Polypropylene Tee Fitting, NPT Female Thread

Female NPT threaded tee fittings: creating a branch in an installation

A tee fitting creates three connection points from a single fitting. It is particularly useful when a line needs to continue in one direction while creating a branch toward a second line, equipment or accessory.

The tee fittings offered by Agrico Plastics are made of Schedule 80 glass-reinforced polypropylene and have female NPT threaded connections on all three sides.

They are available in 1", 1-1/2", 2" and 3". All three openings on a given tee are the same size.

What is a tee fitting used for?

A tee becomes useful when an installation needs to do more than simply connect point A to point B.

It adds a third connection to the system, allowing the main line to continue while creating a branch toward another component.

Depending on the installation, this third branch can connect another line, a ball valve, equipment or an accessory.

The tee itself does not determine how liquid will flow through the installation. System operation depends on the complete setup, including valves, the pump if one is used, line diameters and piping configuration.

Three female NPT connections: what does that change?

This is probably the most important detail to check before ordering.

All three openings on the tee have female NPT threads. This means another component that also has a female NPT connection cannot be threaded directly into the tee.

A fitting with a male NPT connection must then be installed between the two components.

A male x male threaded pipe nipple can, for example, be used to connect the tee to a female NPT valve or another female NPT accessory of the same diameter. If the two connections are different sizes, a male x male reducing fitting may be required instead.

Before choosing the individual parts, look at the complete assembly rather than the tee alone.

Tee, straight coupling or cross fitting?

These fittings may appear similar because they all connect multiple components, but they do not serve the same purpose.

The choice therefore depends first on the configuration you need to create.

Adding a tee simply because you need “one more connection” without considering the location of the other fittings can quickly complicate the assembly.

The four available sizes

Agrico offers female NPT tee fittings in four diameters: 1", 1-1/2", 2" and 3".

All three openings on the fitting are the same size. A 2" tee, for example, has three 2" female NPT connections.

If one branch requires a different diameter, the appropriate reducing fitting must be added to the assembly rather than assuming the tee itself provides the reduction. Depending on the connections involved, consider male x male threaded reducer nipples or male x female threaded reducer bushings.

Schedule 80 glass-reinforced polypropylene

The tee fittings in this category are made of Schedule 80 glass-reinforced polypropylene.

The product specifications indicate recommended operating conditions of 120 PSI at -17 °C, 150 PSI at 21 °C and 90 PSI at 65 °C.

These values also show why temperature is one of the factors that must be checked in an installation. A pressure value should not be considered independently of the temperature associated with it.

For a chemical application, compatibility between the liquid and polypropylene must also be checked, along with all other materials in contact with the product.

Plan the space required to assemble all three sides

A tee fitting requires more planning than a simple straight coupling because three components need to be installed around the same fitting.

Before building the assembly, look at the available space around the tee and how the different parts will be threaded into place.

An installation may look simple on paper but become difficult to assemble if a valve, tank wall, pump or another component prevents a threaded part from being turned properly.

The assembly sequence can therefore become important, particularly in a compact installation or when working close to an existing tank.

When should a cross fitting be considered instead?

A tee provides three directions. If your installation requires a fourth connection point at the same location, a cross fitting may be more appropriate.

Branches should not be added simply because a fitting allows them. Each branch should serve an actual need in the installation, and diameters, valves and other components should be considered as part of the complete system.

A tee generally remains the logical choice when the goal is to maintain a main line and create a single branch.

Frequently asked questions

Are all three sides of the tee NPT threaded?

Yes. The fittings in this category have three female NPT threaded connections.

Are all three openings the same diameter?

Yes. The models offered in this category have three openings of the same diameter. Available sizes are 1", 1-1/2", 2" and 3".

Can I thread a female NPT valve directly into the tee?

No, if the valve also has a female NPT connection. Because the tee is female, an appropriate male NPT connection must be added between the two, such as a male x male pipe nipple when the sizes match.

What is the difference between a tee fitting and a cross fitting?

A tee fitting provides three connection directions. A cross fitting provides four. The choice depends on the number of branches actually required in the installation.

Can I use a tee fitting with a chemical product?

It depends on the product, its concentration, temperature and other operating conditions. Compatibility between the liquid and polypropylene, as well as the other materials in the installation, must be checked before selecting the fittings.