Galvanized Steel Pipe Sizes, Dimensions & Size Chart Guide
Galvanized steel pipe is a widely used piping material in construction, water supply, fire protection systems, and industrial applications. With its protective zinc coating, galvanized steel pipe resists corrosion, enhances durability, and ensures long-term service even in harsh environments.
This guide provides a complete overview of galvanized steel pipe size charts, standard dimensions, classifications, and selection recommendations to help engineers, contractors, and procurement managers make informed decisions.
What Are Galvanized Steel Pipe Sizes?
Galvanized steel pipes follow Nominal Pipe Size (NPS) and Schedule (SCH) standards.
Although the term “size” suggests diameter, NPS does not always equal the actual inside or outside diameter.
A galvanized steel pipe size typically includes:
Nominal Pipe Size (NPS) – 1/2", 1", 2", etc.
Outside Diameter (OD)
Wall Thickness (based on Schedule 20, 40, 80)
Inside Diameter (ID)
Weight per meter
Galvanized pipes are commonly produced according to ASTM A53, ASTM A123, BS 1387, EN 10255, and other global standards.
Galvanized Steel Pipe Size Chart (NPS 1/2" – 12")
Below is a widely used galvanized steel pipe size chart, covering OD, wall thickness, and approximate weight. (Dimensions may vary slightly depending on SCH and standard.)
NPS | Outside Diameter (OD) mm | Outside Diameter (OD) inch | Typical Wall Thickness (mm) | Inside Diameter (ID) mm | Approx. Weight (kg/m) |
1/2" | 21.3 | 0.84" | 2.77 | 15.8 | 1.27 |
3/4" | 26.7 | 1.05" | 2.87 | 20.9 | 1.68 |
1" | 33.4 | 1.315" | 3.38 | 26.6 | 2.47 |
1¼" | 42.2 | 1.66" | 3.56 | 35.1 | 3.39 |
1½" | 48.3 | 1.90" | 3.68 | 40.9 | 4.05 |
2" | 60.3 | 2.375" | 3.91 | 52.5 | 5.44 |
2½" | 73.0 | 2.875" | 5.16 | 62.7 | 8.63 |
3" | 88.9 | 3.50" | 5.49 | 77.9 | 11.29 |
4" | 114.3 | 4.50" | 6.02 | 102.3 | 15.93 |
5" | 141.3 | 5.56" | 6.55 | 128.2 | 21.73 |
6" | 168.3 | 6.625" | 7.11 | 154.1 | 28.26 |
8" | 219.1 | 8.625" | 8.18 | 202.7 | 49.56 |
10" | 273.1 | 10.75" | 9.27 | 254.6 | 70.55 |
12" | 323.9 | 12.75" | 10.31 | 303.3 | 92.50 |
Note: SCH 40 values shown. SCH 20 (light) and SCH 80 (heavy) variations also available.
Types of Galvanized Steel Pipes by Dimensions
Galvanized pipes can be categorized by thickness, application, and manufacturing method:
1. Hot-Dip Galvanized (HDG) Steel Pipe
Most common type
Dipped in molten zinc
Best corrosion resistance
Used for water supply lines, fire systems, steel structures
2. Galvanized Conduit Pipe (HDG Conduit Pipe)
Designed for electrical wiring protection
Thinner than fluid pipes
Not recommended for water or gas transport
Standard: UL 797, BS 4568
Difference from HDG steel pipe:
HDG conduit pipe = electrical use;
HDG steel pipe = plumbing / structural use.
3. Powder-Coated Galvanized Steel Pipe
Galvanized base + polyester powder coating
Enhanced aesthetic appearance
Extra protection for outdoor exposure
Common in fences, handrails, greenhouses
Galvanized Steel Pipe Dimensions Explained
To choose the right pipe, it is important to understand the four key measurements:
1. Outside Diameter (OD)
Determines pipe compatibility with fittings
OD is fixed for each NPS size
2. Wall Thickness (Schedule)
SCH 20 = light
SCH 40 = standard
SCH 80 = thick/heavy
3. Inside Diameter (ID)
Impacts water flow and pressure levels
4. Pipe Length
Standard lengths:
6 meters
21 feet
Custom lengths available
Galvanized Steel Pipe Sizes by Application
Choosing the correct dimensions depends largely on the application.
Water Supply Lines
Common sizes: 1/2", 3/4", 1", 1½"
Why: Suitable for residential and commercial plumbing systems.
High-Pressure Systems
Use thick-wall (SCH 80) pipes:
2", 3", 4"
Structural and Scaffolding
Popular sizes:
1¼", 1½", 2"
Agriculture & Irrigation
Preferred sizes:
2", 2½", 3"
Firefighting (Sprinkler) Systems
Standard:
1", 1¼", 1½", 2", 2½"
How to Choose the Right Galvanized Steel Pipe Size
When selecting a galvanized pipe, many engineers compare it with standard steel tube options. While steel tubes are often used for structural or mechanical applications, galvanized pipes are preferred when corrosion protection is essential. For fluid transport, the zinc-coated carbon steel tube ensures longer lifespan and lower maintenance costs.
FAQs About Galvanized Steel Pipe Size
Q: Are galvanized steel pipes the same as carbon steel tubes?
A: Galvanized pipes are carbon steel tubes that have undergone a zinc coating process to resist corrosion.
Q: Can I use steel tube sizes interchangeably with galvanized pipe sizes?
A: Not always. While both belong to the steel family, steel tube dimensions are typically based on exact OD/ID, whereas galvanized pipes follow the NPS/SCH system.
Q: What type of steel is used for galvanized pipes?
A: Most galvanized pipes are made from carbon steel, offering high strength, durability, and cost-effectiveness.
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