TES-LOK Street Elbow Tube Fittings — male thread on one port (street end), female thread on the other, at 90°. Thread directly into a female socket without a nipple and change direction in a single fitting. SS 304 · SS 316 · Brass · Alloy 400 · Equal and Reducing · 6,000 PSI · ISO 9001:2015 certified.
A street elbow tube fitting — also called a service elbow or male-female elbow — is a two-port fitting that changes direction by 90° and has mixed thread genders: one port carries a male external thread (the "street end") and the other carries a female internal thread, with both ports at right angles to each other.
The defining feature is the street end. Because it presents an external male thread, the street elbow threads directly into the female socket of an adjacent fitting, valve, manifold, or instrument body — eliminating the short nipple that would otherwise bridge two back-to-back female sockets. The result is a more compact assembly with one fewer component and one fewer potential leak joint at every 90° direction change.
TES-LOK Street Elbows are available in both equal configuration (same thread size on both ports) and reducing configuration (different sizes on each port, simultaneously changing direction and pipe size in a single fitting). All are machined from certified bar stock, rated to 6,000 PSI, and available in SS 304, SS 316, Brass, and all major special alloys with full Mill Test Certificates.
| Port | Connection Type | Function |
|---|---|---|
| Port 1 — Street End | Male thread (NPT / BSP) | Threads directly into female socket of adjacent fitting, valve, or instrument body — no nipple required |
| Port 2 — Female End (90° to Port 1) | Female thread (NPT / BSP) | Receives male-threaded nipple, stud, or pipe end for the continuing run at 90° |
The two ports are at 90° to each other. In the reducing street elbow, the male street end and female end carry different thread sizes. Compare with the Male Elbow (both ports male thread, 90°), the Female Elbow (both ports female thread, 90°), and the Street Tee (same street-end concept but with an added branch port).
| Parameter | Details |
|---|---|
| Product name | Street Elbow Tube Fitting (Service Elbow / Male-Female Elbow) |
| Brand | TES-LOK (Tesco Steel & Engineering) |
| Port 1 — Street end | Male external thread — NPT, BSPT, BSPP, UNF, ISO metric |
| Port 2 — Female end | Female internal thread — same standard as street end |
| Elbow angle | 90° |
| Configuration | Equal (same thread size both ports) · Reducing (different size each port) |
| Thread size range | 1/8" to 1" (NPT / BSP) · ISO metric M10 to M42 |
| Max working pressure | Up to 6,000 PSI (SS 316, ambient temperature) |
| Materials | SS 304, SS 316, SS 316L, Brass, Alloy 400 (Monel), Alloy 600 (Inconel), Alloy C-276 (Hastelloy), Duplex 2205, Super Duplex 2507 |
| Temperature range | −65 °F to +1200 °F (material dependent) |
| Thread standard | ANSI/ASME B1.20.1 (NPT) · BS EN 10226 / ISO 7 (BSPT) · ISO 228 (BSPP) |
| Quality certification | ISO 9001:2015 · Material test certificates · 3.1 / 3.2 MTCs on request |
| Industries | Oil & Gas · Petrochemical · Power · Hydraulics · Marine · HVAC |
| Street End (Male) | Female End | Configuration | Typical Application |
|---|---|---|---|
| 1/8" NPT(M) | 1/8" NPT(F) | Equal | Miniature instrument panel bends, gauge socket entries |
| 1/4" NPT(M) | 1/4" NPT(F) | Equal | Instrument manifold 90° bends, transmitter body entries |
| 3/8" NPT(M) | 3/8" NPT(F) | Equal | Process skid 90° direction changes, hydraulic panel bends |
| 1/2" NPT(M) | 1/2" NPT(F) | Equal | High-flow header 90° bends, steam distribution turns |
| 1/2" NPT(M) | 1/4" NPT(F) | Reducing | 1/2" main line reducing to 1/4" instrument connection at 90° |
| 3/8" NPT(M) | 1/4" NPT(F) | Reducing | 3/8" process run reducing to 1/4" analyser tap at 90° |
| 1/4" BSP(M) | 1/4" BSP(F) | Equal | Offshore metric instrument loops, European OEM panels |
| 1/2" BSP(M) | 1/4" BSP(F) | Reducing | Marine metric headers reducing to 1/4" instrument branch |
The reducing street elbow carries different thread sizes on each port — for example, a ½" male street end and a ¼" female port. In a single machined body it simultaneously:
A conventional assembly achieving the same result would need three separate fittings: a nipple + a reducer + an elbow (or elbow + reducer nipple). The reducing street elbow replaces all three with a single component, removing two joints and two potential leak paths.
Wherever a 90° change of direction abuts a female socket — a valve outlet, manifold entry, or instrument body — a standard assembly requires a nipple + elbow. The street elbow removes the nipple: the male street end threads straight in, reducing fitting count by one and cutting one leak path per bend.
