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Sulfuric Acid

Through a combination of innovative features, Poly Processing creates the ideal system for sulfuric acid storage. With their robust load tolerance, crosslinked polyethylene tanks can more than handle the chemical’s heavy weight. The molecular bonding of XLPE and tank wall thickness is particularly important in the bottom third of the tank, where high levels of load are concentrated.

You can use any Poly Processing tank less than 11,000 gallons and under 15 feet tall to store sulfuric acid. This includes Sloped IMFO®, IMFO®, Vertical, and SAFE-Tank® Systems.

If secondary containment is not present, the Poly Processing SAFE-Tank® is a smart choice. Along with containing the chemical from its surrounding environment, this double-walled tank greatly lowers the risk for hazardous contact of sulfuric acid with water. SAFE-Tank® systems are designed with OR-1000™.

If secondary containment* is present, the IMFO® tank is recommended. With the use of an IMFO® system instead of mechanical fittings, the tank’s structural integrity is maximized. Combine this tank design with the OR-1000™ system, and oxidation is reduced dramatically.

All of these features lead to a safer tank – designed to reduce safety risks and improve the longevity of the system.

For additional information on storing sulfuric acid, including recommended storage tanks and components, download our Sulfuric Acid Position Statement below.

Download Sulfuric Acid Position Statement



 Challenging a storage tank’s strength and design safety

Sulfuric acid is used in a huge array of industrial applications, from water and wastewater treatment to the manufacture of chemicals, fertilizer and car batteries.

This highly exothermic acid presents serious storage challenges:

  • Sulfuric acid is an extremely heavy chemical that will test the mechanical integrity of any material.

  • The addition of water to concentrated sulfuric acid leads to the dispersal of a sulfuric acid aerosol – or worse yet, an explosion.

  • If sulfuric acid is spilled on metals, it can create highly flammable hydrogen gas.

  • Skin and other bodily burns from sulfuric acid are potentially more serious than burns from other strong acids. Sulfuric acid dehydrates whatever it touches, and the heat caused by that reaction with water can create secondary thermal damage.

Poly Processing’s tanks and fittings can be combined specifically to contain sulfuric acid, reducing the risks presented by this highly acidic chemical.

Looking for more information on sulfuric acid storage? Read our complete storage guide.

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Chemical Resin Type Specific Gravity Rating Fitting Material Gasket Material Bolt Material
Sulfuric Acid ≥ 93% XLPE with OR-1000™ 2.2 PVC Viton® 316SS
Sulfuric Acid 80%-92% XLPE with OR-1000™ 2.2 PVC Viton® C-276
Sulfuric Acid < 80% XLPE with OR-1000™ 1.9 PVC Viton® C-276

* Containment tank is required with this chemical in all applications.


Tank Specifications

High-density crosslinked polyethylene (XLPE) accommodates the heavy weight of sulfuric acid.

OR-1000™ bonds the XLPE with an antioxidant inner surface, minimizing oxidation, reducing the potential for fault and maximizing life span.

SAFE-Tank® design creates a "tank within a tank," ensuring that water will not enter the containment area. (Recommended where secondary containment is not available.)

Integrally Molded Flanged Outlet (IMFO®) tank is molded as a single unit. This maintains hoop stress rating, adding to the strength of the tank. (Recommended for situations with existing secondary containment.) 

B.O.S.S. fitting® provides bolted one-piece sure-seal design, limiting the seal point to a single gasket for major leak protection.

Recommended System Components

SAFE-Surge® Manway Cover

SAFE-Surge® Manway Cover

Venting: SAFE-Surge® manway cover is recommended on pneumatically loaded systems to support tank longevity. 

Bellows Transition Fittings

Bellows Transition Fittings

Fittings: Recommend bellows transition fitting for bottom sidewall discharge.

The B.O.S.S. Fitting®

The B.O.S.S. Fitting®

Fittings: B.O.S.S. fitting® also recommended to prevent leaks.

NOTE: For concentrations less than 93%, DO NOT use stainless steel.

Reverse Float Level Gauges

Reverse Float Level Gauges

Plumbing: Reverse float gauge recommended to ensure proper tank leveling. 

Technical Overview


11/15 Rule - Less Than 11,000 Gallons and Less Than 15' Tall:

  • Sulfuric Acid may be stored in any tank less than 11,000 gallons and less than 15 feet tall.
  • This includes the Vertical, IMFO®, Sloped IMFO®, And SAFE-Tank®

Secondary Containment:

  • SAFE-Tank® (recommended)
  • Non-SAFE-Tank® alternatives:
    • PPC secondary containment basin
    • Other secondary containment suitable for sulfuric acid, of adequate size for use


  • SAFE-Tank® sidewall: Recommend Transition Fitting®
  • Single Wall Sidewall: Recommend BOSS Fitting®
  • Dome: No restrictions

Plumbing to the tank

  • Required use of flexible connections with fittings on lower one-third of sidewall
    • Allows for lateral and vertical expansion and contraction of the tank. Reduces pump and piping vibration stress on the tank
    • Flexible connections, piping, and valves must have structural support independent of the tank sidewall or dome.
  • Expansion joints must meet the following minimum requirements:

    • Axial Compression ≥ 0.67˝

    • Axial Extension ≥ 0.67˝

    • Lateral Deflection ≥ 0.51

    • Angular Deflection ≥ 14°

    • Torsional Rotation ≥ 4°


Product should not exceed 100°F at delivery or during storage to maintain ASTM D1998 design parameters.


See our Venting Chart

Foundation and restraints

  • Poly Processing structural acid pad or concrete rated to accommodate weight of acid in IMFO®, SAFE-Tank® or vertical tank. All foundations must have an appropriate chemical resistant coating.
  • Cable restraint systems (when called for) must pass over the top of the tank.


SAFE-Surge® manway cover for pneumatically loaded tanks; bolted manway cover for all other applications


  • Restraint systems for wind and seismic
  • Reverse float level gauges
  • Ladders
  • Heating pads and insulation
  • Fume-tight manway cover
  • NSF-61 certification
  • Third party engineering stamp for seismic