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Standard Classification for Non-metallic
Gasket Materials
ASTM Designation: F104
This classification system provides a means for
specifying or describing pertinent properties of commer-
cial non-metallic gasket materials. Materials composed of
asbestos, cork, cellulose, and other non-asbestos materi-
als in combination with various binders or fillers are in-
cluded. Materials normally classified as rubber compounds
are covered in Method D2000.
Since all the properties that contribute to gasket per-
formance are not included, use of the classification system
as a basis for selecting materials is limited.
The purpose of the classification system is intended to
provide a common language for communication between
suppliers and purchasers; to guide engineers and design-
ers in the test methods commonly used for commercially
available materials, and be versatile enough to cover new
materials and test methods as they are introduced.
It is based on the principle that non-metallic gasket
materials should be described, insofar as possible, in
terms of specific physical and functional characteristics. An
infinite number of such descriptions can be formulated by
use of one or more standard statements based on stan-
dard tests.
All fibrous and PTFE type gasketing materials in this
catalog show our F104 Line Callout.
Tension of Non-metallic Gasket Materials
ASTM Designation: F152
The Universal Tester is used to determine the tensile
strength of non-metallic gasketing products. The types of
products covered are those containing various organic
fibers, inorganic fibers, flexible graphite, or fluorocarbons
as described in F104.
F152 is not applicable to the testing of vulcanized rub-
ber, a method that is described in Test Method D142, nor
for rubber O-rings, a method that is described in D1414.
The measurement of tensile strength characterizes
various classes and grades of products of a given type. It
also will aid the purchaser in determining whether the gas-
keting product approved for a given application is being
manufactured to acceptable quality. Various procedures
are given for different types of materials, and in order to
compare results from one lab to another, it is imperative
that the applicable procedure be used.
The measurement of tensile strength should not be
construed as an indication of the performance of that
product in use.
Thermal Analysis System
Thermal Analysis, often referred to as TA, is a series
of techniques that characterize materials by measuring
and analyzing changes in their physical and chemical
properties resulting from controlled and measured chang-
es in temperature. The TA techniques include DSC (Dif-
ferential Scanning Calorimetry), TGA (Thermal Gravimetric
Analysis) and TMA (Thermal Mechanical Analysis).
DSC measures heat flow into or out of a material as it
is undergoing a programmed thermal profile. The resulting
plot of heat flow vs. temperature can reveal a great deal of
information about a material. DSC is being used to deter-
mine such things about a material as specific heat, melting
point, crystallinity, glass transition temperature, degree of
cure of thermosets, purity, oxidative stability, and reaction
kinetics.
TGA measures changes in the weight of a material.
By heating a sample in a controlled manner in various
atmospheres, the composition of various materials can be
determined. The technique is also useful for performing
thermal stability studies.
TMA provides measurements of penetration, expan-
sion, contraction, extension, and relaxation of materials as
a function of either time or temperature. By using various
probes and accessories, TMA can be used to determine
expansion coefficients, softening points, heat-deflection
temperatures, viscosity, creep, and stress relaxation.
Torque Retention
DIN 52913
This test is designed to determine the torque retention
capabilities of gasketing products, when subjected to the
compression load and operating temperature as defined
by the test procedure.
The test consists of applying a predetermined load
on the test gasket via a tension screw, then heating the
gasket/flange assembly to the desired temperature (there
is no internal pressure). The standard test period is either
sixteen (16) hours or one hundred (100) hours. At the end
of the required time period, the compression load which
is left acting on the test gasket is measured. This allows
one to calculate the torque retention capabilities of various
gasketing products.