Surface finish requirements for pharmaceutical equipment

Surface finish is critical in ensuring product safety and integrity for the pharma industry. It is characteristic of the material used in pharma equipment, tools, and instruments. This article discusses surface finish and surface finish requirements for pharmaceutical equipment

Surface Finish for Pharmaceutical Equipment

Surface finish requirements for pharmaceutical equipment

Strict requirements for a product, process, safety, and regulatory regulations characterize the pharmaceutical industry. The main purpose of these requirements is to ensure a safe product for end users and to provide them for which they have paid. Surface finish requirements for pharmaceutical equipment are also one of many methods to achieve and, ensure product safety and therapeutic properties.

Surface finish requirements for pharmaceutical equipment are one of many methods for ensuring product safety and therapeutic properties.


During product manufacturing, such as in pharmaceutical tablet press, pharma product comes in direct contact with different equipment parts. If product contact parts are not carefully selected during , they will contaminate the product, change product specification, and become hazardous for its end user.

To ensure safe products and prevent contamination through the equipment, material that comes in direct contact with the product must be of specialized requirements, including the surface finish.

What is Surface Finish?

Surface Finish is the nature or physical condition of the material. It is the function of many factors, such as roughness, waviness, lay, and coating. Its requirements depend on the specific industry and the nature of the application.



Surface Finish is the nature or physical condition of the material


Surface finish is the major requirement for many critical industries such as food, beverages and pharmaceuticals, as it helps to protect the final product from contamination and it is a major regulatory requirement such as the United States FDA.

Always mention Surface finish requirements for pharmaceutical equipment when buying a new equipment

Before buying new equipment or system, always mention surface finish requirements for pharmaceutical equipment during procurement in a document such as User Requirement Specification.

Because, If a buyer does not include these specifications, then chances are that the equipment manufacturer can use any other non-compatible material. This will, in turn, be bad for the equipment buyer, with nothing to claim.

Let’s discuss surface finish requirements for pharmaceutical equipment

Stainless Steel

Stainless Steel is the most important requirement for product contact parts in the pharma industry. All the critical parts that come in direct contact with the product must be made up of Stainless Steel.

The biggest advantage is that It withstands reactions with chemicals such as sanitizing agents and active pharmaceutical ingredients – API used in manufacturing a pharma product. Additionally, Stainless Steel also resists the occurrence of corrosion.

Many variants of Stainless Steel are developed for the pharmaceutical industry, and the type of process defines the selection of these variants.  The Austenitic series of Stainless Steel called 316, is used for parts that come in direct contact with pharma products. This type has high chromium, nickel, and molybdenum.

Nickel and Chromium make it more corrosion-resistant, while molybdenum makes it resistant to acids, alkalis, and chlorine.

A variant of SS316, called SS316L, has become more common in pharmaceutical applications. It contains low carbon content, so it has the letter ‘L” at its end. This variant of SS is more resistant to contamination. In addition, SS 316L can also be used in processes requiring high temperatures, such as Autoclaves  (where high autoclave temperatures require specialized material for product contact parts), and Dry Heat Serializers, because it has a low carbide precipitation effect.

Surface Roughness

Surface roughness is the measure of variation in the height of a metallic surface. Although the surface can look smooth to the naked eye, it can have height variations.

Surface roughness is a numerical value, which represents the degree of roughness of a surface. Higher the value, the more a surface is considered rough and vice versa.

The symbol for Surface Roughness is Ra. For pharmaceutical applications, the recommended values are less than 0.8. Any material with a surface roughness of less than 0.8 can be safely used for pharmaceutical production processes.

Some disadvantages of rough surface or surfaces having higher surface roughness includes the following


Orbital Welding

Like other industries, welding in the pharma industry is an important maintenance process. There are different types of welding, such as electric and arc. For the pharmaceutical industry, Orbital Welding is the approved type.

Orbital welding is specialized welding that welds a tube by rotating the weld head 360⁰ around the tubing. The welding operation is automated and controlled by a main controller.

It uses a Tungsten electrode and an inert gas, commonly, argon, as an arcing agent. The inert gas is filled between electrodes, which rotates across the tubing diameter. As the electrodes rotate, the arc continues, until it completes the entire rotation.

The benefit of orbital welding is that its welds are consistent, without any dead points from the internal and external of the joint. Consistency can be ensured around a full revolution, and results in a smooth surface finish.

Another major advantage of orbital welding is that there is a minimum or no change in surface characteristics, which is a common disadvantage in other welding types. A change in surface characteristics can lead to a change in surface roughness values and result in microbial growth and contamination.

Dead points

Dead points are the isolated points on a material surface of piping, tubing, or a metallic surface. It can trap any substance that passes over or reaches it. Liquid can easily trap in dead points and becomes hazardous for pharmaceutical products and processes. The trapped liquid in the dead point facilitates microorganism growth and causes contamination in the pharma production process.

These dead points are difficult to clean and sanitize because these are isolated places, and it becomes difficult for the cleaning agent to reach, and remove the contaminants.

ASME – BPE standards, known as Length to Diameter L/D ratio, are used to represent dead points in the material. It suggests that for pharmaceutical applications, the L/D ratio should be less than 2

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