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laboratory , or bacteria affecting a sensitive operation that could result in stock loss , or operating rooms passing an organism onto a vulnerable patient . Here , measures typically involve variously configured airlocks and may also include portable air purification systems . Although an HVAC system and its operation would be well engineered , it would be an unrealistic expectation that such a system would be able to cater to every single possible airoccurrence within a space , and therefore certain other mitigating measures would be available to be included .
Interestingly , the concept of the cleanroom was another major that came about in the 1960s during World War II while advances in military products required the elimination of various contaminants in both production lines and scientific testing that were hindered in more accurate techniques at the time . Since its ‘ invention ’, the base methodology of a cleanroom has remained largely unchanged but has brought great innovations to the world at large – from electronics right through to the biological realm .
Without cleanrooms , we would in fact not have such things as advanced computing or even the smart phones on everyone ’ s desks today . Not only did cleanrooms revolutionise many industries , but they also made new processes possible , opened up better methods in research and development , and continue to offer far safer environment on many levels .
CLEANROOM CLASSIFICATION Operational sizes of facilities range from tens- to thousands of square metres - most with unique design and operational characteristics based on their function . The development of cleanrooms has involved rapid expansion and progress for several decades now , mirrored by an increasing energy demand that can be as much as 10 times higher than that of offices of an equivalent size .
This considerable amount of energy used is to provide large amounts of filtered and conditioned air . Air movement could account for up to 50 % of the HVAC consumption owing to the energy required to overcome high pressure differential on the high-efficiency filters , and other circulation components in the system . Production of high-quality air can account for up to 80 % of the total energy used in a typical manufacturing facility , as an example .
Additional energy demand is then allocated to meet specific temperature and relative humidity for the particular process in the cleanroom , for comfort conditions , to achieve the correct laminar flows and pressurisation of the space . There is therefore significant potential for energy savings by well thought out designs of new facilities , by retrofitting improvements and upgrades to existing facilities .
Cleanrooms are classified according to the cleanliness level of the air inside the controlled environment . Cleanliness relates to the quantity and size of particles per cubic meter of air , ranging from
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Hospitals and operating rooms are some of the most common cleanroom environments .
0.1 microns to 0.5 microns . A cleanroom rating is determined by the ISO classification system : ISO standard 14644-1 .
The standard includes classes : ISO 1 to 9 - ISO class 1 being the ‘ cleanest ’ and ISO class 9 being the ‘ dirtiest ’. Even stated as the ‘ dirtiest ’, the ISO class 9 cleanroom environment is far cleaner than a regular room or space . Prior to the ISO classification , what was commonly referred to and used , was the Federal Standard 209 ( FS 209E ), which was replaced in 1999 .
Cleanroom design and installation may also need to comply with other related international standards where applicable , such as standards applied to pharmaceutical production or related to food safety protocols .
HVAC DESIGN ASPECTS The HVAC system will , in most cases , be found to be the most significant component of a cleanroom design and must provide sufficiently clean and conditioned air to the space no matter what percentage of operation capacity is in effect . For clients , it may also be an area that is the least understood , resulting then in either under-sizing or over-sizing . Given the cost of this particular element in cleanrooms , getting the specification right would be very necessary .
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RACA Journal I March 2022 www . hvacronline . co . za