CleanroomsUSA

Cleanroom Air Flow Systems Explained

Three strategies are employed to uphold the classification of a Cleanroom:

1. Air quality control is maintained through the use of high-efficiency filters (HEPA or ULPA) to purify the supplied air, coupled with pressurization to prevent the ingress of contaminants.

2. Construction materials are carefully selected to prevent the emission of particles, chemicals, or gases, and to facilitate easy cleaning.

3. Personnel within the Cleanroom wear specialized garments designed to minimize the dispersion of micro-particles and organisms from skin, hair, and clothing.

The primary means of regulating air cleanliness within a Cleanroom is through the implementation of an air filtration system that adheres to the certified standards set by the International Standards Organization (ISO). These systems operate in three main configurations:

1. Duct Supply and Duct Return

2. Duct Supply and Open Return

3. Unidirectional

Duct Supply and Duct Return

Air is ducted directly into the cleanroom and ducted directly out. This form of cleanroom is common with manufacturers who have strict guidelines such as the pharmaceutical industry.

Ducted Supply and Open Return

The ducted supply and open return air is a cost-effective and efficient method of air delivery. Air is ducted directly into the cleanroom and freely flows out into an open air plenum.

Uni-directional (also referred to as Laminar)

Unidirectional, or laminar, airflow systems force air in one direction. It has controlled airflow with steady air velocity from the laminar airflow hoods that direct air downward. In most Cleanrooms, the downward airflow pushes particulates out to prevent them from landing on surfaces. With a laminar system, air is pushed through filters that catch microscopic particles.