VMQ O-Rings for Steam & Autoclaves
High-temperature silicone seals for SIP, autoclave and saturated steam service to +200°C.
VMQ (silicone) is the most economical elastomer for sustained saturated steam and steam-in-place (SIP) sterilization above +150°C, where NBR and standard EPDM lose elasticity. Platinum-cured VMQ compounds offer low extractables for pharmaceutical autoclaves and bioprocessing equipment.
Typical applications
- Autoclave door gaskets and chamber port seals
- SIP sterilization lines in pharma and biotech
- Steam trap and boiler gauge glass fittings
- Laboratory sterilizer and medical device reprocessing equipment
VMQ vs EPDM in steam
EPDM handles steam to +150°C well and costs less — it is preferred for food CIP/SIP below +140°C. VMQ extends margin to +200°C and recovers flexibility after thermal cycling better than peroxide-cured EPDM in long autoclave programs (+134°C, 18-minute cycles).
Not for oil service — VMQ swells severely in hydrocarbons. Never install VMQ in zones with hydraulic oil mist or lubricant vapor.
Related: steam & autoclaves application, tri-clamp sanitary seals, VMQ product page.
Why VMQ for This Application
Steam to +200°C
Continuous saturated steam resistance where NBR fails — standard for autoclave and SIP service.
Low-temperature flexibility
Remains flexible to −60°C — suitable for cold storage equipment that also sees steam sterilization.
Platinum-cured purity
Low extractables for pharma autoclaves — specify platinum cure for USP and bioprocessing validation.
FDA grades available
FDA 21 CFR compliant VMQ for food and medical device sterilization equipment.
Common Sizes
| Size | Typical Use |
|---|---|
| AS568 -006 to -012 (1.78 mm CS) | Autoclave instrument port and small valve stem seals |
| AS568 -113 to -120 (2.62 mm CS) | Standard steam trap and gauge cock O-rings |
| AS568 -214 to -222 (3.53 mm CS) | Autoclave door auxiliary seals and large port unions |
| Metric 10×2 through 30×3 mm | European sterilizer and boiler OEM sizes |
| Custom flat gaskets | Autoclave door profiles — quote ID/OD/thickness |
Related Application Guides
FAQ
VMQ or EPDM for autoclave steam at +134°C?
Both survive +134°C autoclave cycles. VMQ is preferred for frequent daily cycles and pharma extractables limits. EPDM is lower cost for industrial autoclaves without pharma validation requirements.
Why do silicone O-rings fail in steam service?
Failure is usually mechanical (over-compression, torn install) or contamination from oil — not steam attack. VMQ is chemically stable in steam. Check groove design and ensure no petroleum lubricant contact.
What hardness for steam autoclave O-rings?
70 Shore A is standard. 60 Shore A improves sealing on rough autoclave door faces at lower bolt load. 75–80 Shore A for high-pressure steam trap bodies.
Platinum-cured vs peroxide-cured VMQ for pharma?
Platinum-cured VMQ has lower extractables and is standard for pharmaceutical SIP and autoclave validation. Peroxide-cured is acceptable for industrial steam where extractables are not regulated.
Maximum continuous steam temperature for VMQ?
Standard VMQ handles saturated steam to +180°C continuously; short peaks to +200°C. For superheated steam above +200°C, evaluate FKM or FFKM depending on pressure and duration.
Do you supply autoclave O-ring kits?
Yes — VMQ and EPDM assortments in metric and AS568 sizes common to sterilizer OEMs. Custom kits matched to your autoclave model available on request.
Order VMQ steam & autoclave O-rings
Specify steam temperature, cycle frequency and whether platinum-cured FDA/USP grades are required. MOQ 1 piece.