Feature
An example of a laboratory fume cupboard / hood quipped with an ULPA-separated laminar airflow system .
Each relevant industry would have a GMP standard for facilities that would be established by sector experts and technical committees , and this standard would influence all aspects of design , including appropriate cleanroom requirements .
WHY CLEANROOMS ARE REQUIRED AND HOW CONTAMINATION OCCURS Contamination causes compromise to a test , product , process , patient , environment , and potentially creates a safety risk for the people involved at any facility . You can image the risk when a contamination incident occurs at a nuclear testing facility . While maintaining high standards and air quality would be essential , prevention is always better than cure , as the saying goes . The most common contaminants are categorised into different components – all of which would require an understanding in order to design the most suitable HVAC system . These could include , amongst others , either or a combination of the following :
• Physical contaminants : chips , particles , material fibres
• Chemical contaminants : moisture , gas , vapor , molecular particles
• Biological components : micro-organisms , viruses , bacteria , fungi
It is crucial to also identify any possible sources of contaminants to be able to implement an appropriate system to manage these too . Often only the major factors are considered such as human error , while in reality several factors may lead to contamination that would affect the HVAC design . Some of these include :
• Adherence to established standards
• The link between divisions or stations within a facility
Esco where poor design could lead to cross contamination or particulate entering clean zone air
• Affected airflow or filtration by equipment placement
• Handling and storage of goods or materials
• Use of materials or tools within the space
• Degradation due to environmental conditions
• Incorrect zoning
• Cleaning requirements and cleaning chemical reaction in the space
• System failure and maintenance management
• Use of PPE within the space , incorrect use of PPE , or failure to clean re-useable PPE correctly
• Supply of liquid or gaseous substances to the cleanroom ( water / oxygen / etc .)
• Packaging or storage units
CARE AND MAINTENANCE OF CLEANROOM HVAC The subject of cleaning and maintenance will always come down to what the system has to ultimately ‘ deal with ’ and if it is having to deal with what was agreed in the design and specification process . It is critical that the engagement between the client , engineering team and suppliers is transparent to provide the appropriate and correct solution . Designing and installing a standard cleanroom while the client intends to run secret chemical tests will of course result that the HVAC system will not be able to perform appropriately and this in return will create a heavy maintenance or repair burden onto the client that could have been avoided .
Depending on the function of the facility again , regular swabbing and testing may occur as well as air sampling that will in turn determine what ‘ corrective measures ’ need to be implemented . Some newer technology is available that can be installed within a space to provide continuous real time sampling of air quality . Here portable equipment such as what is seen in the HVAC sector has made significant progress owing to the Covid-19 pandemic conditions .
Protection of the HEPA / ULPA filters in a cleanroom has also long-been the priority as these particular products are costly to replace as the last line of protection in a facility . However , maintenance is quite impactful at such facilities to ensure a safe and consistent environment , or production line . It was common in past years to have a filter cleaning operation , but due to advances in technology and the significant health risks that exist , replacement has rather become the norm .
In applications where replacements can be done , the HEPA filter installation and service needs special attention . The old filters can ( and do ) drop debris when changed . Some of the wellknown filter manufacturers provide innovative bagging solutions to minimise spillage from filters that are being changed .
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RACA Journal I March 2022 www . hvacronline . co . za