Stockist & supplier ASME B16.21 · EN 1514-1 · ASME B16.5 · ASME B16.47
Compressed Non-Asbestos (CNAF) Gaskets — ASME B16.21
Compressed non-asbestos fibre (CNAF) gaskets are flat gaskets cut from sheet made of synthetic fibres bound with rubber. Teshi Group stocks and supplies CNAF ring and full-face gaskets to ASME B16.21 and EN 1514-1 for low and medium pressure flanges.
Also called: CNAF gasket, non asbestos gasket, compressed fibre gasket, NA gasket, aramid fibre gasket
What is a Compressed Non-Asbestos (CNAF) Gasket?
CNAF sheet is made by compressing aramid, glass or other synthetic fibres and fillers with an elastomer binder, usually nitrile (NBR). It replaced asbestos sheet for general flange gaskets. Ring (IBC) gaskets fit inside the bolt circle of raised face flanges; full-face gaskets cover flat face flanges with bolt holes. CNAF gaskets are economical and easy to cut, and are used for water, steam, oils, air and mild chemicals in Class 150 and 300 piping.
Key features
- Ring (inside bolt circle) and full-face gaskets
- Dimensions to ASME B16.21 for B16.5 and B16.47 flanges; EN 1514-1 for PN flanges
- Thickness 1.5 mm (1/16") and 3 mm (1/8") standard
- Aramid / synthetic fibre with NBR binder; graphite-faced grades on request
- Cut to drawing for non-standard flanges and manholes
Specification
| Supply | Stockist & supplier — Teshi Group, India |
|---|---|
| Standard | ASME B16.21 (non-metallic flat gaskets); EN 1514-1 for PN flanges |
| Types | Ring (IBC) for raised face; full face for flat face flanges |
| Flange standards | ASME B16.5, ASME B16.47, EN 1092-1, IS 6392 |
| Thickness | 1.5 mm (1/16"), 3 mm (1/8"); others on request |
| Material | Compressed aramid / synthetic fibre with NBR binder |
| Documents | Manufacturer's test certificate, dimensional inspection report |
Applications
- Water and cooling water lines
- Low-pressure steam and condensate
- Lube oil and fuel oil
- Air and utility services
- Pump and equipment flanges
FAQ
Compressed Non-Asbestos (CNAF) Gasket: common questions
What thickness of CNAF gasket should I use?
1.5 mm (1/16") is preferred for most raised face flanges because thinner gaskets creep less and blow out less. 3 mm (1/8") is used on rougher or uneven flange faces.
Does ASME B16.21 specify gasket material?
No. ASME B16.21 sets dimensions for non-metallic flat gaskets for B16.5 and B16.47 flanges. The gasket material is chosen by the engineer based on fluid, temperature and pressure.
Ring gasket or full-face gasket?
Use a ring gasket, cut to fit inside the bolt circle, on raised face flanges. Use a full-face gasket with bolt holes on flat face flanges, especially cast iron or non-metallic flanges.
Is CNAF suitable for high-temperature steam?
CNAF has a lower temperature and pressure limit than graphite or spiral wound gaskets. For high-pressure or high-temperature steam, use spiral wound or kammprofile gaskets.
Need a size or grade not listed here?
We source against your specification from approved mills, with mill test certificates and inspection before dispatch.
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From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
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