Compressed Air for pharma applications

Compressed Air is pressurized Air with pressure higher than the pressure of Air at atmospheric pressure. It is pressurized with the help of an air compressor, which forces large volumes of Air into a smaller space.

For forcing large volume of Air into smaller spaces requires a force, which is provided by equipment called Air Compressor. When Air is released, it releases the energy stored during compressing Air.

Compressed Air is stored at higher pressure, which enables it to supply at varying pressure within the limit. Compressed Air is supplied with the help of conduits spread across different areas of the pharma facility. These conduits can withstand high pressure.

For regulating pressure, a pressure control device called Pressure Regulator is used. It is typically installed at the receiving end of the individual equipment and can provide compressed Air with varying pressure.

Application of compressed air in pharmaceutical industry

The pharmaceutical industry has diverse processes for manufacturing pharma products that require compressed air of a specific pressure. Suppose compressed air is unavailable or the required pressure is not provided. In that case, the required process cannot be executed correctly, or it will occur with errors, causing the associated process to become faulty.

Let’s see some examples of pharma processes that require compressed air.

Powering pneumatic components

Every equipment and machine used in the pharma industry contains pneumatic components for various functions. Commonly, pneumatic components are used to handle the movement of entire equipment or part of it. This equipment or part requires strong force to displace from its position. Since compressed air contains energy in it, which is stored during the compression action, it can easily handle these movements.

Compressed air is directly connected to the pneumatic component, and its supply is controlled through solenoid valves, which are electromechanical devices. The Solenoid valve takes input through electrical/electronic signals and, depending upon the input signal, supplies, disconnects, and regulates the air.

Solenoid valves take input from Programmable Logic Controller – PLC or main controller to automatically control the pneumatic components.

For example, using compressed air, a pneumatic cylinder is connected to the door of the autoclave that opens and closes the door. The door opens when the cylinder is activated through a supply of air. When the cylinder is not activated, i.e. compressed air is not present; it closes the door.

Compressed Air as a part of process requirements

Compressed air is also used during manufacturing, packaging, cleaning, and other processes in various pharma processes. Instead of powering pneumatic components, compressed directly comes in contact with the product or product containers. The control method for compressing air is the same as pneumatic components, i.e. through a solenoid valve.

In this application, compressed air blows in for a fixed time, and then it is stopped. After blowing with compressed air, further stages are executed according to the process requirement. A monitoring system is continuously monitoring the blowing process to ensure its authenticity.  

For example, compressed air removes any foreign particles or contaminants inside bottles in bottle-blowing machines. For this application, compressed air is blown for a fixed time. The air removes foreign particles, and bottles are advanced to further stages.

Another example is a tablet coating machine. Compressed air is used to atomize the liquid in the spray gun. Air is blown into the air inlet of the spray gun, which combines with liquid to be sprayed. When compressed air and spraying liquid combine in the gun, atomization occurs. Various drop shapes are formed during atomization, which is critical for a perfect coating cycle. Compressed air must be blown with a specific pressure, which depends on the gun's characteristics.

Cleaning Purposes

A common application of compressed air in the pharmaceutical industry is cleaning; Compressed air is supplied to an air gun, which is manually controlled. The air gun is a mechanical assembly with a small hole and a lever, which controls airflow through the holes. The pressure of compressed air is fixed and the same as that supplied by the air compressor.

When cleaning is required, it is aimed at the desired equipment, and personnel presses the lever. The action of air blows away any lightweight particles or dust. The air gun is particularly helpful for hard-to-reach areas, such as in narrow conduits of equipment and at the panels on the lower side of the equipment.

ISO standard for compressed air

International Standardization Organization is a worldwide organization developing quality standards for various fields. ISO is not an enforcing agency, and accreditation to ISO is voluntary. However, it increased the credibility of pharma organization that adheres to its standards.

