Everything we know about totes, written down properly.

In order of likelihood: the dust cap is loose or missing; the flat gasket between valve body and bottle neck has taken a compression set; the butterfly valve liner has set in the open position; the bottle neck is crazed around the thread root; or the sump has failed.

The first two are cheap fixes. The last two condemn the bottle. Full diagnostic order is in our valve field guide.

Not a standard one. Polyethylene has a surface resistivity around 10^16 ohms per square — one of the best insulators in industrial use — so flow electrification charges the liquid with nowhere for the charge to drain.

Worse, the galvanised cage around an insulating bottle is a classic isolated conductor: it accumulates charge by induction and discharges in a single energetic spark. Use a steel or stainless bin, or a purpose-made conductive IBC with a bonding lug.

Level the container first, then tilt it forward with a 50 mm block under the rear feet. The sump works because it is the lowest point, and two degrees out of level moves the lowest point to the back wall.

For viscous cargo, warm it to 100–120 °F with a thermostatic jacket — never above about 140 °F on HDPE. For high-value product, a dip tube to the sump with a diaphragm pump recovers more than gravity does.

Taking 31HA1/Y/03 25/USA/M5678/1040/127 as an example: 31HA1 is the design type (composite IBC for liquids, plastic inner, rigid steel outer, with structural equipment); Y is the packing group capability (II and III); 03 25 is March 2025; USA is the approving authority; M5678 is the manufacturer code; 1040 is the stacking test load in kg; 127 is the tare.

A separate stamped date records the last periodic test, and that is the one that determines whether the container may be offered for regulated transport today.

Translucent indoors, black outdoors, every time. Translucent gives you level visibility for free; black gives you three to four times the outdoor life.

We measured twelve translucent units pulled after four to six years outdoors: south walls 0.21 mm thinner than north walls on the same unit, chalking on every south and west face, and coupons that snapped like a biscuit when folded.

Three independent sources, and they do not always agree. The UN plate carries a date of manufacture for the assembly. The bottle has a moulded date wheel — a clock face with the month and a two-digit year. The cage usually has a stamped week-and-year code on the lower rail, right-hand side facing the outlet.

Bottle newer than plate means a rebottle. Plate newer than cage stamp means a recertification. We list all three separately on every unit and say why when they conflict.

It is the permissible superimposed load: how much mass may sit on top of that container. It assumes normal temperature, level ground and an evenly distributed load, and a zero means do not stack even empty.

The real-world caveat is temperature. Above 100 °F derate by half; above 120 °F do not stack at all. HDPE creeps under sustained load and heat accelerates it, so a stack that was fine in April can deform in July without anything else changing.

Indoors with a compatible cargo, longer than the business using it — we regularly handle bottles over twenty years old that pass every test. Outdoors, translucent, filled to the brim through Michigan winters: about five years.

What kills them is the combination of UV, freeze-thaw cycling and chemical stress acting together. Any one is survivable. All three together produce crazing, and crazing is the one condition with no path back.

No, and the distinction is worth money. Stress whitening is localised opacity where the polymer has been strained, almost always a forklift impact near the sump. It looks alarming and is often not a failure.

Crazing is a network of fine branching cracks from chemical and mechanical stress together. It is an absolute disqualifier, it never improves, and the test is a raking light at a shallow angle across the surface. If you can see branching, the bottle is finished — though the cage and base are still worth money.

Yes, and that is what rebottling is: a new blow-moulded HDPE bottle fitted into an inspected cage and base. Cages outlast bottles about three to one, which is why the trade exists.

The cage goes through the same inspection as everything else first — 44 to 54 weld nodes counted individually, diagonals measured, base welds loaded, galvanising checked at the welds. We fitted 4,118 new bottles in 2025. Bench turnaround on contract work is 48 hours.

Yes, as stainless bins rather than caged composites. A 350-gallon square 304 bin is 48 × 42 inches and 55 inches tall with a 420 lb tare; a 500-gallon cylindrical 316L is 52 inches in diameter, 74 tall, 580 lb.

They are the right answer for aggressive acids above SG 1.6, for hot cargo, and for anything where you want a container that will outlive several poly ones. They do not stack, and the trailer count drops to fourteen for the 500s.

In practice, 50% caustic soda at SG 1.53 in a 275 — which grosses 3,637 lb — is about where we stop being comfortable, and we check the customer's forklift rating before quoting it.

Sulphuric acid at 93% and SG 1.83 we will not put in poly at all; that is steel or stainless service. The limiting factor is rarely the bottle's burst strength and almost always everything underneath it: forks, beams, floors.

Multiply litres by specific gravity to get kilograms, or gallons by 8.34 by specific gravity to get pounds, then add the tare — 127 lb for a 275, 145 lb for a 330 — and compare against the maximum gross mass on the UN plate.

The plate figure is the binding one. As a rough guide, cargo above about SG 1.4 belongs in a 275 rather than a 330 simply because the taller bottle puts more mass on the same footprint, and above SG 1.6 you are usually looking at lined steel or stainless rather than poly.