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Cleanrooms are places where the environment is controlled to maintain air quality. Therefore cleanroom monitoring is essential. The removal of dust is the primary concern in electronics production cleanrooms. Other industries such as pharmaceuticals and biologics ave different requirements. Some need to maintain cleanliness to avoid contamination tat can skew lab results. Others must maintain the conditions in such a way that potentially hazardous virus’s don’t escape to the outside world. There are standards to follow when it comes to the design and maintenance of cleanrooms.
What is Cleanroom in HVAC?
Cleanrooms rely heavily on the HVAC system. A cleanroom is specially constructed and environmentally controlled. It is an enclosed spaces, where air contaminants are limited. Many industries have cleanrooms, where small particles can adversely affect the manufacturing process. These are electronic hardware, biotechnology, pharmaceuticals, aerospace, optics, and energy. These industries have an environment free from bacteria, viruses, or other pathogens. For cleanroom HVAC it means a lot more than comfort. It controls the temperature and the humidity to the appropriate precision levels. It has an increased air supply, airflow patterns, room pressure, and use of high-efficiency filters.
How are Cleanrooms Classified?
Cleanrooms have classified the air through the number of particles in one cubic foot of air. It is also defined according to the maximum number of particles per unit volume. Non-particulate contaminants are also specified. The maximum permissible density of molecules per cubic meter is determined.
The first cleanroom classification standard is the Federal Standards 209E (FS209E). It is formulated by the U.S. General Service Administration. It was approved for use by all U.S. agencies and broadly applied worldwide. However, the international standards for cleanroom grow. Hence, the International Standards Organization (ISO) established its own set of standards. It published the ISO 14644-1 and 14644-2. Though superseded by the new ISO in November 2001, the references of FS209E are still widely used, and both are legal for use in trade.
What is the Cleanroom in FS209E?
The cleanroom in FS209E is measured by how much particulate of specific sizes exists per cubic foot. It consists of six classes. In a rating of Class 1 to 100,000, the cleanest has a 1, while the 100,000 is the dirtiest.
What are ISO Cleanroom Standards?
Even with the existence of FS209E, there is still a growing need for uniform and international standards. Hence, the ISO Cleanroom standards were formulated. The International Standard Organization established a working committee. They’re responsible for the development of its criteria for cleanroom. So, the global cleanroom standards adopted the ISO 14644-1 and 14644-2. The ISO added two cleaner standards and one dirtier standard compared with the FS209E.
What is the Difference Between ISO and FS209E?
Basically, the ISO cleanroom standard is the supreme governing cleanroom standard than FS209E. The ISO is based on metric measurements, while FS209E is based on imperial sizes. In ISO, the classes are Class levels like Class level 3, 4, and the likes. But, FS209E types are 1, 10, 100, and up to 100,000. The ISO 5 class is like class 100 in FS209E, and ISO 3 has the corresponding class 1 in FS209E, the cleanest class. Since the ISO added two more standards in the most sterile category, there is ISO 1 and ISO 2.
Designing Your Cleanroom Layout
There are many things to consider in designing the cleanroom layout. First, need to consider the cleanroom architecture. The construction and finishes can minimize the internal generation of contaminants from the surfaces. It must be durable enough and hard-shell. It must resist the chemicals and can be easy to clean and sanitize as well. The walls can be made modular with adequately sealed joints and wallboard. These must be smooth and cleanable surfaces. The floor should be covered with heat-sealed sheet vinyl – also seamless and cleanable as well. Windows, doors, and other utility penetrations must be ledge-free, with double panes and flush frames. Pass-through facilities must be available to lessen the traffic. Nonetheless, it will reduce the potential for contamination. Most importantly, materials should be FDA and USDA-approved.
The HVAC system should have proper airflow. It must supply enough volume and cleanliness to support the cleanroom rating. Added to these, it should promote adequate airflow to prevent stagnant areas that could accumulate air particles. Most importantly, it uses HEPA filters to filter the outside air and re-circulate it. It must have good air conditioning for precise cleanroom temperature. It will maintain humidity requirements and ensure specified positive pressurization.
