Mechanical Insulation Design Guide - Design Objectives

by the National Mechanical Insulation Committee (NMIC)

Last updated: 06-19-2014

Condensation Control Calculator for Horizontal Pipe

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

Instructions

  • 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.

Assumptions

  • 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.
1. Select Pipe Size, NPS
2. Operating Temperature, °F
3. Ambient Temperature, °F
4. Ambient Relative Humidity, %
5. Wind Speed, mph
6. Select Insulation
7. Select Emittance of Surface