degree Fahrenheit second/Btu (IT) Unit Converter

Definition of degree Fahrenheit second/Btu (IT) unit

The degree Fahrenheit second per British thermal unit (international table), written °F·s/Btu(IT), is a thermal-resistance unit. It expresses a temperature difference of one Fahrenheit degree produced by a heat-transfer rate of one Btu(IT) per second.

History of degree Fahrenheit second/Btu (IT) unit

The unit combines the Fahrenheit temperature scale, the second as the SI base unit of time, and the international-table British thermal unit. The Btu(IT) was standardized as 1,055.056 joules in the mid-twentieth century, while the Fahrenheit scale originated in the early eighteenth century. Engineers obtained °F·s/Btu by expressing thermal resistance with heat rate measured in Btu per second rather than the more common Btu per hour. It therefore reflects customary engineering practice and converts to 5/(9 × 1,055.056) K/W. Modern SI usage generally favors K/W.

Applications of degree Fahrenheit second/Btu (IT) unit

Today, °F·s/Btu(IT) may appear in legacy heat-transfer literature, specialized databases, and calculations involving transient thermal resistance or thermal impedance. For example, it can describe a component’s temperature rise when heat input is stated in Btu(IT) per second. Designers more commonly use °F·h/Btu in HVAC and insulation work, or K/W in scientific and international engineering contexts.

Complete list of degree Fahrenheit second/Btu (IT) unit conversion