Manways for the Pharmaceutical Market: Corrosion-Resistant Solutions for High-Purity Systems

There has been rapid development of new active and potent products in the pharmaceutical market and fine chemical industries. This has led to the need for a specialist range of pressure vessels, pharmaceutical tank manways, and corrosion-resistant materials to ensure hygiene, minimise contamination risks, and protect operators.

Manways and access panels are critical components in the vast majority of pharmaceutical, biotech, chemical, food, and beverage tanks, allowing access to the vessel for cleaning and inspection processes. Manways are designed for low, medium, and high-pressure applications and can be provided in virtually endless configurations, including domed, oval, rectangular, and bespoke designs tailored to specific requirements.

Demands of Pharmaceutical Tank Applications

Pharmaceutical production is highly complex and requires strict controls and very high standards of hygiene to protect product quality. The following demands highlight the critical role of pharmaceutical manways in production systems:

• Compliance with Industry Regulations: Pharmaceutical tanks and components must meet stringent hygiene standards.
• High Corrosion Resistance: Materials must withstand harsh cleaning environments and highly oxidising media, including high levels of chlorides.
• Minimising Contamination: Preventing discolouration or contamination is critical to avoid costly batch disposal.
• Aseptic Surface Finish: A polished finish (<0.4 µm Ra) ensures sterility, reduces product adhesion, and enhances cleaning efficiency.
• Versatility in Multi-Purpose Plants: Equipment must operate in diverse environments, handling almost any solvent or media.

If a batch is contaminated due to corrosion or inadequate surface finish, it is likely to be discarded, and the equipment must be taken offline, causing production downtime and financial losses.

The Importance of Surface Finish

The surface finish of pharmaceutical pressure vessels and manways plays a key role in maintaining sterility and efficiency in production systems. In high-purity environments, a finish of <0.4 µm Ra (mirror-polished) is standard for internal surfaces.

Benefits of a High-Quality Surface Finish:

1. Improved Cleaning Ability: Polished surfaces reduce product adhesion, making cleaning easier and more effective.
2. Enhanced Corrosion Resistance: A high-quality finish protects against pitting and stress corrosion cracking.
3. Regulatory Compliance: Prevents contamination and ensures smooth production processes.
4. Reduced Downtime: Consistent surface finishes prevent issues that can interrupt operations and increase costs.

Alloy Selection for Pharmaceutical Tank Manways

Selecting the right material is critical for pharmaceutical-grade manways and pressure vessels, ensuring durability, compliance, and corrosion resistance. Below are the main materials commonly used:

1. Stainless Steel

Stainless steel is a preferred material in pharmaceutical applications due to its:

• Corrosion Resistance: With a minimum chromium content of 10.5%, stainless steel forms a passivation layer that prevents oxidation and contamination.
• Durability: It can withstand aggressive cleaning routines, including high-pressure chemical washes.
• Polishability: Achieving a mirror-polished finish ensures compliance with aseptic conditions.
• Heat Resistance: Suitable for high-temperature sanitation processes. Stainless steel is used in the production of pharmaceutical tank manways, pumps, piping, storage tanks, valves, and other equipment.

2. AL-6XN® Alloy

Originally developed for seawater applications, AL-6XN® is highly resistant to corrosion and widely used in the biopharmaceutical market. Key benefits include:

• High strength and corrosion resistance in environments with high chlorides or oxidising agents.
• Cost-effectiveness compared to nickel-based alloys.
• Excellent weldability and formability, allowing for bespoke pharmaceutical manways.

3. Nickel Alloys

Nickel alloys, including Alloy C276 and Alloy 22, are ideal for pharmaceutical pressure vessels operating in highly aggressive environments:

• Alloy C276: Highly resistant to pitting, crevice corrosion, and chloride-induced stress corrosion cracking.
• Alloy 22: Offers exceptional resistance to pitting and chemical processes, particularly in high-chloride environments such as ferric chlorides, seawater, and brine solutions.
• Nickel alloys are used when other materials fail, making them indispensable for high-performance pharmaceutical systems.

Custom Configurations for Pharmaceutical Manways

Manways for pharmaceutical tanks are available in a wide variety of designs to meet specific application requirements. These include:

• Domed Manways: Ideal for high-pressure applications.
• Oval and Rectangular Manways: Provide flexible access for cleaning and inspection.
• Hatches and Doors: Designed for easy access while maintaining hygiene.
• Bespoke Designs: Tailored solutions for unique pharmaceutical production needs.

Benefits of High-Quality Pharmaceutical Manways

Investing in pharmaceutical-grade tank manways delivers numerous benefits, including:

• Enhanced Hygiene: Ensures sterility and compliance with industry standards.
• Improved Efficiency: Reduced contamination risks and easier cleaning lower downtime and production costs.
• Durability and Reliability: Corrosion-resistant materials improve the lifespan of equipment.
• Customisation Options: Configurations and materials tailored to specific operational demands.

The pharmaceutical industry relies on corrosion-resistant manways and high-quality pressure vessels to meet its stringent production requirements. By choosing the right materials - such as stainless steel, AL-6XN®, or nickel alloys - and ensuring an optimal surface finish, manufacturers can improve cleaning efficiency, maintain sterility, and reduce downtime.

For more information on pharmaceutical tank manways, stainless steel alloys, and nickel alloys, visit NeoNickel’s Stainless Steels and Nickel Alloys page.