Instrument tube fitting
Twin/double-ferrule compression fittings for instrumentation tubing, in the full range of configurations below, identified by TSI’s own ordering code (TSI-01-XXX) for easy reference and quotation.
No dedicated fitting standard exists for this product family. Working pressure is governed by the tubing standard (ASTM A269/A213, ASME B31.3), not the fitting body — every configuration on this page carries the same rating for a given tube OD, wall thickness and material. NPT follows ASME B1.20.1; BSPT follows ISO 7-1; BSPP follows ISO 228-1. Fitting body material to ASTM A479 / ASME SA479 (bar stock) or ASTM A182 / ASME SA182 (forgings).
| Tube OD | 316/316L SS | Alloy 625 Inconel-type |
Alloy 2507 Super Duplex |
Alloy 400 Monel-type |
|---|---|---|---|---|
| 1/8 in 0.028 | 8,500 | — | — | 7,900 |
| 1/4 in 0.035 | 7,500 | 7,300 | 10,000 | 7,000 |
| 3/8 in 0.035 | 3,300 | 4,700 | 6,500 | 4,400 |
| 1/2 in 0.049 | 2,600 | 5,000 | 7,200 | 4,400 |
| 5/8 in 0.065 | 2,900 | — | 5,700 | — |
| 3/4 in 0.065 | 2,400 | — | 4,700 | — |
| 1 in 0.065 | 2,400 | — | — | — |
Std. wall shown for the size most commonly stocked; heavier walls raise the rating within the same OD. “—” = no standard catalog rating for that combination, confirmed per order. Sizes beyond 1 in and additional alloys (titanium, 6-Moly, Alloy C-276, carbon steel) available on request.
Joins two tube ends of equal OD in a straight line — the base connector of the family.
Joins two tube ends of different OD in a straight line.
Dimensions vary with paired size.
Passes tubing through a drilled panel wall; locking nut secures it in the hole.
Connects two equal-OD tubes at a 90° turn without bending the tube.
Same function at a shallower 45° turn for gentler routing.
Available in 1/4, 1/2, 3/4 in tube OD only — other sizes not offered
Joins three equal-OD tube ends, splitting or combining a line.
Joins three tube ends where the branch is smaller OD than the run.
Joins four equal-OD tube ends at a single junction.
Connects a tube end to a female-threaded port (male NPT into equipment).
Connects a tube end to a male-threaded component (female NPT).
90° turn from tube to male NPT thread.
90° turn from tube to female NPT thread.
Connects a tube end to a female-threaded port via its own male thread — same shape as the Male Connector above, listed separately as TSI’s reference item when the thread standard is BSPT rather than NPT.
Same physical design as Male Connector — confirmed across major manufacturers (Parker’s own product classification lists both under identical shape/style).
Connects a tube end to a male-threaded component via its own female thread — listed separately as TSI’s reference item when the thread standard is BSPT rather than NPT.
Connects a tube end to a female-threaded port via its own male thread, sized to step between two different tube or thread sizes in a single fitting.
Full dimensional data provided upon RFQ.
Purpose-built connector for mounting a pressure gauge or instrument.
ISO/BSP parallel gauge thread (RG) — confirm exact gauge thread at RFQ
Connects a tube end to a straight-thread O-ring boss port, not NPT.
Seals off an unused tube end.
Seals off an unused port or fitting opening.
Fully internal thread — no external length/width dims.
Compression nut that, with the ferrule set, makes the mechanical seal — spare part.
Sealing ferrule — bites into the tube, seals against the body taper.
Small internal part — no published external dims; shown paired with back ferrule.
Gripping ferrule — sits behind the front ferrule, carries the axial load.
Small internal part — no published external dims; shown paired with front ferrule.
Tube to male tapered ISO/BSP thread — visually similar to standard male connector.
Tube to male parallel ISO/BSP thread, sealed with a washer at the base.
Tube to female tapered ISO/BSP thread.
Tube to female parallel ISO/BSP thread, sized for gauge mounting.
Straight body joining two significantly different tube sizes, no bend, no threads.
Same function as Reducer with a longer straight body between the two ends.
Available in 3/8 × 1/2in only — other combinations require special order.
Bulkhead-mount body reducing between two tube sizes.
90° elbow joining two different tube sizes.
One end a plain weld stub, other end standard compression.
One end a plain weld stub, other end male NPT thread.
90° elbow, both ends plain weld stubs.
90° elbow, one end a plain weld stub, other end female NPT thread.
Full dimensional data provided upon RFQ.
Elbow with a lock nut and washer, rotatable into position before locking.
Run is compression on both sides; branch is male NPT thread.
Run is male NPT on both sides; branch is compression.
Run is female NPT on both sides; branch is compression.
Run is compression on both sides; branch is female NPT thread.