1 inch Instrumentation Tube Fittings: Stainless Steel & Alloy
A 1 inch tube fitting is a mechanical compression (ferrule-type) fitting that seals onto 1-inch (25.4 mm) outer-diameter tubing to form a leak-tight joint in high-pressure instrumentation gas and fluid systems. Crestflo manufactures 1 inch instrumentation tube fittings in stainless, duplex and high-nickel alloys, in single- and double-ferrule designs, performance-qualified to ASTM F1387 for drop-in interchange, with ready stock for standard items, made-to-order for specials, and 6–8 week delivery.
These are instrumentation-grade stainless steel and alloy compression tube fittings built for 1 in OD tubing, engineered to handle high-pressure gas and fluid service. A 1 inch compression fitting in this context grips the tube through ferrule action. That's a different animal from a plumbing or copper compression fitting. It's not a 1-inch NPT pipe fitting either, and it isn't structural tubing or a hydraulic hose fitting. The 1 inch OD here describes the tube the fitting grips, not a nominal pipe size.
Also Known As: 1" Tube Fitting, 25.4 mm & Compression Fitting Designations
Buyers and specifiers don't all use the same name for this component. Depending on the inquiry or the drawing, it can appear as a 1 inch tube fitting, 1" tube fitting, 1 in tube fitting, one inch tube fitting, 1 inch instrumentation fitting, 1 inch compression tube fitting, 1 inch double ferrule fitting, 1 inch single ferrule fitting, 1 inch OD tube fitting, 1 inch stainless steel tube fitting, or 1 inch stainless steel compression fitting. All the same part. Since 1 inch works out to exactly 25.4 mm, some specifications list it as a 25.4 mm tube fitting: an imperial size written in metric terms, not to be confused with a true-metric 25 mm tube branch. Configuration-specific requests, whether for a 1 inch tube union, connector, elbow, tee, cross, reducer, adapter, cap or plug, are simply the same 1" body in a different geometry, and each one is covered on the matching tube-fitting configuration pages.
1 inch Tube Fitting Size & OD: 1" = 25.4 mm Explained
A 1 inch tube fitting takes 1.000 in. OD tubing, which works out to 25.4 mm. That's a fractional-imperial size, not a metric tube size. Drawings might label it a 1 inch OD tube fitting, a 1 inch tube OD fitting, or a 1 inch outer diameter tube fitting; the names vary, but the sizing logic doesn't. It's sized to the tube's outer diameter, not to any bore or thread dimension. This size falls within Crestflo's compression tube-fitting range, which runs up to 2 in. (50 mm) OD on end connections, so 1 in. Counts as a standard size in that lineup.
| Nominal size | Tube OD (in) | Tube OD (mm) | Availability |
|---|---|---|---|
| 1 inch | 1.000 | 25.4 | Standard, within the up-to-2″ (50 mm) compression range |
Check the tube-fitting size chart for the full OD progression. Need true-metric sizing, say 6 mm up to 12 mm? Head to metric tube fittings instead. And don't mix up a near-size 25 mm metric request with this fitting, it's imperial, 1", and counts as a separate size entirely.
1 inch Double Ferrule & Single Ferrule Design
Crestflo makes the 1 in. Ferrule fitting in two versions: single-ferrule and double-ferrule (two-ferrule), with hardened or non-hardened ferrules depending on what the job calls for. Sealing and gripping are split across a front and back ferrule in the two-ferrule design, which gives a repeatable make-up. Single-ferrule fittings use just one ferrule instead. There's less to it. Which design fits best depends on the service, the vibration involved, and how often the joint needs re-making. Installation follows a controlled pull-up: hand-tighten the nut, then wrench-turn it to the specified position so the ferrule swages onto the tube. Full make-up steps and the gap check are laid out in ferrule installation and gauging. A side-by-side comparison of the two designs sits at single vs double ferrule explained, and related products include the single-ferrule tube fittings, tube-fitting ferrules, and nut-and-ferrule sets.
