# Thermal Resistivity and Conductivity

## The ability of a material to resist flow of heat.

Thermal resistance is the ability of a material to resist flow of heat. Thermal resistivity is the reciprocal of thermal conductivity and can be expressed as

r = 1 / k (1)

where

r = thermal resistivity (m^{o}C/W, hr ft^{2}^{o}F/(Btu in))

k = thermal conductivity (W/(m^{o}C), Btu in/(hr ft^{2}^{o}F))

Thermal conductivity - *k* - is the property of a material indicating its ability to conduct heat.