T-Joint, Brass

Quick Answer: The T-Joint, Brass is a three-ended brass pipe fitting, commonly called a tee, that splits one pipe run into two or joins two into one, used when a branch is needed to feed an extra tap, sink, eye wash or gas point from a laboratory service line.

Branching a Service Line

A tee has a straight-through run and a side outlet at right angles to it, like the letter T. Put into a water main along a bench, it lets the run continue to the next bench while the branch rises to a tap. Laboratories use tees wherever supply points are added: a new sink on an island, an eye wash beside the door, a second gas tap on a teaching bench.

Brass tees come as equal tees, with all three ends the same size, and reducing tees, where the branch is smaller than the run. As with other fittings, ends may be female-threaded, male-threaded or compression for copper tube. The size and pattern of this brass T-joint are not given in the listing, so the pipe diameter, thread and branch size should be decided before ordering.

Adding a branch lowers the flow available at points further along the run, which matters on long runs with many taps. On gas lines, fittings and sealants must be suited to gas and the installation leak-tested by a qualified fitter; copper pipe for gas fitting is commonly run between tees and bench taps. For an in-line connection without a branch, see the brass straight joint.

Where Tees Are Used

• Adding a tap or sink to an existing water main along a bench.
• Feeding an emergency eye wash from a nearby supply line.
• Branching a gas line to serve two bench gas taps.
• Taking a feed for a water still or distillation unit from the main supply.

Fitting Tips

• Decide which way the branch must face before tightening, since a tee cannot be turned afterwards without loosening the joint.
• Support the pipe near the tee so the weight of the branch and tap does not strain the threads.
• Seal threads with PTFE tape or a sealant suited to the service.
• Test every new branch for leaks under pressure and look at it again after a day of use.

Specifications

Why Choose LabEquip

Installers extending existing lab services, and furniture makers building bench service spines, buy brass tees in quantity. LabEquip keeps them among its General Lab Products; tell us the pipe size and whether you need an equal or reducing tee through the contact page.

Frequently Asked Questions

What does a T-joint do?

It divides one pipe run into two directions, or combines two into one. The straight run carries on through the fitting while the side outlet feeds a branch at right angles.

What is the difference between an equal and a reducing tee?

An equal tee has all three ends the same size. A reducing tee has a smaller side branch, which saves an extra reducer when a small tap line leaves a larger main.

Will adding a tee reduce the water flow at my taps?

Each new branch shares the supply, so if several taps are open at once the flow at each drops. On a well-sized main with a few outlets the effect is usually small; long runs with many taps may need a larger pipe.

Can a brass tee be used to branch a gas line?

Yes, provided the tee and sealant are suited to gas and the work is done and leak-tested by a qualified gas fitter. A shut-off valve on the new branch makes later maintenance easier.

How do I seal a threaded brass tee?

Wrap PTFE tape in the direction of the thread, or apply a thread sealing compound suited to the service, then tighten firmly while holding the tee with a second spanner so the pipe is not twisted.

Why choose brass for a tee rather than plastic?

Brass tees hold threads well, tolerate hot water and resist knocks, and they are standard on gas lines. Plastic tees suit corrosive drain lines and some cold water systems, but they are not used for gas.

Last Updated: September 2026