As partially full pipes are considered by definition open channels, as they aren't pressurized, the Manning and Chézy formulas can be applied to calculate partially full pipe flow. However, the intended use of these formulas are primarily for considering uniform and turbulent flow. Many other formulas that have been developed since may produce more accurate results, such as the Darcy–Weisbach equation or the Hazen–Williams equation, but lack the simplicity of the Manning or Chézy formulas.