1 inch Tube Fitting Materials: 316/316L, Duplex, Inconel, Hastelloy & Titanium
You can get this fitting in 1 in. Across the entire instrumentation alloy lineup: stainless, super-austenitic, duplex, nickel, and titanium. Each grade has its own material page listing composition and properties. The fitting comes as an instrumentation compression fitting. Brass isn't offered.
| Family | Grades (1 inch) | Grade page |
|---|---|---|
| Austenitic stainless | 304/304L, 316/316L, 904L | 316/316L · 304/304L · 904L |
| Duplex / super-austenitic | Duplex 2205, Super Duplex 2507, 254 SMO, AL-6XN, Alloy 20 | Duplex 2205 · 2507 · 254 SMO · AL-6XN · Alloy 20 |
| Nickel | Inconel 600/601/625/718/825, Incoloy 800/800H/825, Monel 400/K500, Hastelloy C-276/C-22/B-2/B-3/X, Nickel 200/201 | Inconel 625 · Inconel 825 · Monel 400 · Hastelloy C-276 · Nickel 200/201 |
| Titanium | Titanium Gr2 | Titanium Gr2 |
Each composition meets the applicable ASTM specifications, and it's tailored to whatever the requirement calls for. The complete grade set lives in the full materials index.
1 inch Tube-to-NPT Ends, Threads & Weld Connections
Every 1 in. Fitting can be built tube-to-tube, or it can come with a threaded or welded end. Below are the standard end and thread options along with their reference standards, and each one links through to its matching end-configuration page.
| End / thread | Standard | Configuration page |
|---|---|---|
| Tube × tube | Compression (ferrule) | Tube fittings hub |
| Male / female NPT | ASME B1.20.1 | NPT · NPTF |
| BSPT / BSPP / ISO parallel | ISO 7 / ISO 228 | BSPT · BSPP · ISO parallel |
| JIC 37° flare | ISO 8434-2 | JIC-37° |
| SAE O-ring boss | SAE J1926 | SAE-ORB |
| Socket-weld / butt-weld | ASME weld ends | Socket-weld · Butt-weld |
1 inch Tube Fitting Pressure Rating, Temperature & Compliance
A 1 in. Fitting's working pressure comes down to tube OD, tube wall thickness and alloy, not the fitting itself. Engineers calculate allowable pressures from tube wall and material allowable stress under ASME B31.3, and the resulting values follow the applicable standard while staying open to customization as needed. Temperature limits, meanwhile, track the alloy and seal selected. Want the derating method? See pressure-temperature derating and tube sizing and wall thickness. For a certified rating against your own tube schedule and alloy, request it from our engineering team.
| Attribute | Status |
|---|---|
| Working pressure | Per tube OD/wall & alloy, calculated to ASME B31.3, customizable; request certified rating |
| Sour service | NACE MR0175 / ISO 15156 compliant |
| Interchange qualification | Performance-qualified to ASTM F1387 |
| Traceability | Heat/lot number on every part; EN 10204 MTC 3.1 standard, 3.2 on request |
| Certification | ISO 9001 / 14001 / 45001 & PED certified |
Finishes include material finish, electropolish, passivation, and silver anti-galling plating. Oxygen cleaning to the applicable standard is available on request. Datasheets and CAD are available to customers on request.
1 inch Swagelok, Parker & Hy-Lok Drop-In Interchange
Crestflo 1 in. Fittings are built as dimensional drop-in interchanges for major instrumentation brands, and they're performance-qualified to ASTM F1387, the interchange proof most competitors won't publish. We describe this as equivalent, dimensional drop-in interchange, never as "compatible" or "intermix." Need a specific 1" series match? Ask our engineering team for your Swagelok®, Parker®, Hy-Lok®, Hoke®, Fitok® or Gyrolok® cross-reference instead of relying on a generic chart. Swagelok® is a trademark of Swagelok Company; Parker® belongs to Parker Hannifin. All trademarks belong to their respective owners, and Crestflo isn't affiliated with or endorsed by any of them. Check the cross-reference hub, the Swagelok cross-reference, or the Swagelok alternative.
Order 1 inch Tube Fittings: Quote, Sample & Distributor Options
To order 1 in. Instrumentation tube fittings, request a quote with your size, alloy, ferrule type and end connection, or request a sample to qualify the fitting on your system. Every order is priced to specification rather than pulled from a fixed list, so if you're after 1 in. Tube fitting price and cost, send along your requirement and the Crestflo team will return a firm quotation. OEM and volume buyers can tap the private-label program; resellers should look at the distributor program. Standard items ship from ready stock. Specials are made to order, with delivery running 6-8 weeks. US inquiries: sales@crestflousa.com · +1 346 594 9005 · Houston, TX.
