Guia de Seleção e Compra
DN, NB or Inches: Sizing Pipe Fittings Without the Ordering Mistakes
A drawing says DN 25, the BOQ says 1 inch, and a caliper reads 33 mm. Only one of those is a measurement. How nominal sizing works, how to get from a caliper reading back to a size, and how to write a reducing fitting so it arrives the right way round.