A Complete Guide for Contractors, Engineers, and Buyers
Pipe is used for everything from tree stakes to nuclear cooling. Tree stakes don’t usually require knowing material grades, types of seams, or ASME code requirements, but nuclear cooling systems do.
A small mistake in material grade, schedule, or end prep can delay a project, increase costs, or create installation issues in the field. Whether you’re ordering for a municipal job, fabrication shop, or industrial plant, knowing exactly what information to provide ensures you get the right product the first time.
This guide breaks down everything you need to specify when ordering pipe.
1. Start with the Material Specification
The first and most important detail is the material standard.
Examples:
- ASTM A53 – Carbon steel pipe for mechanical and pressure service
- ASTM A106 – Seamless carbon steel for high-temperature service
- ASTM A312 – Stainless steel pipe
- API 5L – Carbon steel pipe primarily used in the petroleum industry
- ASTM B729 – Alloy 20 pipe
The standard is only the beginning. Nearly all standards cover several grades of material. Each grade has unique chemical and mechanical properties.
Examples of grades:
- ASTM A53 grade A
- ASTM A312 grade 310H
- API 5L grade X52
If you ask for “steel pipe for tree stakes”, that should be enough. But a steam pipe will require material standards and the grade.
2. Specify Pipe Size Correctly
There are many different types of pipe sizes. Here are a few common standards.
NPS - Nominal Pipe Size (also referred to as IPS) sizes are defined by ASME B36.19 and B36.10. Many of the sizes within these two specifications are the same, but some are not.
CIOD - Cast Iron Outside Diameter sizes are defined by AWWA
SDR - Standard Dimension Ratio is defined by ASTM F679 and ASTM D3034
A 4” pipe in the above examples will have completely different dimensions. It is also important to note that there is no actual 4” dimension on a 4” pipe in these standards. i.e. 4” CIOD = 4.90” OD and 4” NPS = 4.50” OD.
Examples of a correct specification are:
- 2” NPS
- 6” CIOD
- 12” SDR
In lieu of the sizing standard, it is always acceptable to list the actual outside dimension as long as you define it. i.e. 4.50” OD
3. Include the Schedule (Wall Thickness)
The wall thickness can be defined by the actual dimension, the pipe schedule and standard (B36.10), or the DR designation (DR18). Every pipe size standard has its own defined wall thickness nomenclature.
Common examples:
- B36.19 Schedule 10s
- B36.10 Schedule 40
- ASTM D2665 Schedule 40
- AWWA C900 DR18
The size and wall thickness are typically called out together. 4” NPS Sch40 per B36.10
API Pipe sizes are typically called out by their actual dimensions. 4.50” OD x .237” wall thickness. This is usually acceptable for defining all sizes and wall thicknesses.
4. Choose the Manufacturing Type
Some specifications allow multiple production methods.
Common types:
- Type S - SMLS (Seamless)
- Type E - ERW (Electric Resistance Welded)
- Type F - FW (Furnace Welded)
If it matters for your application, you need to specify it.
5. Define the Length
Pipe can be supplied in:
- Random Length (RL) — typically 20’–24’
- Double Random (DRL) — typically 35’–42’
- Cut-to-length
- Exact footage per stick
If you need specific lengths, you need to specify them.
6. Specify End Connections
This is one of the most commonly missed details. Some types of pipe are available with only one end type of end connection, but many have several.
Common end types:
- Plain End (PE)
- Beveled End (BE) – for welding
- Belled End (BE) - for gasket ends, fusion welding, and solvent welding
- Threaded & Coupled (T&C) – typically NPT
- Grooved – for mechanical couplings
It is a good habit to define the type of end connection you require. This helps ensure your fittings, flanges, and valves will fit up.
7. Coating, Lining, or Finish Requirements
Some pipes are supplied bare, others coated. This is crucial for many applications if you want your pipe to last.
Common finishes:
- Black (painted by the mill for rust prevention)
- Galvanized
- FBE (fusion-bonded epoxy)
- Mill Finish
- 180 grit longitudinal polish
- Bare or uncoated
Your applications may also require a pipe lining. Two examples are Cement Mortar or PTFE-lined.
8. Documentation Requirements
For many jobs, documentation is often required.
Specify in advance if you need:
- Mill Test Reports (MTRs)
- EN 10204 3.1 certification
- PMI verification
- Hydrotest reports
- Heat number traceability
If not requested up front, the ability to furnish these documents may be lost.
9. Quantity and Packaging
Seems like an obvious ordering requirement.
Most pipe is supplied loose or “as bundled”. Special packaging usually incurs additional charges. Some suppliers are not equipped to handle special packaging; if you need it, specify it in advance.
10. Origin Requirements
Many jobs limit the country of manufacture (origin).
Specify in advance if you need:
- AIS - American Iron and Steel
- DFAR
- Made in USA
- BABA - Build America, Buy America Act
11. Example of a Complete Pipe Order
Here’s what a clear, professional pipe order looks like:
4" NPS Sch 40 per B36.10 ASTM A106 Grade B Seamless, Black, Beveled Ends, 20’ SRL, 2,000 LF Total, MTRs Required, No Country Restrictions
That’s it. No assumptions or guesswork. No back-and-forth.
Final Thoughts
Ordering pipe correctly isn’t complicated, but it does require planning and communicating.
If you provide:
- Material spec and grade
- Size and standard (NPS B36.10)
- Wall thickness or sizing standard nomenclature
- Manufacturing type
- Length
- End type
- Coating/finish
- Documentation requirements
- Restrictions - Country of origin, Approved manufacturer, etc
- Quantity
Your supplier can quote quickly and ship accurately.
In industrial supply, clarity equals speed. And speed keeps projects moving.
Feb 9, 2026
