Quick Answer: The Elbow L Joint, Brass is a 90° pipe fitting made of brass that turns a pipe run through a right angle, used when installing or repairing the water and service lines that feed laboratory taps, sinks and benches.
Turning a Pipe Run Through 90°
Pipes rarely run in a straight line from the supply to a tap: they drop from the ceiling, turn along a wall, rise into a bench or step round a cabinet. An elbow, also called an L joint or bend fitting, makes each of those right-angle turns. A brass elbow L joint is among the most common fittings in plumbing because brass machines cleanly, holds a thread well and resists corrosion in most water supplies.
Elbows are made with different ends: female threads on both sides, male on one and female on the other, or compression ends that grip a pipe with an olive. The listing does not state the end type or size, and these decide what the fitting connects to. A threaded joint is sealed with PTFE tape or a thread sealant suited to the service; on gas lines only sealants and fittings approved for gas should be used, and the work must be done by a qualified gas fitter.
Every elbow adds a little resistance to flow, so a run with many turns delivers slightly less at the tap than a straight one. Where the water is soft or aggressive, some brasses slowly lose zinc (dezincification) and become porous, and dezincification-resistant brass is then often specified. On gas runs to bench taps, elbows are used with Copper Pipe for Gas Fitting to reach fittings such as the Gas Tap, Euro, Single cone 90°.
Fitting Tips
- Wrap PTFE tape in the direction of the thread so it does not unwind as the joint is tightened.
- Hold the elbow with a second spanner while tightening, so the pipe on the other side is not twisted.
- Check new joints for weeping when the supply is turned on, and again a day later.
- Replace elbows that show green or white crusting, a sign of slow leakage or corrosion.
Specifications
| Item | 90° elbow (L joint) pipe fitting |
| Material | Brass, as named in the title |
| Function | Turns a pipe run through a right angle |
| Sealing (threaded types) | PTFE tape or a sealant suited to the service |
| End type, size and thread | Confirm at enquiry |
Applications
- Water supply runs to lab sinks, taps and eye washes.
- Pipework turning into benches and service spines.
- Gas pipework to bench taps, where the fitting is suitable for gas.
- Repairs and alterations to existing laboratory plumbing.
Why Choose LabEquip
Plumbers, lab furniture installers and maintenance departments buy brass elbows in quantity for lab plumbing jobs. LabEquip lists them in General Lab Products; send the pipe size and end type through the contact page.
Frequently Asked Questions
What is an elbow L joint used for?
It turns a pipe run through 90°, for example where a supply pipe turns along a wall or rises into a bench to reach a tap.
Why is brass used for pipe fittings?
Brass machines accurately, holds threads well and resists corrosion in most water supplies, so it makes durable, reliable joints.
Is this elbow suitable for gas lines?
Brass fittings are widely used on gas lines, but the specific fitting must be suitable for gas and the work carried out by a qualified gas fitter. Check its suitability before using it on gas.
What is dezincification?
A slow form of corrosion in which some water supplies leach zinc out of brass, leaving it porous and weak. Where the water is known to cause it, dezincification-resistant brass is often specified.
How do I seal a threaded brass elbow?
Wrap PTFE tape a few turns in the direction of the thread, or use a thread sealant suited to the service, then tighten with a spanner while holding the adjoining fitting.
What sizes does the elbow come in?
The listing does not state the size or end type. Measure the pipe or thread it must join and confirm the matching elbow at enquiry.
Last Updated: September 2026
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