Another thing to consider is interaction technology. It pertains to materials’ movement into the area and people’s movement as well. This way, it can help in maintenance and cleaning procedure. These procedures must at all cut the contaminants in the air surface.
What Differentiates Cleanroom HVAC from Conventional Systems?
A cleanroom class 100 is designed to drop more than 100 particles per cubic foot of air in a typical office. The cleanroom temperature and humidity must be considered. It should be planned out during the conceptual phase to confirm the load’s nature.
Unlike the regular comfort air-conditioned office or home space, a cleanroom has an increased air supply. It would require 20 to 60 air changes and could be as high as 600 in absolute cleanliness. The increased air supply eliminates the particulates’ settling. Moreover, it dilutes contamination down to the acceptable concentration level.
Another feature of cleanroom HVAC is the use of a HEPA filter with 99.97% efficiency. Air filtration involves eliminating particles from the air. Thus, HEPA and ULPA filters are installed together to achieve desired filtration efficiency. To complete the cleanest class of ISO 1, HEPA filter coverage must be 100% ceiling. Hence, most of the time, HEPA and ULPA filters together provide 100% ceiling coverage.
Another distinctive feature, the cleanroom must be positively pressurized. There must be an enormous supply of more air and less air. The cleanroom must be pumped up with more filtered air with a recommended value of 0.05-inch w.c. Pressure. The most sensitive areas should be the most highly pressurized by 0.02-inch w.c between adjacent spaces in multiple rooms. Hence, it will ensure that the air does not transfer from less clean to the most stringent cleanroom. However, positive air pressure can be maintained only when there’s proper air sealing in the building. It must be air-tight for low air leakage, which can also reduce energy usage.
As to the temperature, cleanrooms usually have 68 degrees Fahrenheit or less considered the area’s personnel. Preheating during the winter is also taken into consideration.
Cleanroom Monitoring
As the naked eye could not do the most critical work, a monitoring system could identify the cleanroom functions. Accurate cleanroom monitoring is crucial, the system should be able to record regularly the assessment of the room conditions. It must monitor the pressure differential between the outside environment and the inside of cleanroom. This includes temperature, humidity, noise, vibrations, and even dust particle.
Wireless Differential Air Pressure Monitoring
AKCP differential air pressure Wireless Tunnel Sensors deployed in cleanrooms check for correct pressure differential. The wireless, battery-powered sensor makes easy installation with a battery life of up to 10 years. A tube is connected to the outside air and the difference in pressure is calculated. User-defined thresholds for warning and critical levels are set and monitored with instant notifications when limits are exceeded.
Differential air pressure sensors can also be installed on air intakes for clean rooms, checking the difference in air pressure before and after HEPA filters. Increasing pressure before the filter and decreasing pressure after the filter is an indication that the filter is not working efficiently and requires replacing.
Wireless Air Quality Monitoring
The AKCP Wireless Tunnel air quality sensor constantly monitors the quantity and size of particles in the room as well as temperature, humidity, carbon monoxide, and volatile organic compounds (VOCs).
Keeping out dust is the primary considerations in a cleanroom environment. Dust and pollen are sucked in from outside. Maintaining the positive air pressure helps prevent this, but so too does air filtration. FS209E and the ISO 14644-1 standard dictate that depending on the classification, cleanrooms should have between 10 to 600 air changes per hour. This air is filtered to keep out particles. AKCPs sensors will detect particles from 0.5 Microns up to 10 microns, displaying the number, mass, and average particle sizes.
The company has more than 30 years of extensive experience in the industry. It prides itself on the integrity and utmost capability to provide only its clients’ best. AKCP has a wide range of sensors for cleanroom monitoring that would suit specific environments’ high demands. It can also be deployed in many different industries. It also comes with wired or wireless options, depending on the needs and preferences of the client.
Visit www.akcp.com and be amazed by the wide selection of products for Cleanroom Monitoring System!
Reference Links:
FS209E and ISO Cleanroom Standards (terrauniversal.com)
https://www.advancetecllc.com/cleanroom-specifications
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