ISO Flanges and Fittings
ISO flanges are designed for high vacuum systems requiring a reliable elastomer-sealed connection across a wide range of tube diameters. ANCORP stocks a complete line of ISO-K (ISO-LF) and ISO-F (ISO-LFB) flanges, fittings, clamps, and sealing hardware — manufactured to ISO 2861 standards and available in stainless steel and aluminum.
Use the categories below to locate the component type your system requires.
ISO Flanges
Blank and socket weld flanges in ISO-K and ISO-F configurations. The starting point for specifying an ISO flange connection at any tube diameter.
ISO Fasteners, centering rings and O-rings
Complete your ISO connection with claw clamps, bolt rings and bolts from ISO Clamps & Fasteners, and centering rings and O-rings in PTFE, Buna or silicone from ISO Hardware & Seals. Over-pressure rings are available to reduce blowouts in the event of positive pressure.
ISO Nipples
Straight flange-ended tubing sections available in full, half, and reducer configurations. Specified when extending, connecting, or transitioning between ISO flange sizes within a system.
ISO Elbows
Flange-ended tubing bent to 45° and 90° angles. Specified when a system requires a directional change at an ISO flange connection point.
ISO Tees
Three-port ISO fittings for branching vacuum lines. Used when a single ISO connection point needs to serve two downstream paths simultaneously.
ISO Crosses
Four-, five-, and six-way port ISO fittings for multi-directional vacuum line distribution. Available in standard cross and reducer cross configurations.
ISO Bellows & Flexible Hose
Flexible ISO-flanged sections designed to absorb vibration, compensate for misalignment, or accommodate movement between fixed connection points.
ISO vacuum flange specifications
| Spec | Value |
|---|---|
| Standard | ISO 2861 tolerances |
| Flange and fitting materials | 304L stainless steel, 6061-T6 aluminum |
| Elastomer seals | Viton®, Buna, silicone |
| Vacuum rating | 1×10−8 Torr |
| Leak rating | < 1×10−9 std cc/s helium |
| Temperature range | −50 °C to 200 °C (seal-dependent) |
Frequently Asked Questions: ISO Flanges and Fittings
ISO-K (ISO-LF) flanges are held together with claw clamps or a bolt ring, so they pair with the parts in ISO Clamps & Fasteners. ISO-F (ISO-LFB) flanges are bolted through the flange, which suits a connection that stays assembled. Both use the same tube sizes, centering rings and O-rings.
ANCORP offers ISO 63, 80, 100, 160, 200, 250, 320, 400 and 500 in both ISO-K and ISO-F styles. The ISO Flanges & Fittings catalog (PDF) lists dimensions for each size.
Yes. ANCORP ISO flanges and fittings are made to ISO 2861 tolerances in 304L stainless steel with options available by request for 6061-T6 aluminum.
Send the part numbers, sizes and quantities through our quote request form, or contact our team through our live chat with questions about your application.