Size guide · R-05
Valves, threads
& fittings.
Short answer
- DN50 gravity flow ≈ 40 – 55 GPM; DN80 ≈ 95 – 120 GPM
- EPDM for aqueous, Viton for solvents, silicone for hot food
- S60-to-garden-hose adapter is our top-selling part
- Vented lids for hot fill and pump draw-down
Specify a fitting
Master reference
Every thread and fitting on an IBC
| Size / item | Type | Thread | Cap or plug | Typical use |
|---|---|---|---|---|
| DN50 / 2 in | Butterfly, polypropylene body | S60×6 buttress outlet | 2 in NPT or S60 dust cap | Most common on 275/330 composite totes |
| DN80 / 3 in | Butterfly, PP or PE body | S100×8 buttress outlet | 3 in or S100 cap | Faster discharge, viscous product, ex-food totes |
| DN50 ball | Full-port ball valve | 2 in BSP / NPT | Threaded plug | Retrofit for throttling and dosing |
| 6 in lid | Screw cap, vented or solid | 6 in / 150 mm coarse | EPDM or silicone gasket | Top fill port on nearly every composite IBC |
| 9 in lid | Screw cap | 9 in / 225 mm coarse | EPDM gasket | Older bottles and some rigid poly tanks |
| Camlock adapter | Type A/C/F polypropylene | S60 or S100 to 2 in cam | Dust plug | Hose-quick-connect for transfer pumps |
| Garden-hose adapter | Brass or nylon | S60 to 3/4 in GHT | — | Rain harvesting, irrigation, wash-down |
| Gasket set | EPDM / Viton / silicone | — | — | Replace on every rebottle; the #1 source of weep leaks |
Short answer
- Buttress threads are asymmetric and much coarser than pipe threads
- S60×6 = 60 mm major diameter, 6 mm pitch
- S100×8 = 100 mm major diameter, 8 mm pitch
- Half a turn then binding = wrong thread form. Stop.
Gasket compatibility
Nine dollars of rubber, two years of drips
Compatibility is one of the few questions in this trade with a genuinely correct answer. Here it is.
| Compound | Temperature range | Good for | Fails with | Relative cost |
|---|---|---|---|---|
| EPDM | −40 to 120 °C | Water, aqueous chemistry, caustics, dilute acids, most food | Aromatics, solvents, fuels, oils | 1× |
| Viton (FKM) | −20 to 200 °C | Aromatics, chlorinated solvents, fuels, oils, esters, ketones | Hot water >130 °C, amines, concentrated ketones | 4 – 6× |
| Silicone (platinum-cure) | −60 to 230 °C | Hot-fill food, steam exposure, high purity | Solvents, oils, abrasion | 3 – 4× |
| Nitrile (NBR) | −30 to 100 °C | Petroleum products, vegetable oils, greases | Ozone, UV, strong oxidisers | 1.2× |
| PTFE-envelope | −200 to 260 °C | Almost everything, including strong acids | Repeated re-torquing, and the price | 8 – 12× |
Flow rates
What comes out, and how fast
Gravity discharge from a full tote with a clear outlet. Viscous product drops these figures substantially — a 1,000 cP syrup through a DN50 is closer to 8 GPM than 45.
| Outlet | Water, full tote | Water, quarter full | Light oil (50 cP) | Syrup (1,000 cP) |
|---|---|---|---|---|
| DN50 / 2 in butterfly | 40 – 55 GPM | 18 – 26 GPM | 28 – 38 GPM | 6 – 10 GPM |
| DN80 / 3 in butterfly | 95 – 120 GPM | 44 – 58 GPM | 70 – 90 GPM | 22 – 34 GPM |
| DN50 full-port ball | 44 – 58 GPM | 20 – 28 GPM | 30 – 40 GPM | 8 – 12 GPM |
| 3/4 in garden hose adapter | 7 – 11 GPM | 4 – 6 GPM | 5 – 8 GPM | Impractical |
| 2 in camlock to hose | 36 – 50 GPM | 17 – 24 GPM | 26 – 35 GPM | 5 – 9 GPM |
If drain time matters to your labour cost, specify DN80 at order time rather than retrofitting. Changing an outlet size is not a field job — the moulded boss on the bottle determines it.
Replacing a valve
Six steps, fifteen minutes
- 01
Confirm the tote is empty
Not "nearly empty". Open the lid and look. A gravity head of even two inches will cover you the moment the valve comes off, and that is how people get a face full of caustic.
- 02
Note the thread and bore
Read the existing valve body: S60 or S100, DN50 or DN80. Order the matching part before you remove anything, because a tote with no valve cannot be moved safely.
- 03
Back off the retaining nut
Most valves thread onto the moulded boss with a large nut. Use a strap wrench, not pliers — gouging the boss is the one unrecoverable mistake here.
- 04
Clean the boss face
Wipe the sealing face completely clean. A single grit of dried product under the new gasket produces exactly the weep you were trying to fix.
- 05
Fit the new gasket dry
No sealant, no PTFE tape, no grease. A buttress-threaded IBC valve seals on gasket compression against the boss face, and lubricant lets it creep loose under vibration.
