Question 1

Can I substitute MS for GI to save cost?

Accepted Answer

Only if the engineer of record approves in writing. GI is often specified for corrosion exposure or code-of-practice reasons; silent substitution shifts liability to the contractor.

Question 2

Is ERW relevant to the MS vs GI decision?

Accepted Answer

ERW describes how the tube was formed; MS/GI describes base steel and coating. A product can be ERW MS or ERW GI — compare quotes on dimensions and standards, not jargon alone.

Question 3

What should I send for the fastest accurate quote?

Accepted Answer

OD/NB, wall thickness or schedule, length, quantity, standard note from the drawing, delivery city, and whether you need test certificates. Photos of the drawing snippet reduce back-and-forth.