API 6D January 2002 / ISO 14313: 1999
Table 1 reflects minimum bores for full-open valves beginning with NPS 1/2 and ending with NPS 60.
Table 2 for face-to-face and end-to-end dimensions starts at NPS 2 and ends at different sized depending upon end flange type and class. Subsequent tables begin with NPS 2.
Thank you for your answer, on Par. 6.2 the norme stated "Reduced-opening valves shall be furnished in the nominal sizes in accordance with Table 1", so in my opinion API 6D cover 1/2" reduced bore ball valve. I accept further discussion about this my interpretation. Thank you in advance to everybody want to give his personal interpretation.
