Non-Asbestos Gasket Sheet (CNAF): A Practical Guide

30 October, 2026 | Admin

Non-asbestos gasket sheet (CNAF) Saudi Arabia

Short answer: Compressed non-asbestos fibre (CNAF)
gasket sheet is made from aramid or other fibres bound with rubber and
filler, pressed into sheets. It is the common general-purpose gasket
material for water, oils, steam at moderate conditions, fuels and many
chemicals. Choose the grade by temperature, pressure and fluid, and cut
it to the flange.

Asbestos gaskets were once standard, but asbestos is hazardous, so
modern gasket sheet uses safer fibres. CNAF is the successor for general
industrial sealing.

Free engineering tools

Gasket size chart — Find the ASME B16.21 gasket ID and OD for your flange size and class
Plastic weight calculator — Work out the weight of Non sheets, rods and tubes in kg

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Table of Contents

What it is made of

CNAF combines reinforcing fibres (such as aramid), a rubber binder
(such as NBR or SBR) and fillers. The fibres give strength, and the
binder gives sealing and flexibility. Different binders and fibres give
grades suited to oil, water, steam or chemicals. Always confirm the
grade on the datasheet.

Typical uses

water, steam and condensate lines at moderate conditions
oil, fuel and lubricant pipework
pumps, compressors and gearboxes
heat exchangers (with suitable grade)
general flange joints and covers

Choosing a grade

Fluid: oil, water, steam, solvent or chemical.
Temperature and pressure: check the maximum rating
of the sheet.
Thickness: thinner sheets withstand higher bolt
load and pressure; thicker sheets conform better to rough flanges.
Flange type: raised face, flat face or damaged
faces.
Approvals: if your project needs a specific
approval or standard, confirm it before ordering.

Cutting and fitting

CNAF can be cut with a knife, die or water jet. Mark the outline from
the flange and cut cleanly, including bolt holes. Avoid stretching or
tearing the sheet. Clean the flange faces, centre the gasket, and
tighten bolts in a cross pattern in stages. Do not reuse used gaskets,
and avoid joint compounds unless the gasket maker allows them.

Common mistakes to avoid

using a general-purpose sheet for steam or strong chemicals beyond
its rating
choosing a thick sheet for a high-pressure joint
cutting bolt holes too large so the gasket shifts
over-tightening on a thin gasket
reusing old gaskets

Questions to ask your
supplier

What binder and fibre does the grade use? What are the temperature
and pressure limits? What sheet sizes and thicknesses are available? Is
a datasheet provided with the order? Are cut gaskets available? See
ready-cut gaskets.

Diode Trading EST supplies gasket materials across Saudi Arabia, and
every order ships with a Material Test Certificate. request a quote

How CNAF compares
with other gasket sheets

Compared with PTFE sheet, CNAF is stiffer, cheaper and handles higher
bolt load, but resists fewer chemicals. Compared with graphite, it is
cheaper but limited in temperature. Compared with rubber sheet, it holds
up better at higher pressure and temperature. This is why CNAF is often
the first choice for general industrial flanges.

Storage

Store sheets flat, in a dry place, away from oil and direct heat.
Keep the protective surface coating intact until use. Damp storage can
affect the sheet’s flatness.

When to choose something
else

If the fluid is a strong chemical or solvent, move to PTFE or an
envelope gasket. If the temperature is above the sheet’s rating, use
graphite. If the flange is glass-lined or damaged, a softer gasket such
as expanded PTFE helps. CNAF is the economical choice for ordinary
water, oil and steam lines within its limits, so use it where it fits
and step up only where the service demands.

Record keeping

Note the sheet grade and batch on maintenance records for important
flanges, so repeat jobs use the same material and any early failure can
be traced.

FAQ

What does CNAF mean? Compressed non-asbestos
fibre.

Is CNAF suitable for steam? Certain grades are,
within their limits. Check the datasheet.

What thickness should I choose? Thin for high
pressure, thicker for uneven flanges. Ask us if unsure.

Can CNAF be cut to my flange? Yes. Send your drawing
or sizes.

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Diode Trading EST supplies these Rubber Sheets, Gaskets & Seals from stock in Dammam, with delivery across Saudi Arabia and the GCC.

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