The Snyder Industries 3500 Gallon ASTM XLPE Captor Double Wall Tank is a containment-grade vessel built for the cases where a single barrier is not enough: a tank-within-a-tank where the outer shell catches whatever the inner tank releases. The listed 3,500 gallons is the inner (primary) tank's working capacity, and the Captor's outer wall provides secondary containment around that primary. Molded in crosslinked linear polyethylene (XLPE) to the ASTM standard, it carries a 1.9 specific gravity rating and lists in Natural White. The footprint is 102 inches by 102 inches with an overall height of 158 inches, so plan the pad and the overhead clearance before it arrives.
Will it work for your site
The 1.9 specific gravity rating is the number that matters most here. It means the inner tank is engineered to hold contents up to 1.9 times the weight of water. Filled with water, the contents weigh roughly 29,190 pounds; at the full rated 1.9 SG, the contents can reach about 55,461 pounds. Combine that with the 102 x 102 inch footprint and you can size the concrete and any anchoring properly. For working through usable volume against freeboard and thermal expansion, run the numbers with the Tank Sizing Calculator and the Tank Sizing Guide.
Fittings and access
Per the technical drawing on this page, this Captor is configured with a flange, an 18-inch PE threaded and vented fitting, and a manway with 15-inch access. The 18-inch PE threaded/vented opening is the vented port that your freeboard protects, so it should never be crowded by the fill level. For the flange and the 18-inch threaded connection, confirm the gasket and any bulkhead or fitting hardware are rated for your intended contents and for 1.9 SG service before you commit your plumbing, and verify the fitting locations and elevations against the technical drawing. As an XLPE double wall (search shoppers know it as an "xlpe tank" or simply "double wall"), this Snyder is the type of vessel specified where secondary containment is a requirement rather than an option. Call 866-418-1777 and we will spec the fitting layout with you.
Sizing it right and avoiding the common mistake
The mistake to avoid on a tank this large is filling to the brim. ASTM D1998 sizing logic requires freeboard above the working level so the polyethylene can expand thermally and so the contents do not crowd the vent and manway. Two guides walk through exactly that math for this product family: Captor Double-Wall Freeboard Sizing per ASTM D1998 and the vapor-saturated headspace wall-thickness guide. If this tank is going into a regulated containment role, the SPCC 40 CFR 112 compliance walkthrough covers how a double wall Captor fits an oil-storage spill-prevention plan, and the NFPA 22 fire-water reservoir guide covers the rural fire-protection use case.
This Captor ships LTL freight from a Snyder plant, with stock filled from either Nebraska (Lincoln, NE) or West Virginia depending on availability and destination, so a live ZIP quote is the real number. Get one before you order with the Freight Cost Estimator, or call 866-418-1777 and we will work the freight and the fitting layout with you.
