Properly Installing Poly Processing Chemical Storage Tank Fittings

The proper installation of chemical storage tank fittings is important to prevent leaks and address issues during tank installation and to ensure safe tank operation in the future. Below is an outline of installation best practices for the main fittings that Poly Processing offers for their chemical storage tanks. The Poly Processing Installation Guide is the best resource for understanding how fittings should be installed and maintained.

Installing the IMFO® Flange Fitting

Poly Processing assembles and hydro-tests the IMFO® (Integrally Molded Flanged Outlet) to ensure a proper seal. DO NOT disassemble the factory installation. If a field replacement is required, follow the enlarged view picture in the Installation Technical Bulletin as a guide. When storing, transporting, and installing the tank, it’s important to protect the IMFO® flanged nozzle from damage. When storing, the tank can be positioned upright with adequate blocking, or laid on its side and chocked to prevent rolling. This will keep the IMFO fitting, which is lower than the floor of the tank, from getting damaged or scraped.

Installing the B.O.S.S. Fitting®

The one-piece sure-seal fitting also known as the B.O.S.S. Fitting® is designed to give the end user a robust sidewall fitting which is chemically compatible to most chemicals that a XLPE tank can store because of its polyethylene body. This is Poly Processing’s premier fitting for chemical compatibility and long term properties. You can refer to the B.O.S.S. Fitting® Assembly Manual in the Installation Technical Bulletin for drill bit sizes, installation steps, and torque wrench tightening settings. It’s vital to conduct a 24-hour hydro test after the fitting is installed and before filling the tank with chemical to test the gasket seal and B.O.S.S. Fitting® installation.

Installing Bulkhead Fittings

Bulkhead fittings are an economical fitting best used on small tanks in mild applications. They are available in PVC, CPVC and Polypropylene.

Here are a couple key points about the bulkhead fitting:

  1. Can be installed on sidewall, overflow or dome (for dome installation make sure you do not need the fitting 100% level).
  2. The Bulkhead fitting may be used as an overflow fitting with all chemicals due to it being a non-wetted fitting.
  3. Over time, this fitting "creeps" causing the nut to loosen requiring monitoring for drips.
  4. Must be installed from the inside of the tank, sometimes requiring tank entry for repairs and maintenance.
  5. Cannot be used as a drain or discharge on tanks greater than 3000 gallons or tanks greater than 6' in height.

Depending on your specific application, better alternatives include:

  1. Bolted Flange Fittings
  2. Stainless Steel Bulkhead Fittings
  3. B.O.S.S. Fitting®

Bolted Flange Fitting Installation

Refer to the Bolted Flange Fittings link of the Installation Manual for installation steps, and refer to the video below for proper torque tightening of the bolts. It’s important not to over-tighten bolts to avoid damage to the flange and gasket. Again, a 24-hour hydro test is required before filling the tank with chemicals to test the gasket seals and fittings.


Stainless Steel Fittings

Be sure to follow the installation steps outlined for both Coupling and Full Nipple Stainless Steel fittings. Drill bit sizes and wrench torque settings are specified for correct installation.

Installing Universal Ball Dome Fittings

The Self Aligning Universal Ball Dome fittings are designed for use only on tank domes, and are NOT TO BE USED ON THE SIDEWALL OF THE TANK! The UBD fitting is made for the top of tanks only and is not a wetted sealed fitting.

There are two styles of Ball Dome fittings:

  1. Bulkhead Fitting Style
  2. Bolted Flange Style

You should NEVER stand on the tank dome when installing dome fittings. The surfaces are  flexible and slippery and could easily result in a fall. Use portable ladders, scaffolding, or personnel lifts with proper fall protection.

Refer to the Installation Technical Bulletin under Self Aligning Universal Ball Dome Fittings for complete installation steps.

Bellows Transition Fitting

Poly Processing’s SAFE-Tank® is a "tank-within-a-tank" system that keeps contaminants from entering the interstitial or containment area. These tanks provide secondary containment to avoid  damaging of equipment or property, loss of chemical, or injury to employees in the event of a spill.

For this reason, proper installation and following each and every step outlined in the Bellows Transition Fitting Installation Guide and the installation videos for the bellows transition fitting is crucial.

An additional WARNING regarding the importance of the Bellows Transition Fitting that is worth repeating:

The SAFE-Tank® system is designed to provide a minimum of 110% secondary containment. Once the transition fitting is installed, a leak in the inner tank will result in product collection between the inner and outer tank. If this product is not drained off prior to breaking the seals of the transition fitting, serious property damage, injury or possibly death may occur. Great care must be taken to protect people and property when working with a transition fitting.

Each one of these storage tank fittings includes detailed installation instructions when we ship the storage tank. For more information, detailed installation instructions for each fitting are outlined in the Poly Processing Storage Tank Fittings Installation Manuals and Videos.

Contact a chemical storage tank system expert for more questions on fittings installation.

Contact Our Field Service Department