Guide
Crimp or cold-expansion PEX fittings: which ASTM standard should a machined brass fitting follow?
Cold-expansion PEX fittings are the style covered by ASTM F1960, while metal insert fittings closed with a copper crimp ring are covered by ASTM F1807. They are separate standards with different rings, so a machined brass body is drawn for one style or the other, and the choice is made before any bar is ordered.
By Saola Manufacturing engineering team · Published · Updated
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What do ASTM F1807 and F1960 each cover?
ASTM F1807 covers metal insert fittings and copper crimp rings for PEX tubing, and ASTM F1960 covers cold-expansion fittings and PEX reinforcing rings. Both are written for 100 psi hot and cold water distribution at up to 180 °F, per the scope summaries on the ASTM store (F1807-26a, F1960-26).
The public scope of F1807-26a lists PEX and PE-RT sizes from 3/8 to 2 inch, with PEX tubing to ASTM F876 or F3253 and PE-RT tubing to F2623 or F2769. The scope of F1960-26 runs from 3/8 to 3 inch, and it points to ASTM F876 or F3253 for PEX and ASTM F2769 for PE-RT.
Both are the editions the ASTM store lists as active in October 2026, each updated in August 2026, and the earlier editions are marked historical there. This guide reads only the public store summaries, so confirm the current edition and its dimension tables with the standard itself before you release a drawing. It quotes no dimension from either standard, because those tables are sold and are not on the public pages.
The summaries also do not name a body alloy for either style. That matters later in this guide, because the alloy and the bar specification are not decided by the fitting standard alone.
How do the two styles compare on the points a drawing cares about?
A crimp fitting is an insert that sits inside the tube and is closed by an outside copper ring, while an expansion fitting uses a PEX reinforcing ring with a tube that is expanded first. The table sets the two side by side with the plastic style that competes with brass.
ASTM F2159 is the third standard that turns up in the same searches. It covers sulfone plastic insert fittings with copper crimp rings or alternate stainless steel clamps in four sizes, per the F2159-23a scope summary, so it is the non-brass alternative to a crimp fitting rather than another brass style.
The practical point is that the ring and the sizes differ, and the ring decides the profile you turn.
| Point | F1807-26a (crimp) | F1960-26 (cold expansion) | F2159-23a (plastic crimp) |
|---|---|---|---|
| Fitting | Metal insert fitting | Cold-expansion fitting | Sulfone plastic insert fitting |
| Ring | Copper crimp ring | PEX reinforcing ring | Copper crimp ring or stainless steel clamp |
| Nominal PEX sizes | 3/8 to 2 inch | 3/8 to 3 inch | 3/8, 1/2, 3/4 and 1 inch |
| Service basis | 100 psi, up to 180 °F | 100 psi, up to 180 °F | 100 psi, up to 180 °F |
| PEX tubing standard cited | F876 or F3253 | F876 or F3253 | F876 or F3253 |
| Body alloy named on public page | No | No | Not applicable (plastic) |
| Store status of this edition | Active, updated 2026 | Active, updated 2026 | Active, updated 2023 |
How do the brass bodies differ as turned parts?
The ring decides the body: a crimp insert needs a surface that a copper ring can clamp the tube onto, and an expansion fitting needs the profile that works with a PEX ring and an expanded tube. Neither public summary gives dimensions, so build the drawing from the full standard, not from a competing part.
Both styles are small turned or machined bodies in the same families: straight couplings, elbows, tees, adapters with a pipe-thread end, manifold ports and stops. What changes between the styles is the end that meets the tube. On a crimp insert that end carries the ring-seat and tube-stop profile on its outside, and the part has to fit inside the tube, so its wall takes space out of the tube bore. That is the geometric reason a crimp insert can restrict flow more than an expansion fitting, whose insert goes into a tube that has first been stretched open, and the reason a bore figure copied from a catalog or a blog is not a design value.
For the threaded end of an adapter, the thread standard is a separate decision; the guides on NPT threads and BSPP and BSPT threads cover it. For the tube end, ask the fitting brand for the dimensional tables of the edition it designs to, and put the edition on the drawing.
The tube-end profiles, bores and shoulders are turned features, which suit a CNC lathe. CNC turning and CNC milling at the lead plant cover the bar-fed route; what the drawing must give the shop is the profile, its tolerance and the surface condition of the ring seat.
Which brass and which bar standard should feed each body?
The fitting standards, as summarized on the ASTM store, do not name a body alloy, so the alloy follows the brand's own lead-free and dezincification decisions and the bar follows a rod-and-bar specification such as ASTM B927/B927M. Write both on the drawing as a UNS number and a bar standard.
ASTM B927/B927M is titled the standard specification for brass rod, bar and shapes, and it covers round, hexagonal and octagonal rod and rectangular and square bar in alloys identified by UNS numbers (the -23 edition, listed as active). It is one example of a bar standard, not a recommendation of an alloy, and which UNS alloy is right for a potable-water fitting is the brand's decision.
