DN (Nominal Diamita) yana nufin ƙananan diamita na bututu, wanda shine matsakaicin diamita na waje da diamita na ciki.Darajar DN = darajar De -0.5 * darajar kaurin bangon bututu.Lura: Wannan ba diamita na waje bane ko diamita na ciki.

Ruwa, iskar gas watsa karfe bututu (galvanized karfe bututu ko mara galvanized karfe bututu), jefa baƙin ƙarfe bututu, karfe-roba hada bututu da polyvinyl chloride (PVC) bututu, da dai sauransu, ya kamata a alama maras muhimmanci diamita "DN" (kamar DN15). ,DN50).

De (Diamita na waje) yana nufin diamita na waje na bututu, PPR, bututun PE, bututun polypropylene, diamita na waje, gabaɗaya alama tare da De, kuma duk suna buƙatar a yiwa alama alama azaman diamita na waje * kauri na bango, misali De25 × 3 .

D gabaɗaya yana nufin diamita na ciki na bututu.

d gabaɗaya yana nufin diamita na ciki na bututun siminti.Ƙarfafa bututu (ko kankare) bututu, bututun yumbu, bututun yumbu mai jure acid, fale-falen silinda da sauran bututu waɗanda diamitansu ya kamata a wakilta su da diamita na ciki d (kamar d230, d380, da sauransu).

% yana wakiltar diamita na da'irar gama gari;Hakanan zai iya wakiltar diamita na waje na bututu, amma a wannan lokacin ya kamata a ninka shi da kaurin bango.