IV Cannula and fluid flow rates

Cannula size Colour Time to infuse 1000ml Normal saline under ideal circumstances
22 G Blue 22 min
20 G* Pink 15 min
18 G Green 10 min
16 G Grey 6 min
14 G* Red 3.5 min

* French system - 4F = 20G, 6F = 14G

French system

French Size Diameter Examples of use
4F 1.3 mm Paediatric long lines
6F 1.9 mm Paediatric long lines
8F - 20F 3.8-6.4 mm Vascath
10F-18F 3.2-5.7mm NGT
24F - 32F 7.6-10.4 Adult chest drains