Pipe Insulation for Condensation Control (Cold Lines)
The cold-pipe mirror of insulation-thickness, with the target COMPUTED instead of hand-entered: 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.
Formula and source
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.
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