Two rules narrow that decision. First, a fitting that carries drinking water must meet the weighted average of 0.25 percent lead on wetted surfaces under 42 U.S.C. 300g-6, which rules out classic leaded free-cutting brass for most wetted bodies; the guide on lead-free brass for NSF 61 and 372 covers the alloys. Second, brass can lose its zinc in some waters, a failure called dezincification that the public scope summaries of the fitting standards do not mention. The guide on dezincification and DZR brass shows how to write the resistance requirement so a supplier cannot misread it.
Put the UNS number, the bar standard, the temper or condition and the test certificate type on the drawing; the guide on EN 10204 3.1 and 2.2 certificates explains which certificate to ask for.
How should you decide which style to tool?
Start from the sizes and the ring you need to sell: per ASTM F1807 the crimp range stops at 2 inch PEX and per ASTM F1960 the expansion range reaches 3 inch. Then check that your tubing and your target market accept the style, which is the brand's task and not the machine shop's.
The table below turns the scope summaries into a short decision aid. It is derived from the summaries above and is not a statement by ASTM; the trade-offs that depend on installer tools, model-code listings and field experience sit outside what this guide can source.
| If you need | Lean toward | Why (from the scope summaries) |
|---|---|---|
| Fittings above 2 inch nominal PEX | F1960 expansion | The F1960 scope runs to 3 inch; the F1807 scope stops at 2 inch |
| A copper-ring joint | F1807 crimp | The F1807 scope names copper crimp rings |
| A joint that uses a PEX ring | F1960 expansion | The F1960 scope names PEX reinforcing rings |
| A non-metal body in the small sizes | F2159 plastic | The F2159 scope covers sulfone plastic fittings in four sizes up to 1 inch |
| Both PEX and PE-RT tubing | Either; check tubing pairing | Both F1807 and F1960 scopes include PE-RT, with different tubing standards cited |
What belongs in the RFQ for either brass body at ten to twenty thousand a year?
Name the style and standard edition, the nominal tube size and tubing standard, the UNS alloy and bar standard, the lead-free declaration the brand holds, and the volume split by size. At that scale the decision is about setups per size and the cost of a family of bodies, not about one part.
A line-by-line list helps a quote come back comparable. State F1807 or F1960 and the edition, the nominal sizes, and whether each body is a coupling, elbow, tee, adapter or manifold port. Give the thread callout for any pipe-thread end. List the ring-seat profile and tolerance, the bore, and the tube-stop shoulder, taken from the dimension tables of the edition you design to. Add the alloy and bar standard, the certificate type, and any leak or pressure test the brand requires after machining.
Annual volume matters for judgment, not for a price here: a program of ten to twenty thousand bodies a year spread over several sizes is a family of short setups, and each added size adds changeover. Quote the sizes as one family so the shop can plan them together, and say which sizes are the high runners.
Saola runs CNC turning and milling at its lead plant and places other processes, such as surface finishing or blank forming, through partner plants it manages; each quote names the production site and country of origin. The guide on preparing a machining RFQ lists the rest of the package.
Frequently asked
Is ASTM F1807 or F1960 the better standard?
Neither is better in general. They describe different joints: a metal insert fitting with a copper crimp ring and a cold-expansion fitting with a PEX reinforcing ring. The choice follows the sizes, the tubing and the market you sell into.
Do the standards say which brass to use?
The public ASTM store summaries of F1807-26a and F1960-26 do not name a body alloy. The full standards may carry material requirements, so read the edition you design to and add the UNS number to the drawing yourself.
Which editions does this guide read?
The editions the ASTM store lists as active in October 2026: F1807-26a, F1960-26 and F2159-23a. Check again before release, because sizes and requirements can change between editions.
Can one brass body serve both styles?
The scopes describe different rings, copper for crimp and PEX for expansion, so one body profile is unlikely to suit both. Confirm against the dimension tables in the standards.
Where does ASTM F2159 fit?
It covers sulfone plastic insert fittings with copper crimp rings in four sizes, so it is the plastic competitor to a brass crimp fitting, not a third brass style.
Sources
- ASTM F1807-26a, metal insert fittings and copper crimp rings for PEX tubing (store page), ASTM International, 2026 edition (F1807-26a), accessed October 2026
- ASTM F1960-26, cold expansion fittings with PEX reinforcing rings (store page), ASTM International, 2026 edition, accessed October 2026
- ASTM F2159-23a, plastic insert fittings with copper crimp rings (store page), ASTM International, 2023 edition (F2159-23a), accessed October 2026
- ASTM B927/B927M-23, brass rod, bar and shapes (store page), ASTM International, 2023 edition, accessed October 2026
- 42 U.S.C. 300g-6, prohibition on use of lead pipes, solder and flux, Legal Information Institute, Cornell Law School, accessed October 2026