1/2" Tube Fittings: Instrumentation Compression Fittings (Stainless & Alloy)
A 1/2" tube fitting is a mechanical-grip, gaugeable compression connector sized for 1/2-inch (0.500" / 12.7 mm) outside-diameter tubing. It relies on one or two ferrules that swage onto the tube, forming a leak-tight seal and a firm grip in pressurized instrumentation systems. Crestflo builds these 1/2-inch instrumentation tube fittings in 316/316L stainless steel, plus high-nickel and corrosion-resistant alloys. Both single-ferrule and double-ferrule (twin-ferrule) designs are available, and every part is qualified for dimensional interchange per ASTM F1387. Each one ships with EN 10204 MTC 3.1 and a heat number stamped on the part itself.
These are instrumentation-grade 1/2" OD compression tube fittings, built for pressurized gas and liquid measurement and control. They aren't plumbing fittings, not copper 1/2" compression fittings, not push-in water-line quick-connects, and not 1/2" NPT pipe fittings.
Ready stock covers the standard items; specials are made to order, with delivery running 6-8 weeks. Crestflo offers both imperial (fractional) and metric sizes across the entire line. Request a quote for 1/2" fittings, or request a sample instead.
Also Known As: 1/2 Inch, Half-Inch, 0.500" OD & Double-Ferrule Tube Fittings
Buyers and specifiers reach for all sorts of labels here. You'll see it written as a 1/2 tube fitting, 1/2 inch tube fitting, 1/2" tube fitting, half inch tube fitting or half-inch tube fitting. Sizewise, the same part turns up as a 0.5 inch, 0.500 OD or 1/2 OD tube fitting. Within its product category, it's called a 1/2 instrumentation tube fitting, a 1/2 compression fitting (in the instrumentation sense), a 1/2 double-ferrule or twin-ferrule fitting, a 1/2 single-ferrule fitting, a 1/2 gaugeable tube fitting, or simply a 1/2 tube connector. Drawings that call out material will label it a 1/2 inch stainless steel compression fitting, a 1/2 316 / 316L stainless tube fitting, or a 1/2 stainless compression fitting. Whatever the label, all of these point to the same 0.500" OD instrumentation fitting covered on this page.
What "1/2 Inch" Means: 0.500" OD Dimensions & Fit (1/2" vs 12 mm)
The "1/2 inch" in a 1/2" tube fitting describes the tube's outside diameter, not its bore or a thread size. Nominal 1/2" tube OD comes in at exactly 0.500 in = 12.7 mm. Wall thickness cuts into the internal bore, not the OD, so a 0.500" OD fitting will grip any 1/2" OD tube no matter how thick the wall runs. Don't try to swap it for a 12 mm fitting, though. Twelve millimeters (0.472") is a separate metric size, with its own ferrule set. Metric jobs belong on the Crestflo 12mm tube fittings page.
| Attribute | Value (1/2" tube fitting) |
|---|---|
| Nominal size | 1/2 inch tube OD |
| Tube OD (inch) | 0.500 in |
| Tube OD (mm) | 12.7 mm |
| Common instrumentation walls | 0.035", 0.049", 0.065", 0.083" |
| Metric look-alike (NOT interchangeable) | 12 mm OD (0.472"), separate SKU |
Dimensions follow standard imperial tube data, but you can customize them to fit your needs. Check the full tube-fitting size & OD chart to match your 1/2" instrumentation tubing from Crestflo.
Working Principle & Ferrule Options: Single vs Double (Twin) Ferrule, Hardened or Non-Hardened
A ½" instrumentation compression fitting gets its seal through mechanical grip. Turning the nut drives the ferrule (or ferrules) forward into the tapered body, swaging them onto the ½" OD tube. The result is a gaugeable, leak-tight seal with a firm hold on the tube, no soldering, no flaring, no elastomer needed on all-metal designs. Crestflo carries double-ferrule (twin-ferrule) versions, which split sealing and gripping between a front and back ferrule, and single-ferrule versions for jobs where a one-piece ferrule fits better. Ferrules come hardened or non-hardened, depending on what the application calls for.
For guidance on which one to spec, see single vs double ferrule, which to spec and hardened vs non-hardened ferrules. Crestflo also carries the single-ferrule option directly, along with replacement nuts and ferrules for anyone who just needs parts.
1/2" Tube Fitting Configurations: Union, Elbow, Tee, Connector, Cross, Reducer, Cap & Plug
The half-inch size runs across the entire configuration lineup, whether tube-OD or thread-terminated on either end. Each geometry gets its own dedicated page with full details.
| Configuration | Description | Owner page |
|---|---|---|
| Union | Straight 1/2" tube-to-tube coupling | union |
| Connector | 1/2" tube to thread end | connector |
| Male connector | 1/2" tube × male thread | male connector |
| Female connector | 1/2" tube × female thread | female connector |
| Elbow | 90° 1/2" tube turn | elbow |
| Tee | 1/2" three-way branch | tee |
| Cross | 1/2" four-way junction | cross |
| Reducer | 1/2" to another tube OD | reducer |
| Cap / plug | Seal a 1/2" tube end or port | cap · plug |
| Bulkhead / port connector | Panel-mount and port entry | bulkhead union · port connector |
| Weld connector | Socket/butt-weld to 1/2" tube | weld connector |
Each quotation from Crestflo comes with its own ordering-code and part-number series. Need the guide? Request the ordering-code guide from the engineering team.
