[karthik]

Dear Jop & Anton,
Thank you very much for ur reply ? Yup ‘NB’ i mentioned was Nominal bore.
I was really not aware of ‘DN” = Diameter Nominal I have been working in piping for all most 4 yrs but every one uses NB(nominal bore).
do i have any doc which specifies this so that i can educate my colluges with some proof because every one uses trem NB (nominal bore). to specifey a pipe in MM for ex –25NB, 50NB
thank u very much for educating us reg the assumption of NB and DN .