I-DN (I-Nominal Diameter) isho ububanzi obuncane bepayipi, okuyisilinganiso sobubanzi obungaphandle kanye nobubanzi obungaphakathi. Inani le-DN =inani lika-De -0.5*inani lokujiya kodonga lweshubhu. Qaphela: Lona akuwona ububanzi bangaphandle noma ububanzi bangaphakathi.

Amanzi, ipayipi lensimbi yokudlulisa igesi (ipayipi lensimbi eliwuthayela noma ipayipi lensimbi elingapheqiwe), ipayipi lensimbi eliwubunjiwe, ipayipi eliyinhlanganisela yensimbi-yepulasitiki kanye nepayipi le-polyvinyl chloride (PVC), njll., kufanele kumakwe usayizi omncane othi “DN” (njenge-DN15) , DN50).

I-De (Ububanzi Bangaphandle) isho ububanzi obungaphandle bepayipi, i-PPR, ipayipi le-PE, ipayipi le-polypropylene ububanzi obungaphandle, ngokuvamile obuphawulwe ngo-De, futhi konke kufanele kumakwe njengefomu njengobubanzi obungaphandle * ukujiya kodonga, isibonelo i-De25 × 3 .

U-D ngokuvamile ubhekisela kububanzi obungaphakathi bepayipi.

d ngokuvamile ibhekisela kububanzi bangaphakathi bepayipi likakhonkolo. Amapayipi kakhonkolo aqinisiwe (noma kakhonkolo), amapayipi obumba, amapayipi e-ceramic amelana ne-asidi, amathayela esilinda namanye amapayipi, ububanzi bepayipi lawo okufanele bumelwe yi-diameter engaphakathi engu-d (efana no-d230, d380, njll.)

Φ imele ububanzi besiyingi esivamile; ingase futhi imele ububanzi obungaphandle bepayipi, kodwa kulokhu kufanele iphindwe ubukhulu bodonga.