120 Gallon Double Wall Containment Tank, 36" Dia x 51"H, 16" Vented Manway

The 120 Gallon Double Wall Containment Tank (36" Dia × 51" H with 16" Vented Manway) is a heavy-duty, point-of-use secondary containment chemical storage vessel engineered for large commercial aquatic facilities, waterparks, high-volume natatoriums, and municipal chemical feed installations.

Featuring a broader 36-inch diameter profile and an expanded 16-inch access manway, this model offers a wider base of support and increased access clearance compared to narrower variants. It satisfies EPA 40 CFR 264.175 and OSHA secondary containment standards without requiring floor berms, containment basins, or separate catch pans, providing dedicated storage for high-demand chemicals such as 12.5% to 15% liquid sodium hypochlorite, 31.45% muriatic acid, sulfuric acid, and high-volume coagulant solutions.

Mechanical & Structural Architecture

• Integrated Secondary Containment (115% to 125% Buffer): The outer containment envelope provides 115% to 125% capacity relative to the primary inner vessel. In the event of primary vessel mechanical rupture, stress cracking, or thermal fatigue, the full liquid volume is safely retained within the interstitial space, preventing chemical release onto equipment room pads.

• Rotomolded Monolithic Construction: Seamlessly molded as a single, monolithic unit using virgin High-Density Linear Polyethylene (HDLPE) or High-Density Cross-Linked Polyethylene (XLPE). Monolithic molding eliminates welded seams, joints, and stress risers vulnerable to chemical attack and cyclic hydraulic loading.

• High Specific Gravity Rating (1.5 to 1.9 SG): Formulated with heavy-wall construction rated to handle high-density fluids up to 1.9 Specific Gravity, safely holding dense 12.5%–15% sodium hypochlorite (~1.20–1.22 SG) and 31.45% muriatic acid (~1.16 SG) without sidewall bulging.

• 16" Oversized Vented Access Manway: Features an expanded 16-inch threaded or quarter-turn polypropylene access lid with an integrated pressure-relief vent. The wide diameter enables easy internal visual inspection, drop-tube installation, and manual hose filling, while the breathable labyrinth/membrane vent relieves oxygen gas released from decomposing sodium hypochlorite and prevents vacuum collapse during high-rate dosing.

• Wider Top-Mount Equipment Surface: The 36-inch diameter top dome provides a larger, rigid footprint with molded flat landings to anchor commercial electronic diaphragm metering pumps, peristaltic feeders, level-sensor transmitters, and rigid top-draw suction lances.

• Visual Fluid Inventory Tracking: Molded in natural translucent polymer with raised gallon and liter graduation marks down the exterior sidewall, allowing operators to visually check chemical inventory levels without unthreading the access lid.

Technical Specifications

• Nominal Primary Volume: 120 US Gallons (approx. 454 Liters).

• Secondary Outer Volume: Approx. 140 to 150 US Gallons ($>115\%$ containment capacity).

• Overall Exterior Dimensions: 36" Outer Diameter × 51" Overall Height (approx. 91.4 cm Dia. × 129.5 cm H).

• Access Manway: 16" polypropylene vented fill/access lid with breathable labyrinth/membrane vent.

• Specific Gravity Rating: Standard 1.5 SG (dilute acids/water) or Heavy-Duty 1.9 SG (concentrated bleach/acids).

• Operating Temperature Limits: -20°F to 120°F (-29°C to 49°C) continuous service.

• Fittings & Port Landings:

  • Top-dome flats accommodate up to three 2" NPT female bulkhead adapters (for top-draw suction lances, chemical fill lines, and interstitial leak detection float switches).

  • Top-draw plumbing architecture standard to prevent gravity drainage or siphon leaks.

Chemical Compatibility Reference

• Sodium Hypochlorite (12.5% – 15%): Fully compatible. The 16" vented cap allows continuous escape of decomposing oxygen gas.

• Muriatic Acid (Hydrochloric Acid, 28% – 31.45%): Fully compatible. Sealed top-draw piping isolates corrosive fumes from mechanical room equipment.

• Sulfuric Acid (up to 50% concentration): Fully compatible under ambient equipment room conditions.

• Liquid Coagulants & Polyaluminum Chloride (PAC): Fully compatible; smooth non-stick interior minimizes polymer film buildup.