These insulation scenarios for hot-oil applications use bare 2" pipe, and pipe sizes from 2" to 20" with an insulation layer sized to keep outer insulation temperatures below 140ºF.

For those conditions, and other assumptions listed below, the table shows relative heat loss, percent efficiency, energy cost, and cost savings over bare pipe.

  • Geometry: Horizontal steel pipe
  • Outer Jacket: All Service Jacket
  • Bare Surface Emittance: 0.8
  • Insulation Layer: Cellular Glass, Type II, Pipe & Tube
  • Process Temp: 500ºF
  • Average Ambient Temp: 75ºF
  • Fuel:  Natural Gas @ $10/Mcf
  • Heat Content: 1,026 BTU/ft3
  • Efficiency: 75%
  • Hours/Year: 8320
  • Outer Surface Emittance: 0.9
  • Thickness: Varied
  Calculations performed with 3E Plus v. 4.0 Insulation Calculation Software from NAIMA available for free at