Way to describe steel pipe dimensions and size correctly.
For example: a. Expressed as “pipe outside diameter × wall thickness”, such as Φ 88.9mm x 5.49mm (3 1/2” x 0.216” ). 114.3mm x 6.02mm (4 1/2” x 0.237”), length 6m (20ft) or 12m (40ft), Single Random Length (SRL 18-25ft), or Double Random Length (DRL 38-40ft).
b. Expressed as “NPS x Schedule”, NPS 3 inch x Sch 40, NPS 4 inch x Sch 40. Same size as above specification.
c. Expressed as “NPS x WGT Class”, NPS 3 inch x SCH STD, NPS 4 inch x SCH STD. Same size above.
d. There is another way, in North America and South America, usually use “Pipe Outer Diameter x lb/ft” to describe pipe size. As OD 3 1/2”, 16.8 lb/ft. lb/ft is pound per feet.