Connections & Thread Ends for 1/2" Tube: NPT, BSPT, BSPP, JIC-37°, SAE-ORB, Socket & Butt Weld
Pair that 1/2" tube end with any standard thread or weld termination. One option people search for constantly is the 1/2" tube × 1/2" male NPT connector.
| End type | Standard | Owner page |
|---|---|---|
| NPT | ASME B1.20.1 | npt |
| NPTF (dryseal) | ASME B1.20.3 | nptf |
| BSPT / BSPP | ISO 7 / ISO 228 | bspt · bspp |
| ISO parallel | ISO 228 | iso-parallel |
| JIC 37° flare | ISO 8434-2 / SAE J514 | jic-37 |
| SAE-ORB | SAE J1926 | sae-orb |
| Socket weld / butt weld | ASME B16.11 / B16.25 | socket-weld · butt-weld |
Thread dimensions are per the applicable standard; customizable to requirement.
Materials for 1/2" Fittings: 316/316L, 904L, Duplex, 6-Moly, Inconel, Monel, Hastelloy & Titanium
Crestflo machines the 1/2-inch fitting from instrumentation stainless and high-alloy grades. Brass, copper, aluminum, and PVC don't enter into it. Each grade gets its own explanation on the material pages, and Crestflo sells these grades solely as instrumentation fittings, valves, and tubing.
| Family | Grades offered | Typical driver |
|---|---|---|
| Stainless | 304/304L, 316/316L, 904L | General instrumentation, corrosion |
| Duplex / super-austenitic | Duplex 2205, Super Duplex 2507, 254 SMO, AL-6XN, Alloy 20 | Chloride / high-strength service |
| 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 | High temperature, aggressive media |
| Titanium | Titanium Gr2 | Seawater, oxidising media |
Begin with the 316/316L stainless spec, or pick an alloy that's suited to your 1/2" fittings from this selection. For alloy-specific 1/2" builds, common choices include Inconel 625, Hastelloy C-276, Duplex 2205, Super Duplex 2507, and 254 SMO. Working in sour service? NACE MR0175 / ISO 15156-compliant materials are available too.
1/2" Tube Fitting Pressure Rating & Temperature Limits
A compression fitting doesn't carry one fixed pressure rating. Instead, it matches the allowable working pressure of the tube it grips, a figure set by tube OD, wall thickness, and material per ASME B31.3. Thicker walls carry more pressure. The numbers below are standard allowable working pressures for annealed 316/316L seamless tubing at 1/2" OD. Values follow the applicable standard and can be adjusted to fit specific requirements, and alloy grades come with their own derated figures.
| Tube OD | Wall | Material | Allowable working pressure (approx.) |
|---|---|---|---|
| 0.500" | 0.035" | 316/316L | 2,600 psig |
| 0.500" | 0.049" | 316/316L | 3,700 psig |
| 0.500" | 0.065" | 316/316L | 5,100 psig |
| 0.500" | 0.083" | 316/316L | 6,700 psig |
The fitting's all-metal, so its temperature capability follows the base material. The full alloy temperature range applies here; standard metal designs carry no elastomer limit. Confirm the exact rating for your wall, grade, and temperature on the RFQ.
Certifications, Testing & Traceability: ASTM F1387, NACE MR0175, MTC 3.1 + Heat Number
Crestflo holds ISO 9001 / 14001 / 45001 certification and PED certification. The 1/2" tube-fitting line carries the standard approvals you'd expect for compression tube fittings: dimensional and performance interchange qualification under ASTM F1387, plus NACE MR0175 / ISO 15156 material options for sour service. Every fitting ships with EN 10204 MTC 3.1 as standard (3.2 is available on request), and each part carries a heat/lot number, so full traceability is never in question, see EN 10204 MTC.
Testing runs the full range: hydraulic proof, burst, and impulse; pneumatic; flexure fatigue; rotary flex; vibration; thermal cycling; pull-out; and vacuum. Positive material identification (PMI) is included. NDT happens in-house. Destructive testing goes out to labs accredited under ISO/IEC 17025, and third-party inspection can be arranged on request. Customers can also request datasheets and CAD on request.
1/2" Drop-In Interchange for Swagelok, Parker, Hy-Lok, Hoke & Fitok
Crestflo's 1/2" fittings are built to interchange dimensionally, or fit equivalently, with the major instrumentation brands, and they carry ASTM F1387 performance qualification behind them. Swagelok® is a trademark of Swagelok Company. Parker® and A-Lok® belong to Parker Hannifin. Crestflo has no affiliation with any of them, isn't sponsored by them, and isn't endorsed by them either. Competitor part numbers aren't reprinted here as Crestflo's own. Need to match an existing 1/2" line? Request your Swagelok® / Parker® cross-reference from our engineering team, and we'll send back the Crestflo equivalent.
