# Heat Transfer by Conduction Resistance through a Cylindrical Wall

## Heat Transfer by Conduction resistance through a Cylindrical Wall Formula |
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\(\large{ R_t = \frac { ln \; \left( \frac {r_2 } { r_1 } \right) } { 2 \; \pi \; k \; l } }\) | ||

Symbol |
English |
Metric |

\(\large{ R_t }\) = thermal resistance | \(\large{\frac{hr-F}{Btu}}\) | \(\large{\frac{K}{W}}\) |

\(\large{ l }\) = length of material | \(\large{ft}\) | \(\large{m}\) |

\(\large{ ln }\) = natural logarithm | \(\large{dimensionless}\) | |

\(\large{ \pi }\) = Pi | \(\large{3.141 592 653 ...}\) | |

\(\large{ r_1 }\) = radius inside diameter (ID) | \(\large{in}\) | \(\large{mm}\) |

\(\large{ r_2}\) = radius outside diameter (OD) | \(\large{in}\) | \(\large{mm}\) |

\(\large{ k }\) = thermal conductivity | \(\large{\frac{Btu-ft}{hr-ft^2-F}}\) | \(\large{\frac{W}{m-K}}\) |