ERW vs Seamless Decision Helper

Design pressure / class Low (≤ Class 150)Medium (Class 300)High (≥ Class 600 / E=1.00 mandated) Service medium Water / air / steam / structuralOil & gas, standard (gathering/distribution)Sour (HIC) / lethal / cyclic high-pressure Outside diameter NPS ½–24 (≤ 610 mm)Above NPS 24 / small-bore thick-wall Service temperature Ambient to moderateHigh-temp creep range Get recommendation

Guidance only, per ASME B31.3 weld joint quality factor (ERW 0.85, seamless 1.00). Confirm against your governing code and project spec.