Identifying Gaskets and Bolts for Chemical Storage Applications

With over 50 years of experience in creating tanks, fittings, accessories and other materials that ensure your chemical storage solution is safe and tailored to the chemical you are storing, we understand the importance of using the right products for your chemical. We’ve learned how the most popularly stored chemicals, like Sulfuric Acid, Sodium Hypochlorite and Hydrochloric Acid, react to improper storage systems. One part of those tank systems that is crucial is a tank’s gaskets. The tank’s gaskets act as a mechanical seal with a particular fitting to prevent leaks or spills. It is very important to make sure the gaskets and bolts used on your storage tanks are in compliance with what is needed to protect your tank fittings from corrosion caused by reactive chemicals.

Identifying Gaskets and Bolts for Chemical Storage Applications

Our Chemical Tank Storage Gaskets

The following video offers a quick introduction on how to identify the gaskets available and the materials they are made of. Black gaskets are EPDM, our most popular by far, but we offer litharge-cured Viton gaskets for other chemical storage applications. Our stud bolts are recognizable by the bolt head color, and the nuts for each bolt also indicate the metal used to construct the bolts. Watching the video will familiarize you with the different gaskets and bolts available for your chemical tank storage, and more information is available on our individual chemical storage pages.


Poly Processing has developed a chemical resistance guide to help our customers choose the right type of materials, including chemical tank storage gaskets and bolts for many chemicals including hazardous chemicals. There are also notes on combustible issues, flammable issues, incompatible materials, etc.

One of the innovations that we have developed is the IMFO tank. Traditional tank maintenance including gaskets and bolts, can be a challenge with many chemicals – so Poly has developed a unique system that helps minimize the hazards associated with traditional mechanical tank fittings. Poly Processing’s Integrally Molded Flanged Outlet (IMFO®) Tank, is a homogenous flange system that is molded as part of the tank while it is being manufactured, making it a stress-free part of the tank. The flange is created from the same material as the tank — it’s not an insert added during or post-production.

Download IMFO Guide

Some companies create tanks out of one substance and insert a metallic flange post-production, for drainageIMFO with Butterfly Valve and PTFE Expansion Joint (1) and discharge. This is simply to save money on investing in proper tooling to make the right tank. An inserted metallic flange unfortunately is common in the tank industry, but there are critical benefits to using a molded full discharge fitting or IMFO. Besides giving you full tank discharge, enhanced long term performance, and very high static head pressure, any required maintenance to the fitting, gaskets, or bolts is simple and hassle-free. Unlike metallic inserts, the flange extends away from the tank wall and the entire flange system is external with easy hardware access from outside the tank.

Another innovation is the Poly Processing B.O.S.S. fitting. With its streamlined one-piece design, the B.O.S.S. Fitting® (bolted one-piece sure seal) reduces the seal point to a single gasket to greatly reduce chances for leakage.

This unique fitting:

  • It’s streamlined—Its one-piece design is constructed without separate bolts, providing a unique advantage.
  • Shares the same material as the tank—The B.O.S.S. can withstand exposure to the same variety of chemicals that your tank can handle.
  • Multiple metals and alloys available—Although the metallic components won’t be exposed to the chemicalboss-fitting in normal operations, we only use metals and alloys that can withstand the chemicals you’re storing.
  • One sealing surface with one gasket—Instead of multiple sealing surfaces like a standard flange fitting, reducing sealing surfaces to one point means reducing opportunities for leaks and creating a very tight seal.
  • Bolts are welded to a standard metallic ring—This gives a more robust fitting than any composite fitting on the market. It reduces stress on the fitting and help prevent leaking over time, making it many times stronger than standard plastic fittings.

Download the B.O.S.S.  Fitting Quick Guide

The B.O.S.S. Fitting is your best choice for sidewall fittings and lets you rest easy, knowing that you’re covered against human errors. The B.O.S.S. Fitting® is available in three alloy options: 316 stainless steel, titanium and C-276. It comes fully assembled and pressure tested, and it can be installed through the tank wall as with any other standard bulkhead fitting. Learn more about the B.O.S.S. Fitting® under Fittings & Accessories.

Have questions about the right gasket or bolt for your tank? Contact a chemical storage expert today to get answers.