The modular application of the cleanroom solutions for manufacturing facilities

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Berenice Hubbard
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1 White Paper The modular application of the cleanroom solutions for manufacturing facilities Cleanroom facilities in the U.S. have grown fourfold since 1998, reaching an estimated 180 million square feet. Numerous manufacturing procedures now require a controlled environment in which the amount of dust and dirt in the area of the manufacturing is limited. The manufacture of semiconductor and other electronic components, pharmaceutical and biotechnology industries, medical instrument manufacturing and packaging, electronics and computer manufacturing, food preparation and some aerospace and military applications are just a few of the instances that have strict requirements for maintaining a clean environment. In addition to these traditional applications, cleanroom technology has more recently been applied to micro- and nano- system processes. The development of cleanroom technology is likely to continue to be driven by certain key factors including the increasingly technical use of exotic physical and biological phenomena, the central role of increasingly fine structures, the creation and use of materials of the highest purity, and the increasingly broad- based utilization of biotechnology. Given the scale of these challenges, cleanroom technology looks set to remain indispensable to production in coming years. The two basic principles in cleanroom applications The vast majority of the cleanroom install- base (>90%) is positive- pressure rooms that are designed to keep contaminants from entering the room. Air is delivered to the room after treatment with HEPA (High Efficiency Particle Air) and/or ULPA (Ultra Low Particulate Air) filters. The result is a pressurized environment where the air pressure in the room is greater than outside the room. The air inside the room is subsequently pushed out of the room through vents. As a consequence, the air and any contaminants resulting from processes performed inside the room are constantly vented to the outside. The air pressure inside the room is kept at a sufficient enough level to stop contaminants from re- entering the room via those vents or other openings. Negative- pressure rooms are equipped to stop contaminants from getting out of the room. Applications include infectious diseases and pathogens, bio- hazards, processes that include the use of harmful chemicals, flammables and combustive materials. In a negative- pressure room, air is pulled through a reversed filtration process that results in a negative pressure inside the room thus preventing contaminants from escaping the room. Replacement air is constantly brought in through venting or other openings and the force of this air stops contaminants from leaving the room via those openings. Due to the fact that positive- pressure rooms dominate the cleanroom landscape and that the current international standard for cleanroom classification ISO only applies to positive pressure, the balance of this white paper will focus on positive- pressure cleanrooms. Page 1 of 6

Flexible, modular design is the current trend in the cleanroom industry In today s manufacturing environments, companies are striving to optimize their lean manufacturing potential.

2 Flexible, modular design is the current trend in the cleanroom industry In today s manufacturing environments, companies are striving to optimize their lean manufacturing potential. With a focus on improved product flow throughout an operation and a need for flexibility in facility configuration in order to meet changes in market demand and product offerings, permanent cleanrooms often prohibit manufacturers from adopting flex/lean principles. Duroair s solution- based approach of both vented and non- vented air filtration, retractable enclosure systems and integrated climate control and dust collection delivers cleanroom solutions that are uniquely designed to maximize product flow and optimize flexibility in most controlled manufacturing environments. The cleanroom classifications The concentration of airborne particles in cleanrooms is kept below a specified limit through the use of ventilation technology. These limits are defined in the ISO series of standards. ISO :1999 was the first and fundamental standard of this series. It was originally based on US Federal Standard 209 E issued in 1988, and has been continuously revised and supplemented since its initial publication. Technical committee ISO 209, "Cleanrooms and associated controlled environments", is responsible for its standardisation. Even today, the previous classifications in accordance with US Federal Standard 209 are still quoted. This standard was the definitive guide for almost two decades. It is distinguished by its clear representation of concentrations of particles using the reference size of 0.5 micron. In 2001, US Federal Standard 209 was withdrawn in order to make way for the new ISO In addition to keeping the concentration of airborne particles below a specified limit, achieving a cleaner class of cleanroom also depends on airflow. Since the air that is delivered to the cleanroom is filtered through HEPA and/or ULPA filters and subsequently leaves the room through vents, the more filters and vents used, the greater the rate of air change. Page 2 of 6

Class ISO3 ISO4 ISO5 ISO6 ISO7 ISO8 Average Airflow Velocity, fpm 70-100 60-110 50-90 40-90 25-40 10-30 Air Changes/Hour 350-650 300-600 300-480 150-250 60-120 10-40 ISO Class 9 through ISO Class 6

Cleanrooms ISO Class 7 or lower require an anteroom for gowning and air locks for entering and exiting the cleanroom.

Cleanroom air flow principles Filtered air is delivered to cleanrooms by applying either laminar air flow or turbulent air flow techniques to the environment air.

3 Class ISO3 ISO4 ISO5 ISO6 ISO7 ISO8 Average Airflow Velocity, fpm Air Changes/Hour ISO Class 9 through ISO Class 6 rooms are classified based on air changes per hour. ISO Class 5 through ISO Class 1 rooms are classified based on the flow of air through the room on feet per minute. Cleanrooms ISO Class 7 or lower require an anteroom for gowning and air locks for entering and exiting the cleanroom. Duroair s cleanrooms is compliant with ISO Cleanroom standards up to ISO5 (Class 1000), with temperature and humidity control capabilities. Cleanroom air flow principles Filtered air is delivered to cleanrooms by applying either laminar air flow or turbulent air flow techniques to the environment air. Laminar air flow refers to air that flows in a straight, unimpeded path. Unidirectional flow is maintained in cleanrooms through the use of laminar air flow hoods that direct air outlets downward in a straight path, as well as cleanroom design that ensure turbulence is lessened. Laminar air flow utilizes HEPA and/or ULPA filters to filter and clean all air entering the environment. Laminar filters are often composed of stainless steel or other non- shed materials to ensure the amount of particles that enter the facility remains low. These filters usually take up roughly 80 percent of the ceiling space. Cleanrooms employing laminar air flow are typically referred to as unidirectional airflow cleanrooms. Page 3 of 6

Non- unidirectional airflow cleanrooms utilize turbulent airflow systems to clean particulate air and maintain a clean environment.

