Chemical Processing Gaskets & Seals
Sealing for aggressive media, elevated temperatures, and strict emission controls across the chemical process industries.
Australian chemical plants handle corrosive streams, steam and volatile media across joints with different flange designs and available gasket stress. Selection starts with the complete process stream and joint data, then checks the exact gasket construction, every exposed material and the governing plant or OEM specification.
Applicable Standards for CPI Sealing
These documents cover different objects: gasket dimensions and tests, flange ratings, piping or vessel design, and joint assembly. The governing project specification determines which edition and requirements apply.
Generic Stock vs. Media-Matched Sealing
CPI Applications
Each application needs its process stream, joint construction and project requirements identified before a gasket or seal is selected.
Shell-and-Tube Heat Exchangers
Large-diameter joints may combine cycling, movement and uneven gasket stress. Confirm the exchanger drawing, partition layout, normal and upset conditions, facing and assembly procedure before screening semi-metallic or soft-gasket constructions.
Glass-Lined Reactor Gaskets
Fragile glass linings limit point loading and available assembly stress. Follow the equipment manufacturer's joint design and permitted gasket load, and distinguish an ePTFE gasket from a PTFE envelope construction when specifying the product.
Distillation Columns
Conditions can change at each elevation. Record the local media, phase, pressure, temperature, cycling, flange facing and available gasket stress before comparing filler, facing and metallic-component options.
Acid Piping Systems
Acid identity alone is not a specification. Concentration, impurities, aeration, flow, phase and temperature must be checked with flange condition, joint load and every exposed gasket and flange material.
Chlor-Alkali Cells
Brine and chlorine occur at the anode; caustic and hydrogen occur at the cathode. Screen the exact gasket construction or elastomer compound for its stream, concentration, temperature, pressure, cleaning duty and cell-maker requirements.
Tank Nozzles & Manholes
Oversize flanges may have low bolt density, distortion or uneven gasket stress. Manufacture from a verified drawing and select the exact product from the medium, flange condition, joint load and pressure-temperature envelope.
Pump & Valve Gaskets
Bonnet, case, stem and lantern-ring duties have different motion, emissions and corrosion requirements. Use the equipment drawing and exact process and cleaning fluids to select the gasket, packing or seal construction.
Scrubbers & Off-Gas Treatment
Wet scrubber and quench joints can see mixed liquid and gas phases, oxidants and acid condensate. Record the complete composition, temperature, pressure, base metallurgy and upset conditions before selecting candidate materials.
Lined Pipe Flange Gaskets
Lined piping may use raised-face or flat-face joints with restricted assembly load. Follow the lining and equipment manufacturer's flange, gasket and torque requirements; lining chemistry alone does not select the gasket.
Key Materials for Chemical Processing
These families are screening candidates, not service approvals. Confirm the exact grade or compound, construction, medium and concentration, coincident pressure-temperature conditions, atmosphere, duration, cycling and joint data against current product documents.
PTFE / ePTFE
Homogeneous PTFE sheet, filled PTFE, ePTFE sheet or tape, and PTFE envelope gaskets are distinct constructions. Compare chemical resistance with creep, permeation, filler chemistry, flange condition and available gasket stress before choosing one.
Check: Exact product, filler, thickness, medium, concentration and cleaning fluids
Joint: Facing, bolt load, pressure-temperature combination and cycling
FKM (Viton)
FKM performance varies by formulation, cure, fluid and seal geometry. For gas decompression duty, review the exact pressure cycle and the proposed compound's rapid-gas-decompression test data rather than relying on the polymer family.
Check: Exact compound, all process and cleaning fluids, concentration and temperature
Seal: Static or dynamic geometry, pressure cycle and decompression rate
FFKM Compounds
FFKM compounds have materially different temperature and chemical limits. Screen a named compound only after the full exposure sequence, pressure duty and seal geometry are known.
Check: Exact compound and current manufacturer compatibility data
Duty: Process and cleaning fluids, exposure sequence, pressure and seal design
Flexible Graphite
Flexible graphite can be a candidate for steam and high-temperature process joints. Oxidation and service life depend on the exact grade and construction, oxygen exposure, pressure, temperature, time and process chemistry.