Why Crestflo for 1 inch Instrumentation Fittings
Crestflo sits inside a four-decade-old, Government-of-India-recognized export house, and it's built a delivery record across the Middle East already. The 1 in line pairs that manufacturing heritage with logistics built to serve the US: ASTM F1387-qualified drop-in interchange, the full alloy range from 316/316L through Hastelloy C-276 and Titanium Gr2, single and double ferrules, small MOQ runs, private label, and heat-number traceability with EN 10204 MTC 3.1 on every part. Product ships from India, though US or European melt is available on request, full material traceability comes standard, and made-to-order work runs 6-8 weeks. Put that together and Crestflo becomes a single US-serving manufacturer and supplier for 1 inch instrumentation tube fittings, spanning the entire alloy range. We Engineer Confidence.
1 inch Tube Fitting FAQ
What is a 1 inch tube fitting?
A 1 inch tube fitting is a mechanical compression fitting, built around a ferrule, that seals onto 1-inch (25.4 mm) OD tubing used in instrumentation gas and fluid systems. It belongs to the instrumentation family. It isn't a plumbing fitting, a pipe fitting, or a hose fitting.
What is 1 inch in mm for tube fittings?
1 inch equals 25.4 mm OD, exactly. That's a fractional-imperial tube size, not to be confused with a true-metric 25 mm tube, which is an entirely separate fitting size.
Does Crestflo make 1 inch fittings?
Yes. Crestflo compression tube fittings cover end connections up to 2" (50 mm) OD, so the 1 inch (25.4 mm) size is a standard offering across the alloy range.
What materials are 1 inch fittings available in?
Stainless comes in 304/304L, 316/316L, and 904L. For duplex grades, there's 2205 and the super duplex 2507, plus 254 SMO, AL-6XN, and Alloy 20. On the nickel alloy side: Inconel 600/601/625/718/825, Incoloy 800/800H/825, Monel 400/K500, Hastelloy C-276/C-22/B-2/B-3/X, and Nickel 200/201. Titanium Gr2 rounds out the list. Brass isn't offered.
Should I choose a single or double ferrule 1 inch fitting?
Both options are on offer. Double-ferrule designs keep sealing and gripping separate, which gives repeatable make-up even under vibration and after re-making the joint. Single-ferrule designs, by contrast, are simpler assemblies. Which one you pick comes down to the service; it's worth checking the single vs double ferrule comparison for guidance.
Can a 1 inch Crestflo fitting replace my Swagelok or Parker fitting?
Crestflo 1 in. Fittings drop straight in as dimensional replacements, and they've been performance-qualified to ASTM F1387. Need a cross-reference for a specific Swagelok® or Parker® part? Ask our engineering team. All trademarks belong to their respective owners; Crestflo carries no affiliation with or endorsement from them.
What is the pressure rating of a 1 inch tube fitting?
Working pressure isn't one-size-fits-all. It depends on the tube's OD, wall thickness and alloy, all calculated per ASME B31.3. Figures follow the applicable standard and can be adjusted to suit your needs. Get in touch to request a certified rating for your tube schedule and material.
Are 1 inch fittings NACE compliant?
Yes. Crestflo compression fittings meet NACE MR0175 / ISO 15156 requirements for sour service, provided the correct alloys are specified.
What thread and end connections are available at 1 inch?
Tube × tube plus male/female NPT (ASME B1.20.1), NPTF, BSPT, BSPP, and ISO-parallel connections, JIC 37° (ISO 8434-2), SAE-ORB, and socket-weld or butt-weld ends round out the lineup.
What are the lead time and MOQ?
Standard items ship from stock, ready to go. Specials are made to order, with delivery running 6 to 8 weeks, well ahead of the 20-plus weeks that's typical among the major suppliers. Small minimum order quantities are available. So is private label.
What certifications and documentation come with the fittings?
Crestflo carries ISO 9001, 14001, and 45001 certification, along with PED certification, and its products meet ASTM F1387 performance qualification. Every part leaves the shop with an EN 10204 MTC 3.1 (3.2 on request), the heat and lot number stamped right on it. Datasheets and CAD are available to customers who ask.
Where are 1 inch fittings made and are they TAA compliant?
Product's Indian in origin, though US or European melt is available on request, and full material traceability comes standard. TAA/DFARS requirements are covered by choosing the US/European-melt option; check the US origin and compliance page for details.
Related 1 inch Tube Fitting Resources
- Tube fittings hub, the double-ferrule tube fitting family
- Tube-fitting size chart, plus the related page on 3/4 inch tube fittings
- Metric tube fittings alongside imperial-fractional tube fittings
- ASTM F1387 · NACE MR0175 · EN 10204 MTC
- US origin & TAA compliance, with instrumentation applications by industry close behind