Alfiniti supplies extruded aluminum schedule pipe held to the standard tolerances published on this page: diameter, wall thickness, weight, length, and straightness.
Diameter tolerance is controlled two different ways depending on wall. Schedule 5 and 10 pipe is held on mean diameter, the average of two diameters measured at right angles to each other at the same point. Schedule 20 and heavier is held on diameter at any point, and from NPS 2 up it is expressed as a percentage rather than a fixed decimal.
Wall thickness carries a plus and minus band on Schedule 5 and 10, but on Schedule 20 and greater only the minus side is specified. The plus side is capped by the weight tolerance instead.
If your part needs tighter OD control, a thinner wall, or better straightness than the standard extruded numbers below, cold drawing is the route. See Cold Drawn Aluminum Tubing.
Speak with an expert!
Every table on this page is reproduced in full from Alfiniti’s Standard Tolerances, Extruded Schedule Pipe data sheet. The PDF is available at the bottom of the page if you need a copy for a spec package or an RFQ.
Looking for the matching numbers on extruded tube or drawn tube and pipe? Those sheets, along with alloy and ASTM chemical and tensile tables, live in the Resource Library.
Alfiniti, Inc. is the largest aluminum manufacturer in North America.
Aluminum Pipe Specifications
All tolerances are in inches unless noted. Each value shows the allowable plus tolerance first, then the allowable minus tolerance.
Diameter, Pipe
| NPS Pipe Size Inches |
Tolerance, Inches | |
|---|---|---|
| Allowable deviation of mean diameter1 from nominal diameter. Difference between 1/2 (AA + BB) and nominal diameter Schedule 5 and 10 |
Allowable deviation of diameter at any point from nominal diameter. Difference between AA and nominal diameter Schedule 20 and greater |
|
| Under 2 | +.015 / -.031 | +.015 / -.031 |
| 2-4 | +.031 / -.031 | +1% / -1% |
| 5-7 | +.062 / -.031 | +1% / -1% |
| 8-12 | +.093 / -.031 | +1% / -1% |
Wall Thickness, Pipe
| Schedule Number | Tolerance |
|---|---|
| Allowable deviation of wall thickness at any point from nominal wall thickness | |
| 5 and 10 | ±12-1/2%, ±0.12 in. min. |
| 20 and greater | -12-1/2%2 |
Weight, Pipe
| Schedule Number | Tolerance |
|---|---|
| Allowable deviation from theoretical weight | |
| 5 and 10 | For schedule 5 and 10, only diameter, wall thickness, and length tolerances apply.3 |
| 20 and greater | +8%4 |
- 1 Mean diameter is the average of any two diameter measurements taken at right angles to each other at any point along the length.
- 2 Maximum wall thickness is controlled by weight tolerance.
- 3 For schedule 5 and 10, only diameter, wall thickness, and length tolerances apply.
- 4 Minimum weight is controlled by tolerances for outside diameter and wall thickness.
Need a tolerance tighter than standard?
Length, Pipe
| Specified length Ft |
Tolerance, Inches plus |
|---|---|
| Allowable deviation from theoretical length | |
| Up thru 20 | 1/4 |
| Over 20 thru 40 | 1/2 |
Straightness, Pipe
| Pipe size Inches |
Tolerance, Inches |
|---|---|
| Allowable deviation from straight, D (max), in total length or in any measured segment of one ft. or more of total length | |
| Under 6 | .010 x measured length, ft. |
Why it matters:
Schedule pipe is bought to a nominal size, not an actual one, so the tolerance table is what tells you the real envelope your part has to live in. Fit-up, thread engagement, insert and coupling clearance, and weld prep all key off these numbers rather than the nominal callout.
The split between mean diameter and diameter at any point matters most for anything that slides, seals, or telescopes. Schedule 5 and 10 can be within the mean diameter band and still be out of round at a given point, while Schedule 20 and heavier is held at every point but on a percentage basis that widens as NPS goes up.
Weight tolerance is the quiet one. On Schedule 20 and greater, the plus side of wall thickness is not specified directly at all. It is controlled by the +8% weight limit, so a heavy wall run can be fully in spec and still add mass to your assembly.
Alfiniti can help:
Send us the print. Our team will tell you whether standard extruded schedule pipe tolerances cover your part, or whether you should be looking at cold drawn tube for tighter diameter and wall control, and we can quote cutting, bending, machining, and finishing on the same order.
Need the rest of the aluminum tube and pipe data?
See our Aluminum Products page for cold drawn, extruded, and welded tube, or the Resource Library for every tolerance, alloy, and ASTM table we publish.