Check: Grade, construction, atmosphere, continuous or excursion duty and duration
Chemistry: Strong oxidisers require a stream-specific product review
Spiral Wound Gaskets
A spiral-wound construction combines metallic winding and filler, with rings where the applicable standard requires them. Select every component for the process stream, flange facing, available gasket stress and project specification.
Check: Flange standard, NPS, class, facing and gasket construction
Service: Coincident pressure-temperature duty and all exposed metals
Kammprofile Gaskets
A grooved metal core with covering layers can be considered for selected heat-exchanger and large-diameter joints. Core, facing, dimensions and assembly stress must match the drawing and complete service.
Check: Core and facing materials, dimensions, pressure-temperature duty and cycling
Joint: Flange condition, available gasket stress and OEM requirements
Nickel-Alloy Components
Nickel-alloy windings, cores and rings can be candidates for selected corrosive duties. Choose the exact alloy from current corrosion data for the actual stream, then check the filler, facing, flange and bolting materials.
Stream: Concentration, impurities, aeration, flow, phase and temperature
Joint: Crevice conditions and every exposed gasket and flange material
Corrosion-Resistant Alloys
Alloy family charts are useful for screening, but they are not complete gasket service envelopes. Do not select a winding or core alloy from a broad media name such as hydrofluoric acid or fluorine.
Require: Full composition, water content, contaminants, air ingress and flow
Verify: Current alloy-manufacturer data and the plant materials specification
Stop-and-Verify Example: Hot Sulphuric Acid
A 6-inch Class 150 flange on a 93% sulphuric acid line at 120 °C does not provide enough information to specify a complete gasket. Polymer compatibility cannot qualify an exposed winding, core or inner-ring alloy.
- Define the stream. Record the full acid composition, contaminants, aeration, flow, phase and normal and upset conditions.
- Define the duty. Confirm operating and design pressure and temperature, duration, cycling and any cleaning or shutdown exposure.
- Define the joint. Confirm the flange standard, size, class, facing and materials, bolting, available gasket stress and the OEM or project specification.
- Check every component. Use current product and corrosion data for the exact filler or facing, winding or core, rings and adjacent flange materials. Do not infer alloy suitability from PTFE compatibility.
- Apply the construction rule correctly. If an ASME B16.20 PTFE-filled Spiral Wound Gasket is considered, the inner ring is required. The outer guide ring centres the gasket; the inner ring limits inward buckling and compression and protects the bore.
Final selection remains with the responsible engineer under the current plant or OEM specification and manufacturer qualification data. No substitute alloy is implied here.
Three Failures Worth Designing Out
PTFE creep on traced lines
PTFE creep can reduce gasket stress as a traced joint heats and cycles. Compare the exact product's load-retention data and filler chemistry with the flange condition, assembly stress and complete pressure-temperature duty.
Graphite in oxidising acid
Strong oxidisers can attack graphite, but there is no family-wide concentration cut-off or universal replacement. Check the exact grade and stream conditions against current product data.
FKM under decompression
Rapid decompression can blister unsuitable elastomer compounds after gas absorption. Review the exact gas, pressure cycle, decompression rate, seal geometry and compound test evidence.
Products for Chemical Processing
Engineering Guides for CPI
Our technical guides and tools cover chemical compatibility, gasket failure analysis, and pressure–temperature ratings: the data CPI engineers need when specifying sealing.
Browse All ResourcesExplore Further
Send the Complete Duty Before We Quote
For chemical service, include the full stream, normal and upset conditions, flange and bolting data, required gasket construction and governing project specification.
- Exact medium and concentration
- Coincident pressure-temperature conditions
- Flange, facing and available gasket stress
Disclaimer
This page is provided for general engineering reference only and does not constitute professional advice, specification, or guarantee of performance. Actual results depend on specific application conditions. Universal Gaskets Pty Ltd accepts no responsibility or liability for decisions made based on this information. For full terms, see our Terms & Conditions.
Temperature ranges, chemical resistance ratings, and mechanical properties cited on this page are typical values for standard grades. Actual performance varies with compound formulation, filler package, and service conditions — contact us to confirm suitability for your specific application.