<P> Nominal Pipe Size ( NPS ) is a North American set of standard sizes for pipes used for high or low pressures and temperatures . `` Nominal '' refers to pipe in non-specific terms and identifies the diameter of the hole with a non-dimensional number ( for example -- 2 - inch nominal steel pipe '' consists of many varieties of steel pipe with the only criterion being a 2.375 - inch ( 60.3 mm ) outside diameter ) . Specific pipe is identified by pipe diameter and another non-dimensional number for wall thickness referred to as the Schedule ( Sched. or Sch. , for example -- `` 2 - inch diameter pipe , Schedule 40 '' ) . NPS is often incorrectly called National Pipe Size , due to confusion with the American standard for pipe threads , `` national pipe straight '' , which also abbreviates as `` NPS '' . The European and international designation equivalent to NPS is DN ( diamètre nominal / nominal diameter / Durchmesser nach Norm ) , in which sizes are measured in millimetres , see ISO 6708 . The term NB ( nominal bore ) is also frequently used interchangeably with NPS . </P>
<P> Nominal Pipe Size ( NPS ) is a North American set of standard sizes for pipes used for high or low pressures and temperatures . `` Nominal '' refers to pipe in non-specific terms and identifies the diameter of the hole with a non-dimensional number ( for example -- 2 - inch nominal steel pipe '' consists of many varieties of steel pipe with the only criterion being a 2.375 - inch ( 60.3 mm ) outside diameter ) . Specific pipe is identified by pipe diameter and another non-dimensional number for wall thickness referred to as the Schedule ( Sched. or Sch. , for example -- `` 2 - inch diameter pipe , Schedule 40 '' ) . NPS is often incorrectly called National Pipe Size , due to confusion with the American standard for pipe threads , `` national pipe straight '' , which also abbreviates as `` NPS '' . The European and international designation equivalent to NPS is DN ( diamètre nominal / nominal diameter / Durchmesser nach Norm ) , in which sizes are measured in millimetres , see ISO 6708 . The term NB ( nominal bore ) is also frequently used interchangeably with NPS . </P>
what is the meaning of schedule in pipes
what is the meaning of schedule in pipes
wall thickness
wall thickness