§ 05.6Size Guide / Fittings & Valves
Threads, adapters
and what
mates with what.
IBC fittings use a thread standard almost nobody outside the industry has encountered, which is why so many people end up with a tote they cannot connect to anything. This page is the translation table between a tote outlet and whatever your plant actually uses.
- Fill opening
- 6" buttress standard
- Discharge
- 2" buttress standard
- Gasket compounds
- 6
- Camlock types
- A through F
§ 05.6.1Thread standards
Buttress, and why it confuses everyone.
Buttress thread is coarse, shallow and asymmetric — designed to seal against a flat gasket face rather than by thread interference. It looks nothing like pipe thread, which is exactly why people try to force the two together.
| Standard | Typical size | Where | Sealing method | Identification |
|---|---|---|---|---|
| Buttress (coarse) | 6" | Fill opening | Flat gasket against a seat face | Very coarse, shallow, asymmetric profile |
| Buttress (coarse) | 2" | Discharge outlet | Flat gasket against a seat face | Same profile, smaller diameter |
| Buttress (coarse) | 3" | Discharge, larger units | Flat gasket against a seat face | Same profile, larger diameter |
| NPT (tapered pipe) | 1/2" – 2" | Adapters, plant piping | Thread interference plus sealant | Fine, tapered, symmetrical |
| BSP (tapered pipe) | 1/2" – 2" | Imported units, adapters | Thread interference plus sealant | Fine, tapered, 55° profile |
| Tri-clamp (sanitary) | 1.5" – 4" | Stainless IBCs | Clamp with sanitary gasket | No thread — flanged ferrule |
| DIN | DN50 – DN80 | European stainless units | Flange with gasket | Bolted flange |
A 2-inch buttress and a 2-inch NPT are not interchangeable and cannot be made to seal against each other. You need an adapter, and the adapter is a specific part.
How to identify what you have
- Very coarse thread, only two or three turns visible, shallow profile? That is buttress. Measure the outside diameter of the male thread to get the size.
- Fine thread, tapered so the diameter changes along its length? That is pipe thread — NPT in the US, BSP on imported units.
- No thread at all, a flanged lip with a groove? That is a sanitary ferrule for a tri-clamp, found on stainless units.
- A cam-operated lever collar? That is a camlock, already an adapter fitted to a buttress or NPT base.
The adapter chain
Getting from a tote outlet to a plant connection usually takes two parts, not one. The typical chain:
- 12" buttress male outlet on the tote valve
- 22" buttress female to 2" NPT male adapter
- 32" NPT female camlock Type C or hose tail
- 4Your hose or hard pipe
Each junction is a potential leak point. Minimise the chain where you can — a valve with the outlet you actually need is better than three adapters.
- 61%
- Of intake needs a new valve
- 6in
- Standard fill opening
- 2in
- Standard discharge
- 6
- Gasket compounds stocked
The most-replaced component.
Buttress thread.
Buttress thread.
Compatibility matters more than size.
§ 05.6.2Valves and closures
What goes on the outlet.
| Valve | Size | Body material | Flow | Best for | Notes |
|---|---|---|---|---|---|
| Ball valve | 2" | Polypropylene | Good | General purpose, the default | Quarter-turn, simple, cheap |
| Ball valve | 2" | 316 stainless | Good | Aggressive media | Longer life, higher cost |
| Butterfly valve | 3" | Polypropylene | Excellent | Viscous products, fast discharge | Larger bore, less positive seal |
| Butterfly valve | 3" | 316 stainless | Excellent | Viscous and aggressive | Sanitary variants available |
| Camlock-fitted assembly | 2" | PP or stainless | Good | Frequent connect/disconnect | Adapter built into the valve |
| Lockable ball valve | 2" | Polypropylene | Good | Security, tamper evidence | Padlock provision on the handle |
| Closure | Size | Vented? | Use |
|---|---|---|---|
| Buttress cap, solid | 6" | No | Sealed transport, the standard |
| Buttress cap, vented | 6" | Yes | Products that outgas; prevents vacuum on discharge |
| Tamper-evident cap | 6" | Either | Regulated or high-value products |
| Pressure-relief cap | 6" | Relief valve | Products with thermal expansion risk |
| Wide-mouth lid assembly | 9" | Either | Viscous products needing access |
| Dust cap | 2" / 3" | No | Protects the discharge outlet in transit |
The vented cap question catches people out. A sealed tote being discharged by gravity will form a vacuum and the flow will stop or the bottle will deform. Either use a vented cap or crack the fill cap during discharge.
