Stainless Steel Pipe Size & Schedule Chart

Outside diameter does not change with schedule. For a given NPS the OD is fixed — the schedule changes the wall thickness, and therefore the bore. A 2" SCH 10S and a 2" SCH 80S pipe both measure 60.3 mm across the outside; the 80S simply has less room inside. This is what lets fittings and flanges of one size suit any schedule.

Schedule 40S is not always Schedule 40. The "S" suffix denotes the stainless schedules of ASME B36.19M. Up to NPS 10, 40S and 40 share the same wall, as do 80S and 80 — above that they diverge. A drawing calling for "SCH 40" on a 12" line is not asking for the same wall as "SCH 40S". If a specification is ambiguous, confirm it before ordering; this is a routine and expensive source of ordering errors.

This chart is being prepared. Dimensional data is awaiting verification against the current edition of ASME B36.19M before publication. In the meantime, send us the size and schedule you need and we will confirm dimensions directly — contact us.