With no nipple, the street elbow shortens the assembly by the nipple length — typically 20 mm to 50 mm per bend. On congested instrument skids, panel boards, and offshore module piping where dozens of 90° bends are needed, this saving compounds significantly across the full pipe run.
The reducing street elbow performs direction change, size reduction, and nipple-free socket connection in a single body — replacing what would otherwise be a nipple, a hex bushing or reducer, and an elbow. Fewer components mean faster assembly, lower material cost, and a reduced leak-path count.
Instrument panels, analyser cabinets, and control room marshalling frames often have 90° bends within 30–50 mm of the mating fitting. A nipple-and-elbow pair may not physically fit; a street elbow, being nipple-free, often does. It is the preferred fitting type for back-panel instrument piping in space-critical enclosures.
Machined from certified bar stock to TES-LOK's standard dimensional and pressure ratings, the street elbow achieves up to 6,000 PSI working pressure. The all-metal body handles cryogenic through high-temperature service without degradation — suitable for steam, cryogenic, and high-pressure gas service alike.
Available in SS 304, SS 316, SS 316L, Brass, Monel 400, Inconel 600, Hastelloy C-276, Duplex 2205, and Super Duplex 2507. All materials are supplied with EN 10204 3.1 MTCs; 3.2 third-party witnessed MTCs are available on request for critical, nuclear-class, or subsea applications.
| Fitting | Port 1 | Port 2 | Angle | When to Choose |
|---|---|---|---|---|
| Street Elbow | Male thread | Female thread | 90° | One end plugs into a female socket; other end receives a male nipple |
| Male Elbow | Male thread | Male thread | 90° | Both mating parts are female-threaded sockets |
| Female Elbow | Female thread | Female thread | 90° | Both mating parts are male-threaded nipples or studs |
| Male Connector Elbow | Compression tube | Male thread | 90° | One compression tube end; one male-threaded end — instrument tap elbow |
| Street Tee | Male thread | Female thread | T (0° + 90°) | Same street-end concept but adds a branch port at 90° |
Step 1 — Plan orientation. Identify the male street end (the shorter, externally-threaded port) and the female end (the internally-threaded port at 90°). Before threading, hold the fitting in position and confirm the female end will face the direction of the continuing pipe run. Street elbows cannot be reoriented once made up — plan orientation before applying sealant.
Step 2 — Apply sealant to male threads. Apply PTFE tape (2–3 wraps clockwise from the first complete thread) to the male street end of the elbow. Also apply PTFE to the male nipple that will thread into the female end. Do not use PTFE on BSPP parallel female sockets — use a bonded seal washer instead.
Step 3 — Thread the street end first. Thread the male street end into the female socket of the adjacent fitting or valve body. Using a wrench on the body hex immediately behind the street end, tighten 1½ to 2 full turns past hand-tight for NPT/BSPT. A back-up wrench on the body is essential — never torque through the female end hex as this cross-loads the fitting body.
Step 4 — Thread the female end. Apply PTFE to the male nipple and thread it into the female end of the elbow. Tighten to hand-tight + 1½–2 turns using a wrench on the body hex. Hold the body with a back-up wrench to prevent the street end joint from loosening under reaction torque.
Step 5 — Leak test. Pressurise to working pressure and check both joints with a gas sniffer or bubble solution. Depressurise fully before any retightening — never torque a live pressurised joint.
| Industry | Typical Application |
|---|---|
| Oil & Gas | Wellhead instrument manifold 90° bends, chemical injection compact elbows, subsea module piping |
| Refinery / Petrochemical | Analyser sample conditioning panel bends, DCS instrument loop elbows, reactor skid piping |
| Power Generation | Steam header compact bends, boiler gauge panel elbows, turbine lube oil circuit turns |
| Hydraulics & Pneumatics | Compact 90° bends in HPU panels, pneumatic cabinet piping, actuator port entries |
| Marine & Offshore | Deck piping compact bends, HVAC instrument cabinet elbows, ballast piping turns |
| Chemical & Pharma | Dosing system 90° bends, CIP/SIP panel piping, sterile utility compact turns |
▶ What is a street elbow tube fitting?
▶ What is the difference between a street elbow and a regular elbow?
▶ What is a reducing street elbow?
▶ What thread standards are available?
▶ What sizes are available?
▶ What is the maximum pressure rating?
▶ How do I install a street elbow tube fitting?
▶ Which industries use street elbow tube fittings?
ISO 9001:2015 certified manufacturer. SS 304 · SS 316 · Brass · Special Alloys. 1/8"–1" NPT / BSP / BSPT. Equal and Reducing. Short lead times. Mill test certificates included.
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