Tri-Clamp & Sanitary Process Seals
Hygienic gaskets and O-rings for tri-clamp ferrules, sanitary fittings and CIP/SIP process lines.
Tri-clamp (also called tri-clover or sanitary clamp) connections are the standard hygienic joint in food, dairy, beverage, biotech and pharmaceutical processing. The seal — whether a flat tri-clamp gasket, a molded sanitary O-ring, or an FEP/PTFE envelope gasket — is the critical component that maintains product containment while surviving repeated clean-in-place (CIP) and steam-in-place (SIP) cycles. **How tri-clamp sealing works** A tri-clamp joint consists of two ferrules, a gasket or O-ring, and a hinged clamp that compresses the ferrule faces together. The seal must: (1) withstand process pressure and vacuum without extrusion; (2) resist product media (milk, beer, acids, caustics, solvents); (3) survive thermal cycling from ambient to +140°C during SIP; and (4) release cleanly without tearing when the clamp is opened for inspection or maintenance. **Seal types in sanitary service** **Flat tri-clamp gaskets** — molded elastomer or PTFE gaskets that sit between ferrule faces. Most common in 1/2" to 4" lines. EPDM and platinum-cured VMQ are standard for food and dairy; FKM for aggressive CIP chemicals. **Sanitary O-rings in valve bodies and pump heads** — dynamic and static O-rings in sanitary pumps, valves, and homogenizers. These see higher mechanical stress than flat gaskets and require compounds rated for both product contact and CIP chemistry. **PTFE envelope gaskets** — FEP or PFA jacket over an elastomer core (typically VMQ or EPDM). The fluoropolymer envelope shields the elastomer from aggressive solvents and high-temperature CIP while the core provides elastic recovery. Standard for multi-product lines and pharma applications where extractables control is critical. **Material selection for CIP/SIP** CIP solutions (caustic soda, nitric/phosphoric acid blends, peracetic acid) and SIP steam at +121°C to +140°C eliminate many standard industrial elastomers. NBR is unsuitable — it swells in caustic and fails in steam. EPDM and platinum-cured VMQ are the workhorses for food and dairy. FKM handles aggressive chemical CIP and higher temperatures. For solvent contact or maximum chemical inertness, specify PTFE envelope or solid PTFE gaskets. Related applications: [food & beverage processing](/applications/food-beverage-processing/), [pharmaceutical CIP/SIP](/applications/pharmaceutical-cip-sip/), [steam & autoclaves](/applications/steam-boilers-autoclaves/). Materials: [EPDM](/products/epdm/), [VMQ silicone](/products/vmq/), [FKM](/products/fkm/), [FEP-encapsulated](/products/fep-encapsulated/).
Application Requirements
Recommended Materials
EPDM 70 Shore A (FDA)
Standard for food, dairy and beverage tri-clamp gaskets and pump O-rings. Excellent steam, caustic CIP and hot water resistance.
Temp: -50°C to +150°C
White or black FDA-grade EPDM. Specify platinum-cured EPDM for lowest extractables in pharma. Not compatible with fats, oils or hydrocarbon solvents.
VMQ (Platinum-Cured Silicone)
High-purity sanitary O-rings and gaskets for biotech, pharma and dairy where low extractables and transparency are required.
Temp: -60°C to +200°C
Translucent FDA VMQ is standard for sight-glass and high-visibility inspection points. Peroxide-cured VMQ is lower cost but higher extractables — avoid in WFI and injectable product contact.
FKM 75 Shore A (FDA)
Aggressive CIP chemistry, fatty product lines and higher-temperature SIP where EPDM lacks chemical margin.
Temp: -20°C to +200°C
Specify FDA-compliant FKM for food contact. Avoid in steam above +150°C for extended periods — dehydrofluorination risk.
FEP/PTFE Envelope Gasket
Multi-product lines, solvent CIP and pharma applications requiring maximum chemical inertness with elastomeric recovery.
Temp: -200°C to +200°C
Core is typically VMQ or EPDM; envelope is FEP or PFA. See [FEP-encapsulated O-rings](/products/fep-encapsulated/) for pump and valve body seals.
Design Tips
- 1.Match gasket profile to ferrule standard — ASME BPE, DIN 32676 and ISO 2852 ferrules use different groove dimensions; a gasket sized for one standard will not seal correctly on another.
- 2.Specify platinum-cured VMQ or peroxide-cured EPDM for pharma and biotech — extractables testing (USP <87>, USP <381>) may be required for validation.
- 3.Torque tri-clamp hinges uniformly — uneven clamp closure crushes one side of the gasket and leaves the opposite side under-compressed.
