DN (Nominal Diameter) zvinoreva dhayamita rezita repombi, inova avhareji yedhayamita rekunze nedhayamita remukati. Kukosha kweDN = kukosha kweDe -0.5* kukosha kwechubhu rusvingo ukobvu. Cherechedza: Iyi haisi iyo dhayamita yekunze kana dhayamita yemukati.

Mvura, gasi kutapurirana simbi pombi (galvanized simbi pombi kana non-galvanized simbi pombi), cast iron pombi, simbi-plastiki composite pombi uye polyvinyl chloride (PVC) pombi, zvichingodaro, inofanira kunyorwa zita dhayamita "DN" (senge DN15 DN15) , DN50).

De (External Diameter) zvinoreva dhayamita rekunze repombi, PPR, PE pombi, pombi yepolypropylene yekunze dhayamita, inowanzo nyorwa neDe, uye zvese zvinoda kuiswa chiratidzo sedhiyamita rekunze * ukobvu hwemadziro, semuenzaniso De25 × 3 .

D kazhinji inoreva dhayamita yemukati yepombi.

d kazhinji inoreva dhayamita yemukati yepombi yekongiri. Yakasimbiswa kongiri (kana kongiri) pombi, ivhu pombi, asidhi-resistant ceramic pombi, humburumbira mataira uye dzimwe pombi, ane pombi dhayamita inofanira kumiririrwa mukati dhayamita d (senge d230, d380, nezvimwewo)

Φ inomiririra dhayamita yedenderedzwa rakafanana; inogonawo kumiririra dhayamita yekunze yepombi, asi panguva ino inofanira kuwedzerwa nehupamhi hwemadziro.