Polypropylene and PVC Tank Fittings

Polypropylene and PVC Bulkhead Fittings for Tanks

A bulkhead fitting, also called a tank fitting or tank wall fitting, creates a connection through a tank wall. A valve, vent, hose or piping can then be connected for filling, draining or transferring liquid.

We offer polypropylene and PVC bulkhead fittings with female NPT internal threads. Available sizes range from 1/2 to 4 inches, depending on the configuration. Versions with EPDM or Viton gaskets are available according to material and size.

When choosing a fitting, consider the liquid, the tank and the accessories being connected. A fitting with the right connection size is not necessarily suitable for the intended location.

Three Dimensions Not to Confuse

The stated size refers to the nominal NPT connection. It does not specify the fitting’s outside diameter or the size of the opening required in the tank.

Also check available height, wall curvature and spacing between connections. These requirements vary by fitting: do not automatically reuse dimensions from an existing installation.

Polypropylene or PVC: Choose According to the Liquid

The fitting body material must be compatible with the liquid, its concentration and its actual temperature. The tank’s compatibility must also be checked.

PVC is not automatically preferable for every chemical. Polypropylene is not a universal solution either. Select the assembly according to operating conditions across different tank applications and industries.

The Gasket Matters as Much as the Body

The gasket seals the connection through the wall. Its material must therefore be suitable for the liquid, just like the fitting body.

EPDM and Viton versions are not interchangeable in every application. Before replacing a gasket, confirm its material, dimensions and compatibility with the existing fitting. See our replacement gaskets for bulkhead fittings.

Female NPT Threads: Which Accessories Can Be Connected?

The fittings shown have female NPT internal threads, allowing connections on both the inside and outside of the tank. Use a matching male NPT accessory while allowing for available space.

The external thread used for the retaining nut must not be confused with the connection used for piping.

Adding a Valve

To control opening and closing at the outlet, choose a compatible polypropylene or PVC ball valve.

A male × male NPT nipple can join two female connections. First check whether the nipple is already supplied with the valve.

Connecting a Hose

For a hose that needs to be disconnected, consider Camlock quick-connect fittings. The end threaded into the bulkhead fitting must be male NPT; the other end is selected to match the hose fitting.

For a hose barb connection, use a hose barb adapter with male NPT threads. Check the hose’s inside diameter and the threaded connection size separately.

Changing the Size or Direction

A male × female NPT reducing bushing provides a transition between certain sizes. An elbow fitting changes the connection direction.

For a transition to solvent-weld PVC piping, see our male-threaded adapters with solvent-weld sockets.

Plan the Location Before Modifying the Tank

The fitting can provide an inlet, drain or connection for an accessory such as a tank vent.

Before drilling, confirm the fitting, its location and wall requirements. For a replacement, photos from both inside and outside, where accessible, help clarify the existing assembly.

When a pump is involved, also specify the pressure or suction conditions. Chemical compatibility alone does not establish the assembly’s mechanical limits.

Frequently Asked Questions

Does a 2-Inch Bulkhead Fitting Require a 2-Inch Hole?

No. The nominal size refers to the NPT connection. The hole must allow the fitting body to pass through, and its outside diameter is larger than the nominal connection size. Use the hole diameter specified for the selected fitting and allow separate space for the gasket and nut.

Can the Fitting Be Installed on a Curved Wall?

Yes, when the tank’s curvature meets the fitting’s requirements. Check the installation requirements on the fitting’s detailed product page before confirming the location.

Can Only the Gasket Be Replaced?

Yes, when a matching replacement gasket is available. Confirm its dimensions and compatibility with the liquid.