HVAC & Refrigeration Gaskets
Sealing for air handling, chillers, and next-generation refrigerant systems, from ductwork foam strips to high-pressure CO₂ metallic gaskets.
Australia's HFC (hydrofluorocarbon) phase-down is reshaping material choices across the refrigeration chain. R-454B (GWP — global warming potential — 466) is now the dominant R-410A replacement in new commercial chillers and VRF (variable refrigerant flow) heat pumps, with Daikin, Trane, and Carrier all completing the transition by mid-2025. We supply gaskets validated for R-32, R-454B, ammonia, and CO₂ transcritical systems, alongside the foam profiles and compressed fibre that keep ductwork tight and energy bills down.
Air-Side and Refrigerant-Side Are Different Problems
Air-Side Sealing
Ductwork flanges, AHU (air handling unit) access panels, rooftop unit curb seals, and building envelope penetrations. The enemy is air leakage. Poorly sealed ducts lose 20–30% of conditioned air before it reaches occupied spaces. SMACNA Seal Class A requires gasketted flanged joints on all transverse joints, seams, and penetrations.
Key materials: Closed-cell neoprene · EPDM foam · Compressed fibre
Refrigerant-Side Sealing
Compressor gaskets, plate heat exchanger seals, valve bonnets, and refrigerant piping flanges. Pressure, chemical attack, and permeation dominate. CO₂ transcritical systems run at 90–130 bar, while ammonia corrodes copper alloys on contact.
Key materials: HNBR · PTFE · Spiral Wound SS316 · Kammprofile
Refrigerant Transition Alert
Australia's HFC phase-down reaches 85% reduction by 2036 under the Kigali Amendment to the Montreal Protocol. From 1 July 2025, new multi-split and VRF systems with refrigerant charge ≤ 2.6 kg must use refrigerants with GWP ≤ 750. That effectively ends R-410A in new installations. R-32 and R-1234yf are classified A2L (mildly flammable) under ASHRAE 34; R-290 (propane) is A3 (highly flammable). Both flammability ratings affect gasket material selection alongside chemical compatibility. If you're specifying gaskets for these next-generation refrigerants, standard NBR and FKM may not be suitable. Purdue University research shows FKM swells significantly with HFO (hydrofluoroolefin) refrigerants. Talk to us about compatible HNBR and PTFE alternatives.
From Rooftop Units to Blast Freezers
Commercial HVAC
Office towers, shopping centres, hospitals, and schools across Sydney, Melbourne, Brisbane, and Perth. AHU access panel gaskets, ductwork flange seals, chiller plant piping, and rooftop unit weatherseals. NABERS energy ratings and Green Star certification (Australia's building sustainability standards) drive demand for Class A duct sealing.
Industrial Refrigeration
Ammonia cold stores, CO₂ transcritical supermarket systems, ice plants, and abattoir blast freezers. Gaskets must withstand toxic ammonia (no copper alloys), high-pressure CO₂ (≥ 90 bar), and operating temperatures down to −50 °C.
Chillers & Heat Exchangers
Gasketed plate-and-frame heat exchangers (Alfa Laval, Tranter, GEA), scroll and screw compressor end-caps, and chilled water piping flanges. Replacement PHE gaskets are a recurring maintenance item; we match OEM plate profiles in NBR, EPDM, and FKM.
Building Envelope & Specialist
Data centre CRAC/CRAH panel seals, cleanroom HEPA filter frame gaskets, coolroom door seals rated to −40 °C, and cooling tower basin gaskets. Environments where gasket failure means lost uptime or contaminated product.
Refrigerant Compatibility and Material Selection
HNBR and EPDM are the primary choices for R-32 systems. Both show strong dimensional stability with HFC refrigerants and POE lubricants. Standard NBR remains functional but offers shorter service life at R-32's higher discharge temperatures. PTFE is suitable where chemical inertness is paramount.
Ammonia (R-717) attacks copper, brass, and zinc alloys, so all metallic gasket components must be carbon steel or stainless steel. For elastomeric seals, PTFE is the safest choice, followed by EPDM and HNBR. Standard NBR has only marginal ammonia resistance. Never use spiral wound gaskets with copper-alloy winding wire on ammonia circuits.
CO₂ (R-744) transcritical service runs at three pressure stages: gas-cooler outlet 90–130 bar (high-side), flash tank / receiver 35–45 bar (intermediate), and suction 25–30 bar (low). Spiral wound SS316/graphite is standard on gas-cooler flanges; Kammprofile with PTFE facing handles flash-tank service where re-makeable joints are needed. Metal ring joints and SWGs with SS316 windings handle the highest pressures. CO₂ also permeates rapidly through elastomers as a small molecule, making metallic or PTFE gaskets strongly preferred. (Coles, Woolworths, and IGA chains run transcritical retrofits across their cold-chain estates.)
Peer-reviewed research from Purdue University found that FKM (Viton) and silicone elastomers exhibit significant volume swelling and post-exposure softening when exposed to R-1234yf and R-1234ze(E). This is counter-intuitive, since FKM is usually the premium chemical-resistant choice. For HFO systems, EPDM and HNBR maintain better dimensional stability.
