Stainless Steel Bolted Fitting

316 Stainless Steel Bolted Bulkhead Fittings for Tanks

A stainless steel bolted bulkhead fitting creates a connection through a tank wall for a valve, hose or piping. Also called a tank wall fitting, it can provide a filling inlet, drain or accessory connection.

We offer four nominal sizes: 3/4, 1 1/2, 2 and 3 inches. These fittings are made of 316 stainless steel with an EPDM gasket and female × female NPT internal threads. Four bolts and four nuts are included.

The choice depends on the liquid, tank wall and intended connection. A bolted mounting alone does not establish suitability for every operating condition.

Bolted or Threaded Bulkhead Fitting: What Is the Difference?

Distinguish the tank mounting from the connection used for accessories. The fitting shown is bolted to the wall, while its piping connection remains NPT threaded.

Threaded polypropylene and PVC bulkhead fittings are another configuration to consider. A threaded fitting cannot automatically be replaced by a bolted fitting in the same location: the hole size and clearance must be confirmed.

316 Stainless Steel and EPDM Gasket: Check Both

The metal body and gasket perform different functions. Stainless steel forms the fitting, while the EPDM gasket seals the connection through the wall.

Before ordering, specify the liquid, its concentration and its actual temperature. Check compatibility with 316 stainless steel, EPDM and the tank material. A liquid compatible with the tank is not necessarily compatible with all its accessories.

These checks apply across different tank applications and industries, whether for storage, filling or transfer.

Allowable pressure cannot be inferred from the material or the presence of bolts. If a pump is used, pressure or suction conditions must be confirmed.

Female NPT Threads: Plan the Right Accessories

The internal threads allow accessories to be connected on both the inside and outside of the tank, depending on available space. Each accessory threaded directly into the fitting must have a matching male NPT end.

Adding a Drain Valve

To open or close the outlet, choose a ball valve compatible with the application.

If the valve has a female connection, a male × male NPT nipple can provide the transition. Check the parts already supplied with the valve to avoid a duplicate purchase.

Connecting a Transfer Hose

For a removable connection, choose a Camlock quick-connect fitting with a male NPT threaded end suitable for the bulkhead fitting.

For a barbed connection, consider male NPT threaded hose barb adapters. The barb must match the hose’s inside diameter.

Also select the transfer or suction hose according to the liquid and operating conditions.

Changing Direction or Size

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

The bulkhead fitting can also provide a connection for a tank vent, depending on the selected configuration.

Confirm the Location Before Drilling

The nominal size of the internal NPT connection is not the hole diameter required to insert the fitting. Allow for the bolted mounting and the space needed for the complete fitting.

For a replacement, knowing only the piping size is not enough. Measuring the existing hole helps confirm whether the new fitting may be suitable.

Check that the fitting’s overall diameter and selected location allow installation before modifying the wall. This avoids preparing an opening that does not match the selected part.

Frequently Asked Questions

Does a Bolted Stainless Steel Fitting Have a Flanged Outlet?

All fittings shown have a female NPT connection. A compatible flange adapter must be added to obtain a flanged outlet. We also offer welded HDPE flanges for certain locations where a bulkhead fitting cannot be installed, subject to project review. See our plastic welding and welded tank flanges section. Contact our team for a quote.

Can These Fittings Be Used with Every Chemical?

No. Confirm the liquid’s compatibility with 316 stainless steel, the EPDM gasket and the tank, taking concentration and temperature into account.

Can a Plastic Bulkhead Fitting Be Replaced by a Stainless Steel Fitting of the Same Size?

Not automatically. Matching nominal sizes do not make fittings interchangeable. The required hole diameter can vary with the fitting body dimensions and material thickness. Also check the overall diameter and the space required for mounting.