- 06
Hand-tight plus a quarter turn
Snug by hand, then a quarter turn with the strap wrench. Over-torquing distorts the gasket and leaks more than under-torquing does. Test with water before you trust it.
Questions
Fitting questions
What thread size is an IBC tote outlet?
A coarse asymmetric buttress thread: S60×6 on a DN50 (2 inch) outlet and S100×8 on a DN80 (3 inch) outlet. These are not pipe threads and do not mate with NPT or BSP. If a fitting goes on half a turn and binds, stop — you are about to strip an outlet that is not a replaceable part.
What does DN50 mean?
Nominal diameter 50 millimetres, roughly 2 inches. DN80 is 80 mm, roughly 3 inches. It describes the bore of the valve, which governs flow rate; the thread that attaches it is described separately as S60 or S100.
Can I put a garden hose on an IBC tote?
Yes, with an S60 to 3/4-inch GHT adapter — under $20 and the most-ordered single item in our catalogue. Choose brass over nylon if the tote sits in direct sun, because UV embrittles nylon within about two seasons.
How much flow do I get from a DN50 versus a DN80?
Roughly 40 – 55 gallons per minute from a DN50 on a full 275 by gravity, against 95 – 120 from a DN80 — the bore area more than doubles. For viscous product the gap widens dramatically, which is why ex-food 330s so often carry DN80 outlets.
Which gasket for which product?
EPDM for water, aqueous chemistry and most food duty. Viton for aromatics, chlorinated solvents, fuels, esters and ketones. Platinum-cure silicone for hot-fill food. Nitrile for petroleum products. PTFE-envelope when nothing else will hold. Specify at order time — a wrong gasket is the commonest cause of a weeping valve.
Adapters
Getting from a buttress outlet to whatever you own
The outlet is S60 or S100 buttress. Everything in your plant is NPT, BSP, camlock or hose thread. These are the bridges.
| From | To | Part | Typical cost | Notes |
|---|---|---|---|---|
| S60×6 (DN50) | 2 in NPT female | PP or nylon adapter | $9 – $16 | The part people should buy before forcing a fitting |
| S60×6 | 3/4 in garden hose (GHT) | Brass or nylon adapter | $12 – $19 | Brass if it lives in sunlight |
| S60×6 | 2 in camlock (Type A/C/F) | PP camlock adapter | $24 – $58 | For transfer pumps and quick changeover |
| S60×6 | 1 in or 1.5 in hose tail | Stepped adapter | $14 – $26 | Reduces flow; size for your pump |
| S100×8 (DN80) | 3 in NPT female | PP adapter | $18 – $32 | Less common; order ahead |
| S100×8 | S60×6 | Reducing bush | $16 – $28 | Lets a DN80 unit use DN50 fittings |
| 6 in lid | 2 in NPT bung | Lid insert | $18 – $34 | For top-draw dip tubes and vents |
| 6 in lid | Vent only | Vented cap | $14 – $27 | Prevents bottle collapse under pump draw |
Buy the adapter before the hose. A $12 part is the difference between a working connection and a stripped moulded boss, and the boss is part of the bottle — there is no replacement for it.
Fault finding
Diagnosing a leak in the right order
Almost every reported leak is one of five things, and checking them in this order finds it in about two minutes.
- 01
Is it the valve or the boss?
Dry everything, then watch. Liquid appearing at the joint between the valve and the bottle is a gasket or seating problem. Liquid appearing from the valve body itself is a cracked or worn valve. These have completely different fixes.
- 02
Check the torque before replacing anything
Over-torquing extrudes the gasket and is the most common cause. Back the retaining nut off, inspect the gasket for a thinned section, and refit hand-tight plus a quarter turn.
- 03
Inspect the sealing face
Wipe the boss face completely clean. One grit of dried product under a new gasket produces exactly the weep you are chasing. This step alone resolves a surprising share of repeat failures.
- 04
Check the gasket compound against the product
EPDM in aromatic or solvent service swells and loses its sealing geometry within months. If the leak returns after every wash, the compound is wrong rather than the gasket being worn.
- 05
Look at the lid before blaming the valve
A perished lid gasket on a unit that is moved around produces drips that run down the outside and appear at the bottom. Easy to misdiagnose and a nine-dollar fix.
- 06
Only then suspect the bottle
Bottom-radius cracks exist but they are the minority. Torch the four bottom corners from inside. If there is a crack, the bottle is done and the cage is almost certainly a rebottling candidate.
From the Yard Journal
Longer pieces from the people who run the wash line, the test bay and the trading desk.
27 March 2025 · 4 min
Camlocks, buttress threads and the fitting that ruins an outlet
An IBC outlet is moulded into the bottle. Strip it and the whole bottle is scrap — which makes a four-dollar adapter the cheapest insurance in the catalogue.
Priya Raghunathan · Head of reconditioning
Read21 May 2026 · 4 min
What a crushed cage tells you about the bottle inside
Counterintuitively, the worse the cage looks, the better the odds on the bottle. We pulled three years of intake records to check.
Priya Raghunathan · Head of reconditioning
Read
Next move
Tell us the liquid and the outlet size.
We will specify the valve, the gasket compound and any adapter you need. It is the one question in this business with a single right answer, so there is no reason to guess at it.