ISO has also developed standard for quality of compressed air, and there are currently three standards called

· ISO8573 – Compressed Air

· ISO12500 – Filters for compressed air

· ISO7183 –  Compressed air dryers

Among above mentioned, we will discuss the standard, known as ISO 8573 – Compressed Air

ISO 8573 – Compressed Air

ISO 8573 is an ISO standard that deals with the purity of compressed air. It consists of nine parts, where the first part defines various contaminants and purity levels. The remaining eight parts contain test methods for measuring impurities. These parts are mentioned below

· 1 : Contaminants and purity classes

· 2: Test methods for oil aerosol content

· 3: Test methods for measurement of humidity

· 4: Test methods for solid particle content

· 5: Test methods for oil vapor and organic solvent content

· 6: Test methods for gaseous contaminant content

· 7: Test method for viable microbiological contaminant content

· 8: Test methods for solid particle content by mass concentration

· 9: Test methods for liquid water content  

The scope of this article is only the ISO 8573 – 1, i.e. what are the acceptable limits of contamination or, in other words, purity levels of compressed air.

ISO 8573 – 1: Contaminants and purity classes

The ISO 8573 – 1 defines the acceptable contaminants in compressed air in each cubic meter. Purity level is described in the form of Solid Particulate, Water and Oil, each represented by class 1, 2 and3.

How the ISO 8573 is written?

The scope of this When specifying the purity level of a compressor, the standard is written according to acceptable nomenclature, which makes it universal and easy to understand.

The acceptable nomenclature states that “ISO 8573” should be followed by a three-digit number, each separated by a dot. According to the article, the first digit indicates the purity level is only the ISO 8573 – 1, i.e. what are the acceptable limits of contamination or, in other words, purity levels of compressed air.

· Particulate

· Water

· Oil

For example, ISO 8573 – 1 Class 1.2.2 refers to air compressor that should not allow

· Not more than 20,000 particles in the 0.1 – 0.5 micron size , 400 particles in the 0.5 – 0.1 micron and 10 particles in the 1 – 5 micron size.

· A pressure dew pint of -40°C, without any liquid

· Not more than 0.01mg of oil is allowed.

How to select an air compressor that fulfils the requirements of pharmaceutical application?

Let’s discuss some critical points to consider when finalizing air compressors for pharma applications

What is your application?

Before ordering an air compressor, identify your requirements. While it often suits ordering an air compressor that provides a generalized air property, it is often costly during special needs.

Every process in the pharmaceutical industry requires specialized requirements, and it is necessary to supply the required ones. If a buyer provides its requirements, the air compressor supplier will give options considering the difference ISO classes.

 For example, compressed air requirements for cleaning applications are less stringent than those of compressed air used in bottle-blowing machines.

Provide exact classification of air compressor

As mentioned above, ISO 8573 standards have various classes according to the process requirements. When ordering an air compressor, provide the manufacturer or supplier with a detailed classification.

Always check air compressors before installing and using it

Always ensure the air compressor can provide the desired air characteristics with the required purity level. The main reason is that air compressors are often installed on utility floors or areas with severe operating conditions, such as high temperatures and humidity. Additionally, contamination, dust particles and foreign bodies are in higher volume in that area, affecting its performance.

Before using the air in routine production processes, check its performance. This can be easily done during Factory Acceptance Test (FAT) or Site Acceptance Test (SAT). The quality assurance (QA) department can be involved in checking purity levels and adherence, which uses specialized tools, such as a particle counter, to check the supplied air quality.

Ask for relevant certificates

Always ask for certificates from the supplier or manufacturer to produce the same to regulatory bodies during their routine inspection. Certificates ensure the authenticity of using the approved parts during manufacturing.

Filter Integrity Testing

Filters in air compressors mainly provide purification in the supplied air, and for effective filtration, it is necessary that the filter should remain effective and in working condition.

For this purpose, always check the integrity of filters before using them in air compressors. These tests help detect critical errors such as damage, blockage, and information such as working life.

About the Author

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.