Cleanroom HVAC Design and Air Changes Per Hour

ISO 14644-1 Class 5-7 have vastly different requirements. Ideally, a cleanroom should maintain ISO Class 7 by requiring 60-90 air changes per hour. The cleaner the room is, the less often it will change. Furthermore, the more stringent the cleanroom’s standards, the more often it will be necessary to change the air per hour. This is known as the air change rate (ACR) in a cleanroom. It should be capable of filtering out all particles larger than 352,000 microns in size per cubic meter. To meet these stringent cleanroom classifications, the cleanroom’s airflow pattern, ceiling fans, and filtration system all work together.

Another system essential for maintaining control and supporting other aspects of cleanroom design is the cleanroom HVAC system. That is the process of controlling temperature, humidity, and air changes per hour in an enclosed space, also known as heating, ventilating, and air conditioning. This process ensures that the indoor air is clean, comfortable, and acceptable.

Mechanical engineers design HVAC systems using the principles of thermodynamics, fluid mechanics, and heat transfer.

Different HVAC systems have different power levels and capabilities. The cleanroom may not need a high BTU (British thermal unit of heat required to raise the temperature in a pound of water by one degree) system, and strict regulations regarding temperature regulation and relative humidity (rh) may not be needed. To achieve these levels of exactness and ultrafine particulate filtration, however, cleaners may need an extremely powerful HVAC system that can maintain a consistent and controlled environment for their employees.

Cleanroom HVAC requirements vary by the industries that we can divide into manufacturing, pharmaceutical, and laboratory. Exceptions do exist, however.

HVAC Design for Cleanroom Facilities

A cleanroom HVAC system must be designed differently than a standard system used in an everyday environment. Cleanroom ventilation typically requires higher air exchange rates, more sophisticated filtration, and better temperature, pressure, and humidity control. Cleanroom builders and HVAC installers must also consider the speed and direction of airflow within the space.

The ISO ratings 1 through 9 have been developed to ensure optimal cleanroom operation. Cleanroom classifications range from ISO 1 to ISO 9, with ISO 9 being the least clean. Measurement of particulate matter in cleanrooms has led to classifications of cleanrooms. When designing HVAC systems, filter levels, airflow, temperature, humidity, differential pressure, and space restrictions must be considered.

Clean Room Air Conditioning and Ventilation

Air filtration is a critical component of cleanroom HVAC systems. These systems control more than just temperature, humidity, and air pressure. They also direct the direction, speed, and filtration of air flowing into and out of the cleanroom. Cleanroom HVAC systems generally provide much more air exchange than standard systems.

Furthermore, cleanroom HVAC systems can remove extremely fine dust particles and microbes from the air by utilizing high-efficiency particulate (HEPA) filters. Research laboratories, medical facilities, pharmaceutical manufacturing, and testing operations, among others, require these filters to maintain a sterile, controlled environment. Cleanroom HVAC units must meet your specific application’s regulatory standards and requirements.

The air inside your cleanroom must be free of pollutants, and air ventilation must be high quality and reliable to maintain operational integrity.

It is possible to compromise the ventilation in a cleanroom. The air quality can quickly deteriorate due to a worn drive system or fan motor fault. The system’s regular maintenance includes:

• Cleaning the air intake and cooling coils.
• Replacing fan belts and pulleys.
• Replacing prefilters.

Inspections of air handling units should also be performed regularly. Air bypass can cause significant contamination problems when filters fail to seal or gasket. Any potential issues will be discovered during routine inspections, and replacements can be made when necessary.

Routine inspection and testing are also necessary for motorized dampers that regulate the airflow within your duct system.

Incorrectly specified or installed filters in your ventilation system is another common problem. Additionally, this may increase maintenance and operating costs and contamination risk.

Class 7 Cleanroom HVAC Requirements

The outdoor air is similarly filtered and cooled using multiple filters that become increasingly fine to exclude dust. The air is less polluted when HEPA filters are used more often. A room’s size in an hour is divided by the volume of filtered air to calculate the number of air alterations per hour. HVAC cleanroom experts should record all the requirements of a room since many factors must be considered (the number of people in the room, the size of the room, and the equipment in the room).

A cleanroom’s HVAC system is crucial in controlling its cleanliness. Ideally, HVAC should have a well-calculated number of changes and be equipped with filters that provide good filtration, such as HEPA or ULPA.

• HEPA (High-Efficiency Particulate Air: To remove particulate matter, the HEPA filters rely on a diffusion principle, which is extremely important for maintaining contamination control. With a 99.97% minimum particle-collective efficiency, these filters can capture particles as small as 0.3 m. This is quite remarkable considering that dust, smog, and pollen particles may be suspended in one cubic foot of outside air.
• ULPA (Ultra Low Particulate Air): ULPA filters have been developed to achieve a minimum of 99.999% efficiency on 0.3-micron particles for improving the cleanliness of classes and working environments. Ultraclean rooms, for example, require levels of contamination that go beyond what is possible with conventional HEPA filters.

How To Choose the Proper Cleanroom HVAC?

Your cleanroom will have to meet industry requirements and a classification depending on your application. Environmental factors may also interfere with cleanroom operations. Cleanroom HVAC systems and proper filtration and ceiling coverage are essential for maintaining a controlled environment. A cleanroom’s HVAC system controls environmental factors such as temperature, humidity, and ventilation.

Depending on the cleanroom classification and the application’s requirements, the HVAC system might need to be more powerful. Several factors determine your cleanroom’s capabilities, including how well it manages the environment, changes the air efficiently, and removes particles consistently, keeping the space free of contaminants.