Air shower in Pharmaceutical Industry

An air shower in the pharmaceutical industry is a specialized enclosed chamber strategically placed at the entrances to cleanrooms or other controlled environments. Its primary function is to decontaminate personnel and equipment by removing loose particulate matter, such as dust and lint, before they enter the critical clean area.

This is a crucial step in maintaining the stringent cleanliness standards required in pharmaceutical manufacturing, which is governed by Good Manufacturing Practice (GMP) guidelines.

---

How an Air Shower Works

 

The operation of an air shower relies on a controlled, high-velocity air system:

1. Entry and Interlock: Personnel enter the chamber, and the entry door locks. The doors are typically interlocked so that both the entry and exit doors cannot be open simultaneously, which would compromise the cleanroom environment.

2. Decontamination Cycle: High-pressure jets (nozzles) located on the walls and ceiling blast HEPA- or ULPA-filtered air onto the personnel or equipment from all directions.

   • The air velocity is very high (often between 3,000 to over 7,000 feet per minute, or approximately 15−36 m/s), which creates a "scrubbing" or "flapping" action to effectively dislodge particles from garments.

   • Personnel are instructed to raise their arms and turn slowly to ensure uniform exposure.

3. Filtration and Recirculation: The particle-laden air is drawn out through floor vents or return air grilles, passed through a pre-filter and then a HEPA (High-Efficiency Particulate Air) or ULPA (Ultra-Low Particulate Air) filter to remove 99.97% or more of particles down to 0.3 microns (or smaller for ULPA). The clean air is then re-circulated through the nozzles.

4. Exit: After a set cycle time (typically 10 to 45 seconds), the internal air is purged of contaminants, the air jets stop, and the cleanroom-side exit door unlocks, allowing the decontaminated personnel to enter the cleanroom.

---

Key Features and Specifications

 

For pharmaceutical use, air showers must meet specific design criteria to comply with GMP and cleanliness standards:

• Construction Material: Often constructed from Stainless Steel (SS 304) or powder-coated steel, which is durable, non-shedding, corrosion-resistant, and easy to clean.

• Filtration: Utilizes HEPA filters (minimum 99.97% efficiency at 0.3 μm) or often ULPA filters (for higher-grade cleanrooms) to ensure the air used for "showering" is contaminant-free.

• Air Velocity: High-velocity air jets (e.g., 4000 to 7500 fpm) are required for effective particle removal.

• Interlocking Doors: Essential safety and contamination control feature; only one door can be open at a time. All doors automatically unlock in case of a power failure or emergency stop.

• Positive Pressure: The air shower is often maintained at a positive pressure relative to the non-controlled area to prevent the ingress of contaminants.

• Microprocessor Control: Manages the entire cycle, including shower time, door interlocks, and emergency stop functions.

---

Importance in Pharmaceuticals

 

In the pharmaceutical industry, where products like sterile drugs are extremely sensitive to contamination, air showers are vital because:

• Personnel are the biggest source of contamination (up to 80% of particles in a cleanroom). Despite gowning, particles cling to the outer surfaces of cleanroom garments.

• Air showers serve as an extra layer of protection to effectively remove these residual contaminants, significantly reducing the particle load entering the critical manufacturing areas.

• They help in maintaining the required ISO or GMP cleanliness classification (e.g., ISO 5/Class 100) of the cleanroom.

• They support cross-contamination prevention by serving as a barrier between areas of different cleanliness grades.