DN (izina rya diameter) risobanura diameter yizina ryumuyoboro, nikigereranyo cya diameter yo hanze na diameter yimbere. Agaciro ka Dn = agaciro ka de -0.5 * agaciro k'urukuta rwa tube. Icyitonderwa: Ibi ntabwo ari diameter yo hanze cyangwa diameter yimbere.

Amazi, ibyuma bya gaze (umuyoboro wicyuma gakomeye cyangwa umuyoboro udasimba), shyira umuyoboro w'icyuma , DN50).

De (diameter yo hanze) bisobanura diameter yo hanze yumuyoboro, ppr, yashyizweho ikimenyetso cyimiyoboro yo hanze, kandi muri rusange irangwa na DE, kandi ibikenewe byose hamwe na diameter yo hanze * kurugero × 35 × 3 .

D mubisanzwe bivuga diameter yimbere yumuyoboro.

D mubisanzwe bivuga diameter yimbere yumuyoboro wa beto. Amashanyarazi ashimangiye (cyangwa beto), imiyoboro y'ibumba, imiyoboro irwanya acide, imiyoboro ya silinder, umuyoboro w'imiyoboro, umuyoboro wa D230, D380, nibindi)

Φ yerekana diameter y'uruziga rusanzwe; Irashobora kandi kwerekana diameter yo hanze yumuyoboro, ariko iki gihe igomba kugwizwa nubwinshi bwurukuta.