DN (Nominal Dev) txhais tau tias yog lub nroog nominal ntawm cov yeeb nkab, uas yog qhov nruab nrab ntawm cov taub sab hauv thiab lub taub sab hauv. Tus nqi ntawm dn = tus nqi ntawm de -0.5 * tus nqi ntawm lub raj raj phab ntsa tuab. Nco tseg: Qhov no tsis yog cov txheej txheem sab nraud lossis cov taub sab hauv.

Dej, roj kev sib kis cov yeeb nkab hlau (galvanized steel yeeb nkab lossis cov yeeb nkab hlau nplaum), hlau yas comproside (PVC) yeeb nkab ntawm cov yeeb nkab "DN" (xws li DN15 , DN50).

De (sab nraud txoj kab uas hla) Cov.

D feem ntau hais txog lub inner inter ntawm cov yeeb nkab.

d feem ntau hais txog lub inner interer ntawm cov qhob yeeb nkab. Reinforced pob zeb (lossis pob zeb ua vaj tse) cov kav dej av, cov nplais uas muaj cov hlab pas dej sab hauv d (xws li D230, D380, thiab lwm yam)

Sawv cev rau txoj kab uas hla ntawm ib lub voj voog uas yog ib lub voj voog uas yog ib lub voj voog Nws kuj tseem tuaj yeem sawv cev sab nraud ntawm cov yeeb nkab ntawm cov yeeb nkab, tab sis lub sijhawm no nws yuav tsum tau sib npaug los ntawm phab ntsa tuab.