1/2 December 2020
The nickel plating of surfaces is a good and high-quality method to protect components or surfaces from corrosion. At the same time, the question is repeatedly asked whether components treated in this way may be used in the GMP area.
In most cases, nickel-plated parts cannot be visually distinguished from stainless steel. In practice, this indistinguishability actually leads to a risk of confusion, which is why such parts are often banned in GMP operations, e.g. for screws and similar small parts.
Indeed, this indistinguishability leads to a risk of confusion in practice - especially for small unmarked material. Basically, a strict separation of black and stainless steel must be observed in stainless steel processing. For this reason, nickel-plated screws and similar small parts are forbidden in the GMP stainless steel workshop or on such a construction site. Alternatively, one takes care to ensure a strict separation of areas, magazines and tools. The reason: nickel-plated parts are susceptible to electrochemical contact corrosion, especially when the surface is damaged and in a moist environment.
In the product contact zone, nickel-plated parts are typically not GMP-compliant, because these zones are cleaned with purified water (PW) [conductivity less than 1.1µS/cm at 20°C] during the cleaning process of the final rinse. When in regular contact with such ultrapure water, nickel-plated parts are usually not corrosion-resistant.
In the GMP environment, however, surfaces that do not come into contact with the product are often treated with cleaning and disinfecting agents (e.g. clean room walls of class D+C+B+A or the surfaces of machines located in rooms of the clean room classes mentioned). Here, too, ultrapure water as well as various chemicals are used (e.g. ammonium compounds), which can attack nickel-plated surfaces.
However, the use of nickel-plated components is not generally prohibited by GMP. There is no official requirement or concrete written regulations. But: Not to use nickel-plated components in the above-mentioned areas is in accordance with the state of the art in science and technology. And adherence to the state of science and technology is a GMP requirement.
The situation is different when using nickel-plated parts in the field of drives, electrical screw connections or e.g. pneumatic connectors. This is possible in GMP operation and the use is harmless if these parts are separated from the area in contact with the product and from the clean room (preferably by separating the machine room from the process room, if necessary by encapsulating the area).
The use is also possible for GMP clean rooms below class D - depending on the product and the specific cleaning or disinfection procedure.