Snyder Industries 10,000 Gallon HDLPE Captor Double Wall Liquid Storage Tank - 1.5 Specific Gravity

The pad under a double wall tank, and the footprint it has to carry

Where this tank sits is the first engineering decision on the project and the most expensive one to get wrong. The base is 142 inches across, eleven feet ten inches, and the shell stands 226 inches, eighteen feet ten inches, so the whole installation is a tall cylinder on a wide circle carrying 83,400 pounds of water, or up to 125,100 pounds of contents at the sheet's rating, through a rotationally molded floor that bears on the whole surface it touches and nothing else. There is no ring wall, no skirt and no structure spreading that load for you. A low spot, a hollow under the middle, a cold joint that has settled, or a slab poured to the tank's edge instead of past it, all end the same way: the bearing moves to a point and stays there. So the slab is designed and poured before the tank is ordered, flat, level, continuous and wider than the base, with the surround drained so that water from a wash-down, a rainstorm or an overflow runs away from the pad edge rather than under it. Then there is the second thing a double wall asks of the site, which a single-wall tank does not: the interstitial space between the inner tank and the outer containment shell has to stay inspectable for the life of the installation. That means access all the way round, room to get at the annulus and at whatever monitoring the site puts on it, and a layout where nobody has to move a pipe rack to look at the outside of the containment. Build that in at the drawing stage. Because the shell is eighteen feet ten inches tall, everything at the top of it is a designed access job as well: fixed access with a rail rather than a ladder leant against polyethylene, and a fill brought down to a coupling at working level rather than a hose lifted over the wall. The freeboard question is the one most often skipped, and it is where usable volume actually lives, because a liquid that is heavier than water, warms in the day, or gases off, does not give you the nameplate figure to work with; the Captor double wall freeboard sizing guide works that arithmetic properly. What a contained installation has to do to satisfy a site's own containment rules, rather than merely look contained, is set out in the Captor double wall containment walkthrough. Before the pad is poured, check that 10,000 gallons is the right number in the tank sizing calculator and take the reserve and the headspace from the tank sizing guide.

The 10,000 gallon Captor shells, the 8,700 and the 12,500

Read this family as one base with three heights and several wall specifications. Four part numbers put 10,000 gallons in the same 142 by 226 inch envelope, three of them listed at 6,400 pounds and the 1006600N30 at 7,400 pounds; the sheet gives those figures and no explanation for the difference, so we print them and stop. What separates the rows in practice is what the tank is built to hold, and that is the conversation to have before you pick a number: this page is the white tank rated at a specific gravity of 1.5, and a different rating in the same shell is a different part number rather than an option. The volume steps are the genuinely useful comparison. The 8,700 gallon 1006400N46 keeps this tank's 142 inch base and comes down to 197 inches tall at 5,000 pounds, which is the buy when the building, the roof line or the crane you have access to cannot take the taller shell; you give up thirteen hundred gallons and gain two feet five inches of clearance. The 12,500 gallon 1031100N30 goes the other way, the same base at 274 inches and 9,500 pounds, and it is the right move when the pad is the scarce resource rather than the height, because it adds a quarter more volume on the same circle of concrete. Since all three share the base, a site can be built once for the footprint and the height chosen last. Tell us the liquid, the specific gravity you actually need and the headroom you have, and the part number follows from those three answers rather than from the gallon figure.

Height or floor the limit? The table has both shapes; freight to your ZIP is quoted on each row, or call 866-418-1777 with the site.

