Static field route #19609

What do I do when the heel of an insulated 45-degree elbow is sweating and dripping?

Insulation, Liner, Vapor Barrier & Condensation⚠️ CHECK BEFORE YOU FIXField answer expansion

📖 Verified core answer

Condensation usually means humid air is reaching cold metal through an air gap or broken vapor barrier. Dry it, tighten the wrap, and seal the vapor barrier continuously.

Open in Field Rescue Open category

Field verification checklist

Find the exact sweating point on the elbow heel.
Look for loose wrap, air pockets, torn foil, or wet insulation.
Dry the metal skin before resealing.
Maintain continuous vapor barrier around the curve.
Check nearby uninsulated collars, taps, and seams too.

Ask foreman

The 45 elbow heel at [location] is sweating because the insulation/vapor barrier has a gap. I dried the area and found the break. Do you want the wrap replaced and resealed now?

Text to foreman

Route options

A Correct it only if the fix is within your assignment and approved method.

B Hold and document if it affects pressure class, listed assembly, material spec, support load path, fire barrier, equipment, TAB, or another trade.

C Bring the foreman/detailer the location, what you checked, and what decision you need before sealing, testing, cover, or startup.

Do not do this

Do not tape over wet insulation or leave air pockets against cold supply duct.

Why this matters

Sweating duct can damage ceiling tile, create mold risk, and ruin insulation performance.

Final verification

Use this as field training guidance. Final direction still comes from the foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, pressure/material schedule, and AHJ/code requirements.

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