February 04, 2021
DPM-FAQSeries Topic 5: What are the different Drill Pipe classifications?
Class 1 (New) – This class designation applies to new drill pipe tube.
Premium Class – The Premium Class designation applies only to used normal weight drill pipe. The tube remaining wall thickness (WT) shall not be less than 80% of the new nominal wall thickness.
Class 2 – The tube remaining wall thickness shall not be less than 70% of the new nominal wall thickness.
Do note that Class 2 and below drill pipe classifications are rarely used these days.
When the drill pipe is new, the “New” values are referenced on the datasheet. Once the drill pipe has been in the hole, it would be classified as “Premium” and the “Premium” values should then be referenced on the datasheet.
Standard DS-1® Volume 3 includes a new class:-
Ultra Class – The tube remaining wall thickness shall not be less than 90% of the new nominal wall thickness.
The Ultra Class provides acceptance criteria more stringent than that provided by Premium Class for deepwater applications.
For more information, API RP 7G-2 Recommended Practice for Inspection and Classification of Used Drill Stem Elements, Table B.18 lists all criteria for the classification of used drill pipes.