The entire enclosure is designed to use laminar flow and random, non- specific velocity filters to keep the air particle- free.

the air through the filter. Duroair s patented taper- draft airflow technology is at the heart of its market- leading air filtration systems.

4 Non- unidirectional airflow cleanrooms utilize turbulent airflow systems to clean particulate air and maintain a clean environment. While laminar air flow filters are often a component of turbulent airflow systems, they are not the only systems employed. The entire enclosure is designed to use laminar flow and random, non- specific velocity filters to keep the air particle- free. Turbulent airflow can cause particle movement that can be difficult to separate from the rest of the air, but non- unidirectional airflow systems count on this random movement to move particles from the air through the filter. Duroair s patented taper- draft airflow technology is at the heart of its market- leading air filtration systems. It is an innovative alternative to existing cross draft technology. Taper draft works by pulling a high volume of clean air through an intake filter that, once inside the enclosure, creates an envelope of airflow over the work piece and continues to flow directly into the filter chamber. The air envelope creates a clean air chamber that provides high levels of CFM and is nearly completely free of contaminants. It delivers the cleanest environment where it is most needed there where the manufacturing process takes place. Duroair s technology employs Variable Frequency Drives to optimize and control airflow as required. Replacing filters in most cleanrooms usually results in substantial contamination of the cleanroom since the ceiling barrier must be opened in order to access the filters. That means re- cleaning, re- balancing, re- testing and re- certifying the cleanroom after every filter change and incurring the associated costs and downtime. Duroair Technologies air filtration system is unique - the filters are located in a mobile outer chamber that allows for quick filter replacement with minimal contamination and resulting costs. Cleanrooms on demand Modularity and portability are becoming key requirements for cleanrooms in today s controlled manufacturing environments. Flex/lean operations require cleanroom capabilities where needed rather than where available. This calls for a cleanroom that can be easily moved around the factory floor and that doesn t take up valuable floor space during intermittent use. Duroair s cleanrooms can be outfitted with casters while the DuroRoom enclosure retracts to 20% of the extended length when not in use. Efficient material flow can be achieved by manoeuvring the retracted Duroair cleanroom to the area where the capability is required after which the enclosure is extended around the production process. The use of existing floor/building space is maximized. Page 4 of 6

Air conditioning requirements for cleanrooms ISO 14664-1 defines a cleanroom as follows: A room in which the concentration of airborne particles is controlled, and which is constructed and used in a

When temperature and humidity control are required in a cleanroom, the existing high- volume air conditioning (HVAC) system that services the building where the cleanroom is located is likely the

5 Air conditioning requirements for cleanrooms ISO defines a cleanroom as follows: A room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimize the introduction, generation and retention of particles inside the room and in which other relevant parameters, e.g. temperature, humidity and pressure are controlled as necessary. When temperature and humidity control are required in a cleanroom, the existing high- volume air conditioning (HVAC) system that services the building where the cleanroom is located is likely the most economical means to cool it. In buildings without a HVAC system or for larger or more demanding cleanroom applications, dedicated AC systems can reduce operating expenses by cutting energy use and minimizing maintenance shutdowns. Duroair cleanrooms can be designed for integration with existing HVAC systems where possible and efficient. Alternatively, Duroair cleanrooms can be equipped with climate control units in combination with a custom- designed retractable enclosure and/or a dust collection unit. These units deliver both the specified ISO Class cleanroom environment plus required temperature and humidity control. In the non- vented version of the Duroair cleanroom there are no equipment and installation costs for air makeup. Conclusion The number of cleanrooms around the world continues to rise annually. The demand for cleanrooms will continue to grow, but cleanroom suppliers have to adapt to new industry trends; offering customized cleanroom designs, energy- efficiency, and plug & play capability. With the arrival of modular, portable and retractable cleanrooms that offer integrated climate and dust control, manufacturers now have the opportunity to maximize product flow and optimize flexibility in most controlled manufacturing environments. Page 5 of 6

6 Contact: Ryan Watt General Manager Duroair Technologies References: iso:std:iso:14644:- 1:ed- 1:v1:en rooms- hvac- system pdf 1.pdf electronics/cleanroom- Air- Flow- Principles clean- room news/top- stories/single- article/maintaining- cleanrooms- and- clean- manufacturing- areas/b99af77186.html product/2011/01/evolution- of- the- clean- room?fw1pk=2 -.VjI4fYSpR- 4 Page 6 of 6

WHAT TO KNOW WHEN CONSIDERING A CLEANROOM

WHAT TO KNOW WHEN CONSIDERING A CLEANROOM by Simplex Technical Staff Does your business plan include the development of an area in your plant for clean manufacturing? Are you concerned that you make the