Medical & Pharmaceutical Gaskets & Seals

Challenge

A biopharmaceutical facility running 2,000 L single-use bioreactors experienced repeated gasket failures at tri-clamp connections during SIP cycles at 121 °C and 1 bar gauge. The peroxide-cured silicone gaskets were swelling after 40–50 sterilisation cycles, losing compression and allowing micro-leaks. That meant a batch hold every time. Each failure cost two to three days of lost production while QA investigated.

Solution

We replaced the peroxide-cured silicone with platinum-cured silicone O-rings formulated for repeated SIP exposure. Platinum-cured compounds produce fewer extractable by-products and maintain better compression set resistance through thermal cycling. The material met USP Class VI and FDA 21 CFR 177.2600 with documented extractables data. We also recommended a scheduled replacement interval of 80 cycles based on the compound's compression set curve at 121 °C.

Result

Zero gasket-related batch holds over the following 12 months. The 80-cycle replacement interval is consistent with the compound's published compression-set behaviour at 121 °C, and the scheduled programme reduced unplanned downtime and gave the QA team documented evidence of proactive control for their TGA (Therapeutic Goods Administration) audit.

Challenge

A sterile injectables manufacturer was specifying EPDM gaskets for a new Water for Injection (WFI) distribution loop operating at 80 °C continuous with periodic sanitisation at 121 °C. The engineering team needed gaskets that would not contribute extractables above facility-established limits for WFI systems. USP <1231> (the pharmacopoeial standard for Water for Injection systems) provided the extractables guidance. The gaskets also had to survive thousands of thermal cycles between 80 °C and 121 °C.

Solution

We supplied virgin PTFE envelope gaskets with a silicone core for the flanged connections. The PTFE wetted surface eliminated extractable concerns entirely. PTFE is inert to WFI at all operating temperatures. The silicone core provided the resilience needed for thermal cycling. For the tri-clamp joints, we specified platinum-cured silicone with extractables testing documentation per ASME BPE requirements.

Result

The WFI system passed commissioning validation on the first attempt. Gasket extractables are typically among the first items reviewed in WFI audits, so documented compliance up front avoids rework later. Annual requalification testing confirmed extractables remained within acceptable limits per USP <1231> guidance after 14 months of continuous service.

Challenge

A Class 7 cleanroom (ISO 14644-1:2015) used for medical device assembly was failing particle count tests at the supply air diffusers. Investigation traced the contamination to degraded foam gaskets in the HVAC duct flanges. The original closed-cell neoprene had hardened after five years and was no longer sealing against the sheet metal faces, allowing unfiltered air bypass.

Solution

We supplied closed-cell EPDM foam gaskets die-cut to match the duct flange profiles. Peroxide-cured EPDM foam maintains its compression and resilience over a wider temperature range than neoprene (-50 °C to +110 °C continuous) and resists ozone degradation that accelerates neoprene ageing in recirculated air systems. The low-outgassing formulation kept volatile organic compound (VOC) levels below the cleanroom's facility limits.

Result

Particle counts returned to within ISO Class 7 limits immediately after installation. EPDM's saturated polymer backbone resists ozone attack better than neoprene's chlorinated structure, which is the failure mode that ages neoprene foam in recirculated cleanroom air. The replacement gaskets showed no measurable compression set at the 12-month inspection, compared to the neoprene originals which had visibly flattened within three years.