Condensation Control Calculator for Horizontal Pipe  

by the National Mechanical Insulation Committee (NMIC)


This Calculator estimates the thickness of insulation required to prevent condensation on the outer surface of an insulation system.


  • Line 1. Select Nominal Pipe Size, NPS
  • Line 2. Enter average operating (process) temperature
  • Line 3. Enter average temperature of the air surounding the pipe
  • Line 4. Enter relative humidity of the ambient air
  • Line 5. Enter the wind speed of the ambient air (if unknown, use 0 mph for worst case conditions)
  • Line 6. Select an insulation material
  • Line 7. Select the effective emittance of the exterior surface

Notes: Condensation control thickness is highlighted. (The thickness that provides average surface temperature > Dew Point + a safety factor of 0.75°F)

NA = Not Available. Some sizes and thicknesses may not be commercially available and some materials are available in sizes and thicknesses not listed.


  • One dimensional, steady state heat transfer
  • Base structure is a horizontal steel pipe
  • Thermal conductivity based on ASTM Specification Values. Refer to the introductory notes for further clarifications.