No outlet on this sheet, an 18 inch manway, and what that means for the plumber

• What the sheet publishes: an 18 inch threaded vented manway, and no outlet and no inlet. That is worth saying plainly rather than filling the gap with a guess. Fittings on a tank of this class are specified against the liquid, the duty and the containment arrangement, and we will confirm them in writing with the order rather than printing a size here that your drawing then has to work around.
• Why that matters more on a double wall: every penetration through the inner tank has to be made without compromising the containment shell around it, so the fitting schedule is part of the tank order, not a hardware decision taken later on site with a hole saw. Nothing gets cut into either wall in the field.
• Access and venting: the manway is 18 inches, threaded and vented, at the top of a shell that stands eighteen feet ten inches. Fixed access with a rail for anyone who opens it, and a vent path that is kept clear at all times; a polyethylene tank drawn on hard through a blocked vent will pull its own wall inwards, and on a shell this size that is not a repair.
• The headspace is where the wall works hardest: the vapour above the liquid is a more aggressive environment than the liquid itself on many chemicals, and it is the zone a liquid-side inspection walks straight past. What to expect there and why the wall is sized the way it is, is worked through in the vapour-saturated headspace wall thickness guide, and it belongs in the inspection plan from day one.
• The annulus: the space between the inner tank and the outer containment shell is the point of the product, so keep it monitored and keep it accessible. Whatever the site uses to watch it, it needs to be readable without moving pipework.
• Service limit and warranty: 120 F / 48 C, with a 3 year warranty as the sheet gives it. The specific gravity rating is 1.5, and the 125,100 pound maximum contents figure is the arithmetic of that rating against the capacity; nothing beyond it is claimed.

The rest is pipework discipline, and on a tank this tall it is not optional. Every line off the tank gets a flexible connector at the first joint, because a rigid run bolted to a polyethylene wall carries the thermal movement of the shell, the settlement of the pad and the water hammer of every pump start straight into the fitting. Valves ride on their own supports off the pad. Keep vehicle traffic away from the base with a kerb or bollards, because the only fragile parts of this installation are at the bottom of it. And plan the overflow route before the first fill rather than after the first surprise.

Bulk chemical storage where the site requires containment

Ten thousand gallons in a contained shell is bought by sites that have decided a bare tank inside a concrete berm is not the answer they want. The duties: bulk chemical storage at a water or wastewater plant, a mine, a mill, a food or beverage processor, a fertilizer or chemical distributor; a receiving tank that takes a full tanker load and feeds a process or a day tank; outdoor storage where a berm would fill with rain and have to be pumped and tested before it could be emptied; storage inside a building where a berm is floor space nobody has; and any installation where the operator would rather inspect a monitored annulus than trust a liner. The reason to choose a double wall over a tank plus a berm is usually not the purchase price, it is the operating life: a berm is a civil structure that cracks, fills with water and needs housekeeping, while the containment here arrives with the tank and is inspected in the same walk-round. Where stored water rather than chemical is the duty, and the tank is being bought as a reserve for firefighting, that is a separate design exercise with its own sizing, connection and freeze discipline, and the fire-water reservoir design guide is where that argument gets made honestly rather than assumed. One limit the sheet does state: the service limit is 120 F / 48 C, which covers the liquid and the shell standing in the sun. Tell us what the liquid is, how hot it arrives and how hot it sits, before anything is ordered.

An oversize load out of Lincoln at 6,400 pounds empty

This tank is molded at Lincoln, Nebraska and the sheet gives its freight class as OVS, at 142 by 142 by 226 inches and 6,400 pounds. Every number in that line is a logistics question. Eleven feet ten inches of diameter is wider than a trailer deck is meant to carry and eighteen feet ten inches of height is a permitted load rather than a rate off a table, so the route, the overhead lines, the gate, the turning circle and the place the truck can stop are all part of the purchase, and they get walked before the truck is booked rather than on the morning. The freight cost estimator prices the lane to your ZIP, and the listed price is before freight. Unloading needs a machine sized for 6,400 pounds with slings under the body, never a hook through the manway, and the tank goes straight onto the finished, cured pad rather than parking beside it, because an empty shell is easy to move today and impossible once there is liquid in it. Confirm before the delivery date who is lifting, who is standing it up and who signs for it. Inspect the outer containment shell all the way round in daylight, including the side against the wall, before the crew leaves; that walk-round is the last chance to compare the tank against the photographs it shipped with. The vent screen is the cheapest part on the tank and the one that saves it; look at it every time the manway opens.