Definition
Nominal Weight — Nominal weight is the standardized weight per foot of a tubular used to identify and order it — for example 5 in 19.50 lb/ft drill pipe — serving as a size label that correlates with wall thickness and load capacity rather than the exact adjusted weight.
Also known as: nominal weight, weight per foot, lb/ft, ppf
What nominal weight is
Nominal weight is the weight per foot, in pounds, that API assigns to a tubular of a given size — for instance 5 in, 19.50 lb/ft drill pipe or 5-1/2 in, 21.90 lb/ft. It is primarily an identifier: it distinguishes different wall thicknesses of the same outside diameter and is the number used when specifying and ordering pipe.
For drill pipe the nominal weight is a plain-end reference; the tool joints add to the true weight, so the adjusted weight used in string calculations is slightly higher. Even so, nominal weight tracks directly with wall thickness and therefore with tensile, collapse and burst ratings.
Why it matters
- Ordering — OD plus nominal weight plus grade uniquely specifies the pipe.
- Load capacity — heavier nominal weight means thicker wall and higher ratings.
- Hook load — buoyed string weight, derived from nominal/adjusted weight, sets the required rig and derrick capacity.
Renting by nominal weight
Specifying OD, nominal weight and grade ensures you get pipe with the right wall and ratings for the well. We stock drill pipe and drill collars across common nominal weights — contact us with your target loads.