SMACNA defines three seal classes by what gets sealed: Class A (all transverse joints, longitudinal seams, and penetrations, for systems ≥ 4 in. wg), Class B (transverse joints and longitudinal seams, 3 in. wg), and Class C (transverse joints only, 2 in. wg). Class A requires gasketted flanged joints, typically closed-cell neoprene or EPDM foam strips on TDC/TDF flanges. AS 1668.2:2024 mandates minimum outdoor airflow delivery rates, so leaking ducts directly affect compliance.
If the chilled water system connects to potable water supply (including evaporative cooling tower make-up water and some building services loops), gaskets in contact with potable water must comply with AS/NZS 4020:2018. This involves taste, appearance, microbial growth, and mutagenicity testing. We supply tested, compliant materials for these applications.
Gaskets Matched to Your Refrigerant and Application
Closed-Cell Neoprene
The workhorse of air-side sealing. Weather-tight AHU panel gaskets, ductwork flange strips, and vibration damping pads. Good UV resistance when shielded by aluminium weather capping.
−40 °C to +100 °C (continuous)EPDM
Best UV and ozone resistance for outdoor rooftop units. Compatible with HFC and HFO refrigerants. Our first recommendation for exposed HVAC applications in Australian conditions.
−50 °C to +150 °C (continuous)HNBR
The upgrade from NBR for refrigerant-side sealing. Delivers 3.5× the service life of NBR at 80 °C in heat exchanger applications. Compatible with R-32 and R-1234yf in POE oil systems.
−30 °C to +150 °C (continuous)PTFE
Chemically inert to every commercial refrigerant including ammonia and CO₂. Low permeation rates make PTFE the default choice for high-integrity refrigerant connections and valve seats.
−200 °C to +260 °C (continuous)Silicone
Widest temperature range of any elastomer. Cold storage door seals to −60 °C, cleanroom HEPA filter frame gaskets, and high-temperature sections near heating coils.
−60 °C to +230 °C (continuous)Spiral Wound SS316/PTFE
For CO₂ transcritical flanges and ammonia high-pressure joints. SS304 or SS316 winding resists ammonia corrosion. Graphite or aramid filler is the industrial-ammonia standard (PTFE filler also fine). Inner/outer rings must be carbon steel or stainless: never Monel, copper-nickel, or any copper-bearing alloy.
Rated to ASME Class 2500Standards and Regulatory Framework
AS/NZS 5149:2016
Refrigerating systems and heat pumps: safety and environmental requirements. Parts 1–4 covering design, construction, installation, and operation.
AS 1668.2:2024
Mechanical ventilation in buildings, with updated outdoor airflow calculations and ductwork integrity requirements.
AS/NZS 4020:2018
Products in contact with drinking water. Mandatory for gaskets in chilled water systems connected to potable supply.
NCC 2025 Section J
National Construction Code energy efficiency provisions (NCC 2025 supersedes 2022; adoption dates vary by state). Drives demand for air-tight ductwork and building envelope sealing.
ASHRAE 15:2024
Safety standard for refrigeration systems: charge limits, machinery room ventilation, and leak detection mandates.
ASME B16.5-2025
Pipe flanges and flanged fittings. Applies to chiller plant piping (Class 150/300 for chilled water loops).
AS/NZS 1170.2:2021
Wind actions. Sets wind loading requirements for rooftop HVAC equipment securing and weathersealing.
SMACNA Seal Classes
HVAC air duct leakage test standard. Class A requires all transverse joints, longitudinal seams, and penetrations to be sealed with gasketted flanged joints.
Ozone Protection and Synthetic Greenhouse Gas Management Act 1989
Australian HFC phase-down legislation: 85% reduction by 2036, body corporate penalties up to AUD 333,000 (indexed; subject to penalty unit increases) for unlawful refrigerant discharge.
HVAC and Refrigeration Product Range
Extruded Profiles
Continuous foam and rubber profiles for AHU panel gaskets, ductwork seals, and coolroom door seals. Custom cross-sections cut to length.
Soft-Cut Gaskets
Die-cut and waterjet-cut gaskets from compressed fibre, EPDM, neoprene, and PTFE sheet, matched to OEM flange patterns.
O-Rings
HNBR, EPDM, FKM, and PTFE O-rings for compressor housings, valve stems, and refrigerant line connections.
Metal Gaskets
Spiral wound (SS316/PTFE), Kammprofile, and ring joint gaskets for CO₂ transcritical and ammonia high-pressure flanges.
Expansion Joints
Flexible joints for ductwork and chilled water piping. Absorbs thermal movement and vibration without breaking the seal.
Industrial Tapes
Self-adhesive foam strips and sealing tapes for ductwork flanges, equipment panels, and vibration damping applications.
Supporting Tools and Guides
Match gasket materials to refrigerant chemistry, compare elastomer properties, and select the right gasket type for your flange configuration.
Explore Further
Need Refrigerant-Compatible Gaskets?
From foam duct seals to high-pressure metallic gaskets for CO₂ and ammonia systems. We cut to your specifications with material traceability.
- Custom die-cut and waterjet profiles
- Compatible with R-32, R-1234yf, ammonia, and CO₂ systems
- Australian stock — faster than OEM lead times
- Material certificates and test reports available
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.