Why Crestflo for 1/2" Instrumentation Tube Fittings
Crestflo is the instrumentation division of an export house that's been in business for four decades, recognized by the Government of India, with a delivery track record across the Middle East. It now manufactures instrumentation fittings and valves for buyers in the US. Every 1/2" fitting carries real assurances, not just a sales pitch. ASTM F1387 drop-in interchange. A 6-8 week lead time, against the 20+ weeks typical of the major suppliers. Small MOQ and private-label programs are on offer too. MTC 3.1 comes standard, with a heat number on every part. Both imperial and metric sizes are available.
Origin: Indian. US and European melt is available on request too, backed by full material traceability. See US-serving origin & TAA and Crestflo's 6-8 week lead-time methodology for the details. US buyers can reach the sales desk directly at sales@crestflousa.com or +1 346 594 9005, based in Houston, TX.
Order 1/2" Tube Fittings or Request a Quote
Tell us what you need: size, material, configuration, connection. We'll turn around a fast RFQ. Request a quote, request a sample, or take a look at the distributor program. Standard items ship from stock. Specials get made to order, with delivery running 6-8 weeks. Want to see everything we carry? Browse all instrumentation tube fittings.
Frequently Asked Questions: 1/2" Tube Fittings
What is the actual OD of 1/2" tubing?
The nominal outside diameter of 1/2" tubing comes in at 0.500 in (12.7 mm). Wall thickness varies (commonly 0.035", 0.049", 0.065", or 0.083"), but it doesn't touch the outside diameter, only the internal bore. So any 1/2" OD tube will still seat in a 0.500" fitting, no matter the wall thickness.
Is a 1/2" fitting the same as a 12 mm fitting?
No. A 1/2" fitting is 12.7 mm OD, while 12 mm is 0.472" OD, a distinct metric SKU with its own ferrules. The two are not interchangeable; specify 12 mm tube fittings separately if your tube is metric.
Do Crestflo 1/2" fittings interchange with Swagelok?
Every part matches dimensionally and does the same job, and each one is qualified for performance to ASTM F1387. Crestflo has no ties to Swagelok: no affiliation, no sponsorship, no endorsement. Send us your Swagelok® cross-reference request, and we'll send back the Crestflo equivalent instead of reprinting a competitor's part numbers.
What is the Swagelok part number for a 1/2" fitting?
Competitor part numbers belong to the companies that make them, so we don't republish those as our own. Our engineering team instead maps your existing 1/2" part number to a Crestflo equivalent. Request your cross-reference, and we'll send back the matching Crestflo build.
What materials are 1/2" tube fittings available in?
We work in 316 and 316L stainless, along with 304 and 304L. Add to that 904L, Duplex 2205, and Super Duplex 2507. We also handle 254 SMO, AL-6XN, and Alloy 20, plus the full range of Inconel and Incoloy grades. Monel 400 and K500 are on the list too, as are Hastelloy C-276, C-22, B-2, B-3, and X. Round it out with Nickel 200 and 201, and Titanium Gr2. Brass, copper, and aluminum aren't part of the offering.
Single or double ferrule for a 1/2" fitting?
We offer both options. With the double, or twin, ferrule design, sealing and gripping are handled separately: the front ferrule does one job, the back ferrule the other. If you'd rather go with a single ferrule, that's available too. Either way, we can supply them hardened or non-hardened, whichever your specification calls for.
What pressure can a 1/2" tube fitting handle?
The fitting has to match the tube's allowable working pressure, and that's driven by wall thickness and material. Take annealed 316/316L at 0.500" OD: standard allowable working pressures run from roughly 2,600 psig at a 0.035" wall up to 6,700 psig at a 0.083" wall, per ASME B31.3. Confirm your grade and wall thickness on the RFQ.
What thread ends are available on 1/2" tube fittings?
NPT, NPTF, BSPT, BSPP, ISO-parallel, JIC-37° flare, and SAE-ORB threads are all covered, along with socket-weld and butt-weld ends. A common configuration is the 1/2" tube by 1/2" male NPT connector.
Are 1/2" fittings NACE-compliant for sour service?
Yes, we do. Options built to NACE MR0175 / ISO 15156-compliant standards are available for sour hydrocarbon service. Just specify NACE on your inquiry, and we'll apply the correct grade and hardness limits under ISO 15156.
Do you provide material certificates?
EN 10204 governs the mill certs here. MTC 3.1 comes standard, and 3.2 is available if you request it. Every part gets a heat and lot number stamped on it, so tracing a piece back to its source is never a problem. PMI backs this up. Datasheets and CAD files go out to customers whenever they ask for them.
Where are 1/2" fittings made, and are they TAA-compliant?
Crestflo is a US-serving manufacturer of Indian origin. When domestic-melt or TAA sourcing is required, US and European melt is available on request, and it's backed by full material traceability. See US-serving origin and compliance for the specifics.
What is the lead time for 1/2" tube fittings?
Ready stock covers the standard items. Specials get made to order, with a 6-8 week delivery window. Small MOQs work, and private-label is available too. Send over your requirement and we'll put together a firm RFQ.