not dry-run stainless threads under load when anti-seize is required.
  • Do not cover corroded, stained, pitted, or questionable support hardware.

Ask foreman script

This area looks corrosion-sensitive. What duct, hanger, rod, anchor, screw, nut, bolt, washer, coating, and isolation material are required here? Do you want stainless hardware with approved anti-seize, and is there a dissimilar-metal isolation detail?

Field limit

This is a starter checklist, not approval. Project drawings, specs, submittals, manufacturer instructions, foreman/engineer direction, AHJ requirements, and company safety policy control.

Field use: Educational aid only — not job approval. Drawings/specs, manufacturer instructions, employer policy, foreman direction, and AHJ/local code win. Safety Terms Privacy