Snyder Industries 4500 GALLON PLASTIC VERTICAL LIQUID STORAGE TANK 1.9 SG

Thirty-five tons on an eight and a half foot circle

A 1.9 specific gravity rating is sized for a liquid nearly twice as dense as water; rotationally molded polyethylene tanks are sized to ASTM D1998, and the way a tank meets the density it is rated for is in the wall, which the HDPE tank wall thickness guide explains along with why the headspace is where a wall ages. Full, it puts 71,307 pounds on a 102 inch circle at the rating: a full-contact engineered slab beneath the entire floor, per the concrete pad sizing guide, inside a berm sized to the tank when the liquid is a regulated chemical, the tank strapped against wind when empty, with the manway reached from a fixed platform. The tank sizing calculator turns feed rate and delivery interval into a volume, and the tank sizing guide covers the reserve, which for a dense chemical includes freeboard for thermal expansion.

The two 7420000 tanks, and the sizes beside them

The 7420000C37 is the same shell and fitting rated for 1.5, for coagulants and brines that never approach this density. The 7000400 tanks lay the same 4,500 gallons down to 91 inches on a 143 inch base for a barn roof, the 7000500N40 puts 4,600 gallons of cross-linked resin on a ten foot base under ten feet, and the 5210000N40 stands 4,400 on a 90 inch base at 182 inches.

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.

Connections

• Outlet: 3 inch polypropylene female NPT bulkhead fitting, installed; thread in a valve, run a flanged transition and an expansion joint to hard pipe, and support the valve off the slab.
• Access: 18 inch threaded, vented manway, 142 inches up; vent outside on acid and caustic service, a dip tube for the fill, and a vent big enough for a tanker's pump.
• Service limit: 120 F / 48 C.

Polypropylene is the fitting for brine and most treatment chemicals but not every acid; check the liquid at its concentration against the fitting as well as the wall before the first fill, and swap the fitting for the chemical's material where the table says so. Match the level sender to the chemical and put the display at ground level; the manway stays shut so vapor stays in the tank, and a chemical that sunlight degrades gets a shade or a roof. Where it freezes, insulate or drain the outlet valve and the first length of pipe.

Delivery day at the manway

Unloading a tanker pushes air out faster than a stock manway vent can pass it; size the vent for that rate, or fill through a dedicated top bulkhead vented separately. The fill pipe reaches the floor, so caustic or coagulant enters below the surface instead of free-falling and foaming. If the tank is ever used to dilute a batch, water goes in first and the chemical second; the other order boils. Somebody stands at the tank for the whole of the first delivery, watching the slab edge and the outlet fitting as the level rises, and the log takes the date and strength of every load that follows.

What it holds in practice

Ferric and other dense coagulants at a plant with a berm, heavy brine at plant scale, dense process chemicals delivered by tanker, and water where the buyer wants the heaviest rating with the outlet already in, including a fire reserve of the kind the fire-water reservoir design guide describes. Several of them are the storage stage of a reuse system for roof water and condensate, per the industrial water reuse tank topology article. One liquid per tank, labeled for both inspectors at once.

Getting it to the pad

At 102 inches across and 142 inches long on the deck the 7420000C26 is oversize freight (NMFC 156600) on a flatbed at a lane rate; the freight cost estimator prices it for your ZIP, and the listed price is before freight. A forklift with long forks or a small crane sets 900 pounds on the slab. Water-fill it once to the manway, hold it, check the fitting for a weep, then drain and dry before the chemical connection is made. Once it is full and holding, leave it alone for a day before the plumbing goes on; a settled tank is a quiet one.