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Oxidizers
Certain chemicals are known as strong oxidizers and,
as such, will readily combine with organic compounds. We
recommend our GYLON® material for use in oxidizers.
Oxygen Service
We recommend GYLON® Styles 3502, 3505, 3503
and metal-inserted Styles 3562 and 3563. These gaskets
are specially manufactured and packaged to eliminate
contamination by organic material.
pH
The pH scale is a measure of the acidity or alkalinity
of a solution. A pH of 7 is a neutral reading; it is neither
acidic or alkaline. Readings of 1-2 are strongly acidic,
while 13-14 indicates a strong alkaline or caustic media.
Note: A pH reading alone without the names of the
chemicals involved is not enough to select a gasket. Also,
since the pH scale is quite limited in range, a reading of
"1" or "14" does not fully describe the concentration. We
need the concentration expressed as a percentage. For
example, sodium hydroxide at a con-centration of around
4% will "peg" the pH scale at 14, the same reading pro-
duced by a 40% concentration.
Pressure Spikes
Very high pressure spikes can occur in any line pump-
ing a liquid if a valve is closed rapidly, leaving the fluid flow
nowhere to go. The inertia of the fluid may create extreme
pressure spikes. These spikes occur too rapidly to be
detected by a pressure gage but can cause a gasket to
blow out.
Radiation Resistance
We have conducted gamma radiation tests on our
compressed sheet Styles 3000, 3200, 3400, 3700, 5500,
5507, 9800, 9850, 9920 and ST-706. These tests indicate
our compressed non-asbestos styles will handle a total
exposure of approximately 5 x 107 rads of gamma radia-
tion. GYLON® Styles 3510 and 3545 have been tested.
Test results are available.
Refrigerants
A number of new refrigerants have been introduced
in an effort to protect the environment. CFC-type refriger-
ants, believed to be responsible for depleting the ozone
layer, are being phased out and replaced by HCFCs and
HFCs. Our most frequent compatibility inquiries concen-
trate on R-134a, R-123 and R-141b. Information provided
by refrigerant manufacturers indicates Style 3300 will be
preferred for R-134a and R-123. Styles 5500, 3000 and
3300 are recommended for R-141b. Refer to the Chemical
Resistance chart for a complete listing of refrigerants. The
compatibility of the lubricants used with these refrigerants
should be considered.
Reuse of Gaskets
We are frequently asked about reusing a gasket. We
do not recommend this practice. A gasket's function is to
conform to flange high and low spots when compressed,
and its ability to reseal decreases after it is compressed.
Gaskets which contain rubber and which have experienced
elevated temperatures will be even less likely to reseal.
Shelf Life
Garlock has spec sheets detailing proper storage con-
ditions and expected shelf life for our products. Available
upon request.
Spacers in Flanges
Some installations require a very thick gasket to fill a
large gap between flanges. We do not recommend stack-
ing numerous gaskets in the same flange. In-house tests
have shown that a better way to fill a 1/2" gap, for example,
is to install a 1/16" gasket on each side of a 3/8" thick
incompressible spacer ring. Ideally, the spacer ring will be
consistent with piping metallurgy, serrated, and cut to the
same dimensions as the gasket. We recommend higher
minimum torques when using this arrangement.
Steam
Steam can be found in plants in two forms: saturated
and superheated. Saturated steam is standard boiler
steam and has a definite temperature for each pressure.
Superheated steam is steam at a higher temperature than
is found on the saturated steam curve for that particular
pressure. We recommend ST-706 and our GRAPH-LOCK ®
styles for superheated steam. Please be aware of the pres-
sure and P x T limits for each style when making a selec-
tion, and consult with Garlock Engineering when approach-
ing these limits. Also see notes on steam service found on
fiber gasket specification pages.
Thermal Conductivity
See F104 Line Callouts.
Questions? Call Gasket Applications Engineering
at 1-800-448-6688