TES-LOK Union Tee Tube Fittings — T-branch with three compression tube ends and union nuts for in-line disconnection of any leg without cutting tube. SS 316 · Brass · Monel · Inconel · Equal & Reducing · Up to 6,000 PSI · ISO 9001:2015 certified.
Union Tee — Equal Bore
Reducing Union Fittings Range
A union tee tube fitting is a T-shaped fitting with three compression tube ends — two aligned forming the straight run, one perpendicular forming the branch. Each end uses PTFE front and back ferrules for a double-ferrule compression grip. Union nuts on the connections allow any leg to be separated from the body and reconnected without cutting the tube.
The union tee is the standard fitting wherever a branch instrument must be removable from a running tube loop — sample take-offs, pressure instrument branches, analyzer tee-off points, or any branch where periodic disconnection is required without interrupting the main tubing run.
| Variant | Run Tube OD | Branch Tube OD | Use Case |
|---|---|---|---|
| Equal Union Tee | Same OD | Same OD as run | Standard T-branch — all three legs same tube size |
| Reducing Union Tee (run reducing) | Different sizes, run legs | Same as smaller run leg | Inline tube size reduction at branch point |
| Reducing Union Tee (branch reducing) | Same OD | Smaller than run | Small-bore instrument branch from larger-bore run line |
| Fitting | Run Ends | Branch End | In-line Disconnection | Choose When |
|---|---|---|---|---|
| Union Tee | Compression tube × 2 | Compression tube | Yes — any leg | Any branch leg needs service disconnection |
| Standard Tee (Plain) | Compression tube × 2 | Compression tube | No — cut tube to disconnect | Permanent branch, no service disconnection needed |
| Male Branch Tee | Compression tube × 2 | Male thread (branch) | Partial — unscrew thread | Branch to female-ported instrument |
| Female Branch Tee | Compression tube × 2 | Female thread (branch) | Partial — unscrew thread | Branch to male-studded instrument |
| TES-LOK Union Tee Tube Fitting — Specifications | |
|---|---|
| Brand | TES-LOK (by Tesco Steel & Engineering) |
| End connections | Double-ferrule compression tube — all three ends (TES-LOK bite-type) |
| Tube OD range | 1/8" – 1" (imperial) · 3 mm – 25 mm (metric) |
| Configurations | Equal (all 3 legs same OD) · Reducing (branch or run smaller) |
| Body materials | SS 316 / 316L (standard) · SS 304 · Brass · Monel 400 · Inconel 625 · Hastelloy C-276 · Carbon Steel |
| Max. working pressure | 6,000 PSI (SS 316) · 3,000 PSI (Brass) — all three legs rated equally |
| Temperature range | −196°C to +400°C (SS) · −29°C to +232°C (PTFE ferrule limit) |
| Ferrule material | PTFE (ASTM D1710 / D3294); optional SS or Monel ferrules |
| Certifications | ISO 9001:2015 · EN 10204 3.1 MTC available |
| Compatible systems | TES-LOK · Swagelok · Parker A-LOK · Ham-Let |
Union tee on the impulse line allows pressure transmitter or gauge removal for calibration without depressurising the full line — the run stays connected while the branch is disconnected.
Branch take-off from the sample line to an analyzer with union nut disconnection for analyzer servicing, filter replacement, or sample component rotation.
T-branch at the bypass entry point with service disconnection built in — bypass can be connected without disturbing the main flow meter tubing.
Multiple instrument branches from a single sample carrier line in a GC laboratory — each branch disconnectable independently for column or detector swaps.
Pressure tap branches with repeatable disconnection for instrument rotation during multi-point calibration campaigns — no tube off-cuts generated between removals.
▶ What is a union tee tube fitting?
A union tee tube fitting is a T-shaped fitting with three compression tube ends — two forming the run and one forming the branch. Union nuts allow any leg to be disconnected in-line for instrument removal without cutting the tubing.
▶ What is the difference between a union tee and a standard tee?
A standard tee is a fixed fitting — the tube must be cut to remove an instrument. A union tee has union nuts on all connections so any leg can be separated and reconnected without cutting. Essential for instrument branches requiring periodic removal.
▶ What is the pressure rating?
TES-LOK union tee tube fittings in 316 SS are rated to 6,000 PSI at room temperature for standard tube sizes on all three legs. Ratings derate with temperature and larger tube diameters.
▶ What tube sizes are available?
TES-LOK union tees are available in tube OD from 1/8" to 1" (imperial) and 3 mm to 25 mm (metric) in equal and reducing configurations.
▶ What materials are available?
316/316L stainless steel, 304 SS, duplex 2205/2507, monel 400, inconel 625, hastelloy C-276, and carbon steel.
▶ What is a reducing union tee?
A reducing union tee connects tube runs of different ODs — for example, 1/2" run with a 1/4" branch for a small-bore instrument take-off from a larger process line. One fitting handles the size transition and branching simultaneously.
▶ What is the remake rule for union tee fittings?
For all three legs, tighten only to the original marked position on remake. The PTFE ferrules are set after first make-up — do not add turns. Adding extra turns on any remade connection distorts the ferrule and may damage the tube OD.
▶ Are TES-LOK union tees compatible with Swagelok and Parker?
TES-LOK union tee compression ends are dimensionally compatible with Swagelok and Parker A-LOK fittings of the same tube OD. Verify compatibility before mixing brands in critical service.
Equal and reducing union tees — 316 SS, duplex, monel, inconel, and more. ISO 9001:2015 certified. Mill test reports supplied as standard.
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