The Snyder Industries 3000 Gallon ASTM Black Captor Double Wall Tank (SKU 5590000N49) is a tank-within-a-tank built for sites that cannot tolerate a spill: the inner tank holds 3,000 gallons of liquid while the outer wall provides integrated secondary containment in a single molded unit - no separate basin to permit, line, or maintain. It stands 142 inches tall on a 102 x 102 inch square footprint, molded in black High Density Linear Polyethylene with a 1.5 specific gravity rating, meaning the structure is engineered to carry contents up to 1.5 times the density of water. If you have been searching for a 3000 gallon double wall tank from Snyder, this is the black ASTM-rated unit.
Will this tank work for your application?
Sizing starts with weight, not just gallons. Filled with water, this tank carries roughly 25,020 pounds; at its maximum rated 1.5 specific gravity, the contents alone reach about 37,530 pounds. Your pad, ring wall, or slab has to be engineered for that load on the 102 x 102 inch footprint - run your numbers through the Tank Sizing Calculator and review the Tank Sizing Guide before you pour anything. The integrated double-wall design means you get the containment without engineering, permitting, and maintaining a separate spill basin around it.
Fittings and access
The drawing-confirmed fittings on this unit are an outlet flange, an 18-inch PE threaded/vented port for fill and venting, and a manway with 15-inch access for inspection and entry. Confirm your gasket and fitting thread match the 18-inch PE threaded port before you order adapters or run plumbing. See the technical drawing on this page for exact fitting placement and elevations before you set anything. One more pre-delivery check: at 142 inches tall on a 102 x 102 inch base, verify overhead clearance and gate or door width along the offloading path, since LTL delivery needs the route planned in advance.
The mistake to avoid
The 1.5 specific gravity rating is the number people misread. It is a maximum, not a recommendation: it tells you the heaviest contents the wall can hold, but you still have to confirm your actual liquid density and leave proper freeboard for thermal expansion. Snyder's Captor double-wall platform is sized under ASTM D1998, and getting freeboard wrong is how operators lose usable volume or overstress the wall. Two guides walk through this directly - freeboard sizing per ASTM D1998 and where vapor-saturated headspace failures originate. If this is a containment install, the SPCC 40 CFR 112 compliance walkthrough shows how a double-wall tank fits the rule, and rural fire-water buyers should read the NFPA 22 fire-water reservoir design guide.
Freight and ordering
This is a large unit that ships LTL freight, quoted live to your ZIP. Snyder builds the Captor line at plants in Nebraska and West Virginia, so we will quote LTL from the origin that serves your delivery ZIP - which can make a real difference on a 142-inch double wall tank moving cross-country. Get an accurate number before you commit: run your delivery ZIP through the Freight Cost Estimator or call 866-418-1777, and we will line up the LTL quote and confirm fittings, manway access, and lead time for your project.
