Atkinson friction factor is a measure of the resistance to airflow of a duct. It is widely used in the mine ventilation

Underground mine ventilation

Underground mine ventilation provides a flow of air to the underground workings of a mine of sufficient volume to dilute and remove noxious gases . The source of these gases are equipment that runs on diesel engines, blasting with explosives, and the orebody itself...

 industry but is rarely referred to outside of it.

Atkinson friction factor is represented by the symbol and has the same units as air density (kilograms per cubic metre in SI units

Si

Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...

, pounds per cubic foot in Imperial unit

Imperial unit

The system of imperial units or the imperial system is the system of units first defined in the British Weights and Measures Act of 1824, which was later refined and reduced. The system came into official use across the British Empire...

s). It is related to the more widespread Fanning friction factor by



in which is the density of air in the shaft or roadway under consideration and is Fanning friction factor (dimensionless). It is related to the Darcy friction factor by



in which is the Darcy friction factor (dimensionless).

It was introduced by John J Atkinson in an early mathematical treatment of mine ventilation (1862) and has been known under his name ever since.

Further reading

• 1999 paper giving the derivation of
• Atkinson, J J, Gases met with in Coal Mines, and the general principles of Ventilation Transactions of the Manchester Geological Society, Vol. III, p.218, 1862