The Snyder Industries 3000 Gallon Plastic Vertical Double Wall Liquid Chemical Storage Tank (SKU SII-5590000N43) is a primary-plus-secondary containment unit for chemical service where you would otherwise set a single-wall vertical tank inside a separate berm. It holds 3,000 gallons, stands 142 inches tall on a 102 x 102 inch footprint, and is molded in white High Density Linear Polyethylene rated to 1.5 specific gravity. The integral outer wall provides secondary containment, so the stored chemical and its catch basin live inside one molded structure rather than a tank dropped into a concrete or steel dike.
Will this double-wall tank work for your liquid?
The 1.5 specific gravity rating is the number to check first. It means the HDLPE shell is rated to carry contents up to 1.5 times the density of water. At 3,000 gallons, plain water alone weighs 25,020 pounds full; loaded to the full 1.5 SG rating, the tank carries up to 37,530 pounds of contents, so size your pad, anchors, and structural support to the higher figure if your chemical approaches that density. The drawing for this tank shows a flange, an 18-inch PE threaded and vented fitting, and a manway with 15-inch access. That 15-inch access is the constraint on top-mount accessories: confirm any level gauge, mixer, or inspection hardware fits through it before you order. See the technical drawing on this page for fitting locations and elevations, and the level-gauge selection guide if you are choosing radar, ultrasonic, hydrostatic, or magnetostrictive measurement. If you are still deciding between sizes, the Tank Sizing Calculator and Tank Sizing Guide match capacity to your fill schedule.
Chemical compatibility
This is an HDLPE shell rated to 1.5 specific gravity. Within that rating, the OEM chemical-resistance chart supports the following at the listed concentrations, with the fitting and gasket materials shown. Always confirm against the OEM chart for your exact concentration and temperature:
- Acetic Acid, 60% — PP/PVC fittings, EPDM gaskets (details)
- Aluminum Sulfate, 50% — PVC fittings, EPDM gaskets (details)
- Calcium Chloride, 40% — PVC fittings, EPDM gaskets (details)
- DEF (diesel exhaust fluid), 32.5% — 316 stainless fittings, EPDM gaskets (details)
- Ferrous Sulfate, 20% — PVC fittings, EPDM gaskets (details)
- Magnesium Chloride, 30% — PVC fittings, EPDM gaskets (details)
- Sodium Carbonate, 30% — PVC fittings, EPDM gaskets (details)
- Urea Solution, 50% — PP/PVC fittings, EPDM gaskets (details)
- Ozonated Water, up to 10 PPM — PVC fittings, EPDM gaskets
Note the DEF exception: at 32.5% it wants 316 stainless ports, not the PVC default that covers the salts. Match your gasket family to your chemical, not your tank: EPDM covers the salts, DEF, and glycols, while oxidizers and strong acids call for Viton. Nineteen common chemicals are out of range at 1.5 SG and need the heavier 1.9-rated shell instead: Ethylene Glycol, Ferric Chloride, Ferric Sulfate, Hydrochloric Acid, Hydrofluoric Acid, Hydrofluosilicic Acid, Hydrogen Peroxide, Peracetic Acid (Aflas gaskets), Phosphoric Acid, Polyaluminum Chloride, Potassium Carbonate, Potassium Hydroxide, Propylene Glycol, Sodium Bisulfate, Sodium Bisulfite, Sodium Hypochlorite, Sodium Thiosulfate, Sulfuric Acid (CPVC fittings, Viton gaskets), and Zinc Orthophosphate. If your service chemical is on that list, do not buy this tank at 1.5 SG — step up to the 1.9-rated version and call 866-418-1777 to confirm the right SKU. Cross-check your chemical, concentration, and temperature against our Chemical Compatibility Database first.
The mistake to avoid on a double-wall chemical tank
The most common error is sizing fittings and gaskets to the tank rating instead of the chemical. The HDLPE shell may be fine at 1.5 SG, but the wrong gasket material at a fill or discharge port is where most chemical tanks leak first — that is why Viton shows up on the oxidizers and strong acids while EPDM covers the salts and DEF, with Aflas called out specifically for peracetic acid. The second error is treating freeboard as usable volume: a double-wall containment tank needs headspace for thermal expansion, so plan your working level below the rated capacity. Our walkthroughs on freeboard sizing per ASTM D1998, SPCC 40 CFR 112 compliance, and high-level alarm and spillover redundancy design cover the layered safeguards a vertical double-wall storage tank installation should include.
This Snyder vertical double wall tank ships LTL freight from the Lincoln, NE plant, with final origin confirmed at quote, and is quoted live to your ZIP. Get your freight quote on the Freight Cost Estimator, or call 866-418-1777 to confirm resin, SG rating, and fitting layout before you order.
