Condensation Control Calculator - Horizontal Pipe

    This calculator estimates the thickness of insulation required to avoid condensation on the outer surface of an insulated horizontal steel pipe. Input data includes the operating temperature, the ambient conditions (temperature, relative humidity, and wind speed) and details about the insulation system (material and jacketing).

    The insulation materials included in this calculator were selected to be representative of some of the materials commonly used in the industry. The list is not exhaustive and other materials are available. Also note that some materials are not available in all of the sizes and thicknesses covered by these calculators and some are available in sizes and thicknesses not listed. Thermal conductivity data for the materials included in the calculator were taken from the appropriate American Society for Testing and Materials (ASTM) material specification. The table below identifies the ASTM specification and the material type and/or grade utilized in the calculator.


    Insulation Standard

    Cellular Glass ASTM C 552-07 Type I
    Elastomeric ASTM C 534-08 Type II, Gr 1
    Fiberglass ASTM C 612-09 Type I B
    Mineral Wool ASTM C 612-09 Type IV B
    Polyethylene ASTM C 1427-07 Type II, Gr 1
    Polyisocyanurate ASTM C 591-08a Type IV
    Polystyrene ASTM C 578-09 Type XIII

    Condensation Control Calculator for Horizontal Pipe


    Users will need to input the following:

    • Nominal pipe size, in inches
    • Average operating (process) temperature, °F
    • Average temperature (ambient air) of the air surrounding the pipe °F
    • Relative humidity of the ambient air (%)
    • Wind speed of the ambient air, miles per hour (mph)
    • Select an insulation material from the drop down box
    • Select the effective emittance of the exterior surface (Drop down box guidance provided)


    Based on input, calculator will provide the following:

    • Due point of ambient air, °F
    • Insulation thickness required for surface temperature to be above due point
      • Surface temperature, °F
      • Heat Flow, British thermal unit per hour per foot (Btu/h/ft)

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