Pipe Insulation for Condensation Control (Cold Lines)

The ambient dew point from the design-day RH, then the minimum wall that holds the outer jacket exactly at it. A 1-in 40 F chilled line at 75 F / 50% RH needs 0.92 in - round UP to the next stock wall, because a jacket at the dew point is on the edge of sweating all day. Flags the no-risk case (pipe above dew point) and the near-saturation case no thickness fixes.

Tdp from the ambient RH (saturation-vapor-pressure psychrometrics); minimum wall from the outer-surface balance h (2 pi r2/12)(Tamb - Tdp) = 2 pi k (Tdp - Tpipe)/ln(r2/r1), solved for r2; thickness = r2 - r1.

Standard cylindrical-conduction and surface-film heat balance (the same public engineering relations as the landed insulation-thickness and pipe-heat-loss-radial tiles) with the dew point from the catalog's pinned psychrometric functions; no standard table reproduced.

The conduction/film balance and Magnus-form psychrometrics are public engineering relations; manufacturer condensation-control design guides publish the equivalent tables free.

Estimate. AHJ and licensed professional govern.

Field names used by the API: pipe_od_in, pipe_temp_F, ambient_F, ambient_rh_pct, k_btu_in_per_hr_ft2_F, outside_film_coeff_btu_hr_ft2_F, dew_point_F, thickness_in, r2_in

• Dew point source computed from the repo's pinned saturation-vapor-pressure / dew-point functions, not a lookuppure-math.js psychrometrics (Magnus form)
• Film coefficient 1.65 BTU/hr-ft^2-F still-air default, identical to the insulation-thickness siblingpublic engineering reference value
• Vapor retarder assumed continuous; failure moves condensation inside the insulationmanufacturer design guides