Gasket compound selection
This is the decision that matters most and costs least. Full compatibility table on the parts page — the summary:
- EPDM
- Default. Aqueous chemistry, caustics, surfactants, glycols. Not for oils or solvents.
- Viton (FKM)
- Solvents, fuels, oils, acids. The broad-spectrum choice.
- Silicone
- Food contact, high temperature. Poor with solvents.
- PTFE envelope
- Widest chemical resistance; less forgiving mechanically.
- Buna-N (NBR)
- Petroleum products and oils specifically.
- Never reuse a gasket — it is the cheapest part and the commonest leak cause
- Match the compound to the product, not to what was fitted before
- Check the gasket seat face for scoring before fitting a new seal
- Hand-tighten buttress closures; they seal on the gasket, not the thread
§ 05.6.3Connections
Camlock, the quick-connect standard.
Cam-and-groove couplings are the dominant quick-connect in industrial liquid handling. The lettering is logical once you know the rule: letters A, D and B carry threads on the coupler side; C and E carry hose shanks; adapters are E and F.
- Couplers (female, with cams) mate only with adapters (male, grooved)
- A tote valve usually ends in a male buttress; you need buttress-to-NPT first
- Then an NPT-threaded coupler or adapter in the type your hose needs
- Type C coupler to hose shank is the most common tote discharge arrangement
- Always fit dust caps and plugs in transit — camlock seats damage easily
We can supply valves with camlock adapters already fitted, which removes two junctions from the chain. Specify it at order time.
Camlock types, decoded
- Type A
- Male adapter × female thread
- Type B
- Female coupler × male thread
- Type C
- Female coupler × hose shank
- Type D
- Female coupler × female thread
- Type E
- Male adapter × hose shank
- Type F
- Male adapter × male thread
- Type DC
- Dust cap (closes a male adapter)
- Type DP
- Dust plug (closes a female coupler)
Couplers mate with adapters. Two couplers will not connect, and neither will two adapters — which is the single most common camlock ordering mistake.
§ 05.6.4Fitting questions
Connecting and sealing.
My tote outlet won't connect to my hose. What do I need?
Almost certainly a buttress-to-NPT adapter, then an NPT camlock or hose tail. Photograph the outlet and send it through the form at the top of this page — we will identify the thread and tell you the exact two parts.
Can I use thread sealant on a buttress thread?
No, and it will not help. Buttress threads seal on a flat gasket against a seat face; the thread only provides clamping force. If it leaks, the problem is the gasket or the seat face, not the thread.
Why does my tote stop flowing halfway through discharge?
Vacuum. A sealed tote cannot let air in to replace the liquid going out. Crack the fill cap or fit a vented cap and the flow will restore. If you discharge totes routinely, fit vented caps as standard.
Is a 3-inch butterfly valve better than a 2-inch ball valve?
For viscous products and fast discharge, yes — much better flow. For a positive seal on a thin liquid in transport, the ball valve is more reliable. Most general-purpose duty is better served by the ball valve.
Do you fit custom valve configurations?
Yes, as part of reconditioning or on new and rebottled stock. Tell us the connection you need at the far end and we will specify the valve and any adapters, fitted here rather than shipped loose. See parts & accessories.
Send a photo
Photograph the outlet. We'll name the part.
It is faster than measuring and describing, and we identify tote fittings all day.