Tube Union Tee Manufacturer, Supplier & Exporter
A union tee is a T-shaped tube fitting with a compression connection on all three ends. Raaj Fittings manufactures and exports union tees in equal and reducing patterns, in double ferrule and single ferrule designs, in SS 316L, SS 304, duplex, super duplex and nickel alloys, for metric and imperial tubing.
Union tees split a tubing run into two or join two runs into one. They are used for sample taps, bypass lines, secondary instrument connections, gas distribution and any point where an instrument line must branch — without welding, brazing or threading the tube.
All union tees are supplied with EN 10204 3.1 mill test certificates and full material traceability.
We export union tees to instrumentation contractors, OEMs and distributors across the Middle East and GCC, Europe and the Americas, in metric and imperial tube sizes with NPT or BSP ends to suit each market.
Union Tee Specifications
Metric 3–25 mm; imperial 1/8"–1"
Equal tee (all ends the same OD) and reducing tee (smaller branch or run end)
Double ferrule and single ferrule compression; DIN 2353 bite type on request
Male and female run / branch tees with one NPT or BSP threaded end
Double ferrule up to 413 bar (6,000 psi); single ferrule up to 207 bar (3,000 psi), depending on size and material
Machined from forged or bar-stock bodies
EN 10204 3.1 mill test certificate; EN 10204 3.2 on request
Materials & Grades
We supply union tees in the following materials and grades. All grades are supplied with EN 10204 3.1 / 3.2 Mill Test Certificates.
Stainless Steel Union Tees
Stainless steel is the standard material for instrumentation tube fittings across oil and gas, petrochemical, pharmaceutical, and offshore applications. SS 316L is the most widely specified grade.
The industry default for instrumentation tube fittings — low carbon content prevents sensitisation; molybdenum addition provides superior chloride and acid resistance versus 304 grades.
Superior chloride and acid resistance — used where chloride exposure, marine atmosphere, or mild chemical service requires better corrosion resistance than 304.
General corrosion resistance at lower cost than 316L — suitable for water, steam, mild chemical, and food-grade applications where chloride exposure is limited.
Duplex & Super Duplex Stainless Steel Union Tees
Duplex and super duplex grades provide approximately twice the yield strength of 316L with excellent resistance to chloride stress corrosion cracking — the preferred choice for offshore and subsea instrumentation where standard 316L may be susceptible to SCC.
(UNS S31803 / S32205) Offshore topsides instrumentation, seawater injection, and chemical injection systems
(UNS S32750) Subsea instrumentation, high-chloride offshore service, and FPSOs — PREN ≥ 42
Nickel Alloy Union Tees
For aggressive chemical, sour gas, and high-temperature service where duplex stainless steel is insufficient — specified in chemical injection, downhole instrumentation, and severe process environments.
(UNS N06625) Outstanding corrosion resistance in offshore, subsea, and chemical service; widely specified for downhole instrumentation and subsea chemical injection tubing
(UNS N10276) Broad-spectrum resistance to aggressive acids, chlorides, and oxidising media; chemical and FGD process sample systems
(UNS N04400) Hydrofluoric acid service, seawater, and marine instrumentation systems
(UNS N08020) Sulfuric acid and aggressive chemical process sample and instrumentation systems
Special Grades & High-Purity Union Tees
For semiconductor, pharmaceutical, and high-purity gas applications requiring electropolished internal surfaces and ultra-low extractable contamination.
Pharmaceutical and biotech grade — electropolished internal surface for sterile process piping, pure steam, WFI, and clean compressed air systems in GMP-compliant facilities.
Semiconductor grade — ultra-high-purity electropolished finish for process gas delivery, specialty gas distribution, and wet chemistry in semiconductor fabs.
Exceptional corrosion resistance in seawater and oxidising media at low density — used in desalination and marine instrumentation where weight is a factor.
Equal and Reducing Union Tees
In an equal union tee all three ends take the same tube OD. In a reducing union tee one end — usually the branch — takes a smaller tube, so a small sample or instrument line can leave a larger header without a separate reducer.
