What is the Fr in tubing sizes?
• Fr stands for ‘French Size’. It is a world wide standard for medical tubing outside diameter. Developed by a French physician in the 1800’s, it is a measurement of tubing circumference. The theory being that non-round tubes of the same circumference will fit into the same incision in the skin or vessel. One French is approximately 1/3 of a millimeter .013 inch.
