February 16, 2023
Online slide rule & Data sheets. Click here: https://globalsupplyline.com.au/flange-table-chart-size-as-ansi/ for our online flange slide rule.
‘DN’ originates from the term ‘Diameter Nominale’. It’s a rough translation of mm for imperial sizes. It assumes that an inch is 25mm (which it’s not, it’s 25.4mm). For example a 10” flange is referred to as a 250mm in lieu of 254mm.
Even the ANSI imperial system is itself not exact in terms of bore size, hence it is termed ‘nominal bore’ as each class has a different bore. Note: metric ANSI equivalents are not different. However, metric AS equivalents of BS can differ slightly in bolt hole size to accommodate metric bolts.
Click here for the full article: https://www.linkedin.com/pulse/flange-tables-online-slide-rule-data-sheets-brian-g-thompson-/?published=t