- Branch connections — take a second instrument off one impulse line.
- Sample taps — split flow to a sample point or analyser.
- Bypass and vent lines — connect bypasses around instruments and vents.
- Distribution — feed several users from one gas or air supply.
Threaded Variants
Male run tees and male branch tees have one end with a male NPT or BSP thread, so the tee can screw directly into an instrument or valve port. Female variants are also available. These reduce the number of separate fittings in an assembly. See the male connector page for thread options.
Related Fittings
For a simple change of direction, use a union elbow; for a straight joint, a union connector; and to join different sizes in line, a reducing union. Using one fitting design across the system keeps all ferrules and nuts matched.
Applications & Industries
- Instrument impulse lines with multiple transmitters
- Sample and analyser systems in refineries and chemical plants
- Instrument air and gas distribution headers
- Calibration and purge connections
- Offshore chemical injection and control tubing
Tube selection matters as much as the fitting. For stainless steel compression fittings, use fully annealed seamless or welded-and-drawn tubing of suitable hardness, with a wall thickness chosen for the working pressure. Union tees are commonly used in instrument air distribution, where a header feeds several valve actuators and positioners, and in sample systems, where a fast loop and an analyser take-off share one line.
When ordering, give the tube OD of each end, the fitting design and material grade — for example 1/2" × 1/2" × 1/4" reducing union tee, double ferrule, SS 316L. See all tube fittings.
Testing, Inspection, Marking & Packing
Union tees are produced under our quality assurance process:
- Material verified by PMI testing, with full traceability
- Dimensional inspection of seats, bores, threads and centre-to-end dimensions
- Thread gauging on male and female variants
- Pressure testing on request
- Marking with material grade and heat code
Supplied with EN 10204 3.1 mill test certificates; EN 10204 3.2 certificates and third-party inspection on request.
Fittings are capped and bagged to keep ports clean, then boxed and packed in seaworthy wooden cases for export; marking, tagging and packing to your specification are available on request.
Why Choose Raaj Fittings for Union Tees?
Raaj Sagar Steels has supplied piping components since 2003 and today manufactures tube fittings at two plants in India for buyers in the Middle East, Europe and the Americas.
- Manufactured in-house — Union tees are made in our own plants, so material, dimensions and delivery stay under our control.
- Ready stock, short lead times — common sizes and grades are held in stock for prompt dispatch; other sizes, grades and specials are manufactured to order.
- Certified quality — ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certified; PED 2014/68/EU supply available, and NACE MR0175 / ISO 15156 material on request.
- 100% material verification — PMI testing on incoming material and EN 10204 3.1 mill test certificates with every order; 3.2 certificates on request.
- Third-party inspection ready — we regularly work with SGS, Bureau Veritas, TÜV and DNV.
- Export documentation — MTCs, certificates of origin, packing lists and inspection reports to suit projects in the GCC, Europe and the Americas.
- Export packing — seaworthy packing with end and face protection, and packing to your specification on request.
- Fast response — our team replies to enquiries within one business day.
Union Tees — FAQs
A union tee is a T-shaped tube fitting with compression connections on all three ends, used to branch or combine tubing runs.
A union tee in which one end, usually the branch, takes a smaller tube OD than the others.
Tees with one end replaced by a male NPT or BSP thread — on the run or on the branch — so the tee can screw directly into a port.
Double ferrule and single ferrule compression designs, and DIN 2353 bite type on request.
SS 316L, SS 316, SS 304 / 304L, duplex 2205, super duplex 2507 and nickel alloys, plus electropolished 316L for high-purity service.
Follow the turns-from-finger-tight given for the fitting design and size on each of the three ends, and check with a gap inspection gauge where available.
Yes. We supply union tees for projects under the European Pressure Equipment Directive (PED 2014/68/EU), with EN 10204 3.1 certificates as standard and 3.2 on request. NACE MR0175 / ISO 15156 compliant material is available for sour service in the Middle East and the Americas.
