KOSA Valve · Application Engineering
How to Select a Sanitary Butterfly Valve (Pharma & Food Grade)
A sanitary butterfly valve is a quarter-turn hygienic valve with a disc rotating on a central stem, used in 316L stainless pipelines for on/off isolation and throttling in CIP/SIP clean systems. How to match material, finish, seal and actuation to your media and cleaning regime.
Key Takeaways
- Base material should be 316L (UNS S31603) with Ra ≤ 0.8 µm electropolished ID for hygienic duty.
- Seal elastomer decides media/temperature compatibility — EPDM (steam/CIP), FKM (chemicals), FFKM (aggressive/semiconductor) — and USP Class VI for pharma.
- Connection is usually Tri-Clamp or orbital weld; actuation is manual or pneumatic (CIP/SIP automated lines).
Selection checklist
1. Material
316L stainless (UNS S31603, C ≤ 0.030%) body and disc; avoid 304 in corrosive/CIP duty.
2. Surface finish
Electropolished ID, Ra ≤ 0.8 µm (≤ 0.5 µm for BPE/WFI lines).
3. Seal elastomer
Match to media + temperature + cleaning: EPDM for steam/CIP (−40 to 150 °C, common pharma/food); FKM for broader chemical duty and higher temperature; FFKM for aggressive chemicals / semiconductor UHP. For pharma product contact, verify USP Class VI compliance of the elastomer.
4. Connection
Tri-Clamp (easy strip/CIP) or butt-weld (permanent, orbital welded).
5. Actuation
Manual lever for infrequent operation; pneumatic (spring-return or double-acting) for automated CIP/SIP and batch lines.
6. Pressure / temperature
Size to line 0–10 bar and −20 to 150 °C typical; confirm the seal limit governs.
7. Standards
3-A / ASME BPE conformance for food & biopharma duty.
Typical specification table
| Parameter | Typical hygienic value |
|---|---|
| Body / disc material | 316L (UNS S31603) |
| Inner surface | Electropolished, Ra ≤ 0.8 µm |
| Seat elastomer | EPDM / FKM / FFKM (USP Class VI for pharma) |
| Connection | Tri-Clamp 1/2"–4", or weld |
| Pressure rating | 0–10 bar (depends on size/seal) |
| Temperature | −20 to 150 °C (elastomer-dependent) |
| Actuation | Manual / pneumatic (spring return / double) |
| Standards | 3-A, ASME BPE (product contact) |
Values above are typical specification practice, not a guarantee of compliance. Confirm pressure/temperature against the valve size and seal material datasheet.
Butterfly vs diaphragm vs ball (quick view)
- Butterfly: compact, low cost, good on/off + throttling, large sizes — utility and CIP isolation.
- Diaphragm: best cleanability / zero dead-leg, aseptic control — biopharma critical lines.
- Ball: robust on/off, less ideal for clean-in-place drainability than diaphragm.
Need a sanitary butterfly valve matched to your line?
Send KOSA Valve your size, media, seal and connection requirement — we will return a matched valve specification.
Request a quoteRelated: Diaphragm vs ball valve for sanitary service · Technical bulletins
Frequently asked questions
EPDM or FKM for CIP?
EPDM is the default for steam/CIP at typical food/pharma temperatures; choose FKM only when the media is chemically aggressive to EPDM.
Do I need USP Class VI?
For product-contact pharma lines, the elastomer should meet USP Class VI (or an equivalent biocompatibility spec). Confirm with your QA.
Tri-Clamp or weld?
Tri-Clamp for lines that must be disassembled for inspection/CIP; orbital weld for permanent, leak-tight, low-particulate runs (WFI/UHP).