Calculating R-Value AEROFLEX® EPDM™ Closed-Cell Elastomeric Foam Insulation
WHY THERMAL INSULATION?
Mechanical insulation effectively reduces heat exchange between a pipe, duct, or equipment and its environment. An insulation’s thermal efficiency is measured by thermal conductivity (K-value). The lower the K-value, the more thermally efficient insulation is. For example, a K-value of 0.245 is preferable to .280.
WHAT IS R-VALUE?
Thermal resistance to heat flow. The higher the number, the better. For example, an R-value of 8.2 is more thermally efficient than 7.1.
HOW TO CALCULATE R-VALUE?
SHEETS / ROLLS (FLAT)
R = Thickness / K-valueR = 2.0” / 0.245
TUBES (RADIAL) – TUBES ARE CALCULATED DIFFERENTLY THAN SHEETS / ROLLS
Tip: R-value increases as insulation thickness increases and pipe size decreases.
Example: 1-1/2” thick insulation will generate a higher R-value on a 7/8” pipe than 2-1/8” pipe.
Ru = radius of uninsulated pipeRi = radius of insulated pipeK = K-valueln = natural logarithm
Note: Thermal conductivity (K-values) and R-values are listed on Aeroflex technical data sheets.