GI and BI pipe sizes — Schedule 40.
Steel pipe to ASTM A53, sized by nominal bore, standard 6.0m lengths. BI (black iron) is uncoated; GI (galvanized) is hot-dip zinc-coated for corrosion resistance — same steel, same dimensions.
Sizes and weights
ASTM A53 / ASME B36.10M · Schedule 40 (standard wall)
| Nominal size | OD (mm) | Wall (mm) | kg/m | kg per 6.0 m |
|---|---|---|---|---|
| 1/2" | 21.3 | 2.77 | 1.27 | 7.62 |
| 3/4" | 26.7 | 2.87 | 1.69 | 10.14 |
| 1" | 33.4 | 3.38 | 2.5 | 15 |
| 1-1/4" | 42.2 | 3.56 | 3.39 | 20.34 |
| 1-1/2" | 48.3 | 3.68 | 4.05 | 24.3 |
| 2" | 60.3 | 3.91 | 5.44 | 32.64 |
| 2-1/2" | 73 | 5.16 | 8.63 | 51.78 |
| 3" | 88.9 | 5.49 | 11.29 | 67.74 |
| 4" | 114.3 | 6.02 | 16.07 | 96.42 |
Weights are plain-end bare pipe; galvanizing adds roughly 3–5%. “Schedule 20” in the 1/2"–4" range is not an ASME-defined wall — it is a lighter commercial wall that varies by mill, which is why it isn’t tabulated here.
Grades
- ASTM A53 Grade A / Grade B. Schedule 40 = standard weight wall.
How it's sold
Sold per 6.0m length, black (BI) or galvanized (GI). Thin-wall “S-20” commercial pipe is also available — wall varies by supplier, so we confirm it on the quote. Send your pipe list for a same-day price. Send your list — spec sheet, drawing or BOQ — and we quote it back the same day.
Common questions
What is the difference between BI and GI pipe?
Same ASTM A53 steel and dimensions. BI is uncoated (structural work, gas/steam, painted applications). GI is hot-dip galvanized for water lines, railings and outdoor work; the zinc adds about 3–5% weight.
Schedule 40 vs Schedule 20?
Schedule 40 is the full standard wall shown above. PH “Schedule 20” is a lighter, thinner commercial wall that is not ASME-standardized at these sizes — confirm the actual wall thickness before structural use.
Why is the actual diameter bigger than the size?
Pipe is sized by nominal bore, not outside diameter. A 1" pipe has a 33.4mm OD; a 2" pipe has a 60.3mm OD.
Can GI/BI pipe be used structurally?
Yes — railings, canopies, fence posts, light scaffolding. For load-bearing use, confirm the schedule, since thin-wall pipe is much weaker.
Related steel
Specs reviewed July 2026 · Southend Construction & Industrial Supplies, Dasmariñas, Cavite