Plastics vs. Stainless Steel: Revolutionizing Pharmaceutical Plants
In the realm of pharmaceutical manufacturing, where the purity of water lines is non-negotiable, the materials chosen for construction bear the weight of ensuring unblemished quality. Traditionally, Type 316L stainless steel (SS) has been the cornerstone material, revered for its robustness. However, its susceptibility to rust under aggressive conditions, known as rouge, has pushed the industry to reconsider. Enter plastics, presenting an alternative that promises to redefine the standards of purity and efficiency.
The Dilemma of Material Selection
The decision between plastics and stainless steel in pharmaceutical plants is more than a choice; it’s a pivotal strategy that impacts every aspect of production. This was underscored at a forum by the New Jersey section of the International Society of Pharmaceutical Engineers, emphasizing the complexity of selecting the optimal material for pharmaceutical processes.
The Case for Engineered Thermoplastics
Thermoplastics, with their remarkable chemical inertness and cost competitiveness against stainless steel, offer a compelling alternative. Their resistance to a wide array of corrosives and their non-contribution to metallic contamination make them indispensable, especially in high-purity water systems, pharmaceuticals, and electronics where the slightest impurity can compromise the entire operation.
Challenges and Considerations
However, transitioning to thermoplastics is not without its challenges. Internal management approval, justifying capital costs, securing validation, and the overarching concern of potential liability are significant hurdles. Yet, the semiconductor industry’s successful shift to plastics over a decade ago provides a roadmap for pharmaceutical companies facing similar material dilemmas today.
The Rogue of Rouge
Rouge, the bane of purified water systems, results from the oxidation of dissolved iron. While passivation techniques can clean out rouge, preventing its occurrence is a more straightforward solution, possibly achieved by embracing plastics, which are inherently free from iron.
Types of Rouge and Their Remedies
Rouge can manifest in several forms, from dissolution-related Type 1 to high-temperature-induced Type 3. Addressing each type requires specific strategies, including the adoption of automatic orbital welding and meticulous post-welding treatments to minimize heat-affected zones prone to Type 2 rouge.
Stainless Steel vs. Plastics: A Balanced View
While stainless steel offers impermeability to gases and superior thermal conductivity, its sensitivity to chlorides and vulnerability to microbial-induced corrosion (MIC) pose significant challenges. On the other hand, plastics like PVDF emerge as viable alternatives, especially in pure-water systems, offering high thermal stability, resistance to sunlight degradation, and non-support of microbial growth.
Evaluating Cost vs. Performance
Though initially more expensive, fluoropolymers like PVDF provide a cost-effective solution in the long run, thanks to their high purity, resistance to a wide temperature range, and reduced maintenance needs compared to stainless steel systems.
Looking Forward: Plastics in the Pharmaceutical Industry
As the pharmaceutical industry stands at the crossroads of tradition and innovation, the shift towards thermoplastics appears not just viable but inevitable for certain applications. The need for education on both sides—understanding the unique properties of plastics and designing systems to leverage these advantages—presents an opportunity for growth and improvement.
The journey towards embracing plastics in pharmaceutical manufacturing is not just about material selection; it’s about aligning with the future of high-purity, efficient, and sustainable production. As the industry progresses, the debate between plastics and stainless steel will continue to evoke discussions, drive innovations, and ultimately, lead to the development of manufacturing environments where quality, efficiency, and safety are paramount.