- 4.Replace tri-clamp gaskets after every disassembly for product contact lines — reusing a compressed gasket risks micro-tears that harbor bacteria.
- 5.For SIP at +140°C, verify compound steam resistance — standard EPDM handles SIP; confirm batch certification for your CIP chemistry.
- 6.Store sanitary gaskets in sealed bags away from ozone and UV — even short exposure to fluorescent lights degrades EPDM compounds.
- 7.Use only food-grade silicone grease on EPDM and VMQ sanitary seals — petroleum lubricants cause swell and extractables contamination.
- 8.For high-purity water (WFI, PW) systems, specify USP Class VI compounds with full extractables documentation and lot traceability.
Common Sizes
| Size | Typical Use |
|---|---|
| 1/2" tri-clamp (12.7 mm) | Laboratory and sampling lines; small valve body O-rings |
| 3/4" tri-clamp (19 mm) | Pilot plant and small batch transfer lines |
| 1" tri-clamp (25.4 mm) | Standard process transfer — most common dairy and beverage size |
| 1.5" tri-clamp (38.1 mm) | Medium flow lines, CIP return and pump connections |
| 2" tri-clamp (50.8 mm) | Main process lines, homogenizer and heat exchanger connections |
| 3" tri-clamp (76.2 mm) | High-flow transfer and tank outlet connections |
| 4" tri-clamp (101.6 mm) | Tank manways, large vessel outlets and bulk transfer |
Recommended O-Ring Kits
Sanitary maintenance teams stock FDA-grade EPDM and VMQ assortments to avoid line downtime during gasket failure. Our food & beverage kit covers the most common AS568 sizes used in sanitary pumps and valves.
Food & Beverage Kit
270 pieces, 30 AS568 sizes, FDA VMQ and EPDM, translucent/white
Custom Sanitary Kit
Tri-clamp gasket sets by line size (1/2"–4") plus pump O-rings — built to your ferrule standard
Frequently Asked Questions
What material is best for a tri-clamp gasket?
EPDM FDA-grade is the default for food, dairy and beverage tri-clamp gaskets — it resists steam, caustic CIP and hot water. Platinum-cured VMQ is preferred for pharma and biotech where low extractables matter. FKM handles aggressive acid CIP and fatty products. For solvent contact or maximum chemical inertness, use FEP/PTFE envelope gaskets.
What is the difference between a tri-clamp gasket and a sanitary O-ring?
A tri-clamp gasket is a flat molded seal compressed between two ferrule faces by a clamp — it seals the pipe joint. A sanitary O-ring is a toroidal seal used inside pump heads, valve bodies and equipment internals. Both must be FDA-compliant for product contact, but they serve different locations in the process system.
Can I reuse a tri-clamp gasket after opening the line?
No — not for product contact lines. Once compressed, the gasket takes a permanent set and micro-tears form at the ferrule contact line. Reinstalling a used gasket is a common source of contamination and leak failures in audit findings. Always install a new gasket when reassembling a tri-clamp joint.
Which tri-clamp gasket material survives SIP steam sterilization?
EPDM and platinum-cured VMQ both survive standard SIP at +121°C to +140°C for 15–30 minutes. FKM handles SIP but avoid extended steam above +150°C. PTFE envelope gaskets survive SIP while protecting the elastomer core from steam and CIP chemistry.
Are tri-clamp gaskets FDA approved?
The gasket compound must comply with FDA 21 CFR 177.2600 (rubber articles for repeated food contact). Specify FDA-grade EPDM, VMQ or FKM with a certificate of conformance. For pharmaceutical use, also request USP Class VI and extractables documentation per USP <87> and USP <381>.
What causes tri-clamp gasket leaks after CIP?
Common causes: (1) wrong material for the CIP chemistry — NBR swells in caustic; (2) reused gasket after previous compression; (3) uneven clamp torque leaving one side under-sealed; (4) ferrule damage or scratch on the sealing face; (5) gasket profile mismatch with the ferrule standard. Verify material compatibility with your full CIP recipe before specifying.
Do you supply tri-clamp gasket kits by line size?
Yes. We supply individual tri-clamp gaskets by ferrule size (1/2" through 4" and larger) and custom sanitary kits combining flat gaskets with pump and valve O-rings. Specify your ferrule standard (ASME BPE, DIN 32676, ISO 2852), material (EPDM, VMQ, FKM, PTFE envelope) and compliance requirements. MOQ from 1 piece; kit MOQ from 10 sets.
Need tri-clamp gaskets or sanitary O-rings?
We supply FDA-grade EPDM, VMQ, FKM and PTFE envelope seals for food, dairy, beverage and pharmaceutical process lines. Specify ferrule size, CIP chemistry and compliance requirements. MOQ 1 piece.